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 permitting early motion while minimizing loading of healing tissues. The purpose of this study was to determine the effects of such a regimen on the tensile properties of the meniscus. The right knee of 10 skeletally mature sheep received a sham operation after which the hindlimb was placed in a harness that prevented weight bearing while permitting limited knee motion. The left knee served as the nonoperated control. Twelve weeks after surgery, paired specimens from the medial meniscus of each limb were tested in tension with the load parallel to the circumferentially oriented collagen fibers. No significant differences in the modulus, tensile strength, and ultimate strain between treated and control medial menisci were identified. Our data thus suggest that preventing weight bearing while permitting even limited motion of the knee will prevent any detrimental effect on the tensile properties of the meniscus in the circumferential direction.