PRELIMINARY DEVELOPMENT OF A COLLAGEN-PLA COMPOSITE FOR ACL RECONSTRUCTION

Our laboratory is developing resorbable composite implants for reconst ruction of the anterior cruciate ligament (ACL) of the knee. Composite s were fabricated by embedding parallel collagen fibers within a poly( lactic acid) (PLA) or collagen matrix. The mechanical properties, reso rption rates, and subcutaneous tissue reactions were determined for bo th types of composites. The tensile strength and modulus of collagen-P LA composites were twice that of collagen-collagen composites. Subcuta neous fibrous tissue ingrowth was improved and implant resorption was slightly delayed in the collagen-PLA composites. ACL reconstruction su rgeries were performed in rabbits using collagen-PLA composite implant s. After 4 weeks, neoligament tissue was observed in seven of eight im plants; however, four neoligaments had ruptured either in the midsubst ance (n = 2) or at the bone tunnel interface (n = 2). These results an d our previous work suggest that resorbable polymeric composite scaffo lds are potentially useful for ACL reconstruction if the implants can be protected from excessive mechanical loading during formation of hos t neoligament tissue. (C) 1997 John Wiley & Sons, Inc.