The rate of total hip arthroplasty after closed reduction of late-detected hip dislocation : 147 hips followed to patient age 70 years.

Abstract

Aims: The outcome of late-detected developmental dysplasia and dislocation of the hip (DDH) deteriorates with the length of follow-up. The aims of this study were to explore the rate of total hip arthroplasty (THA) with follow-up to patient age 60 to 76 years, and to define risk factors for THA.

Methods: Inclusion criteria were patient age at diagnosis < three years, closed reduction, and no acetabular procedures. A total of 114 patients (147 hips) met these criteria: 98 females and 16 males with a mean age of 1.4 years (0.4 to 2.7). Residual acetabular dysplasia was defined as centre-edge (CE) angle < 20° at skeletal maturity. Information on THA was obtained from the Norwegian Arthroplasty Register.

Results: Overall, 39% of the hips (n = 54) had residual dysplasia at skeletal maturity, with a mean CE angle of 14.9° (7° to 19°). In total, 52 hips (35%) had undergone THA at a mean patient age of 53.2 years (33 to 71). Risk factors for THA were residual acetabular dysplasia and severe degree of avascular necrosis. Kaplan-Meier survival analysis, with THA as the endpoint, showed survival rates of 95% in hips without residual acetabular dysplasia at patient age 50 years and 76% at 70 years. In hips with residual dysplasia, the survival rate was 83% at age 50 years and 41% at 70 years. The estimated mean survival time was significantly lower in hips with residual dysplasia than in hips without dysplasia (62.6 years vs 71.4 years; p < 0.001).

Conclusion: The long-term outcome was very good in hips with no residual dysplasia at skeletal maturity. Only 24% of such hips had undergone THA at patient age 70 years. Dysplastic hips showed markedly worse outcomes, with a THA rate of 59% at 70 years. Routine concurrent pelvic osteotomy at the time of reduction in children < three years at diagnosis is hardly indicated.