Concomitant osteotomy with primary total hip replacement

104

The Journal

of Arthroplasty

Vol. 9 No. 1 February

For uitimate viability, any bone graft musl be: 1) Of appropriate size, 2) Have sufficient vascularity available, 3) Be firmly fixed, and 4) Be loaded in compression. In this femoral revision technique, the graft is: 1) Morselized, 2) Contained in a vascular envelope, 3) Fixed by PMMA, and 4) Loaded in compression by the Collarless Polished Taper Stem. SUMMABY: Exchange femoral arthroplasty with compacted morselized bank bone and cemented collarless polished taper stem promotes the building of a new proximal femoral envelope which shows no attenuation or deterioration over time.

PAPER

of an stablIlt> a three-

Methods and MalewIs. The fmlre clement model was generated from CT uxm data of a human proxrmal femur mlplanled wlh a commercially available prosthesIs Loads were apphed lo the femoral head and greater lrochanter lo s,mulatc smgle-leg stance and stair chmbmg Friction heha\lor of the bone-implant interface \‘las modeled using non-lmear mterface elements to snnulate a smooth, press-fit stem and a porous coated ~lem Relative molmns were calculated along Ihe medial surface of the prosthesis at the calcar. the upper one-quxter. the lover one-quarrer and the stem “P Fmdmps Av~al mot,on was greater under smgle-stance loadmg while ~ra"s~crcc mohons were greater under sla~r chmblng loads (mau~mum of eight llrnes higher I” the calcar loca(~on) For both loading conditions the porous coated sfem showed lower axml relatwe motions than the smo~,th ~fem by about one-third and lower transverse relatwe mo,,ons by about one-fourth except at the stem "p whcrc tbc

The total relal,ve

mol,o"~

\vere below

70 mlcr""s

excep, m the most provlmal locahon where the relabve mofaons were 17@ morons for the smooth stem and I40 morons for the porous coated stem Con~lusmn press-filled proximally

Porous coaled femoral stems prowde grearer stahllay than a smoolh Implam Star cllmbmg loads generate large (ransverse motwns whwh could be detrImental to nnplanl srab,hlv and bony mgrowlh

PAPER 'XRC SEISLDINQ

Ronald M.D.,

#8

INFL"ENCR OF PROSTEESIS IN CRtUNTLR ss TOTAL EIP

E. Talbert, Freeno, CA;

M.D. William

Beaumont, L.

p <

.03).

CONCLUSION: different different of stress design.

This study shows that implants of two designs and materials cause significantly degrees of strees shielding. The phenomenon shielding can be controlled through implant

PAPER

lntroductmn Implant stablhty IS crucial to the long-term performanu uncemented total htp replacement The effects of porous coatmg on implant was studled, under smgle-leg stance and stax cllmbmg loads. usmg dlmensmnal fmlte element model

were about the same

Each patient underwent DEXA scanning of both hips. BO"f2 density was then tabulated by Gwen zones and the density of each zone in the implanted femur was expressed as a percentage of the density in the corresponding zone of the contralateral normal hip. I" Group A, lees density was see" in all zones, with the greatest difference being 55% of normal in zone 7. Group B showed all zones to be greater than 95% of normal except zone 7 (83%). Comparing equivalent ~0x8 in the two groups, the differences were statistrcally significant for all zones except zone 4 (matched t-test,

#7

THE EFFECT OF POROUS COATING AND LOADING CONDII’IONS ON TOTAL HIP FEMORAL STEM STABILII’Y Fu Hau. Ph D, Houston, Jeffrey D Reuben, MD Ph D , Houston, John Akm. Ph D , Houston. TX

values

1994

Bargar,

DESIGN ON REPLACEMENT

TX;

Thomas H.D.,

STRESS

P. Gross,

#9

ROLE OF HYDROXYLAPATITE COATING IN POSTOPERATIVE RECOVERY AFTER CEMENTLESS HIP REPLACEMENT A PROSPECTIVE RANDOMIZED TRIAL C. S. Ranawat. MD, New York, NY, Rajiv G. Deshmukh. MBMS. FRCS. William F. Flynn, Jr.. MD Purms~: To study the role of hydroxylapatite coating on femoral component in reducing thigh pain and improving quality of function after noncemented hip replacements. Conclusion: Hydroxylapatite coated femoral stems appear to offer an advantage by reducing the severity and incidence of thigh pain Sianlflcance: Cementless hip replacements have overtaken cemented ones as the preferred procedure in young, active individuals. thigh pain and delay in resuming normal activity are reported by many patients. Hydroxylapatite coating can enhance recovery. of Method.Results and Discussion: A prospective randomized study is underway at our institution using a noncemented hip replacement system that provides a customized fit in the femur using a range of dlstel diameters and proximal geometries. All implants have plasma sprayed porous coating proximally. The patients are randomized into two groups, one of which receive hydroxylapatite coated implants. The study is divided into 3 phases. Phase 1 compares the thigh pain incidence and severity as well as return to normal function in the 2 groups. Phases 2 and 3 will compare long term clinical and radiological results. Thigh pain was graded into 3 grades based on it’s severity and frequency. Visual analog scales (0 to IO) were used for mail intervlews to eliminate observer bias. Recovery and return to function were judged by the need to use cane or crutch and presence or absence of limp. The first 100 consecutive operations performed by a smgle surgeon with a minimum followup of 6 months are included in this report, The degree of thigh pain experienced by patients receiving the hydroxylapatite coated implants was less though the difference was not highly significant (p=.O55). The maximum benefit was perceived by males with body weight below 165 Ibs. No difference was found in the incidence of limp and the use of cane or crutch. The role of hydroxylapatite coaling in cementless hip replacements warrants further study in view of these findings.

Sacramento,

CA

Femoral implant design may have a strong INTRODUCTION: influence on stress shielding of the proximal femur resulting in varying degrees of bone resorption. This study compares matched patients with Cementless femoral hip lkstheses of two v&y different design philosophies One group (A) received an AML using DEXA analysis. implant (5/S coated, CT-Co, DePuy) which relies on distal ingrowth for fixation and tranemits axial, torsional, and bending loads distally. The other group (B) received a CT-based custom implant (Titanium, Techmadica) with proximal ingrowth pads and a parametric design that maximizes proximal endosteal contact to transmit axial and torsional loads, incorporating a cylindrical smooth stem distally to transmit bending loads. Eight patients in each of two NSZRODS AND IULTERSALS: groups were matched for age (mean = 60 yrs), weight (ew. 168.9 lbe), qender 15 females, 3 males), diaqnosis iosteoarthritip),;ace (c8ucasian), and length of hollow up (3 to 4 years). All patients had an excellent clinical result (Harris ecore > 90), and had a normal implants showed radiographic opposite hip and all evidence of bone ingrowth (Engh's criteria).

#lo

PAPER

CONCOMITANT

REPLACE"ENT Bernasek, M.D.,

OSTEOTOMY WITH Michael D. Ciepiela, Kenneth A. Gustke,

PURPOSE: Evaluation femoral anatomy required arthroplasty. CONCLUSION: Shortening osteotomy heals predictably with standard prostheses of abductor musculature. SIGNIFICANCE: This arthroplasty using standard excessive femoralanteversio" femur 1s necessary.

of

PRIMARY

M.D.,

total hip o*teotomy

TOTAL

HIP

N.D., Thomas Tampa, Florida. pat;ents to

L.

i" whom fac111tate

or

and and

derotatrunal femoral facilitates arthroplasty allows anatomic alignment

technique prostheses or where

fac111tates L" patients shortening

of

hip with the

Selected Twenty one primary hip arthroplasties I" 18 patrents required femoral osteotomy to correct excessive femoral anteversion or to shorten the femur in cases with DDH lost traumatic deformity (4), Morquio' s 112). JP.A 12). i2) or post i&~-al osteotomy (1). Osteotomy level was Lntertrochanterlc in 5 hips. subtrochanterlc ln 16 hips, Intramedullary fixation by the lmplantwas sufficient in but 5 hrps that required supplemental plate a11 Average healing time was 4.5 months (3-12) in fixation. the suhtrochanteric qrouo and 3.2 months (2.5-5) in the lntertrochanteric grbup.Standard off the shelf cement fixation patients. which developed massive postoperatively. At Harris excellent

an

average HL~ Scoring results,

prostheses was used heterotopic

follow

were used in in 3 hips each ossification

up of 45 months revealed there were 2 fair and 1 poor.

permits This cechnlque proximal femoral landmarks abductor mechanical advantage modular implants that do not abductor musculature leading Healing of the 1mplngement.

(17-84). 18 good

all

of

the to

anatomic posLtlonl*g of and musculature allowing without using custom or correct malposition of the to weakness and osseous osteotomy is predictable.

PAPER

“11

OSTEOLYSIS WITH A CEMENTLESS DUALGEOMETRY ACETABULAR COMPONENT IN TOTAL HIP ARTHROPLASTY D. L. Pomemy, M.D., S.B. Sanders, M.D., W. E. Badenhausen, M.D.. J.A. Empson. RN.ONC and K. E. Suthers. MEA. Louisville, Kentucky Forty-nine dual geometry acetabular components matched with a 32mm head diameter were implanted in 46 patients between early 1986 and late 1988 for an average follow up time of 7.6 years. The overall incidence of femoral and acetabular osteolysis is reported as well as the frequency of lucencies in the three zones. The final fixation of the components is reported as well as the incidence of mechanical failure of the components in the form of survivorship analysis using revision as the end point. At final foilow up evaluation using serial roentgenograms, the overall final five fixation scores for the acetabular components were 40 (87%) optimum, There was no evidence of component ( I I %) stable, and one (2%) revised. migration in any of the serial cases. The incidence of acetabular radioluciences is 8.2% in four cases. These lucencies were seen immediately postoperative in three cases and have not progressed. The incidence of femoral and acetabular osteolysis is. to date, 10.9% and 6.5$. respectively. Of the patients demonstrating some form of osteolysis. five underwent revision of the cup liner and a change of femoral head diameter to 28mm. Acetabular osteolysis has been noted in two of these five patients and femoral osteoiysis has been seen in four of the five cases. One additional patient required a total cup revision due to the presence of acetabular osteolysis in zones 2 and 3. Femoral ostcolysis proximally was also noted in this revision case. This represents a 10.9% (5/46) incidence of femoral osteolysis in the index group The revision rate for the acetabular component, therefore. is 2.2% (l/46) with a cumulative survivorship of 99.2. The incidence of mechanical failure for the liner is 10.9% (5/46). At final follow-up the clinical outcome using the Harris Hip score for the overall group was 91.9 pts (range: 58.100). This represents an increase of 42 pts from the overall preoperative score. The overall incidence of gmin or buttock Of the five patients who underwent revision of the pain is 4.4% in two patients. cup liner. only two (40%) reported any groin or buttock pain and this pain was describe at best as mild or occasional. Therefore, 60% of tbe patients with significant osteolysis and wearing of the cup liner requiring revision were clinically asymptomatic. Factors contributing to the failure of the liners were the use of a large 32mm diameter femoral head and a thin polyethylene liner resulting in polyethylene wear debris-induced osteolysis. A more significant finding is that 60% of the patients whose liners were revised were asymptomatic. These preliminary findings make annual radiographic and clinical examination crucial. One further recommendation is the use of 28mm diameter femoral head allowing for a thicker polyethylene insert with this cup design if it is to be used clinically.

PAPER

“12

A PREDICTABLE PRE-OPERATIVE THE FAILED ACETABULUM USING

EVALUATION PLAIN X-RAYS

OF

Wayne G Paprosky, MD, FACS. Glen Myn, IL. Robert E Magnus. MD, Davenport, IA, Michael S. Bradford. MD, FRCSC. Glen Ellyn, IL, Terry I. Younger, MD, Hoffman Estates. IL PURPOSE Determine if plain x-rays alone adequately and

Abstracts

From the AAHKS

Third

Annual

Meeting

105

consistently assess acetabular bone stock to determine the need for CONCLUSION Certain recurrent radiographic support allografi parameters on plain x-rays accurately predict the need for support allografi and type of reconstmction in the vast majority of cases SIGNIFICANCE This inexpensive assessment of acetabular bone stock using plain x-rays facilitates pre-op planning and avoids inconvenient , expensive and technique dependent computer planmng METHODS, RESULTS AM) DISCUSSION 3 IO definitely loose Mean age acetabulae confirmed by Harris’ criteria were evaluated Pre-op standing AP was 57 with a mean time to failure of nine years and lateral x-rays were assessed in three ways component migration was measured using Ranawat and Dorr’s method. bone loss of the ischium and inferior tear drop was graded and the integrity of Kohier’s line was noted At surgery , 59 patients had inadequate acetabular bone stock to stabilize a porous cup and reqmred support aliograft Fit&n had bone loss severe enough IO warrant whole The remaining 236 needed only larger diameter acetabular allograft porous cups with or without a higher hip center Correlation with pre-op x-rays showed that cup migration of less than two cm indicated a supportive dome. Osteolysis of lschium and infenor tear drop reflected posterior wall damage Penetration of Kohler’s line indicated severe anterior column damage Pre-op x-ray evaluation and intra-op correlation shows that superior migration of less than two cm with moderate ischial and inferior tear drop osteolysis Migration of greater requires only a large cup and normal hip center than two cm. with moderate/severe mfenor lysis requires support allografi. When Kohler’s line was also violated . a whole acetabular allografl and cemented polyethylene cup was necessary

PAPER

REVISION EXTENDED

OF THE DlFFlCl~L’I’ PROXIMAL FEMORAL

#13

--__

FEMCIK llSING OSTEOTOMY

AN

Michael S Bradford, MD, FRCSC, Glen Ellyn. IL. .Terry I Younger. MD, Hoflinan Estates, IL, Wayne G Paprosky. MD, FACS, Glen Ellyn, IL; Robert E Magnus, MD, Davenport. IA To develop a new technique for the removal of well fixed PURPOSE cemented or non-cemented femoral implants and to allow correction of proximal femoral deformities CONCLUSION This allows for the relatively simple removal of femoral implants and cement. while allowing for almost guaranteed osteotomy union and no increased complications SIGNIFICANCE This easily learned method will simplify the revision femoral technique while preserving remaining bone stock for component fixation METHODS, RESULTS AND DISCUSSION Thirty-one patients have been treated in this new manner This involves performing a posterolateral proximal femoral osteotomy through one-third of the circumference and then hinging open the femur with the anterior sofi The osteotomy is fixed with at least two tissue attachments still intact cables to provide secure fixation. Mean age was 63 years with an average of two previous procedures The average follow-up is I6 months. The osteotomy was indicated for cement removal in 24 cases. non-cemented component removal in five cases and to correct proximal deformities in two cases Average osteotomy length was I3 2 cm with an average of 8 I cm of femoral component iiaation distally. The osteotomy healed in all cases in three months of followup in no cases was there more than two mm of osteotomy fragment migration Nine of the cases required augmentation cortical strut aliografts due to severe femoral bone loss prior to osteotomy There have been no complications related to the osteotomy This type of surgery can be technically demanding and may be tirther complicated by a well fixed cementless component, well bonded distal cement beyond the apex of the anterior bow. or a deformed proximal femur This new osteotomy addresses all of these problems and changes what may have been a very difficult case into a more simplified procedure