RISK ANALYSIS OF OCCUPATIONAL FACTORS INFLUENCING THE DEVELOPMENT OF ARTHROSIS OF THE KNEE

The aim of this study was to identify occupational activities importan t for the development of arthrosis of the knee, taking into account th e confounding factors that were suspected or could be recognized. In t he archives of the Department of Diagnostic Radiology at the Malmo Uni versity Hospital all radiographs of weight-bearing knees of patients w ith painful knee joints from the period 1982-1986 were reassessed. We found 340 probands, i.e., subjects with arthrosis of the knee of at le ast grade 1 in the Ahlback classification. These probands and their ag e-and sex-matched controls (680) were analyzed by a validated question naire for details of activities at work inducing knee moment over thre e 15-year-periods as well as their history of knee injuries at work or in their leisure time. The questionnaire was answered by 266 (79%) ar throsis probands and 463 controls (70%). The results of the questionna ire answers and of the recorded history of knee injuries were statisti cally analyzed by logistic regression. The relative risk of knee arthr osis was slightly increased (RR: 1.9, CI: 1.4-2.7) in probands with we ight-bearing knee bending, i.e., dynamic load of the knee joint when b ending, whereas knee injuries (meniscectomies and haemarthrosis) were associated with a higher risk. Weight-bearing knee bending corrected f or confounders was not a significant factor for knee arthrosis. Overwe ight was observed to increase the relative risk. A sedentary professio n had, on the other hand, a low risk. The knee injuries (66) were, but for 9 probands, sustained in leisure activities, mainly soccer. We th us conclude that work which induces weight-bearing knee bending by its elf does not significantly increase the risk of developing arthrosis o f the knee - knee injuries and overweight are more important.