Remodeling of the Proximal Femur After Upper Femoral Varus Osteotomy for the Treatment of Legg-Calvé-Perthes Disease

Abstract

Upper femoral varus osteotomy of the proximal femur without rotation has been the surgical treatment of choice by the senior author (D.S.W.) in 124 cases of Legg-Calvé-Perthes disease. There have been no previous studies documenting the nature of the remodeling process after this surgical procedure. The authors analyzed the radiographic changes that occur over time at the osteotomy site and the angle of inclination (neck-shaft angle). Inclusion criteria were a minimum of 2 years of radiographic follow-up. Patient follow-up ranged from 2 to 7 years (average 5.3 years). Goniometric measurements were performed at the osteotomy site as well as on the neck-shaft angle on preoperative, postoperative, and yearly AP radiographs. Results were recorded with reference to the percentage of correction per year. The authors also compared the results of patients younger than 8 years of age (group 1) with those older than 8 years of age (group 2). The average percentage of remodeling at the osteotomy site was 60% at 6 years, with 40% of the correction occurring within the first 2 years. The neck-shaft angle remodeled in a similar fashion: there was approximately two-thirds correction by 7 years, with most correction being evidenced within 3 to 4 years. There was no significant difference in remodeling based on the age of the patient at presentation. In conclusion, radiographically significant remodeling is to be expected after femoral varus osteotomy despite the diseased proximal femoral epiphysis.