Abstracts from the american association of hip and knee surgeons ninth annual meeting

ABSTRACTS FROM THE AMERICAN ASSOCIATION OF HIP AND KNEE SURGEONS NINTH ANNUAL MEETING November 6-8, 1999 Dallas, Texas

244

Abstracts From theAAHKS Ninth Annual Meeting

th February 2000

245

Pmper #1

Paper dO

QUAIXrY OF LIFE AFTER TOTAL JOINT PROCEDURES -A DECISION MAKING TOOL Lawe~.-~meeA. Selml~r, MD, LouLwill¢, A'Y, Donald L. Pomcroy, MD, Walter F... Bedenhausen, Jr., MD, Kathiccn F...Suthers, ME, Marilyn W. Smith, Jan A. Empson, RN, ONC, Jassica I. Curry

TEN YEAR MINIMUM FOLLOW.UP WITH A TAPERED TITANIUM CEMEKrLE:SS FEMORAL COMPONENT IN PRIMARY HIP.4,]I~HROPLASTV RJdmnl H. Rothmam, MID,PtaD, Philadelpkia, PA, Willism J. Hoza~k, MD. Peter F. Shnrkcy, MD. Fabin Omzco, M D

The SF-36 has emerged as or~ of Ibe ancepled standards by which the Oncnd physical and mcntsl h~lth of the pmlient is measured`The use of this ¢ool both ~ and poslop~ralively has documented thc fact thai major joint anhroplasty for arthritis has a positive benefit In the patient. It has becu sugosled thai the SF-36 postopsrativc scores decline over time. and that improvement in health and function may nol be long-lasting. Wc have analyznd the preoperative and postoperative SF-36 scores of joim arthroplasty patients since 1993. indend, the sco~cs do s~:m to deciinc with that. When compared with the ovcndl norms for aO and sex, however, it appsar~ Ih¢~ patients do as well or better than those who hevc never h,ed or needed a joint replacement. Mmtertmis mad Methods: 1937 total hip and knee psticnts received their annual SF36 and Functional .~¢nl forms via the mail in January 1999. Of these 1535 completed II1¢ forms and had a clinical and radiographic evaluation within the year. The sludy group includnd 950 knees and 585 hips. Average time since surory was 48.2 months (6-|56 months). The SF36 manual provided the no•Is for the eight domains by sex and aO, Patienl scores were then cumpared with the non-opcralivc group. A final comparison using the Harris Hip Snort: and Ihe Kncc Soc~cty,~orcs was compleled. Relmlis: Tabulation of the aoores showed a clear decline in the SF36 snores and the function portion of the KJlec Society and Harris Hip scorc~ as the time out from surge~ increased` However. when c~mpsring the norms for ao and sex, as pms,~ntedin 111¢SF-36 manual, even though the postopamtivc palienls ndvanCndin a8e. they demonstrated an inc~.ase in ovcndl scuRs as oppos~ Io the levels slated for the non operated group. With further analysis it was clear that the quality of life for the opc~aled group matched or supcF~'dcd the non-operated group. This information was further used tO compare surgical technique, selnclion of implanl, pomlopconive protocol and mher pertinent facto*~. Condusiom The SF36, when used appropriatcly and in parallel with clinical data, proved to be a meaningful mcasurcmcut tool for assessing quality of life for paticnts with debilitstin 8 arthriticjoints.

Paper #2 M I N I M U M 20 YIEAR FOLLOW-UP OF CHARNLEY TOTAL m P AR'nmOPIJ*,STY USING CONTEMPORARY CEMENTING TECHNIQUE AJmee S. Klmps*d~, MD, Iowa Ch'y,/A, John J. Calisghan, MD, Rlcha~ C Johnston, MD, Devon D. Gootz, MD, Juo~ P. Olejnk=al~ BA

|nU~dudioa: Ostcointeoation is crucial fOe a favorable outcome after toad hip arthroplasty using i cemendcas femoral component. The d~lio fcatun~sof the ccmentless femorM component arc thought to be critical to 1be rate of o~¢ointeOllinn. The puq0o~ of this pspsr is to evaluate the efficacy of the cementl~s femoral ¢omponcm with a Llpcred, coilarle~, wedO shape d~ign, with a Inn year minimum follow.up. MeU~ds: One hundred eighty o11¢primary total hip arthroplasties (THA) wen: i~rformed January 1986 to November 1987 at One instiluUon. Thirty six patients (37 THA) were d~cased due to unrelated cans~ prior to their 10 year exit•in•lion. One hundred thirlccn patients (121 "]'HA) were reviewed nt a minimum of 10 year Idler operation (mean, I1.10 years). The demog'mphins of this gloup included • mean aO of 60.2 years ( n a n , 32 to 79 yearn), mean weight of 167.8 pounds (range IU~ to 240 pounds) with 65 males (3 bilateral) and 48 females (5 bilateral). The p ~ r a t i v c diagnoses incinde, osteolrthrilis in 92~ rh~matoid nrthdds in 5, avascular necrosis in 14, trauma in I, and SCFE I. The fP~TlOralcomponent was titanium alloy with a plasma spray cu~lin8 in |11 case~ The acetabuisr cornponcut was tirsnium, porous coated, u ~ m e n l e d in 84 hip and metal-becked, cemented :in 37 pslients. Results: At • minimum follow up of 10 years, the mean Harris Hip Score was 93 points (ran O, 60 100 points). Mean Chnmicy scores chanod significandy from pRopconive to follow-up values as follows: pain, 2_67 In S.54 points; function, 172 to 5.51 points; and motion, 3.56 Io 5.52 points. Thigh pain was prescnl in 3 patients at 10 yea• with the d e ~ of pain cqualin 8 slight, moderate, and one severe. Radiologi~lly, femoral components showed fixation by bone ing'mwin (92%) and only 3% showed early suheidsncu which suheequemiy devclopnd spot welds and stability. The femoral i~-vision rate w u 0,83% bet acetsbular Rvision rate wM 22%, including 3 cases in the cemcnled cup group and 24 in the cernentlcu cup group. All a~tsbuiar revisions were performed for a combination of wear and ostcolysis. Only or~ femoral revision was psrformed duc In cxtsnsive proximal femoral osleolysis although the mem was mlatinnal and axially mabic. Combining the femoral revision rate for aseptic loosening plus the rate of femond sut~idsnce or mere bi~ka O, the ovcndl mechanical inilurc rate of the c~mentleas stem w ~ 0%. ~ l a d Com~u~on: At long term follow-up, the Rsults of the cerncutless femoral 0xatlon using a Tapsrloc component are excellem and comps, able with thor~ of modem c~r*ent techniques. Component d ~ i o features were though to be critical due to the excellent psrfonnancu of the {cmond component and include a collaricss, tspsred eeetsnolar shape achicvin 8 outstanding fixation mediclate•ally within the proximal femur.

Research or institutional support has been mcuived from Biomet, inc.

INTRODUCTION: Cootempora~ ocrrmnlin8 technique of total hip arthroplasty was developed in III¢ mid 19"70's in the hope of ploviding more durable RSUIrs than those where band packing tcchniq~¢:s wcrc utilized. The porpor¢ of the psaseot study was to evaluate the minimum Z0 ye~ resnlts of cemented C~amley IOml hip arihmplls~y I~rfomled: with ¢ontempom~ cementing technlqucs and compmrc these to the same surgeon's rczults st minimum 20 years using hand packing techniques. MATERLAJ~ & METHOD=. Between July 1976 and June 1978 *he senior author performed 357 ~tive Chandcy cemented total hip a r t ~ l a s 0 a s using contcmporatT cementing tnchniqnc (disrsl plug. cemcm gun delive~ sy~cm). Thcse hips wc~c followed for a minimum of 20 years. The pmicnts were evaluated clinically with a Standard Tcnninology Ouestinmndre and rediographicaily for loosening (criteria of Harris), osteolysis, mxl dd~o~ling. In addition, the need for rcvlsion (for infeclion, dislocalinn, and a.~'lxic IO,O~ning) were documented. A l l on•portents were the Clmmley flatbach polished femoral stems and 40 or 44 mm outer dinmetsr ncctshuinr all polyeinyleee componenrs, These ecsuits were compsn~J to the same surooa's •:suits in 330 Cbe.-nley hips of the same deeio psrt-ormed h n l w c ~ July 1970 lad 1972 using hand poching cementing [~hniqu¢~ The ~ Cdleria was ~ for evaluariofl ~ the evaltimllon ~ p¢fl*ormcd by the same o~lcrv¢/1L RESULTS: At minimum 20 year follow-up 93 hips in 82 podents wen."still living and only 4 hips in 4 patients were Io~ to [/u. For all pstJcnls 10% (36 hips) were revised. 6% were mvL~l for ,~l~iC hx~ning. 2% for sepsis, and 2% for disleeadon. Rcvisinn was psrformed for inmcnlng in 16%, infection in 2% and disior:atinn in 3% In psticnts living 20 years. Revision of the femoral componem for aseptic inoscning was ps~onned in 1% of all hips and in 3 % of tho~¢ hips living at 20 )'cars. Including • vision, 4% of hips demonslrat~l radingraphic k)o~ning of the femoral comlxment. ~ r the acetsbulm"component, 5% were revisnd for mcpdc Iomcning and of thus¢ living 20 yearn, 13% were R'viscd` Including Ihe revisions, mdingzlpbic Ioommin8 wlm presesrt in 14% of the e..nlim Ipro~p. The h~nncal side revision rate of 1% and tbe loosening rate of 4% cumpsms to inc results with hand packing cementing lz~.bniquc, 3% for revisinn and 7% for loosening. Them is • •end towa.,,d improvement, p : .09. Acetsbular I'evision occuned in 13% for hand po¢ldng I¢chniques and this reprercnts no improvement with eontemponury cemcuting ter~nique. DISCUSSION: Cbiu'nlcy total hip am'uoplasty psfformed well with b i ~ cuntemporary and hand packing cementing techniques. TheR is a slight impnwem©m in the senior author's bands using contampomty cementing techniques on the femoral side of the joint of the loud hip urthroplasty construct. Conlempmm7 eemcu0ng tnchniquas allowed the senior author as well as the Or*end population In more predictably provide cement mantles mound the pp~tbesee. It can be emphatically slated that tbere were no detrimental effccs.s assuc~aled with coatemponu7 cementing technique.

Paper #4 A SINGLE CENTER'S EXPERIENCE WITH TIIA USING POROUS-COATED ACE'TABULAR COMPONENTS Chnrk~ A. ~ Sr~ MID, AIo.m~h'in, VA, C. AJIId¢lsonE n d , Jr., MD, Robert H. Hopper, Jr. PhD, Christi J. Sycbier~ MS This study compsr~ clinical and radiographic data from • single c~ler's cxpsriencc with four types of porous-Coated cups and identifies the tempond ps.em of coalphcations related to these dcaloLs. Authors reviewed 2.935 primary total hip mlhroptasticz (THAn) ps:rfotmed with uflcz.-mcnled0porousCOaled femoral and ac~abular cornpocunts botwecu 1983 and 1998. The hemispbedc porous-COaled acembular cups included 263 non-modular A M L cups (DePuy), 449 Arthropor (.IMP), 8I HarrisGalante ('ZJmmcr), 403 ACS ('DePuy), and 1,739 Dunlloc (DcPuy) cups. Implant patron-•anne was characledznd usins Kaplan-Mcier survivorship analysis with conlpoflent revisinn as an endpoint. True polyethylene (PE) wear rates were evaluated for each cup d~ign based on analysis of 3,017 annual radiographs among 719 hips. One hundn~l end eighteen (4.09;,) acutabulal' components wane mvisud. Using cup •vision for any reseon as the nndpoint, overall survivomhip among all cups w*s 88,2 --_ 1.3% at 10 years. Sixty-four (2_2%) cups wcrc eevi.~ for complications ndatsd to the polyethylene Jim:r, which included rim fracture (30 c~pa` all ACS oompoocuts), wear-through (12 cups; 10 AML, 1 ACS, I Duraloc), psnicleinduced synovids (4 cups; 3 Anhropor, I ACS), and osteolysis (18 cups; 10 AML 8 Anhropor). Using cup revision for complications neLQledIo PE wear (excluding ACS rim fractures) Is an endpoinh cup survivorship was 99.7% at 6 yearn, dcClreasnd to 96.7% at 10 yea*m, and to 89.895 at 12 year~. Thirty.four cups (1.2%) wclc revised for rncurl~nt dislocation, typically occurring within five y c m post-op Seven cups (0.2%) were icvised for ~ ioosoning and 6 (0.2%) for tar(orion; 7 PE liners (0.2%) were exchanged with stem revision. Tbe four dealBmshid signi£K=mtly different tree PE wear rates, Tree wear rates averaged 0.18 mm/yr for the Arthropor cups, 0,09 mmJyr for the ACS cups, 0,07 mm/yr for the Harris-Oat•me cslps, and 0.09 mal/yr for the Dundoc cups. Cup d e a l ~ with higher tree v,~ar mica demonstrated S higher incidcuc¢ of wear-rclaled compile•. lions and rcvlsioml. Aseptic cup loosening was an infrequenl reason for mvisinn among thcr,e porous-coatnd hemispheric cups.

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Royaliics have hen• n~ccived from DePuy, Inc. of Johnson & Johnson. Stcuk or stoch opcinns beld in Johnson & Johnson.

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The Journal of Arthroplasty Vol. 15 No. 2 February 2000 Paper ~

10 to 12 Year Follow Up of tho Imodl Burmtdn I Pmtmdor Slabifized Total Knee PrmtBem'm: Were' In Molded Pelyeshylene and Nonmndular Compoaartts Pet•r" J. ~ MD, Los Angeles, CA, St.van G. Ommslan, MD, Bemtis C Bisc~thum, DO, Kelly G. ~ n ~ , MD

IMIguado~: The Onholnc toUti knee replaeement system was designed specifically for cementle~ Iotal knee arthmplasty and employed an intramodulinty aiignmem system with precision cutting guides and secondary, finishing Weparation of the tibia. The tibiai component hid It press-fit stem with modular 81tecfuncnts to enhance press fit, and the tibiai surface had continuous porous coating and peripheral pegs. This combination of insmlmentetiou, seW,iced technique, and design features has been highly m ~ l fOr fixittion of cementless Iotai hire replaeement. The wear features of the tibiai articular serf•ca were not favorable, and resulted in high rates of we~r in some knees.

INTRODUCTION: The fir]a In•all.Bun•sin Pceteriof S~bilized knee pmelbesh (IB I) was developed at Ths Hmpitsl for Spacinl Sergery in 1978. This pro•the=is, used in this sandy, had a rnetal-har-ked non-moduisr Ithisl cmnpoutmL The polyethylcm: articul~ surface was rl;rectiy molded, not machined as has b¢¢onlt¢:comn~tt reor~ reeendy.'l~e palpose of this Mudy was to evainnle long teal v,~:arwith this denJgn. Paper 117

M g r l I o D S : All sulg~riza were performed by m under the direct supervision of the senior iovesfigator. All compouems were cememed and all patellae resurflga~. The first 100 total knee arthlOpisStisS parformed were followed prospectively flora the time of suqge~. The average age of the palk-lrltsIll ~ time of surgery war 69.7 (range 45-88). The p~mary dlagnods was OA in 77 knees, thflamn~tory arthritis in 17 knees, and pomraumafic DJD in the ~nudng 6 knees- Thirty-eight knees had van~s angnlation, 12 had vaignS angnlxtio,, and 48 had n 0-10 deglee tibiofemoud angle ~ r a l i n l y . All were evaiUaled Ill tell tO two:lye yeMS folinW up. Kigg se¢~etyscores nlgl radloffrap~l were obtained. P.F.,SUL'I~: 36 knees were in patients who had died and 2 in patients who were infirm. Phone evaimv lion only was available fOr 8 knees, leaving 54 knees fOr dlrec/clioiCai and radiographic evaluation. NO patie~Mswere leel. The average Y,.nceSeciely clinical scorn at htte~ follow up was 91.6. The nvemge funcriou seo~ was 69, One knce failed dan to 6bi'~ Iomening` I due te potslis wem/fractme, 2 dee Io sepais, and 2 hecaune of nonspnetfic paio. Thsre were 7 patella f r a c t ~ in Ihe entire I (]0 knee& One of the frlgxtues ~esulted in • total knee P:vlsim (noted above), 2 in paleilar oumponent revision, and another in patellar componenl removal. The remaining 3 patella fr, c:.tuns were tiiu:overed incidentally and were •symptomatic. There wen: no pJellar dislocations. At IonB term radiogr~blc analym, vMgus alignment averaged 6 ° (hinge 0 to I1). Polyethylene wear was ~scssed as a radiognq)hi¢ diffcrenec belwce= the medial and literal polyethylene spaces belween the lemon,I and U'btaicomponents; the avenge wan 0.40 miliJme~erLThere was m cau~rophio wear of tibial polyethylene- 'nthly.two kn~s (65%) had radioluceneles in nl least one zone; no Incoucy filled It zone and noue w ~ wider dum Iwo millimeters No osteolylic lesions were acted. CONCLUSIONS: Patellar compliealionc wen~7% in the cunenl mxly, which is comparable to ~ x ~ l ed results for this pmeahssJL Oar results, path•ned flora n couter Other than that which deaigned the pres.. t h e ~ show zero inetdence of clinically Itls~ifgant tibiai wear at imlg Inn's follow up. This absence of wear is of pal~cular i o ~ in this era. The po~erior mbillzed mtioulatiou is characa~z~d by somewhat thi"%r polyethylene (ix]amble because of cruciste liganlenl •artifice) nnd coofamling artioular geomeUy Ihat dacrea~ pobll loading The performance of the molded polyelhylc~ used in this Im3etheaisis cr,c~mlging and needsto he crillcaily analyzed against the mona widely used machining pmce~ thai is employed teday, Comp~lees need to he made with mbnequcnt pmstbetic designJ to determine if we me paying too high n pace fOr modularity. Research Or institutional ~uppotl h u been received from ZJmmer Inc.

TOTAL KNEE ARTHROPI.,ASTY WITH TIIE CRUCIATE RETAINING KINEMATIC CONDYL.AR PROSTllESIS: RESULTS AT 14 T O 2.0 YEARS I)mBel J. BetTy, MD, Rochester, MN, Gregory S. Sextro, MD, James A. Rand, MD intredudJoa: Good mid.term results have been reported with crnclate retaining knees, bet there are few reports Itt greitter than 10 years. The porpe~ of this slody was to evaluate the long-term w.~ults of the Kinematic Condylar prosthesis with, retention of the posterior cruciate ligament. Matt'dab mad M ~ m d a : 168 total knee arthmptastiza in 118 I~ttients (72 femitle. 46 male; mean age 65.2, nmge 21-88) were performed using the Kinematic I condylar Im~thceis. All were inserted with cement, an all polyethylene patella, metal.banked tibia, and posterior ongiitte ligament n~ention. The preoperative disgnmiit was usteounhritis in 64.9%, rheumatoid arthritis in 31%, and other in 4.2%.

I ~ l t l : . Sixty.oue patients (86 Io~'es) had died, l patient had above knee amp•nation, and 3 patients (5 knees) were last to follow-up, therefore 66 knees were available for foIIow~p at • mean of 15,7 *- 1.1 years (range, 14-20) excluding ~vL~om~ ~ patcuoutge of knees rqxxling moderate or •_were poln deoeased from 95.5 % preoperatively to 4.5% at latest follow-up. Of the entire cohofl of 168 knees, thirteen have becn n.-vised One for med;'l femoral condyle fracture, otg for tibiofenxxai instability, one for femoral and two for tiblal componenl aseptic loosening, four for libiai polyethylene wear lad re*at for palellM component arel~ic Iomening. Three of four knees spactfi~liy revir,ed for polyethylene wear had • tibild polyethylene thk:hoear of 8 a m Or less.The 15 year ~:vivonthlp free of any component revision for any reason w ~ 88.7% (CI 82-95). and for aseptic loosening w u 90.5% (CI 84-96). C a • d u d e s : This study demonstrates good function and survivo~Jlip of • posterior cnginte sparing Kinematic i condylar pmsthesb Ill mean of 15.7"1.1 ye.at~

Paper I ~

POLYETHYLENE AND MODULARITY IN A PROSPECTIVE STUDY OF OVER 1000 PCL RgrAINING KNEES AT 5-11 YEARS Richard I.. Worland, MD, RIdouoa~ VA, Alolrew Weber, MBBS Purpme: To determine how the mid-term (5-11 years) results in oven 1000 PCL retaining knees were affected by the polyethylene type and method of productiou as well ar by the ribisl componcnl tmembly (modular vs. one piece mono-blnck).

Paper # 6 I5-18 YEAR RESULTS OF A CEMENTLESS TOTAL KNEE REPLACEMENT WITHOUT A METAL.BACKED PATELLA L¢o A. WI~tedde. MO, Sc Lo~J. MO Intl~ductioa: This study was performed to evaluate the clinical insults of an early design of cement. less total knee replacement in the absence of confounding variables such as • metal-hacked patelis ~ d a poorly locked tibiai polyethylene serf•ca. Clinical results of cementlem total knee arthmplar~y often ire couteminnted by such extraneous f•ctora and cementie~ technique is concidaled guilty by aran¢tanion. During the tint tht~ years of its clinical use, the Ortholnc total knee replacement implants had • cemented rather than • metal.hacked patellar compouenL This group of knees has had femarhably good n=,lts. Methods: Belween January 1981 aqd January 1984,192 patients (2.55 knee3) had total knee replacement with the OTthoioc knee system without a metai.hached patella. Five patients (five knees) was Io~ to follow-up and 66 knees were is4 due to death, leaving 184 knees with 15-18 ycent follow-up. Mean age at the time of surgery was 77 years (nags, 18-92 years). 95%of the kne~ were diag~ned with mteoalthritis, 4% had rheumatoid arthritis, and 1% wen: clansJfind as Otbor. The series was performed sequentially with nil knees receiving cementleu components regeldlesi of age, hone quality, and diagousts, l~e patients wen: followed yearly. Radiographs ware evaluated fOr radiolueent lines, bead shed. ding, and polyethylene m r . Complications and failure rates were determined at each interval. Remlbn One femornl oomponent had n o n p ~ , limited bead shedding oueed at three years pcetoperalive. Six knees had radiognq~icelly detec*nbie libiai polyethylene wear. One knee wan revised for pain, and remained severely painful after ravision Io i cemented total knee replacement. One knee war revised fOr acute infection with • two-stage ptlx:udure and achieved complete pain relief. Three developed iste..o~t iofecliou and had • t w o - s r a ~ revision. Two knees had tibiai component revision for polyethylene wear. None had progressive radioing:ant lines or signs of iolpending Io(~, ening` One knee (2%) had limited femoral componenl bead shedding. The overall survivor•hip was 98% at 16 yearn and 97% at 18 ycera

• Proem~ mm~b4 of ~lm ~ m m ~ rnma*mm hV~bet

Matet'x~da and Methods: A continual experience of 1071 primatV PCL retaining knee arthmplarties (AGC) were parfofroed by It single surgical team be~veen December 1966 and October 1993. All com. ponems were cemented and all patellae gesurfaned. The tibiai components were either comprezaion molded one-pince mono-blnck or modular manufactured from extruded bar. Knees were assessed pre I,xl post-operedvely wi th careful HSS sco~es tud full.length alignment films, and patients were reviewed annually. Rmmlta: The average age It surgery was 70 and the average follow-up w u over 6 years including thcnc lout (63 kne~) and decea~d (200 knees), Redio|u¢¢nl {in¢~. baileon ostcelyitis, and revision rates wen: higher in the modular knees whme tibial inserts were machined from bar-extntdnd polyethylene. Other compiicefious and final HSS scorza (92) were similar in both 81roupa. ~ : We believe this to be the largest reponud series of helloua ostetdyitis (7 ce.u:s) i• cement. ed total knee arthroplarty. While rediolucent line nnaiysl,t without fiuorce¢opo is peuse to i n - - r a c y , we found • significant difference. While we are unable to separate the different variables in these libisl desJlp~, we can comment on their additive effect. The importance of polyethylene pmdnction and modularity is dearly documented. Coadtedoa: A compression molded one-picot: factory arsembied metal-hacked tibiai component may deerease loosening over the mid-term.

• Paper t 9 EARLY OSI~OLYSIS IN PATIENTS IMPLANTED WITH MODULAR HYLAMER LINERS AND FEMORAL FROM THE SAME MANUFACI'URER Btldley IL Vaulgha, MD, FACS. Raleigh, NC, Peter W. Eberie. C. Elizabeth Fulior, PA The porpoee of this study was to describe rapid wear nod early catastrophic celoulyeis following the use of Hylamer neetebolar liners in combination with femoral components and modular femoral heads from Ihe same manofnetumr. Between July, 1992 and June, 1995, 98 primary to¢al hip arthroplastice (]'HA) were parrot'rand in 92 patients by the senior author. There were 6 patient deaths (7 bil~) that were not reisted to the THA procedure and were excluded from this study, leaving 91 hips in 86 patienls for revk,w. Of the ferrmre] components used, 33 (36%) were cemented and 58 (64%) were non-cemenled. All ncetsbulitr componenL,t were insetled without cement. Forty-five (49%) of the linet~ used were sterilized using geme-lrrediitted and packaged in -ir while 46 (51%) were sterilizad using gamnudmtdintion and m~,~,.oed in nitrogen. The manufacturer w ~ contacted and reposed the dates of manofae/uring and the method of slerilizxtiou and packaging for each liner implanted. The

Abstracts From theAAHKS Ninth Annual Meeting average time from manufacturing to implantation was 10 months (-*9 months, range: I - 50 months). The average time to follow-up for the entire poptdation w ~ 59 ~ months. Using radiographic digitization method& the average liner migration for the packaging in air was 0.45 --q).13 mm, and was 0.28 -+0.15 mm for thcee peckagad in nitrogen. This difference was stetlstieally w u significant el p < 0.ftl. Average time to radiographic appearance of mteolytic icsiom was 45 ~ months (renga: 29-63 months) and eccumM in 19 hlpe (21%)* Linear migratirm of the femonti head into the liner wus signifieantly greater for thmc onmpeocnts that ineotlporated a modular ceramic head (p < 0.007). Retrieval analyses revealed significant polyethylene deformation and volume less. Profilomerty of the articulating surface of the liners also revealed hi-directional wear perterns. Analysis of rutHcved biopsies revealed a significanl volume of polyethylene paniculate debris not commonly found this early following THA. In onnelusion, these findings ame of concern, as the extent and frequency of oeteolysis greatly exo,,,,,.t~ OUr expec~tion,

Paper # ! 0

~ctlon of Mustve Femorld I~feots In R ~ Hip Arthlmp~sty Todd Selumdlak, MD0 FRCS (C), W ' ~ Manitoba,Canada,Wayne G. Papronky, MD There are few options when femoral deficiencies extend to and include the fumood isthmus. Proximal aifugrafl trnneplantation is difficult, as them is minimal bone dirtily for fixation. Impactiom graflin8 is also h ~ as on proximal coflleal bone romaine. A pmslx~ive review of 63 revisions (60 patients) fto~ 1988 tO 1996 (average 7.3-yner follow-up) w u undertaken. Recomangtio~ were performed by p~es tilting 10-inch fully pumas-conrad stems, Dinmeter of sterns ringed from 15 to 22.5 rum (aver. age 19.$rum)* Thggg patientS were Io~ tO follow.up. All pellcnts had a'Pype [lib (33) or'1~pe IV (30) Palm3sky defect (41 'Pipe III and 22 ~ VI AAOS defect). Lees Ilum 4 em of femoral isthmus was present in all cne~ Age nmgad from 50 - 87 years (71 nverege)* NO nllogra~ prosthetic compneites were used but s~mt cortiusJ ellognd~ing (32 patients) and metal plate augmentation (8 patients) were used. The aim was to gain rotational and Iongitodftad stability to allow ingrowth it the tip of the stem. 53 ~visions had evidence of ingrowth with no migration after the initial year of follow.up. 7 patients ( l 1.6%) had early migration greater than I cm (]crct- 4cm) with no evidence of radiographic ingrowth and clinical evidence of failure. Six of the~ patiants were revised with clinical and radiographic sucIN3el..operative dislocations occurred in 6 patients (10%)* Infections occurred in 4 patients (6.7%) with 3 intranperative fractures (5%)* Preoperative Hanna hip suntan were 4 to 29 (average 17) With pest-operative score* to 91 (average 75). SF-36 scores showed similar poor scores preoperatively With Ic~ than expected improvement postoperatively.

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p a p e r 1112 SELECTIVE USE O F IMPACT'ION GRA.WriNG IN REVISION HIP Ak'I'HROPLAS'I~ FOR SEVERE CAV1TARY PROXIMAL FEMORAL BONE LOSS Daniel J. I~'rrT. MD, Rockester, MH, Robert T. Trousdaic, MD, Mignel E. Cahenehk MD Introduotim: Favorable mid-torn ruanlts of impacfton grafting have beon reported in several series of tm~eleoted femoral revisions. In North America, becau~ of difficulties of the technique, me~t surScone r e , rye impaotion grafting for selected patientS With femoral canals not ideal for either coeven. tiomd cemented or uncemented femoral revixion. The porpone of this paper was to review results and compiicxtions of impection grafting used selectively only for patientS With large eavita~ proximal femoral bone deficiencies in combination with either a very large canal diameter or abnormal canal gaome.v that made the hip unsuitable for conventional cemented or uncemented revision techniques. Mntet41din Between 1993 ~ 1997, ,104 consecutive femoral revisions were performed. Impaction grafting was used selecJively in 55 of th~ne hips (14%)* All had severe AAOS cavitary or combined eavitary and segmental proximal femoral bone loss and Papmsky type m or IV bone ic~. There were 23 wales and 32 females, mean age 62.7 yearn (mugs 36 to 79). All were revised with impauaed partinttiste ~ fn~an aitoipraft and a cemented collariese polished tapered (CP'I'} stem. Strut Idlografls were used to reioforue the femur in 40 hips. RmJIte: Pxtients were followed 2 to 5.5 yeats (mean 3.0) and none were lost. One parient had the implant removed (for infection ~ implant loosening m 2 yearn). No other patients have been revised. 46 patterns had moderate or severe wdn preoperarively but only 3 had moderate pain It latest for low-up. No unrevised patients had definite radlognaphic Inn:nine and none subsided more than 3 ram. C.Jmcellous bone graft showed at kant pa~ixl remodeling in 38 hips. Complicatious included infection in I hip, inlraopararive femur fracrum in 4 hips, postoperative femur fngture in 4 hips (all treated SUCo ce~foIly With ORIF), instability in 2 hipe and partialsciatic palsy in 1. I[Mac'm~on: The patients s~lec/ively chosen for impa~ion enduring in this series had marked proximal femoral czvita~ bone ices in combination with I femora) canal diameter or geomeUy not ideal for Ira. dilionai cemented and uncemenled farnoral revision. In this diWtonlt group of palierrts impectioct g a ~ log with cement provided good clinical t~ufts and stable implant fomtion at 2 to 5 years. Despite Itheral use of strut allograhs the most common serious complication wen postoperative peripros~hetlc femur fractore.

P a p e r #13 No studies have selectively eddresued these severe femoral defects. Succ~m of these reconstructions cannot be compared to other revision procedures with lesser defects. Failure and complication rates are higher with functional pusl..operative improvements le~. Mobility of Ihes~ patients is, however, dramatically improved fmru a critical level and failures can be easily revised.

COMPARISON O F IN VIVO WEAR BETWEEN PE U N E g S ARTICULATING WITH cERAMIC AND CoCr FEMORAL HEADS ChHed J. Syehtorz, MS, Al~mndrlo, VA, C. Ande w,on Engh, Jr., MD, Anthony M. Yang. BS, Roherl H. Hopper, Jr., PInD, Charles A. Engh, St., MD This study compmt'd the in vivo wear performance of alumina ceramic femoral hea~ with the performance of cobalt-chrome (CoCO heads in a matched gtonp of patients.

p a p e r #1 ! ASSOCIATION AND PREDICTION OF OSTEOLYSIS WITH FEMORAL HEAD PENETRATION RATES James Dowd, Jr., MD, A/e.ue~in, VA, Christi J. Sychterz, MSE, Anthony M. Yang, BS, Chides A. Eagh, Sr., MD This study described the mlstiot~Nip between tree wear rates and usteolysia al i minimum IO-year follow-up, and Msessed if wear patlems prior to 5 years could he used to predic~ the occurrence of usteolysis at l0 yeanL Wc examined Iong-lerm temporal head panelratiofl patterns of 48 primary THA's implanted with an Arlhmpor aCetabular cap (JMP), a poruus-o~ted femoral stem (Depuy), and a 32-rnm ~ femoral head (DePuy)* TWo-dimenslonal head penetration into the polyethylene liner was evalmtted with i prevloualy peblisi~l compuler-akqmisted radiolpmphic technique. Linear regrenaion analysis modeled pencitation verstm time data as a line for each petianL The slope of the regre~ion line indicated each patient's true wear rate. For a subgroup of 25 canes with 3 annual radiographs prior to 5 years, we compared ashy head penetration pettorlkq to liter necut.vence of mteolysis.

For all 48 hips, the true wear rate avoragad 0.10 mm/yr (0.01-0.44 mm/yr); temporal head ponetrarion patterns tended to be linear (mean r~ : 0.91-4"0.16)* Ostonlysis al I ft ye.m~ was strongly amoni~ed With increasing true wear rites. No c u e With • IruC wcar rate < 0.l mm/yr developed o~teolysls. However, 43% of cas~ with rates between 0.1 anti 0.2 mm/yr developed mieolysis, as did 80% of cases With ones between 0.2 and 0.3 men/yr and 100~ of cMes With rates > 0.3 mndyr (p
The ceramic group conshned of 81 Mpa followed for mean 7.0 years (4.0-10.1 yrs); the CoC~rgroup Coneisted of 43 hip~ followed for mean 0.8 years (4.2-9.3 yts)* ~ two groups were matched on acelabnlar component (Triloc cup, DePuy), femoral component (uneemented, portals-crated stem, DePuy), head size (32 ram)* and head manufaelurer (DePuy). No statistical diffc~nce existed in patient age (p=O.12)* weight (p=0.88)* or gender (j~0.71). We me.uured two-dimanaional femoral head penetration into the polyethylene liner with a previously published cornpuler-aumlsted rediogntphic technique. Linear regression analysis modeled pencqretion versus time data us a line for each patient. The slope of the regn:~ion line indicated each patient's "true wear rate."

At a mean of 7 yean, the true wear rate (slope) of cups irticdisting with ceraruic heads ( 0 . ~ . 0 7 nun/year) w u greater than the tree wear rete of cupe imiculating with CoCr heads (0.07_+0.04 mru/year; p
Paper #14

ACCURATE INTRA-OPERATIVE DETERMINATION OF THE NECESSITY FOR LATERAL RETINACULAR REIJF-J~E IN TOTAL KNEE REPLACEMENT Richard F.. White., J r , MD, A ibuque~ue, NM, James K. Allman, PAC, James A. Tmugnr, MD, David A. C a m a r l ~ MD INTRODUCTION: The mo~ common complication following total bno~ mplaa:mem (TKR) involves the patel fufemofai joinL The purpeee of this study w u to cumpm¢ the s u ~ n c y of fig *'nile of nO thumb" test (N'l') to the "towel clip" test ~ to ~ the nece~ty for ixteod retinaculsr relca~.

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METHODS: Two hundred (200) consocutive primary ~ using the identical prosthetic design end the fame m i ~ surgical a ~ were peffonrned. The NT test was performed with no contact of restraint on the patcllar cemponeot. The TC te~ w u performed using a single towel clip at the apex of the a~mtomy. The test was considered positive if there wM any visible elevation of the medial edge of the petellsr component from the truchlus of the femoral component. A lateral re*iancular relca~ was puffin'mud if the TC test was positive. Sunrise views of both knees were performed at six wechs and six months po~.operatively to determine any tilt. subluxalion or dislocation.

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The Journal of Arthroplasty Vol. 15 No. 2 February 2000

IEgSULTS: A literal retinanular release was performed in 13 knees (6.5%). In 187 knees (93.5%) no lateral re/imlc~lar relearn• v,~-~purfmmnd. By radiognipbic exam•••tin• there w u no evidencg of tilt, subiux•tion or dislocation •t six weeks or sin me•he post-opefltively. The NT test provided the following su=unlcy pammetenc true negative - 122/122 (I(X)%); false ncgetive - 0/122 (0%); m~e positive - 13/78 (17%); and fahu: positive - 65/78 (83%), The TC test provided the following accuracy parameters: tree ncgetive -187/187 (100%);, false negetive - 0/187 (0%); rote positive - 13/13 (100%). DISCUSSION & CONCLUSION: The "towel clip* test at~cxirately Ira:diced the need for lateral retinl~ainr relesse in p~m•ly ~ utili~ng the midva~tts surgical s p p ~ , The "role of no thumb" falsely ptndi~ed the neo.~Jty for huerai retimlcular release in 65/'200 (32-5%) TKRs. These rcaolts may no( apply to e4her s~q~ical appmagh~ o4her pv0athetic designs or revision TKR.

Paper #15

THE ~ OF PATIENT WEIGHT ON PERI-OPERATIVE MORBIDITY A w r l ~ TOTAL KNEE ARTHROPLASTY Alexander MIs4rq MD, W. Los Ange/e& CA. Moe Lira, MD, Bathmm Kahn, RN, OC3q, 1"am•re Rozontal, MD, David Bombicig, MD, Thomas E So•ion, MD Much dela has bore pn:=ented reg.'dang the effect Of patient weight on the OUtCOmeof total knee mhroplsuty (TKA). Previous studies have oggtcentrated on post-operative fltm~lo~ oocrtponcot survival, deep vein thrombosis, and wound complications. Iqde, however, has been wd.en addressing the effect Of patient weight on pafioperstive morbidity. A review Of 512 TKA'e performed among 406 patients by • single surgeon over • 2 year purled was condnc~. Body m,m index (kg/m*) was used as the me~ure of patient woighL Previncs authog~ have defined oheMty as • BMI • 210and rended obesity as • BM| > 40. For e•cb patient p l ~ medical biatory, ~ cmtrr,e, rehabilitation and amy complication exlxrlenced during this period Of time was na:otdnd. We defined • compth:ation as any dingltoaiS that reqniled additional treatmenh After • prelim••ely anally•is Of the data, patients were gloupnd into two glmtl~: B M I > 36 and BMI < 345. Patients with • BMI • 36 had • greater chan~ of developing • complication (53% vs 34%, p=0,003) and • greater risk of experiencing multiple c~'nplications (14% ve 6.6%. I)=0.03). Rates of wound, cardiac and GI co•pinna•lop• were •ppmxinudoiy twice as gnmt among the heavier pmienuk however, none of these individual values were aigulfl¢:tntly different. Heavier patients were more likely to require • horpltai Imty of greater than • week (12.8% vs 2.5%, p=0.0004) ~ mo~ likely to be dischluged to • rehabilitation facility (6.5% vs 39%, p<0.(XX)I). Heavier patients were *leo more likely to have been previously d i ~ with diahelca (10.5% wS4.|%, p=O,03) or • caldisc condition (56% vz 33%, p,,0.0001), Heavier patients in this stndy were more likely to experience igrlo~rative complications, were more likely to require • longer hespitsJ onum~, and were. more likely to require the era•st•nee of a rehabilitation facility. In addition, these patients did not need to be morbidly obese (BMI>40) to be Io this higher risk g~up. A BMI • 36 w ~ sufficient to aignifiamtly inc~e.a~ the risk of these events- To our knowledge this is the first study to addre~ Ill aspects of~erloperative car• amaoogobese "rKA patien~

Paper #17 PRIMARY CEMENTL,ESS TOTAl., HIP A g I ' H R O P ~ IN ( g ' r O G ~ N A g l A N S : 2 - 10 YEAR F O L J ~ W - U P Peter K Sbartluey, MD, Ph//ede//~ia, PA, William J. Honck, MD, F•blo OmT.x:o,MD, Wallace Baker, MS, Richard 14. Rothrmm, MD, PhD, Kjell Keis~ In•rod•olin•: Un(:~rminty regu~ding blologh:ai fixation, pain relief, imphmt demand and ccet •re the bash for • widely held belief thel the use of c~monticas pumas ingrowth total hip mhmplmay •hould be rcatrictad to phyaiologloally young patients. Howeveg, there are specific advantages of cgmentlcas fixation in the elderly including reduced surgimd time nnd • significantly lower risk of fat emholism. The purpose Of thin piper is to evaluate safety, efYIcncy and tolerlmce of pdmaty on•entices loud hip afthmphmy in nctogencrinns using • tapered femond onmponenL Meebeds: O~e hundred tw~ty ~ pfimsiT t(toti hip •rthmpl•stlez were perfolmed in 119 patiegts during September 1987 and December 1993. Demographics included 52 males (57 hips) nnd 67 females (72 hips), mean age ot"85 years (80.0- 91 yeats), mean weight of 151 _5 pounds. PTeoparative dlagec4ca was oetocarthtitis in Ill pmiews. A nail•tic•t, tap•red, porous ••4ted, tiuminm alloy femond compon~t and titanium, porous on•ted hemispherical acetsbulmr compuncnt w ~ used in all cases. Follow up hinged helworn 2 sud 11 years. Results: The Chemley scor~ for pain, fonctlou and motion improved from l~eOpemtive mean values of 1.93, 3.20 lind 4.08 to follow up mean values Of 5.60, 4.08 imd 5.26 respectively. The follow-up mean Hanin Hip Scxxc was 84.15. Early medin•l complications occurred in 21% of patients, which is consistent with the lit or•tore on hip ropltccmant in elderly patients. They included, 3.1% urinary tract three•one, 4.7 % pulmomuy emImli, 4.7% cmdinc abrmmmiities (3.1% CHF, 1.6% angina), 0.7% gum attacks, 2.3% inte~lmd problems, 2.1% urin•ly re•eat•o(1 and 0.7% entelrCColitin,Of impu~tm~ there were no per•operative deathe. Pm~zelic mmplinatloos include one patient with frequent dislocatimu. "rnere ~ no intriopecative femoral frantorca, no infections *nd no hem•to•ca that required surge~. At the ~ follow-up visit, four pat•nuts co•pin•ned of thigh pain. were •b~-nt, there were on intraOperative fenlof~ splits, no dlaiocatioos~ no infections ~ Oo he•aromas. Three 3 patients developed mild thigh pain and 1 had mederate thigh pain. All femncai and non•aim•no componen t.` were rediologically ira•hie. Bone ingrowth wits seen in 94% of the hips and fitwous ingrowth was not pit=lent. There were no mechanical failure* or revhdons in this series. Dkcuaaion and C.eodsudom Cam•nil•ca total hip mrthroplasty with the coil•urines, wedge-fit titanium alloy popmm coated re•ned component and titanium alloy porous coated dg~taheinr component • ppeanl to be safe •ed efficacioru in patients over 80 years. Despite I ~ widely 8uumed colggm of uneertainty of stem f'utatlon in elderly, bone ingrowth is possible and w B seen in 94 % of pro•ones. Medical ~ are high, but not immt'monntabic. With ever Inexca~ng life expectancy *nd activity level Of eldedy population, we feel that arbilrmy age criteria for implant selection are not sppmpt~e and the choice of ccfnendem implants for primary hip •rthmplsu~y appears to be pfudeOL

Rasean:h or lostitullomd support his been received from Bin•e•, Inc.

P a p e r #18 P A T E I . J ~ FRACr'URE Af'I'IER T O T A L K N I ~ A I t T i l ~ O P L A S T Y Cedric J, ~ MD, Roc~Jte~, MN, Dani©l J. BenT, MD

Paper #16 COMPUCATIONg OF SIMULTANEOUS VERSUS STAGF.O BILATERAL TOTAL HIP ARrllROPLASTY Rkhled A. Bergur, MD, Chicago, IL, Uyen Van, MD, Andrew C.mran. MD, Joshua Jtcet~ MD, Mitchell B. Sheinkop, MD, •moon G. Rcaenheqt. MD, Jorge Go•ante, MD latreduetinm Simultsnemts bilateral totol hip anhmpissty hits the appeal Of tdlOller toed rehabilitation, shorter innSth Of stay, and lower com. Howev~, do tigse cmt he•cries incxea~ the risk~ Io the parle•? Methodg In • pmepuc~ive study, lofty-•ix comic•tire patients having aimulbugeus bilateral total hip • nhroplaaty *nd 106 consecutive patients having biinterai to~tl hip arthropinsty staged within 6 months were prospec~vely followed. The indic•lot• for simultaneous bilateral total hip •rthmplasty wen: severely debilitating bilateral hip pain. Serious cornplkationa included death, ICU admission, myor~,diai Infarction (MI), and relum to the O.R. for any reason. Minor compile••anus included DVT, wound drainage, UTI, urinary raT•olin•, lieu•, pneumonia, and atrid fitxill•tiesl. Results: Patients having simultaneous bilateral total hip m-thmpinsty bad • three tim~ higher rote of serious complicatiotts u patients undergoing the stlsed plrocedure, 15% vz 5% respectively (p=O.03). The only death eCCml~d In • patient having aimulUmemm bilateral total hip anhmpinsty. The rote of loud cmstpljcatiomt w u also higher with simultaneous bilateral total hip Imhropliisty c o r n l ~ to whoa staged, 43% vs 22%, (p-0.01), Two or more units of blood was required in 57% of patients having aimoitaneees bilateral toud hip m r ~ i n s t y , whereas ooly 22% of patients having bilateral total hip •l~hmplasty needed two or more units (p
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httl~dudi~l: Limited iI~oits ~ •vldinb]e to guide t~stment of patella fracture after loud knee • nhmpthsty (TKA), The purpose of this study wzet to evaluate • Iwge series of these fn~ures, and develop treatment recommendations based on results. Mell~d•: ,~dl patolhi fractures followiAg |2,464 cocai~ntive ~ perle•mad •t ore:: in.stitotion between 1985 and 1996 w~re etmq~e~ively review•d. Eight-live frataun~ In 77 patients were Idontilled (58 [rlctores in 51 nudes, 27 (met ures in 26 female•), Mean age was 69 (nmge, 3 ~ ) , Five (racton~ weto IgeJitledeis¢,wl~re Imd Iwo o ~ ware I~t to foNIow-op. Tn=lmem In the remaining 78 Imcca w e non,c ~ m l v e (47), i~'tiai or complete pal¢llectomy (13), OPJF (10), component resection ned patelloplcaty (6), and frageHmt exclaioo with palell•r revision (2), Frnclu~ were d m l f i e d according to pat•lint impinot fixation Mstt~ integrity of the extensor mechanisol, ~ quality of remzining bone stOCk. Mean follow-up wca 3.6 years, with endpolnts of bony or fibrous union, failure of m:atmenz, or death. RoruJt~ Over the stndy period pro-valence of pal•tint fracture alter T K A was 0.68% (males: 1.01%, fern•ice: 0.40%, P-0.0004). Thirty-eight fractures (49%) bad • stable implant and intact extcmor ngchenism ~ I). Thirty-seven were toe•tad nconperatively; only I failure required •put•tin•. There were no major co•pike•ions In thin group and 28 of 38 weme *symptomatic at last follow-up. '13,~:Ive fcatsu~e:s (15%) had extensor ma:hanbwn disruption and • stable Implant ('P/pe II), Eleven were treated operatively, with 7 complications (6 pen) and 11 re•per•tin• (5 pts). Seven of 12 inKIpain at last follOw-up. V~venty-seven fracmn= had s loose patellor component 11 (14%) had good lemain. log bone stoc~ ~ III-), and 16 (21%) poor bone stock ~ Illb). Nineteen were tw~nd opemtivoiy, with 10 complication (6 pen), 4 ••pure•ions (2 pet) and 10 with pain at last follow-up. Overall, of the 31 fn~urez treated operatively, there were 18 complications (15 ~ 48%), and 18 leopumtioos (g p ~ 2 6 % ~

Ill•cumin• ond Coodanlom: Patella fmctunz after TKA a ~ infeequenL Males outnumber females. Three main c~ited, can guide U~.atment: fLxation tutus of the patelim implant, integrity of the exten. sot" mechanism, and quality of the v..maibing bone. ~ I fractures (intact implant and extensor mechanism) can be ~ , ' e ~__~lly _ treated nonopexatively. 3~pe II fracture (intact implant and extenanf mechanism dla~Jption) gquim operative tlreatmeot to re.ore extensor fumlon. ~ llla f t ' a a u ~ 0 e ~ e Implant msd sufl'gloot bone stock) may be tl~ited with i~dellar revinion or component resection and patellopinsty. ~ Illb fractures 0 o ~ e Implant and po(x beoe stock) m y be Ireated with pattie• or complete patellnctomy. Overall, for pmpuriy SUlorsed pat•eats, mxtopuative Ue.atmont w n largely ~ 1 with minimal compltcsllom. When opumtive treatment was required It was nssociatnd with • high con3pltcatlon and reoparaticQ gate.

Abstracts From theAAHKS Ninth Annual Meeting Paper #19 RESTORATION O F 1 ' l i t J O D e r LINE BASEl) ON THE DISTAL FEMUR REVISION TOTAL KNEE AIRI'IH[ROPIJUwrY Stevea 18era, MD, SahLak~ClOt UT, Amno H. Hofmann, MD, Clint Mnen. MD, Mar~in Camargo, MD IntreduetJoan A clinical and mdingeapbic ImMyals was undellal(e~ In evnhmte joint line pualtiort in patients who undenvent re, talon TKA and cmxclatnd to their clinical outcome. Metheds: One hundred revision total knee m'thmpl~tles wing ~emmnd revlsinn components in 93 patients implanted by a single surgeon using a angle revision knee system were evaluated. Fo~yelght females and 45 males were sludind with an average age of 67 yem~ R a d i n g n ~ of the opposite unop* eratnd knee, the pro-revision knee and finally the postoperative revision knee were reviownd. The joint line was evaluated relative to a line drown ~ the distal point of the Mope of the medial distal femur at the adductor tMgrcle.. Clinical ev'altmtioeat included flexion, extension, total RaM (flex, eat.)' HSS score and pain score and consisted to reproductio~n of the nomud joint line. Pammlta: Average fellow-up ~ 5.5 years. Tbirty-nine ca~s were revised for uepdc Ineeening. 38 for infection and 33 for instability. Average p~,op HSS sco~ was 60 with a pouop improvement to 90. Average puatop puJn score w u 34. Average RaM improvnd ~ 6-94 to 5-105. Ikttet flexion was obiMnnd with the joint line being clnecr to nomad, as the joint li1~ devilled flora what was measured u normal on the pRoperitiv~: knee, the flexinu dac~,.Jed (puO.001). EXtonalon w ~ statistically correlated to normal podtion of the joint line (p=0.004) as was total ROM (flex-eat) (p<0.001), HSS m

(p
I)b~mmio~Conclmiom If the joint line w ~ elevated either 3mm proximal or dlsud from the "normat" joint line, all dependent variables (flex, eXL total ROM, HSS scon~, pain ,~ore) were compromised. Our patients were seen to do much better irrespective of age, sex, mechanism of failure, infection or length of follow-up if the joint line is aneurately reproduced.

