Physical exercise and risk of severe knee osteoarthritis requiring arthroplasty

Objectives. To examine the association between physical exercise and the ri sk of severe knee osteoarthritis requiring arthroplasty. Subjects and methods. A case-control study was carried out in which the cas es were men (n = 55) and women aged 55-75 yr (n = 226) receiving knee arthr oplasty for primary osteoarthritis at the Kuopio University Hospital. Contr ols (n = 524) were selected randomly from the population of Kuopio province . Lifetime physical exercise was assessed retrospectively. Cumulative exerc ise hours were calculated and divided into two classes by mean (low-high). Results. The risk of knee osteoarthritis requiring arthroplasty decreased w ith increasing cumulative hours of recreational physical exercise. After ad justment for age, body mass index, physical work stress. knee injury and sm oking, the odds ratios (with 95% confidence intervals) of knee arthroplasty were 0.91 (0.31-2.63) in men with a low number of cumulative exercise hour s and 0.35 (0.12-0.95) in those with a high number of cumulative exercise h ours, with a history of no regular physical exercise as the reference. For the women. the corresponding odds ratios were 0.56 (0.3-0.93) and 0.56 (0.3 2-0.98). Conclusion. Moderate recreational physical exercise is associated with a de crease in the risk of knee osteoarthritis.