Treatment of Symptomatic Residual Deformity in Legg-Calvé-Perthes Disease: Mid-Term Outcomes and Predictors of Failure After Surgical Hip Dislocation with Femoral-Head Reshaping and Relative Neck Lengthening.

BACKGROUND: Treating patients with symptomatic hips after healed Legg-Calvé-Perthes disease (LCPD) is challenging, mainly because of the complexity of the deformity. We performed a retrospective study to evaluate clinical and radiographic outcomes, measure the survival rate, and identify predictors of failure following a surgical hip dislocation (SHD) with femoral-head reshaping and relative femoral-neck lengthening for the treatment of symptomatic residual hip deformity after healed LCPD.

METHODS: We identified 60 patients undergoing SHD for the treatment of symptomatic residual LCPD deformity. Fifty-one (85%) of the patients (mean age, 16.3 ± 4.7 years; 21 male patients [41%]), were followed ≥4 years after surgery. We defined surgical failure as conversion to, or recommendation for, total hip arthroplasty (THA) or a Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score of ≥10 at the most recent follow-up. We used a multivariable Cox proportional hazards model to identify factors that were predictive of failure. The rate of survival free from failure was estimated using a Kaplan-Meier curve.

RESULTS: Twenty (39%) of the patients met 1 of the end-point criteria for surgical failure, while the hips of the remaining 31 (61%) of the patients were successfully preserved at a median follow-up of 10.2 years (interquartile range, 5.7 to 12.9 years). The estimated survival was 80% (95% confidence interval [CI] = 70% to 92%) at 5 years and 66% (95% CI = 53% to 81%) at 10 years. Independent factors associated with surgical failure were the severity of preoperative pain as assessed by the WOMAC pain score (hazard ratio [HR] = 1.16; 95% CI = 1.03 to 1.30; p = 0.01) and the severity of the deformity as assessed by the anteroposterior alpha angle (HR = 1.06; 95% CI = 1.01 to 1.11; p = 0.01).

CONCLUSIONS: We found that SHD with relative femoral-neck lengthening and osteochondroplasty of the femoral head-neck junction was associated with improved deformity as assessed radiographically and decreased pain and symptoms of stiffness among patients with symptomatic residual LCPD deformity. Preoperative pain and deformity were identified as predictors of surgical failure. Further research is needed to establish the role of SHD and other procedures in preserving the hip over the long term.

LEVEL OF EVIDENCE: Therapeutic L evel IV . See Instructions for Authors for a complete description of levels of evidence.