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RESULTS: All groups had similar patient demogmpbicx" failure mechanisms, and p~topun~ve knee acmes. However, Group 3 had a sii~ificamly bighcg w,~t,,~ion of asvere bone defects (Group 3 had 40%; Group 2, 11%; Group 1, none). "1~ Impinm-reiated feihim rate~ defined am reoperation requirinK oumponent revialon or removal, were: Group I, 26% (11/42); Group 2,11% (4/37); and 3% ( 2 / ~ ) for Group 3 (p-O.002)' CONCLUSIONSx At a mean fcllow~p of 7 years, the clinical m ~o m e of ~"~'~__-ful revhion was similar for all gru~ps. However, pdmmy implants (Group 1) and modified primary implants (Group 2) had signiflnemly higher componont-relatnd fallun: rotes. Although revision implants were used in omltplex reconstru~lomk they ~ththitnd superior pulfornuta~ nnd durlbllity. Selecting wimary implants for revision TKA should be c o ~ l ~ r e d cm~oualy. The impmv~l longevity of reviMon implants josliflcs the evolution of modular revision components.

Paper #22 PREOPERATIVE A.~ESSMENT OF SERUM THROMBOTIC MARKERS AS A RISK PRF.DICTOR FOR DEEP VENOUS TIIROMBOSIS AF]3gR TOTAL JOINT AKI~IKIDPLASTY l)nak.l C. Farbm', MD, H e r ~ PA. Charles M. l~tvid, lit, MD, PhD, Wflllsm M. ~ MD, Vineont D. Pcll©lpini, Jr., MD latr~lueUean Deep venous thmmbneis is the m ~ l commor, fatal complication following total joint mhn~lasty ~ Ira:dieting those at greatasl risk for D v ' r would allow for selective prophylaxis and spurn unneeded anti-congulstion. Activated Pn~eln C Reslsamoe (APCR) nnd deficiencies in Amithmmbin 111(AT Ill), P'~ein C and P ~ e i n S have been cited as increasing risk of DVT in the general population. Our purpose was tO investigate the levels of these markets of thrornbolic susceptibility as risk penditsors of DVT following total hip and ~ mthroplmy. Methods: Levels of A P C ~ Protein S. Protein C., and AT I11 we/'e.pmspu~ively detetminnd in total hip and loud knee arthroplasty petienL~ Patients followed a clinical pathway conslsling of DVT pmphyl u l s with o~umndln (INR 1.5-2.0) nnd rondne screening venoglims on p(~-opemtive day four or five.

Paper #20 A COMPARISON OF.ARTICULATING VERSUS STATIC SPACERS IN REVISION TOTAL KNEE ARTHROPI.ASTY FOR SEPSIS J. Bohannon Mama, MD, Ctmrlorte, NC, Ttmmu K. Fehdng. MD IntroducUoa: Antibiotic laden spacer blocks are frequently used to treat infe~nd TKA. Static spacer blnehe make exposure at ~:implantation difficult a ~ n o ~ y to qund shortening. Unexpected bone Ices due to migration of the spacer block him also been repurted. To avoid thas~ pmblema, a tempunuy molded implant made of antthiobc cement was used in I consecutive series. This implant allows RaM. We sought to datemtine whether this would 8frets the reinfection rate, Improve functional results, or prevent bone loss c~nWund to ststic spacers. Materials i ~ l Methods: From 1987 to 1997, 440 re'vision total ~ trthroplaaties were performed. Seventy-two were treated with two-stage rximplantatinn for sepsis. Twenty-five of these 72 patients were tl~tted with static non4niculsting sptoent. Since 1996 30 patients have been rt~ttnd with Tobramycln-lsden articulating spacem. Fifteen patients tt-~ted in this fashion have two year follow-up. The~ 15 patients were cemlxued with the 25 pmients treatnd with a Static spacer. The average follow-up w~_s36 morllha for the static group and 27 months for the articulating group. HSS scon~ were dneumented in e*ch gxoup. Reonlte: lqm:g patients treated with a static spacer became reinfec*nd ( 12%)' One patient With an arttcelating spacer became reinfectnd (6.6%). Fifteen of the 25 cases with static spacers had unexputsnd bone loss between stages (average 6.2 mm. on the tibia and 12.8 a m . on the femur.) No 8pptv~abic bone Ices could be me4mered in the articulating apecer ga s p. The average HSS score was 87 in the ~ t i c gxoup and 85 for the articulating group. This differen~ was not statistically significant. RaM at final fellow-up averaged 101" in the static group and 105" in the articulating spacer group. This diffel~ce was also not significant. Surgical expusum was fv4iitated in the articulating Stoup, however, no significant difference in overall operative time was noend. DlscuJleo: Articulsting spacem appear to facilitate reimpiantstinn of infe~nd TKA without sddiflonal risk of infection. Unenpeoted bone Iou is no longer I c ~ g e m with this t w o - a g e technique. Articulating specms offered no functional advantage over static spucens in this study group.

p a p e r #21 DOES IMPLANT SgLgCI'ION AFFF.,cr THE OUTCOME OF REVISION KNEE ARTilROPLAS'rYT WUlinm D. Balgbe~ MD, San D/qo, CA, Gerard A. Englk MD, Ik.borsh J. Ammnen, BS INTRODUCTION: RevisJo~ knee implant sy~ems have pmvidad new opUons for I~vlsinn total Imee arthroplasty ('rKA). but indicatious for using thase systems have ye~ to be clearly defined. We sought to deten'nine if implant selection inflnene=d the outeome of revision TKA. METHODS: Authors cx~tq~rtz~l 139 cuesecutiv~ revision TKAs into 3 groups b~ed on implant type. Group I (n=42) were revlsinna with winmry TKA oompunents ( s t e m s ¢ ~ n m ; no augnrents or wedges), Grm~p 2 (n=37) were modified primary nemponents (stem extensions >SGrnm)' and Group 3 (n-6G) were revision TKA components (long stems, angments, or custom components). We ..,~-.,~1 the failure medumbm of the index mlhropl*~y, bone deforl clsssifgation, pum-mvlalon knee seo~s, and the re-revbion me.The mean follow-up interval was 7 years.

l~.mM~memsof~,l rmmmm~m

~

R~nhe: 472 consecutive arthroplasties were perfonnnd from 3/97 thl~gh 2/99. 75 patients were excluded because of incomplete venography or thrombotic panel data, leaving s sample size of 397 (186 THA and 211 TKA). Then: wen: 129 DV'Ps (32.5%), 33 (17.7%) in THA pati~ts (3 proximal (I.6%)) and 96 (45.5%) in TKA patients (8 proximal (3.8%)). The overall prevalanc~s were APCR: 8.4% (32/380) and deficiencies of P ~e i n S: 19.1% (76/'397), Protein C: 6.8% (27/397) and AT l|h 32.0%, (127/397). Of patients with DV'IX, the n~ec*ive p~evMenc¢s were 8.9% (11/123), 17.8% (23/129), 5.4% (71129)' and 33.3% (43/129). Patients with abnormal thrombotic panels had a DVT prevalence of M.4%(11/32) for APCR, 30*3% (23/76) for Pre4eln S, 25.9% (7/27) for Pro4ein C, and 33.9%, (43/127) for AT 111daflclencles. This compass with the DVT p~vMena with normal coagu. lant panels of APCR: 32.2% (112/348). Protein S: 33.0% (106/321)' Pmeein C: 33.0%,(122/37fl)' tnd AT Ill: 31.9% (86/270). Relative ~ g of DVT with an ahilonmd thrombotic pdmcl is 1.07 for A I ~ R , and 0.92 for Protein S, 0.78 for Protein C and 1.06 for AT Ill deficiencies. Com:lnaloa: No oonelatinn w ~ found between the~ thrombotic shnotmhiitias and venoglaphically de.tenninnd pua..operative DV'r following total joint replacemenL Scl~ning for these cuffently available serum thmmbutic markers dons not appear to be a useful pre*olxnrtivs R~'~,qent of the pos~-opurative risk of deep venous thronlboalf~

p a p e r #23 FIBRIN SEALANT REDUCES BLEEDING ~ A RANDOMIZED PROSPECI'IVE TRIAL

Gwe.Jaw Wan& MD, ~ t x , ~

TOTAL KNEE ~

VA, David H t m g ~

ENT:.

MD, Carlton Save~, MD, Aanm

Rmeobe~ MD, Michecl Moat, MD, Sandm Bed~ BSN, Lynne Mayenk PhD, W'dliam D. Spomi~, MD A randomiznd study of 47 unilateral cemented primary loud knee mpthcement (TKR) patients was coodnetnd tO investigel© the efficacy of fi'btln sealant (FS) u a hemoatatlc agenL The pdmaly objective w u tO detelTnine whether the application of an invastigetional FS (Quizi[ , Binpha~ticals SA, B ~ l s , Bclglum) Rducnd peat-operative dndnage, thoreby reducing the need for ~ O n . Poat*.operative hemoglobin and hematoorit levels, u well as asfaty values, were tlso ~tem:d. At the coriclualon of vontine TKR ~ , lO mL of FS vrgs spayed onto the wound of tn~mem g r o ~ (FS) p ~ hefore toemiq~ daflmlon and just p t ~ to wound c ~ Conuei gmep (C) pndenm n:ceived mnd~ her~tstic ~ a l o ~ AJI petiants n:ceivnd dnins tnd outputs w ~ n ~ c o ~ Mean drainage within twelve heunl of surgery was idg~irlclntiy less in the FS ipoup, 184.5 .*.28.0 m L dum for the C group, 408.3 ± 54.6 mL (adjusted for variance in dme of measurement, p~0.(]02). Tom pum-opuratlve me.amfluid drain,lge was less in the FS Ipmep, 410.3 ~ QO.6mL, than for C, $76.4 ~ 90.4 mL (ndjtumxl for drain nm~oval time, pz0.027)' On the first ix~tt-openttlve day, hemoglobin had declined 2.01 _+0.21 g/dL in the FS group and 2.73 ± 0.21 8/dL in C. Hemato~il levels declined by 5.79 -* 0.65 g/dL in the FS group mKI 8.51 -'20.6 g/dL in C. Hemoglobin decline was MgniF~:ondy less (28.9%) in the FS gmep than in C (1~0.005.95% CL [10.2, 43.7 D and hemmoait decline was Mfpnlfkandy leas (30.9%) in the FS group than in C Q~O.002, 95% CL [13.4, 44.9 D. These reanlts dcmooatmte thai the use of PS In TKR significantly n~luc~ overall fluid drainage while maintaining higher hemoglobin leveLs.The clinical safely of fibrin sealsnl is also suppmlnd. Thus, fibnn sealant may be a valuabk and safe mathnd for amaring ~ . . ~ . st the time of TKR.

Research of Institutional suppu~ and miscellaneous nowincome support (e.g., equipment or services), commercially derived henorsde` or Other non-resem~ milled fending (e.g., pu/d travel) has been received from OMRIX.

250

The Journal of Arthroplasty Vol. 15 No. 2 February 2000 Paper Ir~.4

Paper Ir~

EFFICACY OF PREOPERATIVE AUTOLOGOUS DONATION IN TOTAL HIP REPLACE]M[ENT-ARANDOMIZED CONTROl J£11 STUDY I,.. Wbumm,MD, C ~ , IL, Dinna Billone. MD, Dtvld Gleen, M D

ACETABULAR REVISION USING A BILOBED CEMENTLESS COMPONENT 1N PATIENTS WITH ~- ' E r A B U LAR BONE STOCK DEFICIENCY C. ~ ~ Jr., MD, Alaand~, VA, W~I-Mlng Chon, MD, Robe• H. Hopper, Jr., PhD, James P. McAuley, MD, Omutes A. Engh, Sr. M D

I n . d u e l • e : Pdor to tmatl hip m~tmphmy (THR), ~ t l v e antdiogous deoation (PAD) is o0,11monly done to meet pe~emisl ram.•'unions needs following anrgery. With increased mvs~mean over the costs of PAD, ~ t lmptovem~ts in the ~ffe~y of blood supply, and ipuidcli~ sulg~lling lower hemoglobin (1~) values pdor to ~ in relatively healthy pedents, we ques~oe the a p p ~ at~ of PAD for total hip mpiscement surl~ Y. ~ purpose of this s~mdyis to determine the efl}~acy of PAD in pdmmy, unilatend THR. Method~ With Institutional review heard ~qmrovM and petkzt cxxv,scm, reisfivsly healthy, ~ - a a n m ~ (HI)) 212 i~IL) l~isnts wcx,e ~ to drier dOlMIletwo a u l o k ~ units (dooo~) or 004 doIMIle any units (nou-demxs). D~rmlpmphic and h e n ~ daanm well se u'ansfusioo 8rid cmnplk:ltion roles w~rc o®npered he~vn:en dooo~ and no~-doeom. AJI psdems .,e,~el~manq~d usJng Sl~mdmrdtzed cJinical pemways and pemocois. Indicttlom f ~ musfmkm we.~: Mlogu~k: bloed - 8 8/dL and antolog~us Moed 108/dl- Bhiod ICm w u mc~ded at anrKery. Toud blo0d hie• during tho hosplUdisa/Jon w u calcuisted tmcd on lean tedy mm~ the ~ md fmal b r a c t • b i n s 8rid unim me•Stand. Them w~mno dlffcnmee In the final hemoglobin hotwem tho gmupe (p = N.S.) FOr the don~m, 57% received some of their autologous blood while ~d% of the autoloi~us units were wlmted. No patient in either group n~.ived an ~llogemeic ~ . Operative blood lea and tolsI blood loss clu6ng the ho~talizalion for ~ : dooom vmre 564 (*_277) mL and 1696 (_.~144)m L ' 4 . for the nee-deeo~ 403 (-+172) mL and 1529 (_-.'634)mL. (p = N.S.) At • c~m of'$389/autologous •nit, tbu~ was an edditiomd c ~ l of $778 for each pedent In the do•or group. Coechm~.: In thi~ series, them m s no benefit to the use of PAD in routine THR with no petisnts n:qdifing a l ~ i c bleed in either Ipoup. PAD wse seanCisted with an increLqed likelihood of autotmmhmioa, wuuq~c of pro-do•reed unim and imn'emed ceres.

HemOl~

N~-donors

M u a l w defxdancy of sceUdmisr bone stoc~ is a challenging problem •moan patients who ruluim mviMoo for failed hip mlhmplamy. ~ bilobed cem~ntisss a i ~ compon~t is • ~ o n adtematlve for ~ in which I ~ t e d hollSiSphere CiUlnOt be used. This atudy Fqresants the results of bilobed components used for mvislorlT H A 8mong hips with acctaholar bone deficiency, cisrifie~ indic•lions for the comp~:nt's us~ and identifies factors that influm~ce cllni~d and rediogmp~ic ouu:ome. Fofly-ol~ hips in 38 peliants uad~rWanl an liceutb~isr revlaloo with g bilobed, ~ln~lJ~gl I~e.UlbuhLr cemponem. Thee ~ were • anbs~ of 414 seeUd~hu' revis~mm pcrfmmed dunng the ~ n e period. One peliant ~ lest to follow-up; one died during the study period; and two petients could nol mmm for radiographic evaluations hot complmed quc~tounabe~ Authors evaluated Lho m'nalniug 34 petlents (37 hips) with an averagefollow-up oi"41 momhe (7,4 to 66 mouths). RediolpmphJc study•is showed an Imlm~vement in the nvemKc vertical displacement of the hip c~nter. At the islCl~fdilow-up examinaUon, 28 of 37 cupe (76%) .,~.-n~stable. Throe cups (8%) tirol w e • pmb8~y umlU~le ~ • d~Ulg~ i~ ~ po~tiO0 but o• definite Cup milpradom. Six (16%) were unstable. Eight of nlnc ~ or pmhobly Io~e components occurred in patients with cepluded companem migration grcate~ hum two centimelens and dls~plJoo of Kohler's line o~ p~emvisJo~ radiographs. Failure was also mo~ likely wheo the inferior sepets Of the compeoealt did ~ exteed to or below the intcl~eanJmp line ( ~ component). Tho cady 24% ~ilum rate In this study is cause for concern. For complex anetshohur, ,x~.-,...,~smions, the imthon advise having multiple alternatives, includlng miofora:n~:nl cqFs, bulk hilolp'1fl, and tba bilobed compor, an'- Because the procedure is technically demanding, a bllohed compoeem should only be ~ when it is tmpomdbl© to use • hemisphorc p o m u s . . ~ , ",d seetabulur compeeent.

g/dL

44

14.q-~2)

~s(±~.a)

10.q;n.3)

10.,~±1.0)

50

14.5(±L4)

13.7(±1 3)

II.6(-+1.3)

10.1(±1.6)

Consultant m employee of DeFOy Inc. of Johnson & Johnson

Paper#25 PARTICULATE BONE CRAFTING OF os'rEOLYTIC FEMORAL LI~IONS AROUND STABLE CEMENTLESS STEMS Erk R. ~enan~ MD, CA~smmHill, MA, Cbrisdim P. chrs~.n~n, MD, Eric A. M ~ I t h , MD, Shon~ L Gomes, RN, Benjamin F. Bicrhoum, IVlD

EARLY AC~rABUL,&R COMPONENT F A ~ U R E S IN A COMMUNITY-BASED ~ IMPLANT REGISTRY

Introdu~Joo: The m.'am~at of iXOlpmVe pelvic omanlyMs in the p,n~e~c of • well- fixed cementI m m~,tahoisr cemlpom~ bM recently been documented in the oflhqx~dic IJtmlura. We report on the ope~'lliv~ IlrcwmelrJt lad nemlm of 17 cases of ~ v e pm0dnud femoral oateolysls in the ence of • well-fixed cememdm,s femoral stem.

INTRODUCTION: Emly failures in ingrmvth aeetshoisc have open implicated design or mated|l vmiabtes. Since 9/91, we have mf~ste.~d 1812 toud hip arthruplseti~ ('rHA) In • omnm•nity-be.~d total joint mgi~'y em'npf/-Ing two he,q3j~is and ,4.,IoflhopeedJc suqFon•. We mvlew~l MI ~lated see:tllhohtr compe,nen~ levislmm, exclusive of those peffmmed for recurrem dhdo~tion or leg length d ~ . to tdeml~ de~lpu associated with higher fidhim rules.

Mt,~a~8: Sis~-~n pedems (17 cm~s) who averaged 51 y ~ of age undeP,vant curettage and packing of pmxlmal femoral omeolyllc lesions with a l l o l ~ csm~llous bone In the presence of a w~ll-fmed eemanlkm ram. Additional pmoedurts p~t'onncd at the same time include scetsholar liner and head change in 11 c~es and seemhohu mvimon and bead cbamge t• 6 ameL Preopermively, 10 pelianm (10 cases) were m y m l ~ a t t c , 4 pellems (4 cases) had moderate glrdin pain, | patient (1 c~se) bad mlldmtlgm4n pet•, tnd I pedeat with bllmeml pmcedun~lllmodemm ipolu penn on •on side and minInml groin p~n on t]ne other Mde. Pmupemtive mdlographe ~ pmxilmd femoral o~e~lysts (prlmm.ily in Groan z g x ~ I mud 14) In MI 17 cues, ~ ¢ e m ~ Imlycthylel~ w ~ r in 10 cmle~ and sent•bular o~anlysis in 6 csses. T1~cslze of tho femoral c~.anlytlc kslons wcrc n,,~_.•un~lp~:. and posaoper. atlvely with AP and istaml views of Iho hip. Pro•pc•lively, the average le~Jou wse 4.1 by 1.6 cm on the AP view u d 1.8 by 0.7 cm o• the islea'al view. R e . l i r a Follow-up included cUniad e l • m i l l i o n ~ r t ~ n l p h l all am iverige 32 months imstuperatively (minimum 24 momhe), in 16 of I 7 cues, petlants w.nudand symptom-free duflng the follow.up period and n o ~ of the f ~ n d stenms showed redk)grapldc evldence of loommlng. The size of the femoral om~ytk: lesloms averaged 1.6 by 0.6 a n ou the AP view and 0.6 by 0.2 cm o~ ~ lateral vlew, Imd oone of the mtediytic dofeets bed p ~ In 15 of 17 c 1 ~ (88%), the size of the femoral m/eolyUc ~ bed rage•ned. The all•graft bone •ppean~l to have inomporated fully in 9 of 17 c~u~ (53%), p®rflaily in 6 of 17 cJmcs(35%), and no~ at all in 2 of 17 canes (12%). Altho~gh p~llmimuT, the r~ults of the cunant study o~nfinn the c l ~ of deheidlng and bone grafting pmgresstvs oaeolyUc lemons around well-fixed, o ~ e ~ e u s femoral stems. Continued o b e u ~ n and follow-up of Ihese pefiants will be necemuy M the ~tUl~..

HIF

Tenman J. Gtoe, MD, SL Paul, MN, FoterJ. DMy, MD, Kadileen K. Kfllean, MOT, Zhon Hmmg, MS, Susan Me.h~ BY*

METHODS: B~twe~ 9/1/91 und 2128199,1812 THAn were pedonned in the symem, with 91(5.0%) mquirng revision. Of t h o ~ 72 (79%) were mvIMmuJ of the aeeuthulm" campooent(s) •lone. With the exchmlo~ ••led above, 20 •vision• for eady wear, m ~ loosening, or cute•lynn• about the race•bulm"compomem; nm~ined, ~l~-~.,r..atlngtho focus of this study. RlrSUI.;TS: The me.m1age of these 20 petknm m mvistoo wse 60.0, the mean weight w u 84.5 kg. 8rid mean time to revlsioo was 4.0 yems. Them was n pmdemlannce of male gender (60%). We w e • un•ble to mme~mpemupemdve se~lvhy level In the regisu~. FJghtann of the 20 mvisiom involved the • me•dies PSL cup, 15 of which wcm HA coated led 3 beaded; both were n~dular lnlpowth de•lip• with m boles.The Omeoak~ -HA PSL cup revisionsn:pmsemed 9.3% (151162)of the tolalof that d~ilpm buphmted; Ihe beaded PSL renan, 2.I% (3/142).Cox mgnma~n ~ F ~ I S did not reveal a penIIive eoneistioa between acetsbula0r mvi.ston and fiantlm method of the stem, although 13/20 stems w e • ingrov~ danignL This selse~ion btse w u ~ •,ol:ount..,'1 for by age and nc~ivity level. At the dra~ of pdmm7 anrgery, one 26ram hoed und o~e 32ram heed were used; U~ remdiding beads were 28ram. Initial I~'qmhohu" I b ~ hinged hem 44ram (26ram head) to 68ram. DISCUSSIONAND CONCLUSIONS: The T-year cumuh~lve ~visioo rote for tho O~eooJcs HA PSL cup wm 13..32% [6.19~, 2 0 . 4 ~ ] mnuwmcl to 1.0% [0.00~, 1.96%] (1~0.0007) for all other inlp~vth ucetshoisr compooants in this time pm~od. This may I~fl~t design vluiabks such i s liner cm~lpuency, ~xatRxl of the shell Io hoan. polyetbylme quality, or • ~ b i n a t i o n of ~ and o0~er fact0m.

Pape¢m UNDERES'rlMATION OF PELVIC ~ L Y S I S : THE VALUE OF THE ILJAC OBLIQUE RADIOGRAPH Richard IL ZlmlJch, MID,Ckarlesma, 5C, ~ K. Fehring, MD lotmda~lmt: Pod _.o.,_._~lar o~olysls Is a nxx}gnlzed commqucoce of ~at~ntisse THA. A F pelvis radiographs •re p0otinely obtained to detect seymplomadc ~ loessnt an cady stage. The puq~oor of this study was to determine fir an AP pelvis is adequate to define p e d n c ~ ~ e d i y , ~ folJowmg cememlans iorlahoisr receemrucslon.

"Dmem • i mimWq ar vdu, ~ m~J,,,d Pm,muo~ baMU,m

Mai~dm~ nod MeUmd~ Throe m~c cadaver pelvla~ were oblained. ~ i t e l y size c~mentisss acelalmixr compooan~, were plse~. A In••ella• ~ of throe mdiolpaphe w e • then porfonned (AP pelvis, • b i n • o r and ilixc oblique), in the t i m pelvis, • posterior oolumn Imion was simulaled with •

Abstracts From theAAHKS Ninth Annual Meeting 36 ram. nmmer alter ;emoval of • e cumponenL Tbe •net•holm" compueent w u plneed beck In Its odginsi penition, And Ibe net'ks of radiographs was repumed. This process was repeated •re*: Additional timex enlarging • e lesion eac~ time w i n 40, 44 And 48 ram. Ramors nslx~ively. After each lealon was oree*ed, • e volume of the lesion w u computed, And • e radiographic nefies repealed. In the remsining pelvises, pubic end ischinl lexicm were simule*ed in the smae fashion. Each radiographic se*'Seswas • e n mvic~ved~ and the extent of involvement ~eflicd. Remdta: Tbe lealom c~eated in • e pentedor cc4umn were not visible on a sinf0e Ap view of • c pulvis until a 44 ram. defect hud been c~ded. However, • i s lesion was easily demonstrated on tho lilac: oblique view in each instance. By • e time the posterior lesion oenld be uaime*ed to the same extent on the AP pelvis And ililc oblique radiograph , it had become n segmental posterior defect. IAhe tbe oninmn defect, • e ischlal icsiom were not well vlsmdized on the AP pelvis. Tbe pubic isz~as, however, wen= well quentirred on • e AP pelvis. The evaluation of pelvic m~eolyals should not be sn exception to the oflhopudic tenet of ob~ining biphmar imaging. Without • •ree d i ~ undenaamling of the lexJon, one ennno¢ develop • ~ t ploux~l for such ~ We beve shown that an AP pelvis radiograph is inadequate In identifying and localizing entenlylJc lexions of the nee*abulum especially in the posterior ol)lumn. By the time poitedne ne*onlytlc inslons um visualized ott • e AP redingraph, bone Ires in • e pus. terlor c:ninum is severe. Biplnear imaging is mandetmy wbeu mpofling rates of emeoly~ in nementless ac=ttholtr mmponent~

Paper Ir~9 A PROSPECTIVE, RANDOMIZED STUDY OF NONCEMgNTgD TOrAL HIP ARTHROP~ - T H E ROLE OF HYDROXYAPATITE Aatlmuy J. MHrkdlo, Jr., MD,/,anca.-t~, PA, VJ. Ra.tquicho, MD, Bbemt Kelkar, MS, Chitnmjan S. Ranaumt, MD Cemented Item fixation is It proven tecbaiqne in total hip anhmplmly (THA), however aseptic Io~enlng is • noted cm'nplice*ica. Cementlexs fixition is aim popular in THA, however thigh pain and entediysin um known problems w i n shofl-tonu and long-term follow-up, rexpesdvely. In neder to improve the initial developmem and durability of the entooie*ngrit ion of pome.s coated nementim implant&, hydmxyape*ite (HA) has been claimed to provide • bicingical adjuvant for femoral stem fixation in THA. There is no ~ i v e ~ randomized i n ~ study cempsdng diniad and radiolpWhlc fiedtage between proximally HA-ended and non-HA c~tted surfag~ of an IdextJcsi sam deign. We investigated 174 patients (199 hips) who received eitbeg HA.-one*ed or no•.--HA ene*ed identical stems. Clidiad iofoma~on was avell•bic f=om 152 patterns (174 hips) detailing pain, muade power and me*ion, walking ability, and ovendl patient satisfaction and ~une~ion. Evtdencc of Item mJgee*ion, ennal fill, redio•omeks md haetotoplc exalficadm, were meuun:d oe ant~.,,~v,.,,~:fiorend icteml mdtol~tFta. In edditien, ~ Waxcuine on • e intond s a l ~ of • e ixoxinul m m end • m=~ieduced remodeling of clmcellous beac ngalrm pumuz surface (SIRCAP) w ~ noted L~ sism of

Both gloupa el" pe*ieats puffmmed well ou • e basis of Henpital for Special Se.-~ry hip sa~x& Howcver, the non--IJA group demonitte*ed • significant Incrume (p~.03) • ae*ivtty-4elated nigh pain. ~ were no sigMficam radlosr~ dlffct~nc~ between Pslicm cehot~ w i n all demmitlating hone ongmwth. In our m,.,.t,~ive, nmdomized study, we conclude that the use of the HA-cc~ed stem results in ine~tned clinical satisfaction to the THA patient.

th February 2000

251

Remdta u d t3mdoMmun Tbe mnehanlcal Itreng•s fonnd In our Itudy ane he4 • e mLme u • e onsa in • Conlcmpuesry une~nented cup lecktng mechanism ('l~lngy). ~ , early cfinical nsulls suggee* •e* the Itreng• of • "Cemented Locking Mechenl~n" provides adequate fixe*lm. The possibility for ice*aholar liner exchange in • well-tented cup u a • g cement f m • fute*ica is • viable surgical option. Fur•er teeing should be IwJfonned befme a medium or long lenin endoreemenl can be toede.

Paper I;31 THE ACCURACY O F ACRTABULAR REAMING IN TOTAL HIP ~ D I T Pldiip C Nebie, PhD, Hoe•m, TX, Jcny W. Ak:xand~ BS, Emir KJUmek, MS, Dtvkl L ~ ,

MD

I,,tredlN:Uon: Thin mudy wne porfmmed Io nwasure • e size cud ILhapuof • e Ice*zindum alt~ smglcat ~ w i • "chnene-geNu" style rezemn. a d Me/limb Twelve ~ hemi-pulvl we*.e cureinlly reamed in lmm inav:ments u.~ng chcese-gr~et style ~ until contscl w ~ schicved w i • floor of the sce*aholum. Calinge of Ibe machined smtaholum were ira:pared w i • demal implex~on me*eclat u d scanned with • high oinlJon baer meexurcmem system. The spslisl coontina~s of 8ppmximately 40,000 points on •be surhtne of excb cue*ing were menmred at inc~mcmts of 0_5 degrees und 0_smm und displayed on • topographical map of the ~.amed nee*•hot•re. The uverege diameter of each ace*aindum was enlcuinted w i n ne itnemacy of ±75,/am sad enmpmed to the nominal dismetet" of the IP.mnor. Results: The scelabull were lexmed to an •vemge of S6mm (range 54 to 58mm~ The svelnge aentabalum w u ovenenmed by 0.44 ± 0.10ram (n=12), hinging hem 0.99mm of over-r~nsing to 0.Z7mm of under-re•rain& The lunate i n = t~neined mistively spbe~di, with an average yetis•ion in diameter of only ± l.lmm. OCber m of the locket, nine* noCkeably die floor and the •ce*abuisr notch, deviated from sphericity by up to 4ram. Tbe~ w u no matislically sSgniflcam diffetx.nce b e ~ n the enor of reaming and the nominal nutmer ~ r Co = 0.752). lYacmdemn This sUgty demomne*ex • i t , onder Ideal drcunmmcea, • e diame*er of • c Jumcd ~e~oulum varies by sppmximalely ± 0_smm comlxu=d to • e nominal It-,. of the bemtsl~nic~ n~'ner. In clinical prae*ic~ ace*ablaut reaming is expected to be less accurate due to many In~onk including • e trne diaweter of • e reaming instruments, • e renming tochnique uaed by • e suqgne~ end •be eh~icJty of • e palvis. Foe • i s reason, it is reolxamemled • i t an scCUnlto i~cel•holM Irial be uned to menmre the size of the implantation site. indepa~k'nl of the nomiMl size of •be hemispherical reamer.

Research or tentitmimal support b u been received from H o w n ~ i c a - O ~ m J c l Inc.

Paper Ig32 RISK AND BF.,NEFIT OF C E R A M I C IIEADS YJ. l~mqainJm, MD, Hew York, HY, J. A. Roddpcz, MD, AJ. Maorkllo, MD, C.S. Ranmvat, M D

Polyethylene wear is • major enutge of par0cuiste debris in total hip anhmphmy. The role of these paflicles in the initiation of pedpme*hetic bone lout and mep¢lc loosening compromises the longevity of hip Impinnts. Tbe nudn objee*ive of • i s Itudy wex to Itudy • e effect of • e femorel bead In • e genre•ion of pdiy~hylene wear debris utilizing di~tized radiographs. Paper ID0

THE STRENGTH OF A CEMENTED ACWEABUL,AR LOCKING MF-L"HANISM Rumell Meklrum, MD, Mo6//e, AL i n • r e d•d im• Ace••hoist nevblon suqgc~ is • common p,j~ddre •e* can.flea slgelfkant putlem morbldity. To midimize • e modotdity and bene Ira8 samdated w i n u cumpicte nee*alxthw m v l ~ nevereJ advocate cementing a polyethylene lin~ into • pomua ~t,-~l ace/ahoinr shell when • liner exchange is not pueafl~_ "ntis ptocedere is typically done in • well-fixed.shell when • broken locking mnehenism is fmted. It can aino be dine when marhed pefye*byicne wear is Idea0fied aud en ineffnetive locking m,~an~m is Im=ent which ixcvems exdumge. Early "oulmmc" ,,q~,,~. of thYmixonedme shaw IXOmt~ hot • e me~h.-~t I t m ~ b of this "esmemed •cking n ~ - ~ - ~ - " bes .ever been m e ~ d . Tbe pulpote of this Itudy is to qenntitste • e pneh-ont end icvet.ont ~ g • s of a cem~ted nee*•hoist Uum and enmpure •urn to t enatemForuy uacumented n e m h o ~ syitem G'rilngy). ~ Methods: An i l ~ p a a d ~ t lab was t~led to m e n . r e Ihe pu~-~tt lind level'-out ~,ength~ Each ~ m e n (ihall ~ line0 had the same ontor di•~e*er ne the otbere ~ cual~ed of • HGII (Zimmer, Wlrsaw IN) hemispherical p o m ~ ~ t e d aculahoisr ~all made of commercially pure titanium w J • • Trilogy (Zimmer, Wanutw IN) potyethyknc iineg. The Ilnera were ~ e d •ppmpdalely for an In•~.,--t,6~,~,4mm-nement umnlle. Rongbe~ng the concave netf~we of the ~ i n r sbell end the enww.x sugf•ce of the liner w i n • high4peed Imre was done to pmmo~ cement Inteldlgitation. Third generation cementing tnehnlqeex were followed wbea the liner was secured to the cup. Half of the tpaclmem were tested in one of the standenJ techniques for pneh.out of icvor-out m~engtbe. Push..ont •sating wex dene to m e a n ~ • e f m ~ s needed to ~ • e nement-me*aJ jntorincc, and the lever-.mtt testing was done to measure the Itrens• of the enmem-linor interface.

MA'rg.IRIAL & M g r l l o l ~ : 52 me*cbed paint of patients who underwent total hip m~tmplaity with • minimum follow-up of 4 years ~ ~ by standardized clinical and radioBraphic cvaJuations. Tbe only dlffeRnee betwenn • e two ffteupa w'gs • e Winuu'y bearing surface, whk:b wex s i • e r oertmic on pdiy©•ylene or mend m polyethylene. Wear me~su~-tTgnts were determined utilizing compater.assiited vector wear analysis and edge-detnetim me*hods. The radiographs were aim evaluated for evidem:e of oe*enlyals or asep/in Iomenlng. RESULI~: There was • ItatiiticaUy sigdifiamt difference (p~).05) in the mean linear and voinme*dc wear rates between • e groupa, in favor- of ceramic on polye*hyicnc 8nicule*•M. There w u no sigdifiexm difference In the rate of m~colysis or anep¢ic inenonin& Six patients w i n ceramic heads had to ho gevised due to femond beed fixcto~. C I J ~ C . A L RELEVANCE: The supudor endy to medium-term wear char•e-citrics of ceramic on polyethylene hip aJdiCUle*icashas the puteatJld to markedly improve the Iougcvity of contempcmuy total hip •r•ropluty. The p~blem of ceramic head hlCton: bewever has to be eliminated in order to e*lain this goal. The utilization of c~'Jputer.msiited methods of wear c~imaticu on digitized radiograp~bs provides • ttophi6ficated tool w i n Ihe paCential to pfedicl wear pattorl~ and possible early fsilun: of these implants.

Paper I 0 3

PATELI.,AR RESURFACING IN T O T A L KNEE A K r l I R O P L . ~ ' T Y M l d m d A. J_~-.~b-_ _ MD, k l # A ~ e ~ MD, James F. Wenz, M D The peqxwe of • i s Itedy is to I~wkie en in~'lmedisle m repo~ of ore; I , ~ 0 i m u in ~ i ~ ~ l he' n=erfm:in S ,w,J performed ia 77~ of • e putients and mmpm: it to patients in which the patsilne was not nat'faced.

Pmmmm ~

Between 1186and 1/95,1,283 total knee anhmpin.~= wen: performed.A minimum 2-yeor follow--up wne •vaiinbic in 1,153 patients.The dingnnein wen OAth 865 putlentS, RAin 186, 46 pu. spucifically with syatemlc lupuse*'ytbeme*mtet sad 46 with aveneulm' ~ i s . Patients w i n other dingnmcs

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The Journal of Arthroplasty Vol. 15 No. 2 February 2000

m

ancleded. The p~tellae wen: n;suftced in 8SS er, 77% of ti~ p i t and were not remrflced in 26~ 23% of the pt~ The ledicatiem for rettinlng the p*tella induded the onadltion of ~ c a n i l a ~ the age of tha pt. and tha cmglltlou of the buoe haneath tftecantiage of the pttetia.When m~urfaced, onmpononte included metalhached components ia 87 can~. All but 22 of the matsi-becked compmgnts were cengmed. ~ gemalning compoonms we:e allplastic.Clinical fclinw-up ranged from 2-10 years with an average of 4.7 years. Overall resultsdemonmnded that 39 (4,3~) of the feint,faced psteflec mqulonl n:vlalon st~gery. This included 18 failed metal.bucked companetos or 21% of the metal-bucked total.Of these, 14 were seco ~ u 7 to pl•atic wear and 4 due to gme8 lowering. 21 of ti~ ocmonled patellar componenl~ I~quiRd revision sulgel7 foe Ioouming and/m" o~npooent fnctuR:. Tinl lelxeaentod 2.6% of the cen~nted patellae, la 8dditioa. 3 patellae n:qohud revision surgery after spontaneous frecmre of the patella itself about the petefler compoeem. Six pet. (2.3%) in whom the patellae w e ~ not rumrfaced required n:vtdon mugery. All of these pts. had ~ t l a . Four of these 6 pet. had gmmly mbluxing or hanldy disJoc~ing patellas that requin:d fomud soil tierue pmellofcmond realignments st the time of the patella n~.f•clng. Nong of the pi~ with inflanmudery m~hrlthl in whom the petelthe wege not raurfagud wen: clicltally symptomatic. No patellae iq~oalane~ady fractmed in the group that did not receive patella implants. The overall Knee Society rating sy~em acmes were a ~ ligni ftcantiy Wffe~nt for the with peteila impbms ~ conapar~ to I ~ without implants. Range of mo¢ton was ~ nee atathalcally diffettnL

P.~mim suggmt tiud not n:~rfadnlg the petell• b a viable siterontive in pte. with infltmmatow and ,~wm,thrftb of the knee..

Paper ID5 LONG I'gRM RESULTS OF TOTAL KNgE Ag'I~ROPLASTY POI.JLOWING TIlE USE OF S O F t TISSUE EXPANDERS Fred IL C',-t-,-¢, MD, New York, NY, Stephen O. Manifold, MD, Susan Crsig-Sontt, MD, W. Noeman Son•t, MD Imtr~ivctbut: Proper wound healing Is permuonm to s " ' ~ ' ~ 1 t a l l knee 81~tmpl~y (TKA) but can be jonptm'~zed wbett p~.vlous Inclzions and ~ n g an: pcgsont. Tbe purpme of thls mudy w ~ to revicw the long-term mtoha of TKA following soft tissue expaasion in Fudcms at ~ fm wound failure. M ~ IV,.emy-gne p u t m s f30 Imam) who ondawem anft • i s l e anpandm ~ o ~ to Tg.A w e ~ m mqx~lvaly t'oviewed. Then: w~'e 13 ngn and 16 wemen with an •venlge tge of.q6.6 yearn (nmge, 33 to 82 yams). Tbc Incinonce of wonud complicztintm wan mcoedud for all pmicnte, B weU ~mTbu KJge Socicty c ~ k a l mdng ~ p,_~m,u,~.An m~enqgeof 1.9 timoe anpmMem(nmge, I to 3) w~e uacd in anch Iman Ixkx toTKA. Minor woned oemplicmlons occumd foUowing 23% (7/30) of t ~ tJmuc anpemiom and 17% (5/29) of rig anhmphaaleL One 0 % ) mawr wound complla.ion follovml t i m e ~ ~!quing M~ndonrnont of Imee mlhmplaaty. No major wonud cemplications txxaun:d in thoee IX•tiaras who onderwem TKA. At an average fohow-up of 34.4 memha (nmge, 24 to 64 momha), the ~wemge Knee Sodety ~ore wan 83.7 (range, 29 to 9~) and the average range of mo6on wM 1.5 deglgts exteasion (nmge, 0 to 10 ckgltan) to Iftl d e ~ flexion (range., 45 to 125 d ~ ) . lutd C.ol~hldo~: Tlasue expanders have been del:ffoed pfevio~Jy for Ix'~q~ting wound fsilrm~ however, tids is Ibe thrg~t long-term study ova•rutting the sttcce~t of tlds technique with TK/L The results demmmrate that tissue expomdon can ~mocessfelly prevent catg~rophic wound com. plicatinm following TKA and avoid dlafigenng anti tissue

Piper #34 AN IN VIVO DETERMINATION OF CONDYLAR SEPARATION IN SUBJECTS WEARING AN OSTEORAKrHRITIC KNEE BRACE DURING STANCE PHASE OF GAIT Dmql~ .4. Dmm~ MD, Demver, CO, Riclmrd D. Komimek, PhD, Eric J. N o . c u t , MS, Jamez 1". Bnuaely, II

INTRODUCTION: Pleaently, ~ are multiple nonoperative techniques a suq~on can use to alleviate the ixdn of an o~eomlhlittc joint including: oral medlcatiom, physical therapy, injections and off-loading Imee b,TL,~. Tbe ~ v e of this sl~ly Wits to •l~y'zz lubj4a~ onder in vivo, dyuamic conditions using flutnx~py to determine if off-londing Imec bngcs actually sel~rgte the femond condyle from the tibiae plateau dudng the mid-~ar.,ce and hecl-atdke phases of geJt. M g r l l O l ~ : Fo¢ly subjecte with substantial unio0mpartmontal ¢~t~lhrltts were studied under fluom~oplc surveillance in the fmmal plane while perfmming normal fail on • treadmill. The subjects were petit•t• of one serKeon and wen: all clinically diagemed to have merked unice~panngtoal dcgonemtive joint ~ mtnowing, initially, each subject ~ ludged to perform normal gait on s tmedmill undcy flummcopic sut~,¢ill•nce in the fronUd plane. An ofl]oedin S cetemNhfitic knc~ brace was then fixated on the oateoanhrftic knee joinL The subjecte we~ thon Imked to walk on level g/oued while wearing the brace to rate the effectivene~ of the brace in silaviating pain. The subjects wen: th~Cl asked to pefl'Om no(11~J gait on • Weedmlll while wea~ng the brane, Snoot•lye fluoIononplc imqF* of each patient at mid-at•ace and heei-stfiha (with and without • brace) were downloaded to s woO,at•rio• computer. The captured flontogopic imges w~n: then analyzed using digitization.

Paper 1136 IN VIVO KINEMATIC CORRELATION BEINVIEEN CONDYLAR M F T - O F F AND W-JVlORAL COMPONENT ALIGNMENT Richa~ D. Komlate~ PhD, Dow~, CO, Giles R. Scuded, MD, John N. Inutil, MD, Kovtn Math, MD. Mark E. Samjak, MS INTRODUCTION: Recently flnofmonpy has been used to detormine the in vivo kinematics of to•el kaee •rthroplasty (TKA). These luudyses have ~poned that femood coudyler lift-off can occur during welght-~tdng activities. Although the phenomena of condybu" lift-off has been documented, it has yet been correlated clinically with verying surgical p a r a m e ~ The o~ective of this study was to analyze subjects having • T K A to delermlon the incidence of oondylar lift-off and con=late lift-off with the alignment of the femond component with n ~ to the eplonudylar exit METHODS: 'lWetoy-five mthject~ implanted with e poatedor stabilized TKA, were asked to perform ~ v e weight-bearing deep luge bends while under f l ~ c surveilinnce to maximum flexion. Each subject w u clinically anoce~ful (HSS>~), without having any ligametomm I~in or Suit)'. 21) f l ~ images were then o~nvened into 3D using I fully autom~ed computer mudcl-fitting technique. Each subject wls th4n3~ fm the incidence of condylar lift-off. The five subjeom having the maximum tmoner of lift-off wen: lumdyzed a m¢ond time for compedsen. Each subject was then analyzed using competed tomogmphy (CT). Using digitization, the angle between the femoral coedyics and the eplonudyl~ • i s w~t meJsured and correlated with condylar lift-off.

RESULTS: Thitly-fonr of 40 subjects (85%) judged the emonarthritla knee bract effective in ~lucing [mee pain. Six of the subjects (15~) wcn: not able to dereer • change in knee pain. All of subjects wen: overweight resulting in suboptimal braee fixation. "1hit•y-one of 40 subjects (78%) demomtwated irticular aeparatic~B of the degem.-lative knee coerlpmlerent at heel-•trine lad 28/40 (70~) at mid-mm:e, l~lrty-one of 40 subjects (78 %) expedeaned an angular change at heel-strike, while 37140 experienced an angular change at mid-stance. The average mnonnt of cflenge in corulylar tqxtration (A) was 1.7 mm (0.0- 6.4) at heel-atdhe end 1.9 mm (0.0 - 7.9) at midis••ace. The average amouat of dumge in angle~ w u 2.0 degrees (0.0 - 4.8 deBrees) at beel-atdke and 1.6 ~ (0.0 $.1) m mkl4Um,x.

Rlgb'ULTS: The inddon~ of onodyler lift-off w ~ significantly I m for ~abj¢cls in this study oompmed to p~-vic~ flonmeonpic studies. Oa]y 10/7.5 (40~) subjects experience condylar lib.-off. The maximum imount of lift-off was 2.3 mm and the average m o u n t for subjects experiencing lift-off w B 1.4 mm. When reansiyzed, the five mbjeO.s expedonclng maximum Hfl-off had dmllar lift-off vaine= for beth tdsil, occurring at the wme flexion anglez (1.5 & 1.5, 2.3 & 2.2,1.5 & 1.8, Z I & 1.6, 2.0 & 1.6 onzl) (p<0.0l). There was ~ a dl~inCZ COIr¢lation between femoral component alignment and condylar lift-Off. Using CT, it wan de•engined that 74% of the subjecLs had • onneintion betw¢on condylar lift-off and real•ligament of the femoral onmpoonnt relative to the epicoudyler axis.

DISCUSSION: Previous biomechanlczl atudies have documented exce~dve iced• in degenerative compenments of petitnet with unlonmFertmonud erthrmla and associated angular dcfmmitie~. Ofl]oedinlg braces have been devcloped to attempt to k:*m:n load* In the degenerative o n m ~ n t with subeeClUentreductions in knee pain. This pvesem atudy demooatllt~ in vtvo micuher separation of degew..rative Imeg comptnments can be anhicved with oll]o~ling brKgs with suhaequem subjective Rlinf of knee pain. These bnges may have limited effectivettes in ~ pminnm.

DISCUSSION: This ~ t atudy has determined that then: is • coneintioa between tig alignment of the femond compouont with i~pect to the cpicoMyinr u l a and onndylat lift-off. Than:free, it may be impmtant fro"surgeons to ulc the cpicondyler anb to align the fcmond component dudng imrge~ to minimize the Incidence of coudylat lift-off. The clinical relovatge of this study d a w s that the aptcondylar axis is the cong~ podtloa of the femonti compononL By setting the femoral component along the femmal u b surgeons may leduce or negate condylar lil~off and in turn Rduce edge loading of the polyethylene st•inca.

Rerauoh oc imaitotiomd support h ~ bee• received from Bleds~ Brace Syatenm. Reteal~ Of institutional suppo(I has ~

received from ZJmmer Inc.

