title: Rotational acetabular osteotomy for advanced osteoarthritis secondary to dysplasia of the hip.
abstract: BACKGROUND
  Satisfactory intermediate and long-term results of rotational acetabular osteotomy for the treatment of early osteoarthritis secondary to developmental dysplasia of the hip have been reported. The purpose of this study was to examine the results of rotational acetabular osteotomy in patients with advanced osteoarthritis secondary to developmental dysplasia of the hip.
  
  
  METHODS
  We performed a retrospective review of the results of rotational acetabular osteotomy in forty-three patients (forty-three hips). All of the patients had radiographic evidence of advanced-stage osteoarthritis, defined as narrowing of the joint space with cystic radiolucencies and small osteophytes according to the staging system of the Japanese Orthopaedic Association. Forty-one patients were female, and two were male. The mean age was 43.8 years at the time of surgery, and the mean duration of follow-up was 8.5 years. Clinical follow-up was performed with use of the system of Merle d'Aubigné and Postel. The center-edge angle, acetabular roof angle, head lateralization index, and minimum width of the joint space were measured on radiographs made preoperatively, postoperatively, and at the time of final follow-up. Postoperative joint congruency was classified into four grades.
  
  
  RESULTS
  The mean preoperative Merle d'Aubigné clinical score was 13.3 points, which improved to a mean of 15.4 points at the time of the latest follow-up (p < 0.0001). The mean center-edge angle improved from 0.7 degrees preoperatively to 29 degrees at three months postoperatively (p < 0.0001), the mean acetabular roof angle improved from 30 degrees to 11 degrees (p < 0.0001), the mean head lateralization index improved from 0.69 to 0.65 (p < 0.01), and the mean minimum width of the joint space improved from 2.2 to 2.5 mm (p < 0.0003). Ten hips had radiographic evidence of progression of osteoarthritis. Kaplan-Meier survivorship analysis, with radiographic signs of progression of osteoarthritis as the end point, predicted a ten-year survival rate of 72.2%.
  
  
  CONCLUSIONS
  Rotational acetabular osteotomy for advanced osteoarthritis secondary to dysplasia of the hip in properly selected patients can improve clinical scores and is associated with a lack of radiographic signs of progression of osteoarthritis in most patients.
  
  
  METHODS
  Therapeutic Level IV.
authors.affiliation: Department of Artificial Joints and Biomaterials, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima City 734-8551, Japan. yasuyuji@hiroshima-u.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yasunaga
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Terayama
authors.forename: Ryuji
authors.initials: R
authors.lastname: Tanaka
authors.forename: Takuma
authors.initials: T
authors.lastname: Yamasaki
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Ishii
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000328:Adult; D005260:Female; D006618:Hip Dislocation, Congenital / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000209:etiology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D012399:Rotation