Foreign body reactions to resorbable poly(L-lactide) bone plates and screws used for the fixation of unstable zygomatic fractures.

In a previous article in the Journal of Oral and Maxillofacial Surgery, the initial results of treating 10 patients with solitary, unstable, displaced zygomatic fractures using resorbable poly(L-lactide) (PLLA) plates and screws was reported (Bos et al, 1987). This article describes the long-term results in these patients. Three years postoperatively, four patients returned because they were concerned about an intermittent swelling at the site of implantation. The remaining patients were recalled after the same postoperative period. All patients were examined clinically, and six patients were operated on again for evaluation of the swelling and to investigate the nature of the tissue reaction. The explanted material showed remnants of degraded PLLA surrounded by a dense fibrous capsule. The swelling was classified as a nonspecific foreign body reaction to the degraded PLLA material. Ultrastructural investigation of the degraded material showed an internalization of crystal-like PLLA material in the cytoplasm of various cells.