title: Avascular osteonecrosis of the acetabulum.
abstract: OBJECTIVE
  To investigate the possible occurrence of osteonecrosis in the acetabulum in patients with non-traumatic necrosis of the femoral head.
  
  
  METHODS
  One hundred and seventy-nine patients with non-traumatic femoral head necrosis were assessed by MRI and radiography for the presence of acetabular necrosis. Three criteria were established to differentiate between osteonecrosis and osteoarthritic changes: (1) heterogeneous morphology and irregular contours of the lesion; (2) typical demarcation lines of osteonecrosis; (3) deficient accumulation of intravenous gadolinium in the affected regions.
  
  
  RESULTS
  In four patients histological confirmation of acetabular necrosis was obtained. The MR analysis of 22 acetabula (9.5% of those examined) showed changes which suggested osteonecrosis. No cystic lesions were demonstrated in the subchondral bone of any patient. Two cases of acetabular necrosis were found without an ipsilateral femoral head necrosis. In two patients of the 14 who had undergone total hip replacement following necrosis of the femoral head, aseptic loosening of the acetabular component was found.
  
  
  CONCLUSIONS
  The study suggests that acetabular necrosis may be an accompaniment to aseptic necrosis of the femoral head. Further work is required to assess its importance in premature loosening of the acetabular element of total hip arthroplasty.
authors.affiliation: Orthopaedic Department, University of Hamburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Fink
authors.forename: J
authors.initials: J
authors.lastname: Assheuer
authors.forename: A
authors.initials: A
authors.lastname: Enderle
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.forename: W
authors.initials: W
authors.lastname: Rüther
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000328:Adult; D003287:Contrast Media; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications*; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006622:Hip Prosthesis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA