title: Dynamic knee loading is related to cartilage defects and tibial plateau bone area in medial knee osteoarthritis.
abstract: OBJECTIVE
  To evaluate the relationship between dynamic mechanical loading, as indicated by external knee adduction moment (KAM) measures during walking, and measures of articular cartilage morphology and subchondral bone size in people with medial knee osteoarthritis (OA).
  
  
  METHODS
  180 individuals with radiographic medial tibiofemoral OA participated. Peak KAM and KAM angular impulse were measured by walking gait analysis. Tibial cartilage volume and plateau bone area, and tibiofemoral cartilage defects were determined from magnetic resonance imaging using validated methods.
  
  
  RESULTS
  Both peak KAM (coefficient=0.42, 95% confidence interval (CI) 0.04-0.79, P=0.03) and KAM impulse (coefficient=1.79, 95% CI 0.80-2.78, P<0.001) were positively associated with the severity of medial tibiofemoral cartilage defects. KAM impulse was also associated with the prevalence of medial tibiofemoral cartilage defects (odds ratio 4.78, 95% CI 1.10-20.76, P=0.04). Peak KAM (B=0.05, 95% CI 0.01-0.09, P=0.02) and KAM impulse (B=0.16, 95% CI 0.06-0.25, P=0.002) were positively associated with medial:lateral tibial plateau bone area, and KAM impulse was also associated with medial tibial plateau bone area (B=133.7, 95% CI 4.0-263.3, P=0.04). There was no significant association between KAM measures and tibial cartilage volume.
  
  
  CONCLUSIONS
  Peak KAM and KAM impulse are associated with cartilage defects and subchondral bone area in patients with medial knee OA, suggesting that increased mechanical loading may play a role in the pathological changes in articular cartilage and subchondral bone that occur with medial knee OA.
authors.affiliation: Centre for Health, Exercise and Sports Medicine, Physiotherapy, Melbourne School of Health Sciences, University of Melbourne, Victoria, Australia. mark.creaby@acu.edu.au
authors.forename: M W
authors.initials: MW
authors.lastname: Creaby
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: K L
authors.initials: KL
authors.lastname: Bennell
authors.forename: R S
authors.initials: RS
authors.lastname: Hinman
authors.forename: B R
authors.initials: BR
authors.lastname: Metcalf
authors.forename: K-A
authors.initials: KA
authors.lastname: Bowles
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000368:Aged; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging; D016138:Walking; D016474:Weight-Bearing / Q000502:physiology*