title: Determinants of change in patella cartilage volume in healthy subjects.
abstract: OBJECTIVE
  To examine whether the amount of patella cartilage in healthy, middle-aged subjects is stable or changes over time, and what factors may influence the changes.
  
  
  METHODS
  Eighty-five subjects (28 men and 57 women, mean age 55.5 yrs) had magnetic resonance imaging of their dominant knee at baseline and 2 years later. Patella and tibial cartilage volume was measured at baseline and followup. Risk factors assessed at baseline were tested for their association with change in patella cartilage volume over time.
  
  
  RESULTS
  Mean annual percentage loss of patella cartilage was 2.1 (95% confidence interval: 1.1-3.2; p < 0.001). Age, gender, body mass index, and initial cartilage volume did not affect rate of change of patellar cartilage volume. There was a weak association between change in patellar cartilage volume and change in lateral tibial cartilage volume (R = 0.23, p = 0.03) but not medial tibial cartilage volume (R = 0.09, p = 0.43).
  
  
  CONCLUSIONS
  In healthy subjects, a significant amount of patella cartilage is lost annually. The poor correlation between patella and tibial cartilage loss suggests that pathogenetic mechanisms for osteoarthritis in the patellofemoral and tibiofemoral joint may differ. Further work will be required to determine whether the rate of patella cartilage loss in healthy subjects is steady or phasic, and to determine which factors can be modified to reduce cartilage loss.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University Medical School, Alfred Hospital, Prahran, Australia.
authors.forename: Fahad
authors.initials: F
authors.lastname: Hanna
authors.forename: Anita E
authors.initials: AE
authors.lastname: Wluka
authors.forename: Peter R
authors.initials: PR
authors.lastname: Ebeling
authors.forename: Richard
authors.initials: R
authors.lastname: O'Sullivan
authors.forename: Susan R
authors.initials: SR
authors.lastname: Davis
authors.forename: Flavia M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000375:Aging / Q000502:physiology; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000473:pathology; D010329:Patella / Q000033:anatomy & histology*