The development of tissue around various prosthetic implants used as replacements for ligaments and tendons.

Currently, no ideal prosthesis is available for the repair or replacement of tendons and ligaments. Although filamentous carbon is a useful fibrogenic material, it does not fulfill the ideal requirements of a soft-tissue prosthesis. A number of other synthetic fibers were examined for biocompatibility and fibrogenic properties in both cell culture and in vivo implantation. It was found that the less extensible materials could adversely affect the normal morphology of the induced collagen. None of the materials examined exhibited mechanical properties similar to those of collagen; therefore, a composite prosthesis was designed to incorporate three criteria: mechanical characteristics similar to those of the normal tissue, fibrogenic capability to induce replacement collagen, and replacement collagen developing with normal morphologic characteristics. A prototype prosthesis for the Achilles tendon in rabbits, evaluated by mechanical and histologic methods, shows that these criteria can be fulfilled and thus form the basis for future prosthetic tendon and ligament research.