ABSTRACT
Objective To assess the fixation efficiency and biocompatibility of the absorbable high strength poly L lactide (SC PLLA) screws which were designed and made by us through a new material reinforcement process, solid state compression (SC), by investigating the healing and tissue reaction of the rabbits which were given femoral osteotomy and fixed with the screws. Method The right femoral condyles of 12 New Zealand rabbits were first cut off and then fixed with a SC PLLA screw. They were sacrificed at 4, 8, 12, and 36 weeks postoperatively to exam their femurs radiologically and histologically. Results At all the sites of osteotomy was seen obvious formation of bony callus. There were no significant displacements at all the operative sides. Histologically, bony union showed at the site of osteotomy and direct connection between the bone and the implants was observed. Conclusion SC PLLA screws can provide sufficient internal fixation for the load bearing cancellous bone, and possess excellent biocompatibility.
ABSTRACT
Objective To evaluate the security and biocompatibility of a new kind of absorbable high-strength PDLLA-CPP composite, which is used for internal fracture fixation. Methods According to the national standard of the procedure of appraise in food security and toxicology, micronucleus test of bone marrow cell, spermatic aberration test, chromosomal aberration test, and teratogenic test were measured with IP maximal tolerance dose of maceration extract from PDLLA-CPP composites. Meanwhile, chondrocyte culture with PDLLA-CPP composite was used to evaluate the effect of PDLLA-CPP composite on cartilage cell proliferation. Results Micronucleus test of bone marrow cell, spermatic aberration test, chromosomal aberration test, and teratogenic test were not affected by IP maximal tolerance dose of PDLLA-CPP maceration extract. PDLLA-CPP composite also had no cytotoxicity on cartilage cell proliferation. Conclusion PDLLA-CPP is a new and safe medical material with good biocompatibility and absorbability.