A prospective multicenter study of Legg-Calvé-Perthes disease: functional and radiographic outcomes of nonoperative treatment at a mean follow-up of twenty years.

BACKGROUND: Long-term studies have indicated good outcomes for most patients with Legg-Calvé-Perthes disease. However, clinical experience suggests that less favorable outcomes are common. We sought to prospectively document pain and function in a cohort of adults who had previously been treated nonoperatively for Legg-Calvé-Perthes disease.

METHODS: Patients in our region with Legg-Calvé-Perthes disease were enrolled between 1984 and 1991 as part of a multicenter prospective trial and were treated with hip range-of-motion exercises or bracing. Patients returned for physical examination, radiographs, and completion of outcome measures including the Nonarthritic Hip Score (NAHS) and the Iowa Hip Score (IHS).

RESULTS: Fifty-six patients (fifty-eight hips) were examined at a mean of 20.4 years (range, 16.3 to 24.5 years) after enrollment. The mean NAHS was 79 (range, 35 to 100), and the mean IHS was 74 (range, 43 to 100). Three patients had required hip arthroplasty and one patient had required a pelvic osteotomy. Fourteen (26%) of the remaining hips had no hip osteoarthritis, sixteen (30%) had mild osteoarthritis (Tönnis grade 1), and twenty-four (44%) had moderate or severe osteoarthritic changes on radiographs (grade 2 or 3). Femoroacetabular impingement indicated by physical examination was associated with pain and with poorer outcomes on the IHS and the NAHS (p = 0.0004, 0.0014, and 0.0007, respectively). The Stulberg classification was significantly associated with impingement on physical examination (p = 0.0495), the NAHS (p = 0.003), and the Tönnis grade (p = 0.012). Multivariate logistic regression showed that only the Stulberg classification was significantly associated with the NAHS (p = 0.0032); the odds ratio for a Stulberg type of I or II compared with IV or V in patients with a fair or poor NAHS was 0.101 (95% confidence interval, 0.018 to 0.573).

CONCLUSIONS: Pain, arthritis, and ongoing hip dysfunction are common in patients with Legg-Calvé-Perthes disease that was treated nonoperatively. Hips rated as Stulberg type III or IV more frequently had poor or fair outcomes on the IHS and NAHS (61% and 72% for type III and 77% and 60% for type IV). Patients with a lateral pillar type of B, B/C, or C frequently had pain and radiographic evidence of osteoarthritis. Clinical signs of femoroacetabular impingement were associated with pain and with lower functional scores. This prospective study establishes a modern benchmark for outcomes following nonoperative, weight-bearing treatment of Legg-Calvé-Perthes disease.