Long-term results of a modified Spitzy shelf operation for residual hip dysplasia and subluxation. A fifty year follow-up study of fifty six children and young adults.

PURPOSE: The purposes of this study were to establish long-term outcome of the Spitzy shelf-operation and evaluate whether the procedure would delay osteoarthritis.

METHODS: During 1954-1976, 56 patients (70 hips) underwent Spitzy shelf operation at a mean age of 11.9 years (5 to 22). Indications included residual hip dysplasia or subluxation with Centre-Edge angle < 20°. We used survival analysis with conversion to total hip replacements as end-point. For patients without total hip replacement, information was provided from case records and radiographs. Avascular necrosis was assessed in pre-Spitzy radiographs, when available. Kaplan-Meier product-limit method was used to estimate survival function of the Spitzy shelf operation. Survival was assessed by Cox regression. Univariable Cox regression was performed separately for each variable. Potential predictors (p-value < 0.10) were entered into a multivariable regression model; p-value < 0.05 was considered significant.

RESULTS: Mean survival of the shelf procedure was 39.9 years (21 to 53). Survival fell from 83 % 30 years post-operatively, to 22 % at 50 years. Fifty-three hips (76 %) had undergone total hip replacement at mean age of 49.4 years (33 to 64). Seventeen hips had not received total hip replacement, mean survival 47.9 years (39 to 53).

CONCLUSION: The study showed that Spitzy shelf-operation had satisfactory long-term outcome with hip-survival in almost 90 % at patient age 40 years. The results indicate that Spitzy shelf-operation postpone total hip replacement. We consider Spitzy shelf-operation a good alternative in patients above 8 years. In younger children the procedure is not recommended due to increased frequency of graft resorption.