Experimental intrinsic healing of flexor tendons based upon synovial fluid nutrition.

The healing process of totally cut and subsequently resutured rabbit flexor tendons kept isolated in the knee joint cavity and free in the synovial fluid was studied by histological and ultrastructural techniques. This experimental model represents a "tissue culture in situ," where the tendon is nourished by diffusion from the synovial fluid only and where no adhesions are formed. Under these conditions there is a proliferation of tendon cells and deposition of collagen resulting in bridging of the suture line. On the basis of these findings, it is assumed that the tendon cells possess an intrinsic potential of repair, provided they obtain a sufficient nutritional supply. In the present experimental model, this nutrition was provided by way of diffusional pathways from the synovial fluid.