Paper 037 REVISION OF FAILED CEMF_.N'rLES8 POROUS-COATED SOCKEI~: CLASSIFYING AND MANAGING POLYETllYLENE WEAR AND BONE LOSS William J. Mlalo~7, MD, St. LoaD. MO, Harry Rulmh, MD, ~ y ~ PIpro~y, M D

° Dreamam mmm~ af ~ ~mmmm~ ImMbm

~m maW~l

Int,--~J,~,mm: The puqx~e of thb laedy la to n~ort on oar expedonce with rovidon of failed ~ n t less sockets and to introduce a new classifleation system to aid in numagement decisions regarding le-opergtion for polyethylene welt ted pelvic ¢meolysi¢

Abstracts From theAAHKS Ninth Annual Meeting M n t ~ a l ~ & M e t h o d : The n~lullS of 17A revi~o~ ~ were clmaifmd nolo ore of three catelpmtua depending on the radiographic slability of the porous coaled M)Cll immpcmflvety mmi the ability to mpll~e the polyethylane line: ~ I case; ruble soctlcet, lin~ repimmnble, ~ il case; so~*t s;Ible., liner no4 replncuhle, ')~jpe III c ~ ; socket Ino~. A ~matmcm Mgodthm was developed us follows: mmin the well-fixed shclh debdd¢ and g r ~ lytlc defecu and mpixce the liner in ~ l~ remove the well--fixed shell, debrid¢ und graft lyric dnfccts and mpisc~ II~ liner in ~ 1~ remove well-fixed ahetl, d~dd¢ and g r ~ lyric dcfeets and rcvi~ with a larger ~ cup in "PTPeII c a i n ; and remove Um Io~e socket in ~ Ill cases and revise with either s pontus cup or uti-pmlru~o uagua mad cnmemed sockets depending on tbe delpee of bno¢ Io8+. Follow*up ranged from 2 to ,5 y e x ~ Remdts: In the ~ 1 cues, all 40 anckets remained ~ at final follow*up. NO new omeolylic lesions v~re seen and 1/3 of the omeclytlc lesions n=olved. TI~ remaining 2,e3rd~~ in aizn. In aJl 28 ~ II czscs, II1¢revlaio~ ~ done with • larger porous Cup ~ at final follow-up ail 28 s~x~kets m~dned robin. ~ wzs no rccun~nt omnolyllc d~fecu nmnd. In 2 of 6 "P/pe II czsua, the cup w u medial to KOMCPs line and • p ~ f l o r column defucl was c~atnd wben the shell was ram)red. In 42 of ~6 "l'~ne m ca.~.,, can~.llous bm~ geoft was u~d to ipral~ czvfuuy dofects and II~ socket vnm revised with a hug~r porous cup. All 42 ren~iand ruble at final follow-up. In 6 ~ Ill a bulk allolp~ was used to n:cx)~mcl tbe pomeflor column and the m0cket revised with a pormm-noated c~p. One of 6 Inilnd. In 5 l'ype III ~ canccllmm boe~ was uand to grai~ the defec~ and an Intl.prouruaio ring was ui~d+ In the remaining LM~ cases, atl~:lurel bulk ailolp'ldix were u~d with an ~ All cigbt cases using reconsu'uct ino tinge have remained s
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Molll~b - Remdts: Fomtsen mvixkm THA indus an Impanlion gndting technique ~ Imrfonn~+ Minimum fullow*up was 4 years. Pm..4~emtlv~ disgnoml was ~ Inomming of c~r,~nl~ femoral ateml in II cases, and unceme:med m m in 4 el+lOS. 3 reviaion ~ ~ perinlmcd truing stems I~m 1 50ram in Icul~b, ~,: n:mMnd~r milin~ sums from 165ram - 315ram In length. Neck I~gtlm of the m ~ n o implants ranged horn 40 - 80ram. including 4 uak=r repixcgmenm. Undtspisccd lotto-operative fractures occuned in 2 cases and were successfully IJrmttsd with ccrcl•~ wil~e~.Thare w~re 2 pemoperaflve fmcton~ buth in imlients with smms less ~ 150ram. Both were ~ __"~'fu~ Ily tlualed with pixti=i and noixy a i l ~ At moll mcnot follow-up, all Felieuts were pldn-~... All peth~Its were Iml~lllll~g uollmited dhmmo~ ~ i~iems n:quirnd ~ All m : m were well Oxed mdiographically with no evidence of pmgmsaive mdlolmmnclel or Iml~demm. The g r ~ appeared to be Incorlm~ng. The surgical le~aolque ommd~l of I) ~ of psmvtouaiy failed implant and cmr,cnt; 2) plnc~meto of Celclage wins mound femur into whk:b graft will be Impeand; 3) inlrodoclion of impa~nd ailoglMt. 4) mdinlly Impeodng with topen=d, polished, ~ smdght impantum to 8 distono: into femur that pennha firm ~ngage.mmmtwith emtuateal codex for • d ~ of at le.a~ 3cm.; 5) us,= of polished, s m i t h hvoach~s to cz~atc final ~ p ~ of cavity; 6) trial reduction using p o f isbed Ix~ecbes, and 7) inserll~ of implant with 3rd 8coemino cement technique+ Dl~undlon / Cmudmdomm T I ~ repo~ describes • new technique for Impactino Oufting In revisino THA. Thix stody suggests that the use of Ino8 fcmomi tsems with vmiabtc I~mdm=k lanlpha and offs e t in coajunetion with th¢ imlmcfion grafting ~hnique m y reduce 111¢incidence of mbukl~c~ fcmorai ~ and dislocatim~ that ~ occur wi~*n thix l*~*'laiontechniqm: hi used with sbo~ 13ol-

Dik-uml~: This I~.atmeto aikq)lr'ilhm has helped the authors suc~ss~lly evaiume and treat • I m ~ lewes of pellents with polyethylene w ~ r and pelvic o~moly~ in mmoclatino with porous coated a<~tsbuhur components. Cup mabllily and knowledge of I ~ implant th:aign are Important faclors in surgiod mmmgem~.L

Cumufumt or employee of Smith & Nephaw, Inc-

RoyaiUua ~

~

received ~

Zimm~r I~., I~1 [ ~ y

Inc. of Johnsog & Joheeloll. l~iper #40

Paper #38 SURVIVAL MECHANISM FOR ACETABULARRECONSTRUCTION CAGES Wayne G. Pmpcua~, MD, ~ n e / ~ IL, Todd D. S ~ d i x k , M D

~:m with or~ of sL,x~urai MIOgel~ for rccommm:lino of severe acel,tbular defects in revision ~'th, opinaty has le.nd to alternative mcOmmK=inos..~mtalmlm ~ n o uag~ have Imem proposed as in aitenmlive. With shorx term follow-up, • m¢chanixm of failure has been evident while others have _su,'o~_ _ ~ From 1994 to 1996, 24 Papmsky ~jpe m A (10 oases) m~ Paprm~ "13+pelira ( 14 c m = ) (AAOS "P/pe Ill and IV) K=udmlmr d~fecls in peliems of avenge age 61 ymus (M-83) wme reconMmcled using an i~etabuixr recoanlru~no cage. Six of the ~ O a n had In ~ pelvic discm~Unohy. AJI patients had m l l i z e d ailognd~ to ugm
HIGH FAILURE RATE OF ALL,OGRAFT EXTENSOR MECHANISM RECONS'rRUCTIONS FOLLOWING TOTAL KNEE ARTHROPLASTY Seth Leopold, MD, El Paso, ~f, Rk:fuud A. B c q ~ , MD Wayne papmaicy, MD, Nelan~ Omidanu~ MD, Azrou Rc~al~-ib MD

ImltU,dlm~O~: Disruption of the ualemor mechanism is an uncommon but d~aslming compllcalion of toni knee m p ~ t mbmp~._~y. Several techniques have been reporlnd for xrecommuctlng the exla:mt,or n~mchanisre fuHowing Imal knee anhmph~y, but to date, thc remdm of any one method have nm been CmTObOmledb y , mm~xl group uaing the m lehniqu.e. 'lq~ m~qcaev~dual=i the ri~olts of exleanor m~d~mism renomL,'ra*c~on uaing Mfugn~ Ind the method dmcriT0cd by ~ a l . M e ~ d l ~ Seven n~omm~tions in six pmisnts wore perfom~l according to the technique d~crthed by Emcmno ~ al., using • bnoc landno-bnoe ailognd~ in all cases. This method included dKid internat fixation of Ibe libtai mbe~ule~ n ~ l , teaMo~Jngof the geldt to allow some fluaino (40* - 60*) o~ th~ ruble, leaving ~ ailogr~ p~elix unm~url~nd, and immobilizing the knee In exlmmlon for six wuak~. Patients were followed pl~peclively ~ g U~ Ho~itsl for Spe~ai S u ~ ~ I~on~, patient's e x l e ~ r lag+ Iml~llllOlry Isaistive ~ required, lind ImbuixtoqffJ ~ ~ m ~ I~.Z:orded piP.- ~ pem-opemflvcly. Patients were ahm ,cmened for epmod~ of falling related to quadrlcepe ~ a k n m following the ~ o n . Follow-up nveraged 39 months (nmgc 6 Io 115 momha); beczusc hdlur~ of tbe mcmmmm:lionofltm occurred early, • minimum follow*up period of six mnolha was umd in this mdy.

ReuaNm All a~.vea mcmtsm~imm are mtnd as clinicM F-liun~ b i r d on a pemimmt or resonant e x l e ~ lag of grimier thin 30 d ~ g ~ all but one require full-tim asaislJve dcvieel for wllking+ five of the acven have had episodes of falling documented in Ibe medical renold bocau~ of giving way Of the •ffecled kane. Foar of the reco~ru~dolM~ were revised, ot~ with Inothcr ailogmi~, and thrl~ with n medial gastrm:mm~lusrotation flap. Three 0~ber clinical fullure~ have no( been revised. Tha mcan uatemor ixg at Fumi fullow-up w ~ $9 degnm~, Ind the nman find kmcem for the entire Ipnop is ~2 not of 100 (.rome). Diacamfua: Underlenaioning of lha ailo~ recnosunollno et surge~ and ailolplfl ettonuatlo~ bo~ m y have played a role in the pmleuts' ianbllity Io regain active knee uat~nu0dno. Altsmmive tsolmiques of cxtsm~" m c h a o l m n~noatnx:(ino, or modlfiualioem of this technique, aimuld be consldel~l in me of this (rift]cult pmolum.

Paper #41

Paper 139 RADIAL IMPACTION GRAF'FING IN REVISION THAn A NEW TECHNIQUE & RESULTS USING FEMORAl. STEMS OF VARIABLE LENGTHS AND NECK OFF-SETS S. l)evkl Stulbeq~ MD. C/u~ag~/L

lnlroducdom: The Jml~c~on gra~Jng leclmique appears to be • vefT useful methyl for revising fulled T H A with exlenaive uavitsry pmximai femoral ~ loss+ Howewr, its uan with short, polished s ~ t s has barn mlsocleted with femoral fractori~ slem subaid~tm and imubility. This mudy dalc~dbi~ • new anq~al impeetino lpmfllog tanhniqi~ llnd reports lha results using femoral store of variable kmglbe, with variable huacl-n~k of~'ts and Icm~lbe.

• D ~ ~ m~ddq ct vlhm~ ~ Pm~mn m htshm

TIBIA[. BASEPLATE WEAR: A MAJOR SOURCE OF WEAR DEBRIS WITH CONTEMPORARY MODUL,a~ KNEE IMPLANTS

Gorzrd A. IrJ~_ . MD, A l ~ Chriml J. Sychtcw., MS

VA, Auaed Rao, BS, Smmdn Louolci, MS, Debomh Aren,~:~n, BS,

Imlmeduetfum; (~leolysix has increuand with the Jnlreduction of medul•r tibiai imm:lX~Several stodJ~ havo id~ltified backside polyetbyknc wear, and one stody stslislicaily smoclaled it with tthtai omoly,ais. Another stody him shown that comemporu~ modular tthixl compnoenl locking reechanbms have failed to climiuate mic~-omolion. Our I ~ l y uammJned medu I-, libiai compommts eet~ved et revision p m o ~ n ~ and from anlOl~les to d~=naim if tibixi Imcphac wear uau~d aiplt'mmt wear debris. MmlerhdE 29 modular tibl -I trays with val+oua romp-fit and Ionpe4ndiproove IoclcJng me~h*nhums wcm evaluated for buaspixle wear. |replants,/m .~m 6 montha to 13.2 years, included 12 uadavmic mlri~ and 17 implants ~thnd ILlreviaino laUl~'~~. Tibl-I iaseN-tnty slablHly was receeded by meanm~ng ante~'ior-postodor ~ medlai-isteml dixpllccmcml with i n cxtslmome4er. Insert mJ<:ml~lion values m compered to 9 unimplanted cnotrol specimens. Visual i n ~ o ~ and slenmenopy (50X) w l ~ u~d to detenolr~ • ~ I~ (Orld~ I-4), besod on the = t • g e of wear

254

The Journal of Arthroplasty Vol. 15 No. 2 February 2000

Autho~ dutrac~rized modes Of wear through SEM uJdys~ and evabmted dmnges I~ ~mrftge Ioughne~ with white light profiinmct~, Remit•: 15 of 29 compommts had Grade 4 meud w~tr ( > ~ ) area of involvement) ¢omhatng Of exten~ve me.asof wen" polishing in dlscre~e pslten~ ("stippling") tint con~qx>eded to the iwedomimint direction of micnwnotiol~ Nine compooents had Grede 3 wear (10~-50% agca of invuivermmt). in m of pitting and l¢~mtd~ing,imffan¢ roughne~ i ~ more then Iwo-f~ld. SEM co•firmed melai removal in "stippled" and pitted ~ panicuinriy with titanium bseeplates. Mi~mmo~on >100 miomm occunud with both tongue-aud-gronve and mutp-fit deallpm; in many cases > 1000 mleloni of micl~notinn was ol~crvcd. There w ~ • highly I d ~ t ~tion betw~n bemeplatewear and micmm~ion vldues with an R: of 0.81 (p<0.fl~01, 2-tailed ~ Cog~|lKinfl). Cmgludm~g Tlbisl hese.piate we~r is a major sou ~ Ofmetal and polyethyler~ deinb after toni knee minopl~ty. Either the in~n locking ~ mma eliminate miommodon og the tibml he~pistcs must he md~igned to minimize psrlleuh~e debtor.

Psper 844

TOTAL, HIP AK'rHROPI.A,TrY IN YOUNG ADULTS FOLLOWING FAILED TRIPLE INNOMINATE ~ M Y C'hrbtopber L ~ MD. Saltl.,a~ Clo~ UT, Harold K. Donn, MD Introduction: When dguificam degeneration of th~ hip occurs after triple innominate cmeotomy (TIO), tmal hip a~thmplns~y (THA) b rec~r~meeded. Because "rio mdiRcts the anetsl~inm into • more anatomic and blom¢chanica]ly Imperiog po~tinn, it is commonly timught, although unploven, th•t 'I'10 fK'ilitat~ fmure THA. ~ p o ~ of thb seedy is to compare the n~uil~ ~d'THA after failed 1"10 to an age and ~¢x mstd~d group of pstierlts who undenvenl THA without prior'nO. Melhudm Eleven pstients with 13 hips who undenvent THA after • failed 1"10 wen: identified. The average •&n:I t the time Of THA was 37 yenra (range 16-~0). The~ hips were evaluated Ima)psmtively, immedialuiy po~oporativaly and annual inter•is with I Hawis Hip Score (]'HIS) and radiolpal~c analysis. In ~dition, operative time ~ ¢~imaied blood Ic~ (EBL) were recorded. These resuits were then compsred to•n aguandsex matched gmupof 11 psticnts with 13 hips who undenvent THAwithc~tt prior 1"10. The avmge follow-up of the patients who underwent THA for failed " n o wus 36 months and for the control Broup was 28 months.

P~per #42 CEMENTED LONG-SlT,M REVISION T O r A L KNEE ARTIflIOPLA,.qrY AT 10 YEARS FOLLOW-UP Robert T. ~.~_.~.t% PAD,Rod~ter, MN, Aden D. l b n s s ~ , MD, James A. Rand, MD, Aedmw L Wh~ey, MD Intr~lm:aloa: Bone ic~ seen during mvialen loud ~ arthmpiasty (TKA) o ~ n requir~ the use of additional flx•tico with intramcdulimy taemL Whetheg these stems should he eemented or pren~fit remains conttovegalal. The pollx~e of this s~dy wan to evaluate the ralltively Iong-telm lenuits o f l o0oseculive group of patients who underwent revision TKA using enmented leng-slanented ix~les~or s~bitized compooen~ Msterin~ mml Methodsx From 19~1-1989 40 ccme~ted poeacriogstabilized revision TKA's were performed at the authors' lztstitution in 35 pstients using the stenmled kinematic stabilizer pro•heals. were 19 me• and 16 women with • mean nge of 67 yr~rs at the time of revision atthroplsety. The underlying diaguods was c~tanerthdtis in 23 ~ thenmatoid arthritis in 16 knelt, and post-tranmluic imhritis in one knee. No pstlenm bad masdve periplrend bone defects and noc~ required smlctund grafting. ~ mean follow-up w ~ 9.9 ysa~ (range 5-17 years). Oae p•tient was lem to F/U keying 39 ~ in 34 pstienm fm review.

I~mdta: One hip in each grOUpunderwent revision for dialog•tin•. '~Nvoof the hips in the "nO study group ned one hip in the ccm~ui gnmp ~m~dned ix~tolgmtive dislocation. At final follow.up, the avenge HH$ in the ~udy group was 76 wbiie in the control gnmp it was 88 (p<0.05). Notably the pain component of the HH5 in the study ~poup averaged 32 while in the contlol Boup it ivcragl~l 40 (p<0.0~. Function acorn hetween the two groups wel~ similar, with the study group averaging 37 and the control group averaging 39. Radiographlcally, Ihere w u no difference belween the two g~oups. EBL for inn hips perfmmed fog thiicd '1"10averaged 721..(:¢ while in the control group the EBL averaged 448-cc (p<0.05). There was no differen~ in oporative time. Dleeul~ou & CoadmatoB: It is helleved that the anatomic and binmea:haniad lmplovement of the hip Minr "nO fadlilates future 1"HA, especially with rege~l to placement of the m h o i n m and hip f~m:lion. The Rauits Of this study tedleate that, although the r•dins~tphic R~tits of THA after 1"10 •re equivalent to THA without prior "nO, cJinical n:~lts In t©~msof pain raliof and the technical difficati. ty of THA arc not equivalent to n~tits in ycenqgadult patients who undergo THA wtthoot p~og"nO.

Paper ~4S

Remdls: The YmeeSodety sexes a v e r ~ 38 puints ~ to revisions and imwoved to 84 points •t final follow-up. The pl~tevidon function m •vernged 47 points u d Improved to 65 points •t final follow-up. PRopsmtiwly Ihe m a n ROM ate ~ 9"P ('25"-110~ and improved Io an •vcrige ROM arc Of I01" (90"135") at final follow-up. Ouly ] knee (2.S%) t~quired t~-vbJon Iegond~y In ueptic looseolng. ~ t I-Oialcon)pol~nt WaS Itx~ mdingrqddenlly hot was not sympIomalic enough to con• ;der revision. No other components were redlog~phkuily in~e. Thee mher knees ('/.7%) required re-revision: 2 fog deep infectiott ~ otg fog • periplosth~ic tibia] fnglure. Implant survival free of revidon w ~ 94q~ st 10 yenm. ~ a ~ l o d o a : ~emented stem flxmina in ~viuion to~l knee erllu~plasty providea exeelicnt clinical l~lults with dmable flenthm st an avenge Of l0 yMra of follow-up.

Paper t 4 3

"G[ELID.WING"OSTEOTOMY OF THE PATELLA IN TOTAL KNEE AlgrlIROPLASTY Kdly G. Vlnc~ biD, LosAngele.~, CA, Dennis C B l a n k k ~ DO, S o n G. Otaulan, MD, Peter J. Thedanl, MD The exten..~r mec~nism aud patella continue to ~ pmbl¢~m in revision and primaty knee mhmpin~y suqgety. At revision, it is po~u'ble to leave • compstiblc e.Ji~ng psleller button, to remove and resurflce if udeqmlte bone remains, or to w.mov¢ • Ioen¢ button and Rshapo the psl¢ller bulten se • pstelisplasty. 'There h u not, however, been • l a t ~ o ~ y tointion Io the plobl4~l of • vel7 sc•phoid pstelis u is often anon with r.xtenaive csteolys~. This cup-draped pstelis t~(b to hug the lateral femoral oondyle daking dlMocudcm. It quite •imply does not fit ~ the femor~ condyh~ Fo~t pstie~ts in this series were ira•ted with a "gull-wing" nggJtsl osteotomy of the pstelin. This was perfmTm~ st reunion surgery in ~ and in prlnmry in one, All fc~tt l~ttlen~ have enjoyed centrally tracking psrellas on physicll examination and Mmrchant view fuilowing the uu~-~y. The NOWI~d for Spodai Surgery Imee sengi• have imwoved from an avera~ of 32 points to 75 points postop~stively. Knee poin has proven negligible in these amholetmy pstients, all Of whom sptadf~tily deny anterior Im~ psin. Rediolpaphic evehiation has ahown consuiidedon of the entenlomy with ommdly tracking psleHtr fragmen~

The Imgical tedlldque fm this astet~omy incledes the ever•ion of the pslelisr shell, debddement of all membranous interfan¢, and a simple enteotomy from the supsrlog pole to the inferior pole. This ctezte~ • medial end Imend piece Of patella ~11 Intimalely oenma:~d with the extemor mechanism proximally and distally. By cracking the oslenlomy end pushing its •pex towards Ihe knee and the two facets away f~0m the knee, • gull-wing shape is c~ated. This new onrmm~ •ccxxnmudates ftself well to Ihe Intemondyiar groove. This techhiqu¢ has proven = _,,','~,_Jfulin deaLing with the patient with • ~ thin, scapboid patella where re•eft•dog is 110¢feanible and the ablpe of the fr•gusem prevents c~ntnd I]lcldng.

" I~s0~ di.mmlq

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WOMAC SCORES EMPROVE PREDICTIVE MEASURES FOR TJA Dm4d C. ,~Vetn, MD, Syracu.w. NY, Rajeab IC Jain, MPH, Matthew 1". Ben•elL MD, Kevin Setter, MD, M ~ Roger-., PhD, P a n d a D. Franklin, MD, MBA, MPH, David G. Mum•y, MD Intmeh~tlon: To date then: has been little data that cow:eisl¢ gene~c to disense slx~fic outcome menr,ures. ~ use Of the WOMAC in conjun~ice with the SF-36 may improve the ability to predicl outcom~ after'nA.

Metlmd~ A prenpsctive study Of 189 pstien~ was uedertaken (97 THA and 92 TKA). SP-36 w ~ used to de~mir~ physical ~ p ~ score (PC:S) ~ 1 menUti composite tcom (MCS) p ~ and po~opsratively. WOIVLAC~ for imin, sill/•ms and physical function were determined. Fo~low-up was limtied to one yPar he•role previnus resean:h ban demomlrsted little dumge in seog~ trier tim time. ANOVA, PCerann coITeletion coeWIdenm and R2 for aan0d~inM •long with pvalm:S wen: calc~thiled. R u u l t g Fm'THA and TKA. pereopenmve ~ we• correlsted with Wroporative WOMAC pain score (THA: r=0.473,p-.0001,'rKA: p=0.409,p=.l~01), mtffrgas snore (THA: r=0_~p=.0001; TKA: ~-0.32~,p~.0015) and physical funclion soon: (THA: r-0.459,p-.0EOI;TKA: r,,,0_.~41, p,,.(0032). Change in FCS was he~ coerehaed with cbunge in WOMAC p h ~ u i function a¢o~ ('n'LA: r~0.464,p=.0~01;TKA: r~0.3~,1~.0034). Fog THA, preopenltive PC~ and MCS explained 21.5% of tbe variability of the change in PCS (R~,21.5%,p<.001 ). A maximum explanation of ?.5.2%of the vedability ~ obluined by eddin8 ~ t i v e WOMAC p~da and pby~dcal fimctlon ~ 01"=25.2%, p<.001). For TKA, i ~ l ~ . t i v e PCS and MC~ explained 30.5q5 Of the variability of the change in PCS 01~30.5%,p<.001 ). The addition of p~opsnttive WOMAC psin, stiffnel~ and physical function ~ improved the explan•tion of vad•bility to 36.1% (R~36.1%, p<.00l). These relationships wen: indelxmdent of age, geed~r and BML tT~u~S The generic health wrvey SF-~6 provides valuable infonufion for all pslicn~ undergoing TJA. The addition of the dise~x specific WOMAC improves the ability to ixedict tn:ndm in outcome. Fur•hen•on, the two iudic~ show highly siguiftenm congislico with each other.

Proper

ANATOMIC CONSEQUENCES OF SCREW PI.ACEMENr IN ACErABULAR RECON. S T R U C r l O N CAGES Cmri~J. ~ biD, Mimni, FL, Chrimophcr Cooke, MD, Ruben A, Hemaedez, MD INTRODUCTION; Luge •ccUlbular defec~ can he n:conmucuui witb eli•graft h i n t , c~nent or n:conwxuctlon cage~ Our objective wse to ~ the aveiisbl© cage dealgu,s and the anatomic co•anquentin Of r,~ew phiccmem while using aenttholer recmmngtion cages.

M E I ~ O I ~ : Every commen::ially iwalleble nag= w~l obtained from the In~ofsegu~m and implanted on cadaver hemipelvil= by an cxpsriem:ud ertlroplesty smgeon. One design was t~incted and implanted on l 0 spoctmemLThe cages wera flx,-d with sogewzthat were ISmm longer than what WaS mens~n:d with the tiepth gauge. The d i ~ i ~ file aglow tip and impollant anatomic slruct u ~ were n ~ . RKSUI3['S: Rim ~ tended to hit the extenlal ilian vein and artery. I~erio¢ly p i a i ~ rim •crews were me~ trouble~em©hitting extenud and intemui iliag veseeis as well as the obturatog nen,e. I ~ i n l tinge screws tended to stdkn the I ~ neulovaaculer bondle. Cages with long " r a d i i ear~ supe-

Abstracts From theAAHKS Ninth Annual Meeting rior flanges tended to place bowel and the deep dimumflex ilinc ve~eis at i~lC. Designs with oblum1or honks were found 1Opn=s against the ob~umor ncurovascular bundle. 25% of the scows p l ~ : d in the Ilion Ixxm, 64% of the rim scr=ws and 45% of the ischial sc:m.wshit • major mmelure. The pudendal nerve wan hit by 31% of the tschlal scows. DISCUSSION: The death quadnmt zones of Wmd¢fewskJ el hi. do not apply tO cages. Surgeons utilizing lhese cagns should not use screws latll~ ~ 15 mm in the upper quadrant of the llthc wing. Rim scrr,~ should be avoided. Carehfl meamrornent mum he done in the ischihi smcws since major structures me id risk.

Research or institutiomd mJl~Ort hss beau reenivnd hem Depay Inc. of John.son 8nd Johnson. Stock or sloch op~ons held in Depay Inc. of Johmon & Jobm~.

.

