Abstract
Objective: To compare the outcomes of two cementless total hip arthroplasty systems in young patients.
Methods: Between 1987 and 1995, 68 cementless total hip replacements were performed in 50 patients younger than 40 years (range 22–40). Five patients were excluded, and 61 hips in 45 patients were available for evaluation after 7.6 years (range 3.1–11.4). There were 27 Anatomic Medullary Locking (AML, Depuy, Warsaw, Indiana) and 34 Porous Coated Anatomic (PCA, Howmedica, Rutherford, New Jersey) prostheses. The two groups were comparable in gender, age, pre-operative diagnoses, activity levels, sizes of components used and the follow-up periods.
Results: Seven PCA (20.6%) and one AML acetabular components (3.7%) were radiologically loose (p = 0.02). Osteolysis was seen in five AML (18.5%) and 24 PCA hips (70.6%) (p = 0.001). Harris hip scores, revision rates, cumulative survival rates, femoral loosening rates, extent of stress shielding and the average linear penetration rates did not show significant differences between AML and PCA hips.
Discussion and conclusion: the PCA acetabular components had a higher loosening rate; the latter was comparable to the reported rates with this design. Osteolysis was more frequently seen in the PCA hips. Since the two groups were otherwise comparable, it was possible that either the polyethylene particles generated at the articulation could be different, or there could be increased backside wear in PCA acetabular components.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
