Purpose: Premature physeal closure of the proximal femoral physis has been reported in Legg-Calve-Perthes Disease (LCPD). However, the timing of its occurrence had not yet been reported. We proposed (1) to determine the timing of premature physeal closure in unilateral LCPD with serial radiographic evaluation, and (2) to evaluate the relationship between the premature physeal closure and Herring classification, leg-length discrepancy (LLD), Stulberg classification, and trochanteric overgrowth.
Methods: We performed a retrospective study with serial radiographs of 27 patients diagnosed with LCPD. The difference in the timing of physeal closure between the hips was calculated. The involved hip was classified according to Herring classification. The LLD and ATD index at latest follow up was measured. The mean values were calculated and statistical comparison of variables was done using the Fisher's exact test.
Results: The mean difference of physeal closure at the involved hip compared to the uninvolved side was 3.5 years (range, two to five years). Hips demonstrating premature physeal closure were associated with Herring B/C and C (p = 0.01) and LLD >1 cm (p = 0.02). There is no correlation between Stulberg classification, trochanteric overgrowth and premature physeal closure (p = 0.06 and p = 0.19).
Conclusions: We may expect premature physeal closure of the proximal femoral physis in patients with LCPD to occur 3.5 years earlier than normal hips. Presence of premature physeal closure can be an adjunct diagnostic tool in the prognostication of LCPD outcomes. Future studies directed toward premature physeal closure in LCPD and associated growth disturbances are necessary.