February2000

tsm-mndially 0nti antem-medially. Gapa Ima fium 0.smm revere ~ robndcally p ~ ~wifie~ mmpumd m 50% for the manually p ~

~

255

69% of the ~mrfeenof the cases (p~0.14).

ond Coadmionm This experiment dcmmmmtes fimt pu:pm'ation of the femur using conveotiomLI manual tecimiqucs leads to significant gaps between the pmelhesis and the femur. Robotic machining reduces the width of ~ by appmximuteiy 50% with • signifcaJrlt improvement in the "press-fit" of the pm~hesi~ Mcel impuaandy, m~olic prepuratiou incxeased the area of the implant anfinen I ~ t l ~ within 0.smm of bony cavity. This may lead 1Oenhanced fixation and a mdacnd incidence of omeolysin in the long-aorta.

Paper iu19 PRESS-FIT FIXATION OF A POROUS-COATED ACErABULAR COMPONENT WITHOUT SCREWS IN PRIMARY TOTAL IIIP A R T H R O ~ w n u t m L Gdflh~ MD, ClmrJo~e, NC, Thoman K. Fellring; MD

Pzper #47

A META-ANALYSIS OF TIIROMBOEMBOLIC PROPHYLAXIS ELECTIVE TOTAL HIP A R T H R O P I ~ S T Y (']'HA) IL Fne~dmmn, MD, Voo~ee~ N/, Kelth R. Bmokenthal, MD, Sankey Wiliimm, MD, Robert H. FfixlFmld, ME*,Jem H. Loaner, MD Par]poan: Despite oeveral agents skowinll eWcacy against thnxrthoembelic discaan, them mmhian no clam" choice for thmmboembollc pmphyluis in aleelive THA. The purlx~e of this study was to perform a meta-amdysis to define the eWcacy and anfely of the currently used agents for deep vcaot~ thrombosis (Dv'r) pmphylanls; namely, Iow-motenuisr weight hepudn(LMWH), warfm~n, upifln, Iow-dcae heparin, imeumolic compreuion, and placebo. Melbode: A M E D I INE literature scaluh from 1966 to 199~ w u pa~norned 1Oideotify all nladmTliznd control trials enrolling patients undergoing elective ~ compminll one of the pmphylantic agents of interest with any mher method of pmphyluis or plea:be. Inclusion mquit~l all studies to confirm DVT by bhatend vonography. Fifty-two studies, enrolling 10,929 patient& met the inclcaintl orheflu and were included in the analysis. The incidence of each of the following ontonmes was obLalned for each agent in the individual studies: distal, proximal, and total DV~, symplomatic and feral pulmomu~ embeliem (PE); minor and major wound bleeding; major nowwonnd bleeding; and mml momdity. The ahaolute risk for each enlaXae was detsrm~r~d by c~culotiug the number of events divided by the n u m ~ of putlents at risk. A general linear model with mndmn eflec~ was used 1Ocalculate the 95% coufldence interval of risk. A crmelaha of study by outc~ne was pulrfmmnd to te$1 homogeneity (combinabillty of s~udtes). Risk for each m,ttcm~e wan c~pured among agents and agnlnst placebo. Resultll: The risk of 1Otsl DVT was: LMWH=17.7%; poeumatic compmanion=20.7%; warferin=23.2%; tspirin~,0.6%; low-doe hepmtn=31.1%; mud phicabo=48.5% Lo<0.0001]. The risk of proximal DVT wan Iowe~ for warfarin (6.3%) and LMWH (7.7%), which were stelistically al~nifiCLqtiy different fTam piscclx3 0.5.8%) (p
InWuducflom: Initial fixation of cementiean aenmhid~ components remains o commveminl lapin In loud hip mlhmpisaly. Surgical options include the u ~ of sacwe" spikes, or s~c:zdh~J "pscm-fl" without ndjuvam fixation. This study p r o ~ v e i y evelm,lca the umeof Ixlan-fit ~ t J d ~ l ~ compoc,ems in 324 primary total hip arthroplantim. Mmtedafe u d M e t l ~ d ~ Of the 324 press-f• pulOd-ceotnd ~ t ~ u l ~ r components (Dundoc-DePuy) with minimum 5-yam follmv-up, 206 were available for radiographic ,rid clinical ~vinw. Average follow-up w M 72 months with e nmgt of 60-82 months. In all ~ the ac~uthular mml~oent measured 1-2 ram. Iluger than the fon] retorter used th Older to achieve en thitial pll~l-fit 8t the rim of the acelabulum. No scrawl were used to augment initial fixation of the cup. Results: "l~re wcre no intraopurative fractun~ in toy of the 324 Im=s'-ft acetsbuinr components at the time of surgnry. ~ t h e 206 ~ l a r : p u o e n t s followed heym~d five ye.m~ nooc were revised for ueprie Ioneoning. One cup with Imm c~tinueu~ mdJoltmeocy in Zones l , 2, and 3 with no cvio der,¢¢ of mQpmtioo, and w u clualfind u pusaihiy umsmble.These components remalnnd uymplomelic and no revlsiorll ~ pending. Four well.lured anetshulm oompuoemi were mvtsnd; one foe infection, cme for oaleolysis and two for n~xtrmnt dhdocalintl. Six e x ~ of the polyelhykno liner were porfm,med, oae for entsolyais with wear and throe for morn*matdisincatio~ role for femorlli compunent revialen and one for pudpmm.betlc f m u r f n ~ u ~ . Zone 2 mdiohicencks were pl~mnl on the lnitild x-my in 3.5 cases and 23 of thesehad resolved el final follow-up, Thirteen portents developed o new onliolucency in Zone I, which was n ~ present on the initial x-my. Ostmlyals developed in 8 patients (4~) and wns sees I~madly in Zone 2 al the site of the central dome hole in the cmnponenL DhieundloanWe conclude that plv=~-fI f xelinn of a purons-ccalcd i,celahulaf cmtlponent without supplementary fixation provides enc~*Afentihitild fi.utlon at intermediste follow.up with no teviolons for aseptic loosening. The favorable mmha of this technique eliminates the need for oc~*wz and the risks ass~:intnd with their u~:.

Royultles hove been received from DePuy the., of Johmm~ & Johemou. CommlUmt or employee of DePuy ~ of J ~ A, JohpJon.

Coadonloem A pmticulu mugnon's choke of DVT pmphylanis must consider the efficacy and safety of each agenL This study ideutifies thai Ibem are significant differences in the rote of thmmbcembuilt disease among pmphyth~fic agnnbt, with warfarin having the Iowe~ risk of proximal DVT and symplomulic FF_ However, the cumml evidence does not suplx~ algnif~caol dlffemncca in the rate of fatal puimomuy embolism or death. Paper # S0

CEMENTLESS ACETABULAR RECONSTRUCTION IN CONGEJqlTAL DISLOCATED HIPS WITHOUT STRUCTURAL BONE GRAFTING D. Hodm'i Bro~t~ MEt, Char/otto, NC, Thomas K. Fabling. MD. Willinm I.. Griffin, MD Paper # 48 IMPLANT/BONE FIT IN CEMENTLESS THR: SURGEON VS. ROBOT Viimr Pscavfe, MD, Houaroa, TX, Philip C. Noble, MD, Joanph C. McCarthy, MD latrnductimz: This study was perfom~l lu enmpm~ tbe accuracyof • surgeon and a ~rgtcal mbM in preparing the femur for Implantation o f a cemenliess prosthesis.

Mmlertafe u d Methods: Five pairs of ~ cadavedc femora were pro'pond for placement of a stendord alndght-~emmed cemendcas pm~hesis. One femur of each puir vnm machined using a ~mrglcal rob~ while the contmistend ~mur was p ~ by conventional broaching. Replicas of the approprints size femoral premhaniswere Implentnd and seelioeml every Smm. G~ca el the eemontle~ interwere mapped with digital miQ'oelc~py.The distn'buthxl of ~ wan c o m ~ between the man. uldly.-p~pamd and roboficafiy-p~pa~l p ~ k ~ Robotic machining Induced the width of ~ al the i m p ~ n V l ~ intuthce by ~m r a g e of 47% (manual: 0.71.-0.54mm, robot: ll.38-0.20mm, p.dl.00001). AI kvel of the femoral ne(k mtenlomy gnpa we~ generally narrow (0.1-0.5mm), h,,kl.,~,~eot of the method of canal psepmtlon. However, within the distal and mid4mnn regioes, gaps of up to lmm were otmen~ in the manuMly-peelxund bem~ onmpmnd 1o lela than 0,Smm oiler mimde Im**pmadon.13mac diflel'extccawere mere appm~:ntpus*

* Dmmm~mm m ~ or,,~m~ mm~d

int~xludlom: .t.cambethr n:conmmction in CDH can be challenging. Optiem for reconstn~ion include cememnd or cemenlieu reoonmmctine with or without bone grafting. The purpose of this paper is to analyze 8 cmu~utive sr.rh~ of" congenitally dislocated hips mmmd with cementhnm coin. pueenm without structural bone gnd~ing.

Materhds and Method: From 19SS to 1997, 30 hips in 27 patients were mcoeumucted with enmenlle~msockets without mmctuml bee~ grafting. There wen: 13 ClOWe I, 8 Cmwe II, 7 Cmwe Ill end 2 Csowe IV hips. No eltempl was made to place the cup st the Imc hip canto. In each case the en~et was placed when: the Ixme stock was anffi~-m 1o pmvine ndequme coverage. Thirteen hil~ were placed within 2 ram. of the approximate hip center, 14 hips were placed 3-10 ram. cephalnd to the hip center;, and 3 hips were placed > 10 ram. cephaind to the hip center. ~ .anmtaken nm Io lelendize the hip. Small camontfem icelabel~ components with 22 linens were used in the majority of cases. fit anembuisr compueents were used in the majority of case~ Mean follow-up of this group of patients w*s 4.2 yean (nmge 2-11 yearn). Rwultm The avemgn HHS ~ mm 42..5 i m ~ g m i v e l y (31-51) and 92.7 ~ m t i v e l y (till00). All patients had good or excellent msul~ Them were no ae~s of Imstapuisr Inomeningor mliFZlion. No cues h*d p ~ t v e or enmplete mdiolucem lines. Location of the hip center did not influence resultS. One patient developed a deep puelopemfive infc~lon wllJch requbed • two.stsgn ruonusUuclion. 'This was Ihc only revisin~nin lira series. ~ only other complicaliom were two early dislocations which o¢cun~ in the mune putienL D l ~ ' l d o m : While the treatment of the immbulm" side in a congenhally dhdeceled hip caa he chal. lenging, the anthem have si~wn the• a simplimk: eppronch can Ix: very succz=dul el mid-term folio w.up. Merely placing z cemcmless cup where ,he Imno stock is mm~ apundem tamp[ilk= the pso~dora while providing cy~cllelzt n~lits. Noliug thel half (57%) of our palients woe Cxowe II or lpeater, the authors conclude thai stn~clond grafting is nuely nece~my fm" the pmahel~ .onlment of CDH.

256

The Journal of Arthroplasty Vol. 15 No. 2 February 2000 Paper #51

INTERMEDIATE RESULTS AT FIVE TO NINE YEARS OF A SECOND GI~IERATION FEMORAL COMPONENT IN PRIMARY ~ TOTAL HIP ~ l ~ q ' r

Paper IP~3 PERIOPERAT][VE MORTAIJTY AS~DCIATI[~ WITH TOTAL KNEE ART]H[]ROPLA,STY MD, ~ biN, Robert T. "l~mur&lale.MD, David G. Lewallon, MD

Thom~ S ~

David A. Camam~, PAD,Alb,querq~ NM, J a m ~ A. Tmuger, MD, B m 14. Dales, MD, James Kirk AIIman; PAC, ~

E Wh0n, Jr~ MD,

lntroducfleu: This study documents the incidence and cause* of periopereflve momdity in e large group of pstianli underSolng TKA at a single im¢imflon.

INTRODUCTION: Second ~..,-,~,~;Ion crone•leas femond ~,~pv6ents in total hip replacement 0"HR) were designed to incoq~stc femuret that eddn~ the problem of,,q~,,,,;,,cibl¢ bone InlFow~h and dlstal omeolyMa. The putpom of the • M y was to detotmlne the interim:allure results of a m~xmd Oenursfion cemenflcas femural component in primly THR. M E T H O I ~ : The design festures of the Multi-LeckY, (Zimmur, Warmtw, IN) include • straight titanium stem, proximal drommlereaUal pomu crating, and dtatal Imala-flk CI]nicd evaluation included and po~-operative Harris hip ratings. RedinSraphic evaluation included the Immm~era of: ~ i oha:~ncy; rm~lvc, radiodeme tin•s; cakar reanq0(km; eatcoiyals; distal p , , . b ~ : Engh bone fixation chuMflcation; and subMdexx~ Complications were noted to include fractu~ dlaincztion, sepsis and revision anqp.-zy. RI~'ULTS: One hued~l flay-elght (L58) pdm~y c~montium fumond componcuts were performed in 139 patients with an average foUow-up of 7.2 years. The average age was 64 years. The pe~inent radiographic findings included: ~ ostmly~s 1.7%; distal ~at~olysts 0%; and subsidence 0%. The Engh bone thgmwth chmdficatinn was: bone inlpmWn - 98%, •able fibrous - 2%, and unstable 0%. The.re w,~m on cagz of st••mane mechanknl Ioom:=dng that have heen revhx:(L O~e case (0.6%) developed traumsllc loosening lifter • pedpmsthedc fracture. Seve~ cues (4.4 %) have undergone I~,'Jston anq~ury: f~ur In¢ recurrent dialoafion~ two for mx~Jbois mc~lysls; and one for m h a l a r mechanical Ionanning. All femoeal ~ m p o ~ m m w ~ m boon Inoov~.

MatorinJs and Metbed~ From 1969 to 1997 theae we~ ~ 1 8 , 1 6 5 p~maty and 4,375 revision) TKAs per•re'reed at the authors' institution. We identified all the patients who died intrmpenttively and pcdopurmlvely (within 30 days of surgery)ReRIlm: There wure 23 males mM 18 femalaswith anaveragengeof74 yomm(60-90) at the time of mlhmplm~. The overall mortality role was 0.219[,(39/18,165) for primary and 0.0~% (2/4375) for revisioe mthmplasty. There were 2 (0.009%) Intmopemtvc ~ Both wen: ma:ondm~ to sudden curdlo-msplratot'y collapm~ during c~neotaflon. Bllalend TKA was m a o d m ~ with • MgeificanUy higher (p<0.002) incidence of death titan unilateral TKA(0.48% va 0.16%,13/7.679 vu 28/17,182). All deaths were in patients receiving cemented Implants. Tha~ ~ nO deaths among 3730 patients receiving uncemenled p m ~ g s l ~ The came of death In the 13 pedeats who had an autopsy was 8~tte pulmonm~ edema in 10 and acute myocardial iofat~:tim In 3. The presumed caus~ of death in the remaining patients w ~ sudden gespimtmy failure In 19, curdha: a n ~ t in 6, sepals from • source • h e r than the knee in 2, and , ~ b ~ . a s c u l m - accident in 1. CoKhtdea: The ovendl pedoperative mortality following TKA Is low (0.19%). The majority of ira•tents die of c~rdio-respimtory cotiq~e relmed at lema In pan to the conm:qonnc~ of cementing. Patients morn at risk of death after T K A um the eldedy, thole with pr¢-exkling cardio-RzpimtoPj disease, thone undelgolng • cemented knee tnhmplasly, and thaee undeqloing bflatentlTKA.

DLqC',JSSlON & CONCLUSION: At Intetured~e foiinw-up at an average of 7.2 yearn, the Multi-Lodk® has icldev~ cxcelkat fixation in younger petionts with 98% CthSalfled as Eagh bone thgrown. Dtsud omeolysts hie an* boca seen.

POSTER #I SAFg SCREW PLACEMENT IN A C E T A B U ~ S I O N Paper gS2 AN IN VIVO DwrERMINATION OF PATEILLOFEMORAL K/NEMAT/CS Jsme818. Stlehl, MD, Milwaukee, WI, Douglas A. De~is, MD, Dylan T. Aedenm~ INTRODUCTION: Prevlons ~ have been made to dem'minc the imlelinfemoral kinefl~tJ~ under in v i i • conditinr~ The ebjecdve of this pn~-'nt stedy was to use f l ~ to determine the In vivo kinemati~ of the patella relative to the femur and the tibia, while the knee was under weight-ha*ring conditiont M~TIIOINt: Seventy-five subjects were studied under fluo~l~opic tmt~eillan~ while peffonming a welghtheurhig deep knee bead to maximum flexl~. 19~elve anbje~ had • onmud kncc, twelve had an interim" ,mJciate ligament deficient (ACID) knee, twelve had a f i n d bearing peeturiof cn~iste retaining (T~R) implant, tweaty-thn;e had • fixed bearing posterior c~udate sulmimting (IS) implant, eighl had • mobile bearing Implant with an unto•finned p~ella (MBU) and eight had • mobile bearIng implant with • •surfaced pmella (MBR). The videos wcr~ analyzed on • wurkstmlon computer and analyzed In two,,dlmemdon (21)) uaing dlgidzatio~. Pttellofemmal c~tsc~ positie~k relstive to the supcrioffmfedor midlth¢ of the pstellt in the ~ t t a l plane m initially de~ermined for each subjets. Then the sngfltal plane angle of the I~telth, rehttive to the tibia was m4~umm¢ Finally, each Imee was lulaemu:dfor pluellofemoral Npamtion •l full exteminn. Kinematic co•pro-irene w~m then made for u c h mbjots wimln ench gnmp and mlbleqmmt/pm,aps w~¢ ~ wire ml~r OrOUl~. REb'ULT~ At iml , = l a n ~ ti~ m a n pstelin~moral mmlts podfion was ~ to the midlina of lhe psadk for all Ime¢ types, excq~t for the subjec~ having the mobtie hearing knee with a n:mufac~d pmella (Nmmal---7.Tmm, ACl.~--8.4mm, PCR=-0.~mm, PS=-3.3rem, MBU~5,6mm, MBR=I.4mm). Throughout flexim, ou average, all dx greeps cxpedum:ed tomb•ion of the pmelk~umond cemm:t pmttim In the sq~urloy dJrec~*ee.At 90 dcpons of flexie~ me m e m a pmtbou for MI Mx ~ was th the rmMleof 5.3 to 8.8 ram, mpedor of the patetht mMIthe. At 0dl exa:minn, on m,ereSe, all six groups expe. denoed e m ~ l * tth angk when: me umst Iofedur imalon of me puena wm naned towards the m m , i ~ aspe~ of the t ~ a 0qomml~7*, A ~ *, PCR~.6 *, ~ 2 ", MBU~6.5 *, MBR=.4_N*)- Thmugheut Imee flanlon, the m ~ infedur poain~ of the patella weuld ••teed away f~m the ~ ~ ~ ~ m gmupL At 90 delpere of Imee tkxlno, the~e was a Mgnificmt diffenmce in the pmeUotibhd angle fer rob. jetss heving a nemud Imee ~ , p m e d to the aubjecre having an lmphmtsd knee (Nmmal=9* ACIJ),.12 * FCR=2~ ", PS=26 ", MBU=14 ", MBR=20 "). Some mbjec~ having a pCR (86%) ur FS (44%) fix~ ~ leg TgA expertem-4 ~-.nofumond mpmeon st Inn e a t • m • , whne me mbjem t. the oS~ fe.r gmulm dld am. DISCUSSION: This present in vivo, weight-boating study has determined that the onmud l~leUar kJnanlati~ is d ~ t •fief 'rKA. FID~ full ~a.'Ualon to 90 d n g n ~ of knee flexkm, the pmelinf, mmnd ccmlc~ IX~tflon mov~ in the anpurior dina:xinn and the pmlht ~ttends away from the tibia. The differing kinematic pattel~ I ~ u in this study for the subjoc~ having a TKA companM to throe having a normal knee •'my plsy a role In the tncrumed content streascs that •my Iced m TKA patelin i m i n ~

SURGERY

Rnmdl M d d m m , MD, Mob//t, AL, R. l.anc¢ Johanmm, MD Intruductinu: The op¢Jons for igvisinn of an lulgp¢lc~ acetahalit enmpommt with marked boo¢ Ires Include the placetmmt of an u ~ e m e d pontus coated compnoonl high on the wall of tha ileum (High Xip Center - HHC) o~ one ~ than 6bmm (Jumbo). Acetabuhu" roof reiofmcemont rings and cnges a ~ another oF¢ion for revtsinn suqgery. Son.,w placemem In thase reviMon ~ o u with mira. real risk of damaging the intrapeivk: n e ~ , ~ and vaguitr mmcmrez has never been tbot'mtgh|y examthed. The pmpme of our mudy Is to evaluate and compare the an•my of Ktew fumtlon in the HHC and Jumbo m:glabollff coreponent its well as the Muller, Ganz ecatabelur reininwement d n p and Ben:h/S~noidur calF-. M ~ I ~ = Fourteenpalm of cedaverichemipelvas wen: prepm~ by aeedoning timmgh the lower luml~r vertebraeand the pubiL The hip jointwas disanlculaledand all tofttissueson the outer tsbleof the ileum removed. Ou the medial tide., all mmctun~ were removed, with exception of the muscular, nea'v~s and vasculur otis. Each left 8cgta~lum was ealalged to 68ram (Jumbo) and an HGI (Zlmmcr, Inc., Wan•w, Indiana) cup of the same size wan temd. A $2mm reamer was used to make • bone dofecl 3.5cm mpuriurly in the tieum (HHC) and a HGII (Zlmmer, Inc., W~.anw, IN) acgtobolar cemporgnl of the asme tdz~ wss eJuuuined. With cagh cup, the polar sagw and oOw.t I~cKnmtive oaes wege interred in each of the quadrants used to guide grew placement in a prinut~ unc~mented acelab* ulag reamsm~lon. The intrapetvle vlmcular smgtomz at ~ were evaluated with each cup. in the right m:etabolum, n~murs were treed to enimKe its diameter to 62onn and • ~ 58ram Muller &cctabulat Rctofntcnmcat Ring (Sulzer Orthopedics, Amldn, TX) was ~umdned ~ represantstive screws in each quadnm! were ira•erred. The ~ of the fight acetabolum was then enlarged to 68ram and • 64ram Gm~z I~ioforcmmml Ring (Sulzm" Orthopedics, Austin, TX) was lemed in • st•iIra" fashion. The Burch/Scin~ider Cage (Sulz~r Orthopedics, Austin. TX) was than placed into the same -,.,.~,hqlsr void and checked. R m u l ~ In 0 ~ HHC, the qu*dmnm used in an u . c ~ a n t e d pdmm~ *cmabolm" revidon comporT~.m provided asfc la'~v plac,m',eat wtth the exception Uua the polltr K='ew bole and the ~ r half of the superiur-pemedur quadrant placed the lilac ve~els at risk. Safe ~rew placement In the Jumbo aoetsbular compoonnt, Mallet and G m ~ ac~abolar tinge and Bw~h~dm¢idcr Calf fc41owed the same qmld. mum. The safe quadumts for ~ phu~*Jnont in the m b o l a r flails and cages not ouly exlead the limits of the scembolum, but aim include the exlra4cemimltr ~ needed fur fixation. DIKumkm: Soew plaeem~t In pl~uuy oncemeated a c c t a h ~ enmpem:nt has haen done asfely and ~vely mdng the quadnmt symem fre- primary hip replace•eat. Many anti•re have Mu)vm thst the risk amonimed with sc*=w fixation m'e minimized if they avoid the supedor4nterlof quadrant. Since the medhd muctore* st risk from mugkal mmma uma fiasd dismm:~ mlXdody from the brae of lhe acetabuinm, and m tig ace*at•let implant mort• pmxinmtiy on the we0 of lhe ileum or e~hugez luflkiemly, the note asfe ~ can beonme pefiinu in revlalon mngery. We c o n e • with 'Wasiekwdd who •bowed thst In the HHC Mmatim, the quadumt symem sbould ha altered for •slaty. Crex:hmino: The quadmm me•heal of m'ew piece•ant can he uaed to era•re mfe fixatlon, except in the I.B-IC In the HHC, the two immurior qandontts we~ md'e for acmw ~ with the ~ that the polar hek and the •rater•or haJf of the mpedof..pma:rim- quedrem plane tha tibu: vemels al risk.

Reseagh o¢ inatlmtinoM mppofl has been ~ I v e d horn DePuy Inc. of JohMon & Johmu~ C_onsultsm m"employee of DePuy Inc. of Johnson & Joiman~

POSTER #2 T H E CLINICAL OUTCOME O F PROXIMAU.,Y AND EXTENSIVELY POROUS,COATED STEMS C. Andecuoa F _ ~ J r .

• m.a., e,,*,~,w=s d m ,,,,, ~ m t.mm,,

MD, Al~andria,VA, Rohan H. Hopper, Jr,,PaD, Charl~ A. Engh, M D

The authors reviewed the clinical outcome of ],354 porous-ceded mmm implanted -* one Institolion between 1984 and 1990. The study group ~ of 465 cbcumfenmtially pmxlmMly onmed A M L

Abstracts From theAAHKS Ninth Annual Meeting s;ems (-DePuy) with n m~Amfollow-up of 8.8 years (melF 0-14.6 ymum) and 889 extamdvely corned A M L slenm (i~Puy) with •mesn follow-up of 7.1 ymlm (range 0-14.9 ye.a~). Amon$ the pmximMly co•rod stems, 221 had minimum 10-year fofiow-up; 204 of the mmmMv¢ly ~ su:ma, had nt least 10*ye~r follow-.up. Among tiN: pmximMly cemted sunm, tbe~ were 10 mviskxm: 6 for iemenlng (nt 2.1,2.4,2.8~.2~.8 and 4.9 yearn pom-op), 2 for recurrent disfocntk~ I for infection, eed t for thigh Ixdn. Amonfi the extensively corned stems, then: were 7 revisions: 5 for lo~c~Ing (at 2.0,2.2,3.4,3.6, and 11.1 ycam post..op), 1 for Infectine, and I for pore-operative femoral franmre. None of the I 1 meres revised for asep~c loosening damonmmual bone Based on Kepis• Meter survlvor~ip analysis mieg men mvIMon for loo~nlng 8s an endpolnh proximxily ~*~***d S I ~ demom~ntcd • iprealor ~ of early i e ~ i n g than emenslvcly coated stems. However, o0mddm~g Inte revixinne for u e p ~ Ion~:olng armmg ex;emlveiy ox~led s;em~ the difference• in an~'ivo~hip wen no( stnttmieally Mgnificm~t (p~0.25, Log Rank teal). Using revision for any re•non u an endpolnt, overall muvlvonthip at 10 yearn was 97.6 + 0.8% for the pmxim•lly coated stems and 99.2 + 0.3% among the extensively coated ~ For tbusc ¢Immmfenmtially pormm-c~ted uterus, lute aseptic iemeolng has not been obeorved among bone ixgn~n st•ms.

.

February 2000

257

By contrast, nt two v a ~ h following ~ plman~m of PMMA, hlmologkxi findings include mbl~doMe.M b o ~ formation and remodeling. A vamaixr ~ within the mbpe~ou~.xi bune developed and adjoining tralmcula~ w ~ fined with TRAP-slxined om~molm~ Co~Icxi def~ta ob~rved, and I n ~ l l m ~ me•my ~ through Ibe defects into the v a ~ l ~ r ~ Inlm'fe¢~ tissue ~ betw*~n PMMA ~ and tbu newly fom~d b o ~ was devold of TRAP..~dning cells, indiealing thst it wss noc involved ie cmcolyMs. Al eight Wee.ks,a porfcoled m-nmmt of the orig. lmd cortex w ~ visible, • new emtex developed mbperiemexily, and intervening Imbucolan wen n.-p~ced by buoc mmow. ParticulateP M M A elicit• both bone from•lien and mleolyl~ when placed at • s u l ~ c x i

sitc. Our findings commdict many of the cummt views on the edololD, of osamlyML This medal m y prove to be valuabJc ie futom mudies of ptnJcJe-induecd lyMk butommplc ouJf'lentkm u d the fnte of 8clivto. ed mu:mphages.

P O S T E R #5 ROLE O F PATIENT EXPECTATIONS IN PREDICTING FUNCTIONAL OUTCOMES AND SATISFACTION WITH TOTAL H]gP & KNEE AK'rHJUOPLASTY

POSTER #3 TIMING T H E SURGICAL, I ~ I ~ R V E N T I O N IN AKTHROPLASTY SURGERY." OPTIMIZING THE OUTCOME

Nianr N. M M h ~ Anne H. F.omel

MD, Tomaw, O*z~m.io,Jeffmy N. Kntz, lVID, Mnttbew H. Lisng* MD,

INTRODUCTION: Parle.at expectafio~ are an impoalmt determinant of outcomes and could be modified In maximize outcomes and psllem mtisfectinn.

Carfee J. £awend~ MD, M/am/, FL, Ruben A. Hemmclez, MD, Rabbi l. Sierra, MD INTRODUCTION: Most surgeons wait until the patient has Mgnifmandy impaired funeUoa end s~q~re pain before offoring m~dm~plss;ym q ~ y . Tbe e.emcttime In d~ dismu~ pmo~m In whk~h mlhmplorly S u l g ~ should be don: nmmlne c o m i c a l . Our ~ was to maem the effect of pq~opemllvc quality of life, Fain and function level on Ibu c~Icom~ of s u r l ~ at tbu I -year mark. METHODS: A pmspoctlvc cohort of 198 pntknnt undeqloing primary total Idp (83) or knee (115) ~plscornent w m usesaed using onlcom~ Instmm~mls. The Imtienm were divided In 2 Ip~up*. Patients I sm.qdmd th.'vistion (SD) below the sumdord mlhopedic scores wen: compu.~J with the re~ of the cohofl. A/qOVA, K,,mdcxiI.Walbe tesl were ut/lix~l. P< 0.05 ~ c0osklored stgnillcanL RESULTS: I~tiants willl HaiTi• m undor l SD had • laathgieally significant difforenc¢ In Fqreop QW~ mo~fity domain (0.29 + 0.003 SE v~ 0.18 + 0.(]05 SE; p~GO~), pm-op SF.~6 physical function domain (13.81 + I..52 SE vs 3.46+ 1.64 S ~ p=0.004). A sUtdalicMly erie•it]cant diffe~nc~ w ~ in Hmris Hip, PD Hip, KS zmd HSS knee tots/s~m'es and p~n and function subecaies (p<0.001). A st•finically significant diffor,.'m:c at one year w u seen in OWB (0.60 + 0.01 SE vs fi.54 + 0.01 S~; p=0.03). DISCUSSION: Our data demonstrates that patience undeQIoing THA and TKA that m n with lower scorns p~-op (1 SD below the mean) buy• lower l -ye n hip ~ than those with beUer pre..op scone. Wuidng ~ long for • joint m p l = t is datrlmenUd. It is ,.Sear from our data thnt the qu~lfly of life lmpmvornem oh•dried with • joInt reply.none is • fixed mutant and wxidng for severn ch~edoralion will ~mlwomise the outcome.

PURPOSE: To cvlduntc thc misllomthJp betweors pntisnt expect•lions fo~ pl~lury toud hip (THA) knee mh~dmlly (TKA) and immediate pom-opernttve fen~tinmd beslth outcom~ and pntinnt antixixc~ion. METHODS: Efigthle patients (minimum age 50 yearn, with o~eom'lluttix, and no prevloan orthn~ plorty) were enrolled in this prospective obuervntlonxi coh~x mudy betv,~-en Jan.1994 and June 1996. All were ev*luated prc-opcmllvely and 6 montl~ p ~ anrgery with sumdandiszd qne~lom~drm including (SF-~6, WOMAC, damolpaphics, cxpentstinne, end sntixfanllon). Primary dependent vnrisblm were selected~mbec~le scores from the WOMAC end SF-36. Reisfionship l~wocu expectations and outcomes were examined with uxivsdalc and muidvuiste linc~r relpmaion medcis. RESULTS: Tbem were 103 T H A and 89 T K A In thix o~cm. Mean sge wM 67 + 9 yearn, with dlghtiy mo~ females than males (55% vs. 45%). AJI onlce~¢ scorns wen "~golflcudy Improved by six months ¢ompo~l to ixlseline. At follow-up, the WOMAC pain and fimaino a~xrcs wore 86 + 16 79 + 16, rmpectively. Sevemy-Mx percent of individuals exFectod to be completely free of pain after ~mqge~y.In contrast, only 40 % e x p o ~ d In hew no llmimtinns in Ibulr daily activities. Seventy-fiv~ p~c~*nt exla~.'led • I n than 10 % ~ of r . x p ~ i n g joint ~ complicadons. ARer edjusllng for all slgnifi~mt bu.~linc variables including f~ncllmud slams, i~tlents who exposed to have no pain a~cr suq~r~ had on average 8 point higher scores oo the SF-36 physical functioa subucale lind the WOIVlAC pein and function mm-,~3~s (p<0.05). ~ m u s mlpu~ng complJmfions were ~dao signiflc~mt pred~or~ of ~mtisfentinn. DISCUSSION AND CONCLUSION: Expectations •re an impommt ~ of sJ~r~-term outcmm~ and should be ~edied fum'~r to maximize nmulta ~ lwopcdy evslume T H A / T K A . Pntleat expect•lions regarding p4in mlisf are sigxificam pl~lioa~ of p b y ~ x i function and p*dn u m~mted by the WOMAC and SF-~6 in early pm/-opemtlvc p¢~d.

POSTER 114 OSTEOLYTIC AND OSTEOBLASTIC RESPONSES TO PART/CUL~TE POLYMETHYL M ETHACRYLATE Tmvor l.swnmne, MD, CTmHoamv~/~ VA, GwoJew Wang. MD, G a ~ Badim~ PhD Osteolysis the principal caus~ of long tram fxiinre of replacement mrthroplmay. Many ~,,~.~_~ of the pntlmphyxioingy of onteolyMs m well mablhd~L However, the prevalcnee of osumlysis in both m r n ~ d and cementium arthroplamy mJUorta that this Imx:ms cannot simply be de~dbud as a granulomatous reaction to metal debris, l~mieul~ polymntbylmethac~ylntn (PMMA), u d polyethylene accumulating at ll~ bomb*Implant interface. Although In v i m findings mmegly suppo~ the ~ of paniele-induced e~tonlysilG in vivo evidence is hum convincing. 0 ~ difficulty in drawing o0oclusimm fnxn in vtvo data has been diffcremieling be~veon the p~ysloIng~d n~pon•e to injury wixm ixmldea are Intmdmx~d into a bony cavimemant and the c¢lluixr n~pop.s¢ to panic•lute debris. Acconfingly, our l u d y c~npangl Ibu effects of applying PMMA at • mbpedomexi site In the mq~afiy exposed right tibia of • mmme model with the Fe~manzou~ Injoclion of Ixmiclea at the mumc Inemion. "1~ ie~ limb• served am s c~tml. B e c s ~ the pemutaneous In~ec~Ion pmdu~cl lure pe~mgexi and coRk~ injury, the ol~.~ed n~xxme was almo~ exclusively pmiefe mimed. AntruM• wore nulls•teed at two, four and eight wcelug Spe~mens were snaly-~d by meline his;ologtcdmiques, and c ~ e ~ q . m wen identified by mining for tannin resistant acid pbusplmmse CrRAP). Two w~olm following p~rcman~us Injection of Ixmicuinte PMMA, buth betcmtoplc o~ification and corniced lysie were evidanL At the poripbu~ of thc maumof pm'tic~s, intad'ec~ mcfnbtanc fom~d Ix~/ween the Ixul~ea aml ll~ undorlyin8 onfllcol beoe and cortical ermfo~ wen ol~-qrved. At the center, butormopl¢ ossification extended f~m the cmlex into thc hum of P M M A pmllchm. Some pmlielm lay within the vascular space of the l~torompl¢ bone., engolfed by macmphnge~ He~erotoplc bone w u mill pnmem nt eight weeks, sunounded by a nmmw dm of prank:ion.

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IMPACT OF ADVANCED MIXING TECHNIQUES ON VOIAJME SHRINKAGE IN SIX COMMERCIAL BONE CEMENTK W~tpns ~ MD, Bosto~ MA, Andrea OUm~I, MD, Anu8 k l l m ~ PhD, TlmmB S. Tbumhill, MID, Riebuol D. Scott, MD INTRODUCTION: IntmducUc~ of centfi fegull~ and vacuum mixing has helped to m con~nt po~thy to eppmximtoly 5*8% and <2% rmlx~clively, but has led to s marked tnc~ue in volume sluqnlmge., which has been implicated us s fsc~or in uep~ic Io~ming. The puq~me of this study was to omlnp*~ the n:actinn of MXof t ~ m ~ t commonly used buo¢ o=mema to c~Ui fugatlon, hand- and v~um-mixing* and Io address the need to establish s mlxorlcement oomMnmlon offering good pom~ fly n ~ c t l o u with minimal increase In shdolmfic. METHODS.. The following mmcam won: treed: OvlWI, CIVlW3, Enduran¢~ Om~mmd, PManos R. Simplex P. Hand mix~g used • Stryk~r Prism Mixing Bmvl; cmnent was mmffcs~d to the syringe using • spntolmm. For vaoaum mining, wc used a Stoker Advanced Cement Mixing Bowl and mmsfem.'d eemem to an ntua:horl sy~mge, all under 21 in Hg of vacuum. Contrlfugntino used omtrtfogstion at 2000rpm foe 1 rain in a Zlmmcr OmuifoF Sy~em. Density w D detormlned *t $ and 20rain after mixing. Volume shdnlmge wss mkolmed using the ratio of throe two vMum. RESULTS: ~ the six cmnent~ aVCml~ shrinkal~ and demdty wen mlo0ixtad as 4.98% and 1.218/~m3 for hand mixing, 5.76% and 1.24fiR~3 for mau'lf~p mixing* and 6.60% end 1.268/cm for vacuum-mixed c ~ e n l s . These va~minne ~ highly silpniflam (unp*ired I-t~t, p<0.0001). To munn jura two examples of dlvmipmt n ~ i m m m mixing tedmique, shdnknge in vacuum.mixed P s l ~ Im~*.._.~cl to 6.7% born 3+7% in burial*mixing*while c~nuifueing of Ostoebond iecxexsed s h d ~ from 5.2% to 6~%. DISCUSSION AND CONCLUSION: The concern of reduced fatigue fife due to high IXx~ahy has born eddrmmed by the Inlmduc~tieu of mm-lem mdudques for cement I~pm'ntion. Both sdvanc~l mixIng tcdmiqnes in this study mdu~d pomM~ and In~eaned density, slthongh vacuum mixing proved to be morn e6qolqmt. Noteworthy w,•s Ibu varying e.x*,*nt to ~ dlfflmmt ~ cements h©a¢fited Iron these todmlqne~ For comparable levels of pon0Mty ~ Ml~fi¢Im~ly lllffcrmlt ~ In volume shrinkage w~re l~orl. Volume l ~ r i ~ m ~ IS of OOn¢orlG Im it is poroejved to Inflnee~ belx~l*

258

The Journal of Arthroplasty Vol. 15 No. 2 February 2000

thil at the imphmt-camamt interface, which cam lead to aseplic Ionecoing. Fitrther reaeagh co the compmiilon and mixing conditions of mmdmd PMMA bone cements is requited to inveatlgnte a compromise hatween mdactimt of p o l i t y aad inc~asud slu~nhagn.

POSTER 19 BILATERAL TOTAL HIP AKrEIROPI.ASrY: COST ~ F . S S COMPLICATION RATES

AND

Eric A. Momsmlth, MD, Boston, MA, Louis gizto, MD, Sben7 Oomas, RN, David A. Maningly, MD, Benjamin E. Blerhaum, MD

POSTER #7 CEMENTLESSFEMORAL FIXATION IN THE RHEUMATOID PATIENT UNDERGOING TOTAL HIP ARTHROPLASTY: FIVE TO TEN YEAR FOLLOW UP Fablo Ornege, MD, PhO~e/p&/a, PA, Kjall seam, MD, Stnekholm, Swuden, William J. Hneack, MD, Peter E Shad=y, MD, R l d u ~ H. Reahman, MD IntmdlucBea: This study reported a series of cementima total hip arthmplastil= perframud in the rheumatoid arthritis population using a single component dealgn ~ addlgsaas tha themedcal conceras of poor bone ing]rowth potential and milled compl]catioml in this patient population. The pugpenn of this pepex is In evaluate the efficacy of cemende~ total hip lurthrop]tMy in patients with rhaummoid mlbritis. Methods: Fifty five loud hip mlhmpisslics were performed in 43 patients dudng January 198"/lind November 1992. One peliem died prior m five year follow-up due to untainted cattses. Ten patients (12 THA) were lost to follow-up prior to their $ year examination, leaving 32 patients with 42 total hip mlhropl~les who were mvicwed with a minimum 5 year follow up (mean 6.97 ycam, nmgn $ to 11.7 ycara). The demographics of these patients ineJude • mean age of 53.7 years ('2.6-7"/yams), mean weight of 145.3 pounds (98-206 pounds). Preoperative diagnmes were thnomaloid anihiida in all patients. Tapered, collmicas, porous cnate(L titanium alloy femoral component and titanium, porous neared bemlsphodcal ac~#oolar c~uponnot wen: used in all cases. Ruudtm The Chamley scores for p~n, function and motion improved from preoperative mean values of 2.2, 3.1 and 3.0 to $.7, 5.5, 5.3 respectively. The follow-up mean Harris Hip Scone was 91.4 Thlgh pain was present in only ] patient (2.3 96). No femoral frac~ns neconud intntopenttlve]y with the in~gtlco of the pmstbe~m. No femtmd oumpcocots demomamted evidence of rad]olgraphic Iomenthg or required ravtt;on fog aseptic: ]ococoing or i n a p ~ t s i l n g thigh pain. in addition, s~thle bone fatslion was identified in 100% of the femoral compcocots. Four m:embu]ar revision was performed for ]ooscning and eccco~c wear.

A retmepective review, utilizing a teaal hip outcomca softwara (O.P.U.S.), was performed to compare bilateral total hip vs. uniintera] total hip t.qhropl~y. Cost effectiveness and complicailom were examined in this study. Fifty biintera], primary toad hip anluQpisstiog(100 hips) were performed by two surgeons between 1996-1998. Pedoperailve complications and cost dam for tha~ pene~Jun:s were mconJed in s prospective fashion. A demographically matched cohort Of uol]atend Inhropisaty patients was used fog com. psrison. Tbe cohom woge matehed fne age, tax, weight, ASA sgogez aud year Of surgn~. Complications were divided into lead and aystemin. Systemic complications include D~rr, PE, infectione not reinled to the hip, medical complications nenesltsting ICU care, of death. Local comp]icalions include dislc~ilon, neumpraxi~ iofeclim~, inmmperative fracture, non*operative hematoma, etc. OR time averaged 224 minutes for biistends, 107 m]nulog for uniinlenda. When the unilateral lime was doubled, there was no significam difference, p=0,06. EBLaveraged 981ml. fog biisterals, 5181111.for unilaterais. When EBL w u doubled fro" the un]istsnd group, them was no significant difference, p=0.96. Surgical approach and implant fmailco was simiim in boot groups. The biintenti gmep had 2 systemic compllcotinm, one DVT aud one death due to massive fat embolism in a bilateral hyhiiti hip r e p l m a n t . The uniisteral group had 2 systemic complications, I DVT aad 1 plgumobia. ~ diff e n , g t In complicatico rates was nm statistically significant, p=0.63 (Fischer exact test.) Length of m y averaged 4.06 days for bilateral& 4.6 fog uniimerals. This diff¢rence was statistically significant with p=0.018. Doubling of the stay for unilaterals equal 9.2 days, an even mote dramatic difference. Hospital costs fog the years 96-96 were examined for both btiatenil and unilateral hip geplacemcnL Performing bilateral IOla] hip anhmp]uly in a single Se~ling intuited in cast uvinss of 35% vs. the cne~ of two unilateral hip mthmp]asilca. We conclude that biimeral hip anhrup]asty is a safe aad cost effective pmcudum. Significant cost savIngs can be realized without ine~tslng the complication rata and compromising n=ults.

Dt'euadms alld CeodoMml: Ccmcotiem femogld fiasflon in tho thcomatokl ix)pulatino at icog.ml~ for k)w up can achicve excetient nsulls Bcoe tngn~vth was csxtsislentiy achieved, imggmlng no edveng effect of vmylng hi~e quality In the ~ petlcoL Tbe utitiasfion of nemel~cal totel hip arth.,opimty th the thetmunold pup~datlco may pmvlda a theon~cal advantelpe of a dymualc llving hoee.pmttheata intstface that enabias the junoilral to edapl to the metabolic chang~l that occor with thnomatold hone rmhe~ than the degrading ql~lily of the al:ry]ic CCgneaStJOOOeh l ~ that ~ with lime. POSTER #10 RESULTS OF T W O STAGE REYISION FOR TREATMENT OF ~ AgrHROPLASI~

TOTAL KNEE

Thomm Beck, DO, Philadelphia, PA, Harold Rees, BA, Jess H. Lonoer, MD, Pat,] A. Lathe, MD POSTER 18 PERIOPERATIVg BLOOD SALVAGE AS AN ALTERNATIVE T O PREDONATING BLOOD FOR PRIMARY TOTAL I~IEE AND HIP AIn'HROPI.A.wrY

Matthew G. Prkderk~ MID,Salt Lake C/ty, L/T, E. Marc Mmtani, MD, Michael H. Bcome, MD Two huud~d patients who underwent p~mary total knee and hip atlluupissty were n:tmelx~lve]y reviewed to asae~ the need for homologous blood transfusione when pedoparailve blood salvage was perfmmed, l ~ e study 8mup consisted or 132 patients who u n d m m , p~tla~ total knee anhioplasty and 68 patients with total hip arthmphmty. All pmnedures wexe perfonlnud by the two se.nior authors. All patients had perioperative blnod salvage utilizing a system of washed nod cenU~qgud biomL No peilem predonamedbiae~ The mean preoperativeHematnotitwas 4 I.!~ forT K A and 40,9% fm THA. The mean pmtuperative Hamatoail was 34.396 for TKA and 33.296 for TFIA. Pe~oF~ative blood Icaa incJuding intmoperative In sin imura l~moperafive]y was 674 mi]]tiltera for TKA and 764 mil]llimrs for TILA. The average mo u n t of washed saJvegnd b~od mtun~d pemopemtively was 276 mil]llitera for TKA and 293 mltiithers fog THA. Five of the 132 (3.896) TKA and three of the 68 (4,496) THA patients required Irandusico of homologous b]nod. Of the ixaicots who were mmsfused, all but two patilmts had preoperative Hematocrits of • 3796. There w e e no complications attributable to blood salvage in ~ F~ient 8map. The c~m at our inatitulinu fm peltopemtive blood stdvagn including the ceti saver, inbor, supplies and relw.ffmdon is ommpmable m pn:domd~ 8 two units lum]ogcos b]cod. In munmauy, we fee] that role of perioperative blood milvagn is no axnelle~t alternative to predmulting in patients with a haselthe Wnopemive Hematocrit of • 3796. Our study demonstrates that utilizing periopenttive washed lind ccoltlfuged salvaged binod is hath iofe lind cam effective and malu~ it polMble In diao~tinue the practk~ of Imalonailng blood fne ixrinul/y T K A and THA.

lntredncthio: The optimal treatment fog iofec*ed total knee (TKA) continues to be debated. Then: have been multiple mlxxts of diraa exck~mge, 2-stegn t~,isJon, and even three stagn revisions. The initial emhiudasm fog 2-stage ra-impllmtetico as the treatment of choine for infected TKAs eneoumging. However, as the indications for this approach broadened, lnc~'¢asing f-Iluml have been noCed. In older to better define the caus~ of these failures, we have carefully mvicwud the n ~ l t s of our 2-rage mvininn for lnfneled TKA. Method~ Fihy-slx 2-mgn re-implnotatloas were ped'onnud in $3 peilents between 1983 and 1997. All were followed for at least two years with an average follow-up of 53 mmlth& Outcomes, comorbities, and complications wen: recorded. Remlte: Then: were nine reament infecilcos fog s success rate of 83%. Five of the reconences ($$%) were by aew o~is4rne. The initial o ~ h ~ l did nol predict recurmnee or failure, Then: were throe significnot comogbitie~ assoclatud with the initial infection, including 10 patients (1996) who n:poned Ix~-operaflve wound Woblema, I I petieate with rheumatoid ~thdtin (21%) and 6 with diabetes (11~). These comofoitica did not pmdk= mconcot failure. IMacomioa uad Coodmious: "/'he 83% ~ ~ is lower than generally reported ]n the ]ltsmtura. Of noCe,55% of the fid]un= were related to new oqgantsms. Whether they mpn:sent new iofectlno, or exprcs~lco of pravioualy p~sent bot u n ~ organisms, is uudetenninud. 'The reduced sune~s rote aBer staged rc-implantst]no for nelxic total T K A should suggnst alternative therapy fog selected patients. The presence of new oggnnisms must alert us to take careful multiple cultures at the time of prima:y debddamgnt and at the time of re-implantation.

POSTER #11 IS RECURVATUM A CONTRAINDICATION TO TOrAL KNEE REPLACEMENT

Jolm IS. Medlq, MD, .qoonuvlV~ IN, E. Michne] Kcatlng,MD, Men'/]]A. Rittsr,MD, Pbi]ipM. Paris.MD, Michael Bercod. MD, Brian (:rites,M D

• Dmmmlira ~ d vxlmi,~ mm'~d Pmmmmm ta~Uim

GCOu recurvatum is an uncommon deformity p~og Io total knee replacement (TKR). Its presence, however, may raise concern over achieving a stable, well-fuln:~ioning knee at the time of surgery. We evaluated the fumainoal atsttn of thane knees aner TKR to determine if this pccopenttive defom'tity mcum or has any potential deictedm~ effect Oll the eventual OUtComeOfa TKR.

