Paper #5 Metal-on-metal articulation for total hip replacements

Paper #5 Metal-on-metal articulation for total hip replacements

226 The Journal of Arthroplasty Vol. 11 No. 2 February 1996 Paper #1 U N S A T I S F A C T O R Y R E S U L T S O F A 1ST G E N E R A T I O N M O D U...

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The Journal of Arthroplasty Vol. 11 No. 2 February 1996

Paper #1 U N S A T I S F A C T O R Y R E S U L T S O F A 1ST G E N E R A T I O N M O D U L A R C E M E N T L E S S STEM. A 4 - 9 YEAR F O L L O W UP Michael H. H u t , MD, Baltimore, MD, Mark A. Fye, MD, Richard P. Martin, MD, Laurine E. Zaturski, RN, Kristaps J. Keggi, MD A leading problem in cementless THR is failure to achieve initial optimal fit-fiIl of the femoral canal. This can be improved upon in part by using modular distal sleeves. We now report our experience with one such stem design in a consecutive series of primary surgeries done by a single surgeon and followed prospectively. MATERIALS 121 cementiess THR's were performed using a first-generation modular stem made of Co-Cr-alloy with proximal porous surface and offered distal methacrylate sleeves between 9/85 and 3/88.35 were done for rcvisioas, 3 for complex CDH and tumors, 2 were lost to fulhiw-up, and 1 died prior to 4 years. There were therefore 80 hips (72 pts) for review. There were 48 men and 24 women. The mean age was 63 yrs, height 172 cm, and weight 85 kg. Diagnoses included OA in 74 and ON in 6 hips. 5 different cups were used. Distal sleeves were used in 27 hips (33%). Sleeve sizes (greater than stem substrate) included 2mm in 21, 3ram in 4, and 4ram in 2. Clinical evaluation was with the Harris Hip Scale (HHS). Radiographic evaluation was with the methods of CaUaghan et at, Dorr et at, Engh et at, and Johnston et at. R E S U L T S CLINICAL The mean F/U was 81 months (48-108). The mean preop HHS was 42, which was improved to 92 at 2 years, and 87 at final F/U. Them were 39 excellent, 20 good, 7 fair, 3 poor, and 11 (13.8%) failures. All failures were due to stem loosening, one of which also had cup revision. R A D I O G R A P H I C The mean cup angle was 46 °, cup height lg mm, and mediaiizafion distance 32 ram. There were I pess, 3 prob, 4 def loose cups. There were 16 Dorr A, 47 B, and 17 C femora. The mean proximal canal-f'dl was 84% (AP) and 83% (lat), while distal fill was 97% (AP) and 94% Oat). The mean canal-fill was in fact lower in those hips with sleeves (82% proximal AP & lat; 93% distal AP and 92% distal lat). There were 4 puss, 16 prob, and 7 def loose stems. The overall mechanical failure rate was therefore 11% for the cup and 48% for the stem. Failure incidence was 26% for stems with sleeves and 59% for those without (p<0.01). There was no acetabular osteolysis, but femoral lysis was present in 15 nips (19%). Sleeves were used in 6 of these hips. C O N C L U S I O N Our experience with this particular stem design has been disappointing. Distal sleeve did not appear to have improved the fit-fill, although the failure rate was lower in that subset.

Paper #'2 I M P A C T I O N A U T O G R A F T E N H A N C E M E N T OF F E M O R A L S T E M S IN PRIMARY CEMENTLESS TRA Peter A. Keblish, MD, Allentown, PA, Steven K. Neu reid, MD, Carol Varma, BS PURPOSE: To evaluate the technique of"biologic cement" autograft canal fill using femoral head reamings (via aeetabular graters) in straight stem cemenfless components. CONCLUSION: The technique of impection autograft enhancement using femoral head reamings was successful in a 4 to 11 year follow-up. Femoral stem fixation was successful in 108 of 110 eases (98 %) using moderate-sized straight stem cellared porous-coated prostheses. SIGN/FICANCE:/mpaction autograft enhancement avoids the need for large, stiff femoral stems that have potential for proximal stress shielding, preserves normal bone, enhances corticocancellous interference fit in canals of different geometry, avoids canal splitting/hang-up, and appears to seal off the diaphysis from wear particles. S U M M A R Y O F M E T H O D , RE,S U L T S AND DECISION: Key steps of the procedure include stem selection sized to broach cortical contact in one proximal area; injection of a bone column distal-lateral to proximal-lateral, beginning 1 cm proximal to the measured stem; partial insertion of femoral stem to compress the lateral graft column; injection into proximal-metaphyseal voids; and prosthetic impaction to the cullar-calear stop. Bone slurry density was controlled by adding saline and was inserted via a cement plug syringe. The contained, compliant slurry was driven into cancellous voids as the prosthesis was guided into a slight valgns position by the medially placed proximal bone. Interference press fit was accomplished without risk of fracture. Femoral stem sizes were 10.5 mm (52), 12 mm (33), 13.5 mm (18), 15 mm (4), and 9 ram (3). Clinical and radiologic evaluation of 110 AML femoral prostheses with 4 - 11 years follow-up (mean= 6.9 years) was carded out. There were 42 males and 68 females whose mean age was 66 years (34 -90 yrs.). Diagnosis included OA (86), RAt (16), post-trauma (4), and other (4). Femoral stem fixation was successful in 108/110 of cases (98 %). The autograft fill was visualized radiographically within the first six weeks. Mean item fit-fill ratios at proximal 1/3 and distal 1/3 junctions were .63 and .73, respectively. This suggested that most stems were stabilized via cortleo-cancellous bone interface and not by extensive cortical contact. O f the 2 fixation failures, there was 1 stem fracture and I aseptic loosening; both were in large males with undersized stems. Implants were radiologically stable in 95 % of cases. There were 6 cases of localized osteolysis secondary to seetabular UHMWPE wear in Gruen zones I, VII, without distal extension and no lucency > 2 rnm in zones 11 - VI (distal 2/3). There were 10 cases of incomplete pedestal formation. Average measured subsidence was .6 mm. There were 10 acetabular failures (wear/loosening) and 1 traumatic prosthetic neck fracture. There were no infections.

Paper #3 FIRST GENERATION CEMENTLESS HIp ARTHROPLASTY: LONG TERM RESULTS John S. Xenos, MD, Fort Benning, GA, R. David Heekin, MD, William I. Hopkinson, MD, Carlton G. Savory, MD, Milan S. Moore, MD, John L Callaghan, MD PURPOSE: The purpose of this study is to evaluate the results of a ftrst generation cementless hip prosthesis used in primary hip arthroplasties at a nine to ten year follow-up.

ql- Denotes that s o m e t h i n g of value was received. Presenting a u t h o r is boldfaced.

C O N C L U S I O N : Failure of the acetabular component was the primary cause for revision. The incidence of osteolysis progressed to 64% at nine to ten yeats. Despite the downward trend of the Harris Hip rating, outcome measurements reveal overall patient satisfaction. SIGNIFICANCE: This study provides insight to the performance of uncemented primary hip arthroplasty over a nine to ten year period. S U M M A R Y O F M E T H O D , R E S U L T S AND DECISION: One hundred primary cemenfless total hip arthroplastieg were performed in 91 patients in a prospective consecutive series. The porous coated anatomitr'(PCA) prosthesis was used in all patients. Patients were followed serially at yearly i n t e r v ~ for a minimum of nine to ten years and were evaluated with radiographs and clinical asses~thent. Patients were also queried with a standardized outcome questionnaire at the most r ~ e n t follow-up.

Sixty-nine of 91 patients were still living at the nine to ten year follow-up interval with 72 acetabular and 74 femoral original primary components in place. The average Harris Hip rating was 83 points with 70%-good to excellent scores. Ninety-two percent responded that they were, satisfied with the surgery. Periprosthetie bone loss not due to stress shielding was present in 64% of the hips. Bone loss adjacent to the femoral stem alone occurred in 49%, around the acetabular cup alone in 3%, and around both components in 12%. Revision of 6 acetabular cups and 4 femoral stems had been performed in 7 patients by the 10 year interval. Categories of aseptic failure which necessitated revision included: failure of ingrowth (2 stems), aggressive osteolysis without loosening (2 cups and 1 stem), aggressive osteolysis with loosening (2 cups and 1 stem) and failure of the polyethylene component (1 cup), One acetabular component was revised early to correct malposition.

Paper #4 T C O MP A R I S O N O F F I R S T AND S E C O N D G E N E R A T I O N C E M E N T L E S S PROSTHESES Sreve Tankersley, M E , Baltimore, MD, Michael A. Moot, MD, David S. Hungerford, MD I N T R O D U C T I O N : There have been several studies comparing the radiographic appearance and long term results between first and second generation as well as third generation cemented prostheses. There have been no studies comparing the results of second generation cementless prostheses. The purpose of tnis study was to compare the second generation PCA "E" series to the first generation PCA cemenfless prosthesis. M A T E R I A L S AND M E T H O D S : Forty-two patients who had a PCA "E" series second generation cementless hip replacement were compared to 42 patients with a f'trst generation PCA prosthesis. Patients were directly matched for age, sex, diagnosis, Charuley classification and length of follow-up. A complete clinical and radiographic analysis was performed with a statistical comparison made between the two groups. R E S U L T S : In the "E" series (seannd generation) group there were 40 out of 42 (95%.) good and excellent results at an average follow-up of five years (minimum four year follow-up). This can be compared to 35 out of 42 (83%) good and excellent results in the PCA group (first generation). There was one acetabular component revision in the "E" series group (2%) which can be compared to 6 revisions (15%) in the first generation group (p<.001). The incidence of femoral radiohieandias was 16% (7 hips) for the second generation group compared to 50% (21 hips) in the ftrst generation group (p<.001). The radiolucancies in the "E" series group were small and confined typically to Zones IA and lB. D I S C U S S I O N AND C O N C L U S I O N S : This study has demonstrated a significantly better clinical and radiograpnic result when comparing a second generation cementless prosthesis to a first generation prosthesis. We believe that improvements in design which have included more femoral component sizes, better quality plastic, the use of a 26 millimetar versus 32 millimeter femoral head as well as thicker plastic, may account for these differences.

Paper #5 t M E T A L . O N . M E T A L A R T I C U L A T I O N F O R T O T A L [HP R E P L A C E M E N T S Kevin R. l'Iflton~ MD, Los Angeles, CA, Lawrence D. Don', MD, Zhinian Wan, MD p U R P O S E : Polyethylene articulate debris is known to cause osteolysis of bone with THR. Decreasing wear is necessary. We report our 4 year experience using modem metal-on-metal articulation. C O N C L U S I O N : No wear can be measmod radiographically. Satisfactory clinical and radiogrsphie results are obtained. SIGNIFICANCE: Short term follow up shows that modem metal-on-metal articulation is an alternative which can reduce the particulate debris. S U M M A R Y O F M E T H O D , R E S U L T S AND DECISION: 71 patients were operated with metal-on-metal articulation between 1990 and 1994 with 60 patients having 2-4 year follow-up. The acetabular component was the Weber cup which was cemented into each nip. Patients were followed prospectively with Harris Hip Scores and radiographs. 40 patients had bone ingrowth stems and 20 had cemented stems. 17 patients had bilateral hips with one metal-on-plasbe and one metai-on-metah 60 hips with 2.8 year average follow-up is 3 deaths, II revisions, 1 infection, 0 loose cup or stem, and II hips with osteolysis. No wear can be measured radiographically. 2 implant retrievals of patiants who died show no metal staining of dssues and no measurable wear. 1 of 60, patients has a click, but no other symptoms are present from the metal-on-metah HHS improved from 49 to 93. 17 patients with bilateral hips can tell no difference. 7% of sockets have radioincent lines which were present postoperatively with no progressinn.The amount of particulate debris and ion readings from synovial fluid were determined in twelve patients at more than one year from implantation. None of the patients had significant particulate debris; however, metal particles of one to ten microns were detected in five of these patients, only one of which had a cemented femoral prosthesis. Metal particles were also found in four of seven patients with metal-polyethylene prostheses implanted greater than one year. Modem metal-on-metal does not have the same rate of socket loosening in the first 2 years as occurred with the McKee-Farrar. This fact combined with satisfactory clinical and radiographic results, implant retrieval, and synoviai fluid data suggests that continued study of metal-on-metal articulations is indicated.