title: Eccentric rotational acetabular osteotomy for acetabular dysplasia and osteoarthritis: follow-up at a mean duration of twenty years.
abstract: BACKGROUND
  The aim of the eccentric rotational acetabular osteotomy is to correct the deficient acetabular coverage in the dysplastic hip in order to limit the development of secondary osteoarthritis. The purpose of this study was to investigate the results in patients managed with an eccentric rotational acetabular osteotomy after a mean of twenty years.
  
  
  METHODS
  The clinical and radiographic outcomes for the first 126 consecutive patients (132 hips) who underwent an eccentric rotational acetabular osteotomy at our institution were retrospectively evaluated. One hundred and twenty-four patients (130 hips) were evaluated; 117 were women (123 hips). The mean patient age was thirty-seven years (range, fifteen to fifty-nine years) at the time of surgery, and the average duration of follow-up was twenty years. Twenty-three hips in twenty-two patients were also treated with intertrochanteric valgus osteotomy at the time of the eccentric rotational acetabular osteotomy to further improve joint congruency.
  
  
  RESULTS
  The mean preoperative Harris hip score of 70 points (range, 51 to 90 points) improved to a mean of 88 points (range, 35 to 100 points) at the final follow-up. Thirty hips had a fair clinical outcome (Harris hip score, <80 points). In seventeen hips, the eccentric rotational acetabular osteotomy was converted to a total hip arthroplasty. The cumulative survivorship at fifteen years and at the final follow-up at twenty-three years was 97% and 80%, respectively. Four factors led to a poor outcome: a small (≤2.0-mm) preoperative minimum joint space, joint incongruence, simultaneous intertrochanteric valgus osteotomy, and lateral subluxation of the femoral head postoperatively.
  
  
  CONCLUSIONS
  Eccentric rotational acetabular osteotomy is an effective surgical procedure for treating symptomatic dysplastic hips before, and in the early stages of, osteoarthritis. The majority of patients maintained excellent or good native hip function at a mean of twenty years after surgery.
  
  
  METHODS
  Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya City, Japan. E-mail address for Y. Hasegawa: hassey@med.nagoya-u.ac.jp.
authors.forename: Yukiharu
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya City, Japan. E-mail address for Y. Hasegawa: hassey@med.nagoya-u.ac.jp.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Iwase
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya City, Japan. E-mail address for Y. Hasegawa: hassey@med.nagoya-u.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kitamura
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya City, Japan. E-mail address for Y. Hasegawa: hassey@med.nagoya-u.ac.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kawasaki
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya City, Japan. E-mail address for Y. Hasegawa: hassey@med.nagoya-u.ac.jp.
authors.forename: Jin
authors.initials: J
authors.lastname: Yamaguchi
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D057234:Preoperative Period; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome