title: Distribution of MR-detected cartilage defects of the patellofemoral joint in chronic knee pain.
abstract: OBJECTIVE
  The aim of the study was to detect cartilage defects and determine the center of these defects in MR imaging of the patellofemoral joint (PFJ) in middle-aged people with chronic knee pain.
  
  
  METHODS
  In the format of a prospective study of early osteoarthritis (OA), this cross-sectional study of the signal knee (the most painful one at inclusion in the study in 1990) in 59 individuals, 30 women and 29 men (aged 41-58 years, mean 50 years) with chronic knee pain, with or without radiographically determined knee OA, was examined using MR imaging on a 1.0 T imager. Cartilage defects and the center of these defects in the PFJ were recorded.
  
  
  RESULTS
  Cartilage defects were found more often in the patella (40 knees) than in the femoral trochlea (23 knees) (P<0.001) and were unevenly distributed in the patella (P<0.001), with most cartilage defects in the mid-patella.
  
  
  CONCLUSIONS
  Since cartilage defects occur more commonly in the mid-patella, radiographs obtained with a knee flexion of approximately 45 degrees may be more accurate to show cartilage defects of early OA of the PFJ than views with another knee flexion.
authors.affiliation: Department of Diagnostic Radiology, County Hospital, Helsingborg, Sweden. t.boegard@telia.com
authors.forename: T L
authors.initials: TL
authors.lastname: Boegård
authors.forename: O
authors.initials: O
authors.lastname: Rudling
authors.forename: I F
authors.initials: IF
authors.lastname: Petersson
authors.forename: K
authors.initials: K
authors.lastname: Jonsson
mesh_terms: D000328:Adult; D002357:Cartilage Diseases / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D010146:Pain / Q000175:diagnosis*; D011446:Prospective Studies