Bioabsorbable rods and pins for fixation of metacarpophalangeal arthrodesis of the thumb

We report results on the use of bioabsorbable pins and intramedullary rods made of high-molecular-weight polylactic acid in both experimental and clinical conditions. In the experimental study, bioabsorbable rods were implanted in rabbit femora. Histologic assessment on nondecal cified bone showed that resorption of the material began at 4 months after implantation and gradually fragmented over a period of 3 years. In 12 patients 13 metacarpophalangeal joints of the thumb were arthrodesed by using one bioabsorbable intramedullary rod with one or two oblique pins. All joints fused within 6 to 8 weeks. During that period there was no sign of inflammation and there were no nonunions. Postoperative magnetic resonance imaging assessment was done in all rabbits and eight patients. This modality is a useful tool in postoperative evaluation of the position and shape of the rod but is not sufficiently senstive to assess the presence of local inflammation and the rate of resorption of the rods.