title: Knee-straining work activities, self-reported knee disorders and radiographically determined knee osteoarthritis.
abstract: OBJECTIVE
  Earlier studies indicate an increased risk of knee disorders in trades with knee-straining work positions, but no dose-response correlation has yet been documented. This study examined whether self-reported knee complaints and radiologically diagnosed knee osteoarthritis are dose-related to kneeling and squatting work positions.
  
  
  METHODS
  Worktasks for floor layers and carpenters were video-recorded, and the time spent in knee-straining work positions was quantified. A questionnaire study included 133 floor layers, 506 carpenters, and 327 compositors, all without earlier acute knee trauma. Radiological examinations were carried out on a stratified sample (N = 150) from the questionnaire study. The individual exposure was calculated from the amount of knee strain quantified in the video-recorded worktasks, the self-reported time spent in the worktask, and the number of years in the trade. Statistical analyses were carried out with a binary logistic regression model, adjusting for age, body mass index, smoking, and knee-straining sports activities.
  
  
  RESULTS
  The odds ratios for self-reported knee complaints and radiographically determined knee osteoarthritis were increased in relation to the degree of knee-straining work demands for workers with low-to-moderate, high, and very high exposure to knee-straining work demands in a comparison with the reference group, without knee-stressing work activities.
  
  
  CONCLUSIONS
  The results indicate that there is a dose-response correlation between knee-straining work activities and the development of self-reported knee complaints and radiologically diagnosed knee osteoarthritis.
authors.affiliation: Department of Occupational and Environmental Medicine, Viborg Hospital, Resenvej 25, DK 7800 Skive, Denmark. lilli.kirkeskov.jensen@sygehusviborg.dk
authors.forename: Lilli Kirkeskov
authors.initials: LK
authors.lastname: Jensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003718:Denmark; D005160:Facility Design and Construction; D006801:Humans; D007407:Interviews as Topic; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D010003:Osteoarthritis / Q000000981:diagnostic imaging*; D011859:Radiography; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D014743:Videotape Recording