Use of a collagen‐platelet rich plasma scaffold to stimulate healing of a central defect in the canine ACL

The anterior cruciate ligament (ACL) of the knee fails to heal after primary repair. Here we hypothesize that a beneficial biologic repair response can be induced by placing a collagen‐platelet rich plasma (collagen‐PRP) material into a central ACL defect. A collagen‐PRP scaffold was used to treat a central ACL defect in vivo. In the first experiment, the histologic response in treated and untreated defects was evaluated at 3 ( n  = 5) and 6 weeks ( n  = 5). In the second experiment, biomechanical testing of the treated ligaments ( n  = 8) was performed at 6 weeks and compared with the results of biomechanical testing of untreated defects at the same time‐point ( n  = 6). The percentage filling of the defects in the treated ACLs was significantly higher at both the 3‐ and 6‐week time‐points when compared with the untreated contralateral control defects (50 ± 21% vs. 2 ± 2% at 3 weeks, and 43 ± 11% vs. 23 ± 11 at 6 weeks; all values mean ± SEM. Biomechanically, the treated ACL defects had a 40% increase in strength at 6 weeks, which was significantly higher than the 14% increase in strength previously reported for untreated defects ( p  < 0.02). Placement of a collagen‐PRP bridging scaffold in a central ACL defect can stimulate healing of the ACL histologically and biomechanically. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:820–830, 2006