Physeal response to absorbable polydioxanone bone pins in growing rabbits

Absorbable fixation materials would seem especially useful for treating tra nsphyseal fractures in growing children, but their degradation products may affect physeal growth. The histologic response of an open physis to placem ent of transphyseal, polydioxanone (PDS), bioabsorbable pins was studied in skeletally immature New Zealand White rabbits. A 1.3-mm PDS pin was insert ed across the right femoral physis, and a 1.3-mm empty drill hole across th e left femoral physis served as a control. The animals were sacrificed at 3 , 6, 9, and 12 weeks postsurgery. Biplanar radiographs, bone length measure ments, and histology sections of the physis and adjacent bone were made. Th ree independent observers graded the histologic response of the physis to t he drilling and implant. There was no evidence of inflammation, foreign bod y reaction, or distortion of the growth plate during the entire growth peri od, This suggests bioabsorbable pins do not cause any appreciable inflammat ory response or adverse effect on physeal function during active longitudin al growth of the bone. (C) 1999 John Wiley & Sons, Inc.