Results from 26 hips of 24 Legg-Calve-Perthes disease patients were evaluated retrospectively. There were 22 male and two female patients in the study group. The mean age of the patients was 8.3 years and the mean follow-up was 13.03 years. All the patients were older than 6 years of age and all of them had lateral pillar group C hips. The patients were treated with intertrochanteric uniplanar varus osteotomy. All the patients were mature at the time of the last evaluation. Radiological end results were evaluated according to Stulberg's classification. Six hips healed with spherical congruency (Stulberg class 1 or 2), 19 with aspherical congruency (Stulberg class 3 or 4) and one with aspherical incongruency (Stulberg class 5). Six of 14 hips treated before 9 years of age healed with spherical congruency but all hips treated after 9 years of age healed with Stulberg class 3, 4 or 5 results. Trochanteric overgrowth was evident in 20 hips. The results of this radiological outcome study showed that Herring class C hips treated with proximal femoral varus osteotomy had a poor outcome, especially after 9 years of age in this group of patients. (c) 2005 Lippincott Williams & Wilkins.