title: Rotational acetabular osteotomy in patients forty-six years of age or older: comparison with younger patients.
abstract: BACKGROUND
  Satisfactory intermediate and long-term results of periacetabular rotational osteotomy for early osteoarthritis secondary to dysplasia of the hip have been reported for patients in the third and fourth decades of life. The purpose of the present study was to examine the usefulness of rotational acetabular osteotomy in patients older than forty-six years of age.
  
  
  METHODS
  A retrospective review of two groups of patients who had been treated with a rotational acetabular osteotomy was conducted. The older group consisted of twenty-four patients (twenty-six hips) with early-stage osteoarthritis who had a mean age at the time of surgery of 50.9 years (range, forty-six to fifty-eight years) and a mean duration of follow-up of 8.2 years (range, five to thirteen years), and the younger group consisted of sixty patients (sixty-three hips) who had a mean age at the time of surgery of 34.4 years (range, thirteen to forty-five years) and a mean duration of follow-up of 8.3 years (range, five to fourteen years). Clinical follow-up was based on the system of Merle d'Aubigne and Postel. The center-edge angle, acetabular roof angle, and head lateralization index were measured on radiographs made preoperatively, postoperatively, and at the time of follow-up. Preoperative and postoperative joint congruencies were classified into four grades.
  
  
  RESULTS
  Preoperatively, the mean Merle d'Aubigne clinical score was 13.9 points in the older group and 14.1 points in the younger group. In both groups, this score improved significantly to a mean postoperative follow-up score of 16.6 points (p < 0.0001), with no significant difference between the two groups. The mean center-edge angle improved from 3.2 degrees preoperatively to 34 degrees postoperatively (p < 0.0001) in the older group and from -2.1 degrees preoperatively to 34 degrees postoperatively (p < 0.0001) in the younger group. The mean acetabular roof angle improved from 29 degrees to 5.9 degrees (p < 0.0001) in the older group and from 31 degrees to 2.9 degrees (p < 0.0001) in the younger group. The mean head lateralization index improved from 0.67 to 0.64 (p < 0.01) in the older group and from 0.66 to 0.61 (p < 0.0001) in the younger group. Progression of osteoarthritis was observed radiographically at the time of follow-up in five hips in the older group and in four hips in the younger group. Kaplan-Meier survivorship analysis, with radiographic progression of osteoarthritis as the end point, predicted a ten-year survival rate of 70.0% in the older group and 93.7% in the younger group; this difference was not significant, with the numbers available (p = 0.062, log-rank test).
  
  
  CONCLUSIONS
  Our results indicate that rotational acetabular osteotomy for elderly patients can prevent progression of osteoarthritis (as indicated by a survival rate of 70% at ten years) and that in selected cases it is worthwhile at least as a temporizing operation.
authors.affiliation: Department of Orthopaedic Surgery, Hiroshima University School of Medicine, Kasumi, Minami-ku, Japan. yasuyuji@hiroshima-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Yasunaga
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Ochi
authors.forename: Y
authors.initials: Y
authors.lastname: Ikuta
authors.forename: T
authors.initials: T
authors.lastname: Hisatome
authors.forename: J
authors.initials: J
authors.lastname: Nakashiro
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D018450:Disease Progression; D005260:Female; D006618:Hip Dislocation, Congenital / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000150:complications / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome