Stress analysis prediction on screw orthopedic implant in trabecular bone

Abstract Trabecular bone fractures heal through intramembranous ossification. It is a highly porous biological tissue with an open-celled cellular structure, which accounts for up to 20% until 60% of the bone mass in humans for healthy bone while about 80% for an osteoporosis case. In bone healing, there is very little callus formation, woven bone forms directly without a cartilage intermediary, and the woven bone is remodelled to form trabecular bone. Trabecular bone has less mineral and porosity percentages compared to the compact bone. Thus, the stress distributions around the screw were affected by the amount of the porosity within the trabecular bone. In bone healing mechanism, stability may speed up the bone healing process. The interface contact between external fixator pins and screws of internal fixator influence the fixation stability for bone healing. This study aims to investigate the amount of stress distribution on the around screw implant through the trabecular bone porosity condition under pull out loading. Finite element analysis is employed to simulate the stress distribution associated to the screw implant and cortical-trabecular interface As a result, the area of screw head is found to be yielded as the porosity of trabecular bone is considered.