88 Original article Radiological outcome of proximal femoral varus osteotomy for the treatment of lateral pillar group-C Legg–Calve ´ –Perthes disease M. Cemalettin Aksoy a , M. Cenk Cankus b , Ahmet Alanay a , Muharrem Yazici a , Omur Caglar a and A. Mumtaz Alpaslan a 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. J Pediatr Orthop B 14:88–91  c 2005 Lippincott Williams & Wilkins. Journal of Pediatric Orthopaedics B 2005, 14:88–91 Keywords: Legg–Calve ´ –Perthes disease, treatment, varus osteotomy a Department of Orthopaedics and Traumatology, Hacettepe University Faculty of Medicine, Ankara and b Department of Orthopaedics and Traumatology, Sani Konukoglu Medical Center, Gaziantep, Turkey. Correspondence and requests for reprints to M. Cemalettin Aksoy, Angora Evleri, Ruyalar Cad., Masal Sok., e-2 blok, no# 31, 06530, Beysukent, Ankara, Turkey. Tel: + 90 312 305 1793; fax: + 90 312 310 0161; e-mail: caksoy@hacettepe.edu.tr Introduction The treatment of severe Legg–Calve´–Perthes disease (LCPD), especially after the age of 6 years, is still a challenge. The main aim of treatment is to change the natural history of the disease and provide a good long-term outcome. Numerous radiographic classification systems have been proposed for LCPD [1–4]. The purpose of all classification systems is to predict the natural history of the disease and aid in selecting a treatment modality. Herring’s lateral pillar classification has been shown to be easy to use and reliable [2,5,6]. The prognosis of Herring group C hips, especially at older ages, is relatively poor. Proximal femoral varus osteotomy is advocated for the treatment of these hips [7,8]. The aim of this treatment is to contain the femoral head in the acetabulum and provide an optimum environment for healing [9]. The results of this treatment, however, are still debatable. In the current study, we evaluated the radiological outcome of proximal femoral varus osteotomy in patients with Herring group C hips and who were older than 6 years of age. Materials and methods Results from 26 hips of 24 patients with Herring group C Legg–Calve´–Perthes disease (LCPD) treated with uni- planar, intertrochanteric varus osteotomy, older than 6 years of age and who had lateral pillar group C hips were evaluated retrospectively. Patients who had lateral pillar group C hips treated conservatively or with other methods were not included in the study. The decision to operate was based on clinical and radiological risk factors and the surgeon’s discretion. All the hips had lateral subluxation (considered present if more than 15% of the ossified femoral epiphysis was uncontained by the acet- abulum or Shenton’s line was broken). Lateral calcification was observed in eight hips, Gage’s sign was observed in three hips and horizontal alignment of the growth plate was present in 14 hips. There were 22 male and two female patients in the group. There were 17 left hips and nine right hips. Both hips of the two bilaterally affected patients were treated in the same way. The mean age of the patients at the onset of the disease was 8.3 years (range, 7–11). The age of the patients was less than 9 years in 13 cases. All patients had Herring group C hips and they were at the initial or fragmentation stage of the disease at the time of surgery. Herring’s lateral pillar classification defines the lateral pillar as the lateral 15–30% of the femoral head [2]. Group C hips are defined if less than 50% of the lateral pillar is intact in anteroposterior (AP) pelvis radiographs during the fragmentation phase of the disease. The minimum follow-up in all patients was 10 years and the mean follow- up was 13.03 years (range, 10–20). Containment of the ossified epiphysis in the abduction position was confirmed in all patients before the surgery 1060-152X  c 2005 Lippincott Williams & Wilkins Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.