Abstracts From theAAHKS Ninth Annual Meeting Between Jtm¢ 1987 lad March 1997, a comeotltive ledex of dxty ~ were pedomred in 56 patients presenting with at lasul a five dean:e hyperexteanio~ deformity pteoperetivcly. "ale avemae returva. tern meanun~ 11.6 degreei (nmge., 5 - 20 degreen)' Only oo¢ c s ~ of myopathy wan noted (poliomyelidQ with no ~ of major ligementotB i n ~ i l i t y. I~eopenltively Knee Society (KS) lutee, fmtttiort, ~ pain scores averaged 40, 40, and 12, n~pe~vely. A PCL-reteildng proethenis wan implanted in 58 of 60 can~. All tibial and patellar proslbesea were cemented. KS clinical and radiographic scot~ were noted at each follow-up. Follow-up averaged 4,5 yea~ (nmge, 3 - 10 yeas). KS knee, functiort, and pain suoRI impvovud to 82, 80, and 43, ~ i v e l y . Pextopenttive exrenolm avmged 0,5 degreen ((:OOtlaCtore) (nl.q~ +10 to-10 deBrees). Rexloa averaged 113dtgRes (nmge, 8 5 - 1 3 0 ~ ) . O n l y two kneex (3.3%) holed a hyptrextemtinll defonrnily poltolmnllively. Both defomtiti¢i nu~iured tart duipees with 8 p t ~ r a tive d i c t a of oiteoar~ritla. Ten cases of mild medial inlulbility wele noted, all 10 mm or ~ No cases of lateral, postedoG or po~emlateml instability were noled. At final follow-up, no knee was revised for any reasu~ including infection, Iomening, wear, or inlsabllity. Furt~rmore, only oee c~te of a IXOlpenalve radinin¢¢at line gluter than 1 mm (labial zo¢,e 7) was no4ed. Although the etiology of a hypemxtemdon dufomtity should be thorou@ly elucidated preoperatively, its Im=en~ does rot Im~Jode a well fenctioning TKR.

*

February2000

259

Diatumlesu The lasue of lateral rele~me la mmplex and the pfo¢¢dum no4 benlaSL We had a high incb dance of lateral ndean¢ (51%) bet a low frsuture rate (I.2%) and a very low instability rate (0.60%). Patollaf fractmwt and immthllity were a minor clinical problem in our ~fles as only 4 required operative intervention (3 for fracture and I for 81obel imtobilily). ~mtesu Fraetur~ and instability of the pltella have a multlfactional etioloay including alignmeal, prmthetic slat and dealge, surgical tcchnklu¢ , lad ialeraJ releasu. We mcommeod lateral Rlclu~ continue to be performed judidotmly with cm~ldtnltioo thai tbe~ ka¢~ are generally more problematic at pRsentstion, i.,ong.let.m sequelae flora Intend R ~ reWorem • very minor clinical problem.

POSTER #14 CLINICAL RESULTS OF MODULAR POLYETHYLENE INSERT EXCHANGE w r r H TOTAL KNEE COMPONI~NT RETENTION

C,emrdA. ~

MD, Alemr4r~ VA, Lisa M. Kondowkz. MPH. Tnom~ It. Pendea, MD

Re~md~ or inaltiutiomti support has been received from Blomet, Inc. INTRODUCTION: Modular polyethylene irdedu have enabled surgeom to perform holated tlbinl imtn exchange while Rlaining w¢ll-flxod compmw.nts. This study reviews re~lls of insurt evialo~ and clarifies the ale of this op41on vemm complete Imee mviMon. P O S T E R #12 A META-ANALYSIS OF T H R O M B O E M B O U C PROPHYLAXIS IN TOTAL KNEE ARTHROP~ (TKA) Kolth R. I~molumthal, MD, P/6/ade/l~a, PA, Kevin B. Freednum, MD, Robea H. Fitzgerald, MD, Paul A. Lo~e, MD, Je~B H. Lonaet', MD Deep venous thromboals (DVT) is common in TKA. Pmphylexla aaalrm DVT bowev~, may lead to serious complk:ariom as well. Because of the rarity of tha mo~ surioul o~teomea, i m ~ alngk, randomized controlled trials lad[ the powcr to eladfy the choice of pmphylexis. We present a rnctemudyals analyzing the e~cacy and safety of agenla comm¢ldy used for DVT pm~ylaxh following TKA. A main-analysis was pett"ormed for D V T IXOld~yinxlain T K A uling a Mediim: mearch. Study indexion critefla were: randomized ¢orltmlled trials comparing plophylanlic agents in elective TKA confirming DVT by bilateral venoamphy. Low-moincalar-welght hl~exdn (LMWI I), warfarin, aspirin (ASA), subcutaneous heF4fio (SQH)' Imeumatic oompmudon stochiaas (PC:S)' and plsu~b~ were iludlad. The alxminte risk for each outcome was determined by dividing the number of events by the number of patients at t ' ~

MEFIlOI]~: Tbe senior author managed 56 padents (63 hae~) by reviling the tibinl polyethylene i~¢rl and retaining well-aligned und stable femoral and tlbinl eemponents. 0/'48 knees with complete 24-mo~th follow-up, 22 underwent modular Imlert excinmge for wear, 21 for well" identified during failed metal-hacked pltellar Rvili(m. and 5 for other Rsuom. Implants ~ in situ a mean 59 monlhe prior tO the llaerl reviainn with no imphmt in sam more than 9 yearn. In~:n~ Rmovod at e.xchange Braded for wear using the Hood dasalrlealiOO system. Cases we~ followed a mean 7.2 years after inst~ reviaion. RESULTS: Seven of 48 knees failed amen excinmge due to accelerated wear of the new it~en an average of 54 months after exchange. All required full knee revlalrm. Six failures were from t ~ subset of 22 (27.3%) that initially failed for i n s ~ wear;, ooe was horn the failed patella iFoup. Inserts initially exchanged for a,4vanoM wear were more likely to fail ageln (p
1'3flenn slodJes(4289 patieam) met includoo criteria. Total DVT rates wen:: PC3 (29.6%)' LMWH (31.1%)' SOH (38.4%)' Warfarin (47.0%)' ASA (55.395), and Placebo [p
P O S T E R #13 THE LONGER-TERM CONSEQUENCI~ OF LATERAL RELEASE IN TKR - A REVIEW OF OVER 1600 KN EF.S BETWEEN S AND 1 ! YEARS

Richard L Wodaw& MD, Rkhmmw~ VA,AndrewB. ~ t ' ,

MBBS, FRACS, Douglas E. Jemup, MD

PulII~I~. TO determine the Ionger.lcrm consequences (patella frantums, instability, and ¢ornpoe,ent io~enina) of intend mlea~ performed daring pdmmy total knee arthroplasly and to Mtow thai intend reieaf~ IhmJld be ~ U II¢¢¢dl,~al~witho*Jt Cotx¢~IrIBfor IO~g4mTll suqlreine. Matedala u d M ~ We examined 1071 pdmary knees p,,.~.~ively with a follow.up of 5-11 years. Knees were examioed pro and Felt-openuively with HSS ~ and alilprmeat films. Lateral mleasen were Ftrformed Is clinically indicated ruing abe "no-thumbe ~ technique. Otherwise., the patients were a reinlively homogen~,.J group with two ~ t l ~ woddng together using an identical technique, p~mlbesis, cemeafing all components, resudactng all patellae and retaining the posterior cnldate lige~ent. R~aP,,: The latend a l e u t group was younger, heavier, and had lower HSS ~ pre-o~retively. Poll-operative HSS scores were dmiinr, yet more complinatioes wen: seen in the intend rele.a..mgloup aS they were more likely to have a fracture, lucent lint under the I~tellar bulton or pateUar inlllbility.

• Dmumdms m m ~ ~fw~s ms mmb~ I,m~m m k l w =

P O S T E R #15 IMPACTION BONE GRAFTING IgOR SEVERE P A ~ DURING REVISION TOTAL KNEE ARTIlROPLASTY

BONE LOSS

Arim D. Hammm, MD, RocIR.~r, MN Introduction: Seven: patellas"beoe loss which ptedodea adequate fixation of another pmclhur promhe~ n:prcsunm a major ormolvodproblem in r~,,ision teud knen anJuopinW/. The cummt options of patellectomy or ~ e o t i m oftbe nmminlng pmelhur fragment (lmtellar msuc~iona~m~insO,) provides ~ din. ical resulm with ~ knee acofcs, in I ~ t dec to penbaent retrel~telinr pain. padelhit nud--eackin 8. and delayed paleliar fragmentation. Rcstonition of txm¢ stock to provide impmvod quaddcqm lavelage desirable. This study descnn'bestim smgio] tsuhnklue and emty n~anlts of a novel Ixecodure dealgeod Io n:stme pmellar bane swch end ixXeminlly hnFmve funodoo in the ptttient with suvare pmellar bone dell ciency d~ng revis~ m~d kn= armmp~*y. Mateda/s aad Methud~ In Ihesc pstlm~ts,arvem cavim~y I:etellar bene into Icsven ooly the antet~r cortex and variable ammmts of the penphend pmelinr rim (a Imetiar s~Al). Adsme flap, cremed horn pe~-~teUm" fil~otic thtsu~ a fz~ timue ~tp ~ J n e d f~om the sulxa-Faelbe" pouch, or a lucia ~ ~ obteined in the interai gettex la Itwn to the Fedphend palelllt dm with multipk sutuns w provide a warer6ght do~ro. Canc¢linus I ~ ~ allhar locally harv~ted I m t o ~ or mm~oled a l l o ~ is I~htiy iml~ into the palellat dofed.. The ttssee flap eomaim the booe Uafl and ani~,cs I an i ~ t ~ ~ the femond trochka and bone gntiL The patellu shell-bone gnt~ t ~ n s m ~ undergo~ remodollog ageJr~ the mx:hlea and the ImmpslPJla=mxrfacc usum~ the shRpe of the IXOSth~lc m0ddenr ~ . Nine pmelinr bone grafting pmo:dures we~ performed in 8 patieots (one patient blinm~)' ~ wen: 3 women aed five mea al an average age of 66.3 ym (rsuge, 45 to 79 yr.~)with su ~ folin'w~lp of 26.8 mo (rsuge, 15 to 43 too). Tbe RalOl~ for revido~ sulgel~ indmled polyethykn¢ w~ar Ilxl ~ ~ yah In 5, flexion amiability in 3, and flexion conmwtere with imtellar ormelylla in or,t : All pltlants had meodated mvlaino of the femoral and tiblal omlqxm~ts. Ftmond b o ~ defldencies IwJuded ~ ~-A, 7 F2-B, and one F3 defenL Alsudated U'binlbeoe dultclendea Included two TI-A and 7 1"2-A ~ Itesul~ Preoperatively, ROM aveta/Fd 6.8 degmea ememlon (nmge, 0 to 25 degm~) with flexim ivcraaing 82.8 deBre~ (range, 40 to 105 degrees) fm an average ROM arc of 76.1 deaRen (rana~ 25 to 105 deaxees)' PorlopetaSvely, axiom.ton averaged I delF~ (nmge, 0 to 5 delpeel), 9esioe ~ 98.9 deaRte (nmge. 90 to 115 deaRex)' and the ROM am averaged 97.8 degxees (nmge, 85 to 115 deBre¢l). The mean Immpetative Knee S(x:iely pdn and fuachon suo¢~ were 39.1 polml (nmge, 18 to 82 point') md 40 polnm (20 to 60 I~nts) n=pectively. Thole aeorei iml~Wed aiBdflcendy m ileal follow"up m a mexn lli~ sum~ of 91 pointl (finite, 80 to 98 polms) and fmledoo Kore of 84 polma (nmge, 6.~ to 160 points) (p~0.0~). Radiographic analysis at final follow up revealed that the i~tella was amtrally located ia 5 and llnlaily sublexed intendly in 4. Pltell~ height, as ~ r e d on MeldUl~ views, averaged 19.7 millimeters (range, 17 to 22"5mm)' O~¢ pwieal undmwent renpemtina with ~ of a tlblal polyethylene iine~ at 18 mocti~ for 6blofemrmd instsbgity. Al suq~'f~ tha pmallar tiasu¢ finp was intsct and the pmlinr bone was 5 i n p ~ One additional pedem, at 43 months follow..up, has developed intend ,~,~v~ell~ pain m,'.-~ted with Intend imelinr subluxadm and ~ of the in.rid p a e l ~ reaion. The Rstoretion of booe laock has I~naitted m m m ~ for a pitellar nmurfiida8 pmcndm¢ ll~(I ha la tellmnfly pmding mviMon ilmgePJ to RmJrfiloe the pltelin with a pllelim' buuoll.

260

The Journal of Arthroplasty Vol. 15 No. 2 February 2000

Com~m~m: ~noc,inn p~.n~r ~

nam~ aptera *o pmv~e ~

pmeme m~ m~ pam:mwith n

sev~.ly compromiued i~lelin. "i'his Fq,.,,.~,,re nojquely impm~ the poumtiM f~r resuxndno Of bnoe •u:~ck and mey hnWovz the fuue~noal noluc~no'leic these i~Jtkmts by fa";Hu"%8 patelhu" uuc~io8 and ImprovinB

q ~

ic~,,m~.

POSTER #18 REVISION OF T H E STIFF TOTAL KNEE AICr[IROPLASTY Chrlndan R Chr;~teawa, MD, Dw/mm, NC, J. Jay Crawford, MD, Theman P. Vail, MD

POSTER #I~ RESULTS O F AU.. POLY T m l A L COM]PONENI~ AS A COST SAV~qG ~ I Q U E Dnoald L* Pomemy, MID, ~ KY, ~ A. S~mper, FAD, Walter E. Bndanl~uen, Jr., MD, Kau~lean E. Suthem, Marlly'n W. Smith, Jan A. EmFnoa, RN, ONC, Jessica L Cumj Intrmheetiem: With dslng costs Ofjoint replauengnt surgery *rid Ihe decrease in I ~ m b u ~ t ever imsant In Ihe minds Of both the hnopiuds and physicimm, co,~ cmtinJ~ mcJumme hevc bmm henome uppa~ue~ In ~ Involved directly wilh normjoint ~ . At nor Institution we have slnc¢ ]992, Io uee an all poly lJbinl nompooenl In om mintivoly ises active pall•ors over the agn Of •evenly who peemmt for palm•v/tmal knee repinc~leuL Resulls of 312 cuees padmmnd belvmen Man~ of 1992 and March of 1998 ate presantnd In the hope• Of demoanlrating fllh*technique es a vinb~ ce~ esvin 8 m~alre.

puq)me of this study was tO ~vMum~ the Impmvemnol in range of motion nflor ~.vtsinn lolol Im~ urthropic~y in It c~s¢cutive series of tolal knee m~hmpl~tica pee~nIIng with noutndly limilad rno~ of ram/no. Eleven stiff (ran8e of motino less than 70 degnam) and painful total knee mplueemenm wen: reviued with n poMerior s/Ibtlitzd condylar ~ nnd n : ~ v ~ l y reviewed after an avem8• of 32.5 m n t h a (n~ge 24-.q3 rJr~nU~). ~ tO nevitloo, one OUl of eleven had buen man]pulatnd and thr~ of elevenhid undergone open surgcv/foradffnees. Nine Of elev~ knees had evidence of loosening, nodelii~unm~t, owr-eized comFommts, or haremtopic a~lficatino p~oper~vely. Infuelinn was ruled nut prim" In mqgety and Inlm-oporatively. After revtsfun, the avcm8e nmgn Of motion Inamasnd from 41.1 delprean plc-o~penlUvely tO 81.8 d e g ~ l puel-~.lllivdy. The mean flexion contngtuge decreesnd horn 11.8 degmca to 1.4 delpues. In the Iteven cas~ whe~ rig PCL was cx~mpatem m revision, the ROM lmpmvnd from 38. I In 75.0 degreca. In Ihe fnor caues whelg the PCIL.hnd aln:aKlyheen esc~flcnd ue was innompatenl, the ROM improved from 46.3 to 93.8 degrees. Four of eleven mvislons n~luired a quadficepa esip fm exposure. No quadrioq~ lumdowns or tibinl mhemle omeommisa were needed. Fore'of eleven patienls reqolmd closed manipoladoa In the first month following revision imrgery. Other complicatioes included pendslcnt stiff~g~G palelis Infenk and two minor wound problems. AJI paticnts had lmprovemem in pain end weee satisfied. This study demomumes ded knee nmgn Of motion can Improve Mgniflcamiy after mvisine mud knue authrophmy clcapile esmMIshed capsular cnou~mm pmqxm~lveiy. Key wes.d~ to~l kalee i~lhmphmly, mviMo~ p ~

s ~

nmgn of mOlioa.

Mmm.4ab and M¢lhod~ 312 p~mav/tocM Imues were perfuemad al non luetitutino by the mane 8 ~ u p of surs~m- 14 died IXtor to their t i m year evMuatlno leaving an Index Ipoup Of 29~ kue~ In 231 paticuls. The avemgn qp." of the I ~ k n l s was 75.2 ycam (hinge 61 to 94 yem'~) with a pmfomlnule dingnmit of mtnom~hdtls (285). 118re wese 197 femMca nod 102 tomes In this ipoup. 218 averase time sleet anrgevj is 3.5.3 months (ran/F 24*84 months). All c e m ~ ~ evaluated u~n 8 the mtioowaic tnd olinical pe,imetem Of me K m mc~ety. Hospl~ t~x Spatial Smguy OISS) scoma we~ also calcuisu:d ReanJl~ Both the HSS anti K.~ Korca dtownd dramulk: Impmv~rl~¢m from an avz~gn Of 55.9 to 83.4 fm the H ~ and 38.0 to 78.9 fun the Knee Suelety rating system. The Knue Saclety anuee, when dividnd between fuactJno and joint, are ,,,ely s i x . t i c In demomm~ng the tree manlm of the pmuedew- Due m incxeund age, the avoragn functino m of 640. c~eady shows the deollne In dlslauee walked and the ubilily to climb Halts without aeslmam~ However the joint m tells the tree plclure as il anaI ~ nmge of motion, in~mblHly and pain. The averagejoint It~ore is 91.2.T ~ n : have buea 3 geviin this index ~toup (0.,79~) but none were for aseptic Ioo~ml~g. Radinlplphic review revealed 295 of tha~ imphm~ with an optimum flxatino with no 1 ~ of omnolys~ to dale. Co~chnd~ The u ~ of this type of tibinl cno~pnoent has, to delit, affotdnd us excellent ~ and mdingml~ic r~ulls. Further follow-up is needed In dlcmommq~ the InogevltyOf theseI~ults and In mo~tm weor or s u ~ Of these ~ Should the~ t~uha continue to prove maisfaaory in thl~ particular group of misl/vely low demand pellets, the significant co4t savings may he l~dlz~d.

L O N G TIgRM REb~ LTS O F CEMENIX,E~ A N D HYBRI~ X O r A L K N E g ~ P L * A S T Y Be~mmln E, BiedNm m, MID,Bo~o~, MA, Paul Dimond, MD, ShellnMcAllhaer,~I" The e,mly n~ultsof CcmenlleaslOlM knee m~tmplmay were promising.H o w ~ , tho~ emly result* have noC held up In Ihe le~ of lime, We parfomlnd a [emxqx~tive review of It ida, in Su~p~o~*Sexpe= fie.ace with Ct.menU~s and hybrid toud knee imhrophmy The flint group c0azlm of ccm=nllcs, PC.Aloud knee anhropits~iss. This group had 22 patinn,,~ with 9 los/to follow-up, leaving 14 knees in 13 palinnts. Avera~ length of follow up was 122 monti~ Of these 14, 7 had revislno al an average Of 45 months, for n failure mitt of 50~. F a i l u ~ were due In polyethyleno fitilure in 3, palelis Ino~ning in 2~ and llbinl la~ening In 2. The Kcond group c o r m of hybrid, tmal knee arthroplasties utilizing ~ PFC knee. This group had 42 patianls with 13 Ical In follow-up, leaving 32 kno~ in 29 patients. Average I~gth of follow-up was 109 monlha.Of ti~se,7 faUadalan averageof 72 mnotha fora falimeroteOf 22%. Fnor fallur~wc~e dee to Iononoin8 of a metM-buched patelin(oaly four metal backed patellm were done in this Kales), • II of which were revised to • cgmentnd, all polyethyle~ l~Clis. Two knees with unn~urfaced palelies were mvitnd for anterior knee pain, and mqutrnd the nddilinn of an all poiyethyleme Qlpalis. One knee w ~ revised for ieslabilily, and was treated by imm=sing the tibisJ liner thickness.

POSTER #17 COMPARISON O F INACTIVATI~ VEI~qUSACTIVATI~ C]PM MACHINES ~ KNEE ARTIEROPLASTY

P O S T E R #19

TOTAL

Otto J. Sdumcklor, MD, Chicago, IL, Samba L Levi, PhD, PT, W'dlItm J. Robb, IVlD, lutmduc~aa: The puq~oz of this study w*s Io ~tcrmiuc if continuous imssive mmino (CPM) In addition to an active physical therapy mglman wus bcueflcinl aPxr total knee mlhmplmay CrKA). This study compmes nmge Of motino mad functional notcengs aft~ T I ~ between an Inm:Uvatnd CPM group and an activmed CPM Iproup. Methodg Sinty.4in pmiems undeq~ng pdmmy to~l kne~ nqdacem~st by no~ anqlam wcm randomly pthcnd Inla the actlvalnd or inactivalnd CPM Ipmup."rim uetlvalnd group follovn:d a mndmd CI~I peon•coL The inactivatnd Onop hnd the operative k g Idac~l In the CPM machine al zero degree. ~ gmupa m:eived the mine active ~ysical therq)y pmemm. Kuee range of n~Xicn meaL~.m,~,,~,',~and the 5F-36 were chlainnd ~ l y , al the time Of dinchat8e, 6 wueks and 6 nlogttha pa4topemtive. 'P,vo lafind t*lest w ~ cand to comp~e functinmd rams, isngth Of may and Imee rang• Of motion. ResMts: Then: were no stathlfically Idgnlfic~t diffenmo~ in range Of motion or functional nUln 8 al dischmge, 6 weeks or 6 months between the Inu~tivmnd and activated CPM 8roupa (p~.05). There no diffenmo~ In length of may (p=.O~ I)bcumlitm 11de study shows tina cnolinumm passive minion ~ e r TKA offem no I~'nefil In obcain. icg nmgn Of motion, fuuetimml status or IItnglh of stay when used with an active phyMcai thenq)y pro&ram. Use of the iuectivmnd CPM was an effort to mole uenomtely mcamre differences due o~y to the minion, net to the apparatua. Basod on thiit randy, we reenouneml only an *Clive phyMcal therapy program in unnomptlcaind pflmmy T K A patients.

long litnn reanlls for the cementing, PeA d~dgn demnomme thai Its early promise has n ~ endured. Cementie~ fixittion does nee wm~ ufilinln 8 this d~dgn. Our hybdd PPC results demonstmtit variable Inog term n~olm. Cemantleas fixation of the femur is durable utilizing this pf~h~ds. If the mbgroup of lugca with hybrid fixation and cemented, polyethylene patellas is exandnnd separately, the m ~ i v M is 100%.

POSTER #'20 PAIN REDUCTION IN "IEq'AL HIP ARTHROPLAb'TY FOLLOWING ADMINb-q'RATION O F A CY'rOKIN~ REGULATING AGENT EIPo2M CUffued W. Cdwdl, Jr. MD,/~/a//~ CA, BeverlyA. Mon11, RN, CNP, MBA, So.tan N. Cop~ /rID,P m a Hanmu, IVlD INTRODUCTION: There have been few new Inlerveminml fot impcovement of acute p~t*opamive pain management until the discovery of HP-22& FIP-228 it n mm-muno6c compound that is • cytokine regulating •8not mspo~dble for the cascade of chemlad slfpuda acnonombic fo¢ Inflammatinn and

hypemndSad*. Evaluate the Itfl']cacy and esfe~y of HP-228, the primary efl*'~*cy ~jectiv¢ was to reduce mucotic cnoanmptino by ~ % . METHODS: ~ais lqume O double blind mudy looks m cue•latin 8 dcaes of HP-228. 81 patiems were randomly assigned to elther plan~o or HP-228. Both grnopa utilized mmphine anlfure (MS) by patient controlled mmlgesic ('PEA). 3 dosing schedoles of HP-228: 511glkg. 10ps/kg und 20,ug/k8 were ndmlnhaenal IV evmy 6 hnom. The tim dose wan administered with hip capsular closure, dosing cnoIlnued until the INT..Awire disctmtinund.

* Dmmmm~~

Myra*~ m ~ , d

R.I~-~I.3~: Evafusbic palhmtu reselvicg I'IP-228 ~ I Ig/kg and 10pgAg d e n s utilized 44% and 43% Ima MS tespeaivoly than the pincabo ipoup. The 20pl~g group attained a 25% decease in pain over me p i s c z ~ group Mthnop this wes r,~ malisdadly significant.

Abstracts From theAAHKS Ninth Annual Meeting ,~fvcnc events d ~ mil~l bc m : a l d t r / t o d m ~ I ~ sea n d Itching ~ simlhu- in both Kloups.

of hYl~culoL RepaU of JedalJon, u u -

CONCLUSION: HP-228 as • phannwologlc Jntctv~tJoo ILled Ifl com~Jl)ltJOtl with MS ~gtmeS sll~ niF~sndy nxhJced nan:odc consumption and impnwed ovcndl retxxled pldn Icvcls. It was well tolerated and safe in thhJ Plume fl cllnk:ad trhd. l"rcatmcut Pllcebo HP-228 3 m ~ HP-228 10m/k6 HP-228 2(hntkg

O

hmmmm ~

Gender MaJe/fcmllc 10/11 8/13 7/10 16/6

Alp: yeml 65.9 71.2 70.2 69/1

N: 17 19 17 20

Inb~l-to-tr~l FCA-MS(mg) 52.7 36.9 33..5°0 39.2 °

Nm 13 17 17 18 01~<0 0.5

Evlluable l~t-MS(1118) 58.5 363 33.5 +* 37-60" "*p=
•

February2000

261