Absorbable plugs of self-reinforced poly-L-lactic acid in the internal fixation of rabbit distal femoral osteotomies

An absorbable plug for the internal fixation of fractures and osteotomies, measuring 4.5 mm in diameter and 30 mm in length, was constructed of poly-L-lactide using a self-reinforcing fibers-in-matrix manufacturing technique. To increase the rotational stability and grip of the device, the plug has deployable distal fins. The plug was used in the fixation of a transverse distal femoral osteotomy in 20 rabbits. The consolidation of the osteotomy was investigated histologically, histomorphometrically, and microradiographically in groups of five rabbits observed for three, six, 12, or 24 weeks. Fifteen osteotomies showed bony union. In five rabbits, no bridging trabeculae across the osteotomy had developed, but these rabbits belonged to the groups with the shortest follow-up times of three or six weeks. No mechanical failures of the plugs were encountered, and the short-term biocompatibility of the implant was excellent. Future clinical applications are planned.