Ankle fractures treated using biodegradable internal fixation.

In order to reduce the resources needed for the removal of metallic fixation devices in fracture treatment, absorbable implants of biodegradable synthetic polymers were developed using self-reinforced lactide-glycolide copolymer and polyglycolide. In a prospective study 102 patients with displaced unimalleolar or bimalleolar fractures of the ankle were managed using internal fixation devices consisting of cylindrical biodegradable implants 3.2 or 4.5 mm in diameter and 50 or 70 mm in length. After open reduction of the fracture a channel was drilled from the tip of the malleolus into the cancellous bone through the fracture surfaces. A biodegradable rod of the same diameter was then tapped into the drill channel to fix the fracture. Postoperatively, the ankle was immobilized by a plaster cast for six weeks. An anatomic initial reduction was achieved in 93 patients (91%). A slight secondary displacement occurred in four patients. In six patients a sinus formation yielding remnants of the degrading implant was seen two to four months after the operation. This minor complication did not influence the union of the fracture or functional recovery. At the one-year follow-up examination there was no change in the ability to participate in sports and other physical activities in 89 patients (87%). The biodegradable fixation method is now the routine approach of the department in treating displaced unimalleolar and bimalleolar ankle fractures. New clinical applications for the implants are under trial.