Articular cartilage changes mechanically induced "in vivo". An experimental method approach in animals.

A machine designed upon the principles of a crank lever mechanism was built to produce excessive use of the joints of small animals by means of continuous flexion-extension movements. Articular cartilage changes could be consistently produced after 5 to 10 days of exercise. Histochemical studies of the articular cartilage demonstrated a decrease in proteoglycan and an increase in acid phosphatase. These findings suggest that this animal model may be of value for the analysis of the earliest degenerative stages of the articular cartilage.