Remodelling of femoral head-neck junction in slipped capital femoral epiphysis: A multicentre study

Abstract

Purpose: We examined the remodelling of the femoral head-neck junction in patients with slipped capital femoral epiphysis (SCFE) and the frequency of residual cam deformities. Methods: We reviewed 69 hips in 56 patients with stable SCFE who had undergone in situ pinning. Mean age at slip was 11.7 years and the follow-up period 63.4 months. Cam deformity was evaluated using the anterior offset alpha (α) angle and head-neck offset ratio (HNOR). Results: The average α angle and HNOR significantly improved from 76.2 to 51.3 and 0.086 to 0.135, respectively; 25 hips (36.2 %) still had an α angle greater than 50, and 32 hips (46.4 %) had an HNOR of under 0.145. A multivariate analysis selected age at onset and slip angle as risk factors for cam deformity, with cutoff values 11.1 years and 21.0, respectively. Conclusions: Although most hips had remodelling of the head-neck junction, 29.4 % had residual cam deformities that may be susceptible to femoroacetabular impingement. © 2013 Springer-Verlag Berlin Heidelberg.