In vivo and in vitro studies were performed over the past 6 years to e
valuate the short- and long-term biocompatibility, absorbability, stre
ngth, and efficacy of polylactic acid (PLA) as a suitable material for
an internal fixation system of bone, consisting of a plate and screws
. The study was conducted on 30 dogs that underwent osteotomy of the r
adius and three dogs that underwent osteotomy of the femur. Bone fragm
ents were fixed by the PLA plate and screws. In all specimens, the ost
eotomy healed in the usual length of time. The dogs were killed after
12 weeks to 4 years. At the time of death, specimens were obtained for
mechanical testing and histological analysis. It appears that PLA is
biocompatible, is of adequate strength, and has a suitable absorption
pattern in the canine model in which it was tested. PLA did not interf
ere with the process of bone healing and was completely absorbed 4 yea
rs after implantation.