ABSTRACT
Using Kaplan-Meier's method, the authors found a survival probability of 50% after 25 years in a group of 68 shelf arthroplasties in adult hips. Forty-four shelf procedures, performed at a mean age of 33 years, had sufficient clinical and radiological data to perform a retrospective study with at least 26 years of follow-up. There were 16 dysplastic non-dislocated hips, 19 subluxated hips and 9 dislocated hips. Fifteen shelves (34%) were still in place in 1996 with a mean follow-up of 31.6 years and 29 (66%) underwent reintervention after a mean interval of 20.4 years. The functional result at the latest follow-up, or just prior to reintervention for the reoperated shelves, was good in 13 cases (30%), fair in 28 and poor in 3. Progressive deterioration following shelf procedures was mainly associated with two factors: preoperative congruency (ratio of the largest to smallest joint line thickness), especially if below 0.7, and preoperative osteoarthritis. Reoperation rate climbed from 30% for grade 1 or 2 osteoarthritis, to 73% for grade 3 and to 88% for grade 4. The mean age at the time of reintervention was 54.5 years. Shelf arthroplasties performed for secondary hip osteoarthritis with joint space narrowing (77% in this series) had a mean survival of 20.5 years. The authors believe that a shelf procedure has its place in the conservative surgical management of painful acetabular dysplasia in the adult, even in the presence of osteoarthritis.