Formation of cartilage from rib perichondrium grafted to an articular defect in the femur condyle of the rabbit.

In immature and adult rabbits perichondrium from the rib was autologously grafted to a surgically created defect of the articular surface of the femur condyles exposing the subchondral bone. After one week of immobilization the animals were allowed to move freely until sacrifice after 7 and 13 weeks. In all grafted cases newly formed cartilage of a hyalin appearance filled the defect. Using the technique of intraarticular administration of tritiated thymidine, mitotic activity was found in the superficial zone of the regenerated cartilage indicating that the proliferation of cells is initiated from the perichondrium. In control cases where no graft covered the defect no cartilage was found.