Fixation of experimental osteotomies with absorbable polylactic acid screws

Absorbable screws made of self-reinforced poly-L-lactic acid (SR-PLLA) and poly-DL/L-lactic acid (SR-PDLLA/PLLA) were used for fixation of cancellous bone osteotomies of the distal femur in rabbits. The initial molecular weight of PLLA was 260.000 and that of PDLLA 100.000. The follow-up times were from one week to 96 weeks. Seventy-two rabbits were operated on, 36 in the PLLA group and 36 in the PDLLA/PLLA group. After sacrifice, radiographic, micro-radiographic, histologic, histo-morphometric, and oxytetracycline-labelling studies were performed. In the PLLA group 34/36 (94%) osteotomies and in the PDLLA/PLLA group 31/36 (86%) osteotomies healed without delay or angular deformity. The present investigation shows that absorbable SR-polylactic acid screws are suitable for fixation of weight loading cancellous bone osteotomies in rabbits. Based on these promising results, a clinical study where cancellous bone fractures are fixed with SR-PLLA screws has been started.