| A first generation reconstituted collagen tendon/ligament prosthesis was evaluated using rabbits as an animal implantation model. Collagen fibers were extruded and synthetically crosslinked by physical and chemical means. These fibers had ultimate strengths ranging from 14 MPa for dehydrothermally and cyanamide treated fibers to 42 MPa for glutaraldehyde treated fibers, and ultimate strains of 12 to 14%, respectively, comparable to natural soft tissues. Biocompatibility studies in rats showed degradation rates ranging from 2 weeks to over 6 weeks depending on the treatment of the fibers. As an Achilles tendon and anterior cruciate ligament replacements in rabbits, the strength regain of the structure closely related to the healing process and turn over of implant to host tissue. In the Achilles tendon model, implants with fibers treated dehydrothermally followed by cyanamide gained strengths at a faster rate than autograft controls by the 20th week reaching 75% of the strength of an intact tendon. These collagen fibers may enhance remodeling of tissue, in contrast to, autografts which may require additional remodeling of tissue inhibiting regain of strength. Delayed biodegradation of the implant (Up to 1 year post-implantation) such as those fibers treated with glutaraldehyde resulted in encapsulation and chronic inflammation. These studies suggest that by mimicking the physical structure of tendons and ligaments and controlling the biodegradation rate of the synthetic collagen prosthesis, early recovery of an injured or torn tendon/ligament structure is promoted. |
