Knee joint moments in work-related situations

Circumstantial evidence in the literature points towards a relationship between heavy labour and arthrosis of the knee. The aim of this study was to demonstrate which occupational activities yield the greatest knee moments and thus indicate possible gonarthrosis-inducing occupational hazards. Twelve healthy and uninjured medical students were studied in set occupational situations in a laboratory for gait analysis, using a force plate with video display of force vectors and knee joints (VIFOR). With normal walking as a baseline for moment it was found that activities involving knee flexion, such as lifting objects from one level to the other, climbing stairs and ladders, and jumping down, revealed a significant increase in moment. On the other hand, carrying objects in one or both hands did not yield significant increase in knee moment compared with normal walking. Flexed knee lifting had significantly lower moment than jumping down from a height of 0.5 m on to one or both feet. Three levels of knee moment could thus be identified, i.e., normal walking, flexed knee lifting and jumping down.