title: Association of bone attrition with knee pain, stiffness and disability: a cross-sectional study.
abstract: OBJECTIVE
  Bone pathologies as detected on MRI are associated with the presence of pain in knee osteoarthritis (OA). The authors examined whether bone attrition assessed on x-rays was associated with pain, stiffness and disability.
  
  
  METHODS
  The authors analysed x-rays of 1326 knees with OA from 783 individuals participating in the cross-sectional population-based Somerset and Avon Survey of Health. The diagnosis of OA was defined by the presence of osteophytes in anteroposterior (AP) or lateral views. Bone attrition was graded from 0 (no attrition) to 3 (severe attrition >10 mm) and Kellgren and Lawrence (K/L) scores were assigned on AP views. Logistic regression models adjusted for gender, age, body mass index, effusion and K/L scores were used to determine whether bone attrition was associated with pain, stiffness and disability.
  
  
  RESULTS
  Pain was reported in 84 knees (74%) with radiographic bone attrition compared with 505 (42%) without bone attrition (adjusted OR 2.22, 95% CI 1.29 to 3.80). The adjusted OR was increased for day pain but not for night pain (p for interaction <0.001). Stiffness was reported for 85 knees with bone attrition (75%) and 437 knees without (36%) (adjusted OR 3.23, 95% CI 1.85 to 5.64). Disability was reported by 40 individuals with bone attrition (50%) and 140 individuals without (24%) (adjusted OR 2.09, 95% CI 1.19 to 3.68).
  
  
  CONCLUSIONS
  Bone attrition detected on conventional x-rays using a simple cheap technique is strongly associated with the presence of day pain, stiffness and disability in knee OA.
authors.affiliation: Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine, University of Bern, Switzerland. rbach@ispm.unibe.ch
authors.forename: Stephan
authors.initials: S
authors.lastname: Reichenbach
authors.forename: Paul A
authors.initials: PA
authors.lastname: Dieppe
authors.forename: Eveline
authors.initials: E
authors.lastname: Nüesch
authors.forename: Susan
authors.initials: S
authors.lastname: Williams
authors.forename: Peter M
authors.initials: PM
authors.lastname: Villiger
authors.forename: Peter
authors.initials: P
authors.lastname: Jüni
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D010146:Pain / Q000209:etiology* / Q000473:pathology; D011859:Radiography; D016059:Range of Motion, Articular; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology