title: The repair process of osteonecrosis after a transtrochanteric rotational osteotomy.
abstract: BACKGROUND
  Many studies have reported the factors influencing the progression of collapse and development of osteoarthritis after a transtrochanteric rotational osteotomy. It is not well understood how the healing process of the osteonecrotic area occurs after this procedure.
  
  
  OBJECTIVE
  We evaluated (1) the osteonecrotic area after a successful transtrochanteric rotational osteotomy radiographically; and (2) determined whether specific perioperative clinical and radiographic factors related to the difference(s) in the healing process after a transtrochanteric rotational osteotomy.
  
  
  METHODS
  We retrospectively reviewed 64 patients (70 hips) among 402 patients (507 hips) who had a transtrochanteric rotational osteotomy between 1981 and 1996 and showed no evidence of progression of collapse or joint space narrowing at 10 years after the osteotomy. Forty-eight hips (45 patients) were males and 22 (19 patients) were females, with a mean age of 37 years (range, 12-57 years) at the time of surgery. An anterior rotational osteotomy was performed for 57 hips and a posterior rotational osteotomy was performed for 13 hips. We recorded various perioperative factors potentially influencing repair and assessed the radiographs at last followup for various features indicating repair.
  
  
  RESULTS
  Ten years after the transtrochanteric rotational osteotomy, the osteonecrotic area in 50 hips (71%) had osteosclerotic changes radiographically (Group I), while 20 hips (29%) had normal bony architecture without sclerotic changes (Group II). We observed no difference between Groups I and II with regard to the age, gender, use of corticosteroids, etiology, and radiographic stage.
  
  
  CONCLUSIONS
  Although the reason for this difference in the healing patterns remains unknown, this study indicates the majority of the hips showed osteosclerosis after a transtrochanteric rotational osteotomy, while approximately 30% of the hips showed a normal bony architecture.
authors.affiliation: Department of Orthopaedic Surgery, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. yamataku@ortho.med.kyushu-u.ac.jp
authors.forename: Takuaki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ikemura
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sugioka
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D011859:Radiography; D013997:Time Factors; D016896:Treatment Outcome; D014945:Wound Healing; D055815:Young Adult