title: Association of radiographic osteoarthritis, pain on passive movement and knee range of motion: a cross-sectional study.
abstract: BACKGROUND
  Knee pain is associated with radiographic knee osteoarthritis, but the relationships between physical examination, pain and radiographic features are unclear.
  
  
  OBJECTIVE
  To examine whether deficits in knee extension or flexion were associated with radiographic severity and pain during clinical examination in persons with knee pain or radiographic features of osteoarthritis.
  
  
  METHODS
  Cross-sectional data of the Somerset and Avon Survey of Health (SASH) cohort study.
  
  
  METHODS
  Participants with knee pain or radiographic features of osteoarthritis were included. We assessed the range of passive knee flexion and extension, pain on movement and Kellgren and Lawrence (K/L) grades. Odds ratios were calculated for the association between range of motion and pain as well as radiographic severity.
  
  
  RESULTS
  Of 1117 participants with a clinical assessment, 805 participants and 1530 knees had complete data and were used for this analysis. Pain and radiographic changes were associated with limited range of motion. In knees with pain on passive movement, extension and flexion were reduced per one grade of K/L by -1.4° (95% CI -2.2 to -0.5) and -1.6° (95% CI -2.8 to -0.4), while in knees without pain the reduction was -0.3° (95% CI -0.6 to -0.1) (extension) and -1.1° (-1.8 to -0.3) (flexion). The interaction of pain with K/L was significant (p = 0.021) for extension but not for flexion (p = 0.333).
  
  
  CONCLUSIONS
  Pain during passive movement, which may be an indicator of reversible soft-tissue changes, e.g., reversible through physical therapy, is independently associated with reduced flexion and extension of the knee.
authors.affiliation: Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland; School of Health Sciences, HES-SO Valais-Wallis, University of Applied Sciences and Arts Western Switzerland, Valais, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Hilfiker
authors.affiliation: Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland; CTU Bern, Inselspital, Bern University Hospital, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Jüni
authors.affiliation: Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland; CTU Bern, Inselspital, Bern University Hospital, Switzerland.
authors.forename: Eveline
authors.initials: E
authors.lastname: Nüesch
authors.affiliation: University of Exeter Medical School, Exeter, UK.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Dieppe
authors.affiliation: Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland; CTU Bern, Inselspital, Bern University Hospital, Switzerland; Department of Rheumatology, Immunology and Allergology, Inselspital, Bern University Hospital, Switzerland. Electronic address: rbach@ispm.unibe.ch.
authors.forename: Stephan
authors.initials: S
authors.lastname: Reichenbach
mesh_terms: D000704:Analysis of Variance; D015331:Cohort Studies; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D015588:Observer Variation; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010147:Pain Measurement; D010808:Physical Examination / Q000379:methods; D011859:Radiography / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology*; D012720:Severity of Illness Index
keywords: Knee osteoarthritis; Pain; Range of motion