The effect of an intramedullary self-reinforced poly-L-lactide (SR-PLLA) implant on growing bone with special reference to fixation properties. An experimental study on growing rabbits.

Polylactic acid (PLA) is a synthetic biodegradable material. The self-reinforced implants made of poly-L-lactic acid (SR-PLLA) were manufactured of biodegradable polymeric matrix reinforced with fibres of the same material. The purpose of this study was to find out the effect of an intramedullary SR-PLLA implant on growing bone and its applicability to the fixation of a femoral shaft osteotomy in a growing rabbit. In seven rabbits 6 weeks of age a SR-PLLA implant 2.0 mm in diameter and 50 mm in length was introduced into the intramedullary cavity of the right femur. A proximal femoral shaft osteotomy of the right femur was made in another ten 6-weeks-old rabbits. After accurate reduction, fixation of the osteotomy was achieved with an intramedullary 2.0 mm by 50 mm SR-PLLA-rod. The follow-up times were 6 and 28 weeks. An intramedullary SR-PLLA-rod neither caused any disturbance of the bone growth nor abnormalities of the peripheral blood cell counts. Solid union of the osteotomy was seen in six weeks after fixation with SR-PLLA implant.