Knee disorders in carpet and floor layers and painters. Part I. Isometric knee extension and flexion torques.

Knee morbidity, knee extension torque and knee flexion torque were examined among 168 actively working carpet and floor layers and 146 painters. The study included a questionnaire concerning knee disorders and knee symptoms, a clinical examination of the knees and measurement of isometric knee extension and flexion torque. Knee accidents were reported more frequently by carpet and floor layers than by painters. Tenderness of the knees was noted to an equal extent in the two groups. Knee extension torques gradually decreased by increasing age among carpet and floor layers, but not among painters. Body weight and thigh girth were not related to age among carpet and floor layers, but gradually increased with age among painters. Analysis of covariance showed that the torques were most consistently related to thigh girth and age. In addition, the right knee extension torque was related to occupation and tenderness of the patellofemoral joint; the left knee extension torque was related to the knee pain index. These results suggest that occupational kneeling and internal derangement of the knee affect thigh muscles among actively working house builders.