Absorbable intramedullary implants for hand fractures. Animal experiments and clinical trial

Prince of Wales Hospital, Hong Kong, Shatin, New Territories.

Biodegradable implants made from polyglycolic and polylactic acid co-polymers undergo degradation by hydrolysis which results in loss of their mechanical strength. The degradation of 1.5 mm polyglycolide rods (Biofix) was studied after intramedullary and subcutaneous implantation in rabbits. Two weeks after implantation there was a 73% reduction in strength of the intramedullary implants and a 64% reduction in the subcutaneous implants. Polyglycolide implants were compared with Kirschner wires for intramedullary fixation of extra-articular fractures in the hand. In one group of patients fractures were fixed with a 1.5 mm intramedullary rod and in a similar group a Kirschner wire was used. In both a wire loop was added for extra fixation. At six months there was no significant difference between the two groups. There were no allergic reactions to the polyglycolide implants.