Experimental models to promote healing of tears in the avascular segment of canine knee menisci.

Longitudinal tears were created in canine lateral menisci and techniques were applied to induce healing by removal of a core of tissue from the periphery of the meniscus to the tear or by implantation of a vascularized synovial flap into the tear. The meniscal tears did not heal in knees that were not immobilized, and they healed poorly and sporadically in knees that were immobilized in a cast but bore some weight. However, a higher percentage of tears that were treated by the core-removal or synovial-flap technique healed when the knee was firmly immobilized and weight-bearing was prevented by the use of an external skeletal fixator across the joint for eight to twelve weeks. Neovascularization and access to a source of reparative cells appear to be important in the healing process.