title: Comparison of patella cartilage volume and radiography in the assessment of longitudinal joint change at the patellofemoral joint.
abstract: OBJECTIVE
  To compare radiological assessment of the patellofemoral (PF) joint and cartilage volume as measured by magnetic resonance imaging (MRI) in a longitudinal study.
  
  
  METHODS
  One hundred and two subjects with osteoarthritis (OA) had baseline and followup skyline and lateral radiographs and MRI of the same knee. Duration of followup was 1.94 +/- 0.23 years. Mid-patella joint space and narrowest joint space were measured on lateral PF radiographs. Minimum joint space in the lateral and medial facets was measured on skyline radiographs. Rate of progression of PF joint OA was measured quantitatively at each site. Patella cartilage volume was measured from the MRI. The rate of change in each radiographic measure was compared to the rate of change in patella cartilage volume.
  
  
  RESULTS
  The average loss of patella cartilage was 133 +/- 143 microm(3)/yr (4.4%). The loss of joint space over the same period on lateral radiographs was 0.7 +/- 2.6 mm at the narrowest joint space and 0.2 +/- 3.8 mm at the mid-patella joint space. On the skyline radiographs, the loss of joint space at the medial facet was 0.4 +/- 3.9 mm and 0.2 +/- 3.4 mm at the lateral facet. Only change in narrowest joint space on the lateral PF radiographs correlated with change in patella cartilage volume (R = 0.22, p = 0.03).
  
  
  CONCLUSIONS
  Our data suggest that narrowest joint space measured on lateral PF radiographs correlates best with loss of patella cartilage. Further work will be needed to determine how different radiological measures of the PF joint relate to the disease process in OA.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University Medical School, Alfred Hospital, Prahran, Victoria 3181, Australia. flavia.cicuttini@med.monash.edu.au
authors.forename: Flavia M
authors.initials: FM
authors.lastname: Cicuttini
authors.forename: Anita E
authors.initials: AE
authors.lastname: Wluka
authors.forename: Judy
authors.initials: J
authors.lastname: Hankin
authors.forename: Stephen
authors.initials: S
authors.lastname: Stuckey
mesh_terms: D000368:Aged; D001837:Body Weights and Measures; D002357:Cartilage Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging*; D010329:Patella / Q000000981:diagnostic imaging*; D011859:Radiography