title: Anterior femoro-acetabular impingement due to acetabular retroversion. Treatment with periacetabular osteotomy.
abstract: BACKGROUND
  This study was performed to evaluate whether symptomatic anterior femoro-acetabular impingement due to acetabular retroversion can be treated effectively with a periacetabular osteotomy.
  
  
  METHODS
  The diagnosis of femoro-acetabular impingement was based on clinical symptoms, a positive anterior impingement test, and findings of acetabular rim lesions on magnetic resonance imaging. The radiographic diagnosis of acetabular retroversion was based on the cross-over and posterior wall signs. Twenty-nine hips in twenty-two patients (average age, twenty-three years) underwent a periacetabular osteotomy. An arthrotomy was performed in twenty-six hips in order to visualize intra-articular lesions and, in selected cases, to improve a low femoral head-neck offset. The range of motion of the hip was measured, clinical evaluation was performed with use of the score described by Merle d'Aubigné and Postel, and the anterior center-edge angle of Lequesne and de Sèze was measured on radiographs preoperatively and at the time of the latest follow-up.
  
  
  RESULTS
  The duration of follow-up averaged thirty months (range, twenty-four to forty-nine months). The anterior center-edge angle of Lequesne and de Sèze decreased significantly from a preoperative average of 36 degrees (range, 26 degrees to 52 degrees ) to a postoperative average of 28 degrees (range, 16 degrees to 46 degrees ) (p = 0.002). There was a significant increase in the average range of internal rotation (10 degrees, p = 0.006), flexion (7 degrees, p = 0.014), and adduction (8 degrees, p = 0.017). The average Merle d'Aubigné score increased from 14.0 points (range, 12 to 16 points) preoperatively to 16.9 points (range, 15 to 18 points) postoperatively (p < 0.001), and the result was good or excellent for twenty-six hips. Three hips underwent subsequent surgery: one, because of early postoperative loss of reduction; one, for correction of posteroinferior impingement; and one, because of recurrent signs of anterior impingement.
  
  
  CONCLUSIONS
  Periacetabular osteotomy is an effective way to reorient the acetabulum in young adults with symptomatic anterior femoro-acetabular impingement due to acetabular retroversion
authors.affiliation: Department of Orthopaedic Surgery, University of Berne, Inselspital, Switzerland. klaus.siebenrock@insel.ch
authors.forename: K A
authors.initials: KA
authors.lastname: Siebenrock
authors.forename: R
authors.initials: R
authors.lastname: Schoeniger
authors.forename: R
authors.initials: R
authors.lastname: Ganz
mesh_terms: D000077:Acetabulum / Q000503:physiopathology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D005260:Female; D006617:Hip Dislocation / Q000150:complications* / Q000175:diagnosis / Q000000981:diagnostic imaging; D006621:Hip Joint; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011859:Radiography; D012399:Rotation / Q000009:adverse effects*; D016896:Treatment Outcome