THE EFFECTS OF NON-WEIGHT-BEARING AND LIMITED MOTION ON THE TENSILE PROPERTIES OF THE MENISCUS

Recent clinical studies have suggested that many of the complications of prolonged immobilization after knee surgery can be prevented by per mitting early motion while minimizing loading of healing tissues. The purpose of this study was to determine the effects of such a regimen o n the tensile properties of the meniscus. The right knee of 10 skeleta lly mature sheep received a sham operation after which the hindlimb wa s placed in a harness that prevented weight bearing while permitting l imited knee motion. The left knee served as the nonoperated control. T welve weeks after surgery, paired specimens from the medial meniscus o f each limb were tested in tension with the load parallel to the circu mferentially oriented collagen fibers. No significant differences in t he modulus, tensile strength, and ultimate strain between treated and control medial menisci were identified. Our data thus suggest that pre venting weight bearing while permitting even limited motion of the kne e will prevent any detrimental effect on the tensile properties of the meniscus in the circumferential direction.