title: Cartilage lesions in the hip: diagnostic effectiveness of MR arthrography.
abstract: OBJECTIVE
  To evaluate the diagnostic performance of magnetic resonance (MR) arthrography in the detection of articular cartilage lesions in patients suspected of having femoroacetabular impingement and/or labral abnormalities.
  
  
  METHODS
  Forty-two MR arthrograms obtained in 40 patients with a clinical diagnosis of femoroacetabular impingement and/or labral defect were retrospectively analyzed. Two readers independently interpreted the images for cartilage lesion location, depiction, and characteristics. Within 6 months after MR arthrography, each patient underwent open hip surgery, during which the entire cartilage of the hip joint was inspected. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated. kappa values were calculated to quantify the level of interobserver agreement.
  
  
  RESULTS
  At surgery, most (37 [88%] of 42) cartilage defects were identified in the anterosuperior part of the acetabulum. In 23 (55%), 12 (29%), 10 (24%), and 10 (24%) hips, lesions were found in the posterosuperior acetabulum, anteroinferior acetabulum, posteroinferior acetabulum, and femoral head, respectively. The sensitivities and specificities of MR arthrographic detection of cartilage damage in all regions combined were 79% (73 of 92 regions) and 77% (91 of 118 regions), respectively, for reader 1 and 50% (46 of 92 regions) and 84% (99 of 118 regions), respectively, for reader 2. At interobserver comparison, agreement was fair (kappa = 0.31) for detection of cartilage lesions in the femoral head and poor (kappa <or= 0.2) for detection of lesions in all acetabular regions.
  
  
  CONCLUSIONS
  Cartilage lesions are common in young and middle-aged patients with femoroacetabular impingement and/or labral abnormalities and are most frequently found in the anterosuperior part of the acetabulum. 2003
authors.affiliation: Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland. mariusschmid@hotmail.com
authors.forename: Marius R
authors.initials: MR
authors.lastname: Schmid
authors.forename: Hubert P
authors.initials: HP
authors.lastname: Nötzli
authors.forename: Marco
authors.initials: M
authors.lastname: Zanetti
authors.forename: Tobias F
authors.initials: TF
authors.lastname: Wyss
authors.forename: Juerg
authors.initials: J
authors.lastname: Hodler
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D006621:Hip Joint / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity