Nano-hydroxyapatite reinforced polylactic acid bioabsorbable cancellous screws for bone fracture fixations

Abstract

Bioabsorbable polymer implants aid the fracture treatment to overcome the limitations of metallic implants like stress shielding, corrosion, and revision surgeries. The cancellous screw is one of the internal fixation implants more frequently used in fixation procedures. In this work, nano-hydroxyapatite (nHAp) reinforced polylactic acid cancellous screws were developed for bone fracture treatment. The biocompatibility and mechanical tests were performed before and after in-vitro hydrolytic degradation studies. The addition of nanofillers (10 wt% nHAp) enhanced the pullout strength, torsional strength, and shear strength by 18%, 48%, and 5%, respectively. The performed thermal studies confirmed that the nanohydroxyapatite facilitates the crystallization process. A mass loss of about 18% in the case of neat PLA and 12% in the case of 10 wt% nHAp was observed for 90 days of in-vitro hydrolytic degradation studies. So, the developed combination of biocomposite could help fabricate patient-specific bioabsorbable fixation devices like screws and plates.