[Sports activity and risk of arthrosis]

Although the potential risk of exercise-induced osteoarthrosis (OA) of weight-bearing joints such as hip, knee and ankle is of great public health importance, very little is known about it. One reason for this lack of knowledge may be the multifactorial etiology of degenerative joint disease, rendering it difficult to quantify the effect of an isolated factor such as exercise and sport on OA. The present review summarizes the current state of knowledge. Recent epidemiologic studies consistently find a slight increase in the risk of OA of hip and knee in those exercising very heavily, which is more marked in ball games than in endurance disciplines. Several epidemiologic studies (including the methodologically best ones) have investigated the effect of jogging on OA risk. They find that extremely active runners may be exposed to increased risk of OA of hip and knee that should not be totally disregarded. On the other hand, regular jogging in middle age is likely to help maintain physical function. A typical finding is that in former athletes the radiologic signs of degenerative joint disease appear to correspond more to the hypertrophic type (with osteophytes and subchondral sclerosis) than the destructive type (with joint space narrowing). This observation raises the question of the prognostic value of the radiologic signs observed in heavy exercisers. Accordingly, taking into account animal experiments and occupational studies as well, a slight increase in the risk of OA of weight-bearing joints due to very frequent and heavy exercise over many years cannot be entirely ruled out. However, for the majority of (less active) exercisers, recreational physical activity seems neither to increase nor decrease the risk of OA to any marked extent.