title: The clinical and radiographic results of intertrochanteric curved varus osteotomy for idiopathic osteonecrosis of the femoral head.
abstract: OBJECTIVE
  In this study, postoperative results of intertrochanteric curved varus osteotomy (CVO) for idiopathic osteonecrosis of the femoral head (ION) were studied retrospectively and optimal indication of CVO was considered.
  
  
  METHODS
  Between 1995 and 2011, CVO was performed in 51 patients (53 hips) for the treatment of ION in our department. The patients who had the potential to obtain acetabular coverage of more than one-third of the intact articular surface on pre-operative AP hip radiographs in maximum abduction were considered suitable for this operation. For radiological assessment, a ratio of necrotic volume, a ratio of postoperative intact surface on the weight-bearing area, progression of collapse, shortening length of the lower limb, and lateralization of great trochanter were evaluated.
  
  
  RESULTS
  The mean ratio of necrotic volume was 16.9 %. The mean ratio of postoperative intact surface on the weight-bearing area of the femoral head was 51.7 %. The progression of collapse was observed in two hips (ratio of necrotic volume 10.4, 39.8 %; ratio of postoperative intact area 36.5, 38.1 %). The mean shortening length of the lower limb was 9 mm, and the mean lateralization of great trochanter was 3 mm. One hip (ratio of necrotic volume 11.6 %, ratio of intact area 35.8 %) was converted to THA because of the progression of osteoarthritis at 55 months after CVO.
  
  
  CONCLUSIONS
  The results of CVO for ION were successful, if this procedure was indicated for cases with intact load-bearing area more than 40 %.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan, michiosprinter@yahoo.co.jp.
authors.forename: Michio
authors.initials: M
authors.lastname: Hamanishi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yasunaga
authors.forename: Takuma
authors.initials: T
authors.lastname: Yamasaki
authors.forename: Ryo
authors.initials: R
authors.lastname: Mori
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shoji
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology / Q000601:surgery*; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult