Abstract
Purpose: The purpose of this work was to evaluate clinical and radiographic factors affecting early outcome of resurfaced hip prostheses in young adults.
Material and methods: Among 119 hybrid resurfaced prostheses with a metal-on-metal bearing implanted in patients aged 40 years or less, 94 were retained for analysis at minimum two years follow-up or failure. Mean age was 34.2 years (15–40), 71% of the patients were men and 14% had had a prior hip operation. A risk index (SARI) was developed from the Chandler index.
Results: Mean follow-up was three years (2–5). Items of the UCLA score improved: pain 3.1 versus 9.2, walking 5.8 versus 9.4 (p=0.00). Three hips required revision total hip arthroplasty at mean 27 months (2–50) and ten patients had radiographically significant modifications. Comparing these 17 hips with the 47 others, indexes showed 4.7 versus 2.6 for the SARI (p=0.000) and 2.6 versus 2.8 for the Chandler score (p=0.358). There was no correlation with reconstruction mechanics, function, walking or scoring. Valgus implantation of the femoral piece and the lateral lever arm were significantly correlated (r=0.39, p< 0.001).
Discussion: If the SARI was > 3, the relative risk of early complications was 12-fold higher than if the SARI was 3. Because of the distinct fixation of the femoral implant, a SARI=2 was attributed when there was a cyst in the femoral head and weight was < 82 kg (lower weight correlated with smaller implant, r=0.60). This index can be used to improve patient selection in order to define the role of arthroplasty resurfacing in the treatment of hip degeneration.
Correspondence should be addressed to SOFCOT, 56 rue Boissonade, 75014 Paris, France.
