Preliminary Development of a Collagen–PLA Composite for ACL Reconstruction

Our laboratory is developing resorbable composite implants for reconstruction of the anterior cruciate ligament (ACL) of the knee. Composites were fabricated by embedding parallel collagen fibers within a poly(lactic acid) (PLA) or collagen matrix. The mechanical properties, resorption rates, and subcutaneous tissue reactions were determined for both types of composites. The tensile strength and modulus of collagen–PLA composites were twice that of collagen–collagen composites. Subcutaneous fibrous tissue ingrowth was improved and implant resorption was slightly delayed in the collagen–PLA composites. ACL reconstruction surgeries were performed in rabbits using collagen–PLA composite implants. After 4 weeks, neoligament tissue was observed in seven of eight implants; however, four neoligaments had ruptured either in the midsubstance (n Å 2) or at the bone tunnel interface (n Å 2). These results and our previous work suggest that resorbable polymeric composite scaffolds are potentially useful for ACL reconstruction if the implants can be protected from excessive mechanical loading during formation of host neoligament tissue. q 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1423–1428, 1997