BIOMECHANICAL STUDY ON PROXIMAL FEMORAL NAIL ANTIROTATION (PFNA) FOR INTERTROCHANTERIC FRACTURE

Abstract

The proximal femoral nail antirotation device (PFNA) is a typical implant to the treatment of intertrochanteric fractures. However, re-fracture of the femur shaft after nailing are usually been reported. The purpose of this study was to investigate the biomechanical features in the healed proximal femur at different stages in the healing process. Stress and strain distributions, total strain energy density (SED) along the femur and PFNA were analyzed in walking and stair climbing. Results showed remarkable stress concentration occurred near the locking bolt hole with retained PFNA, decreased after PFNA removal. Stair climbing resulted in higher strain at the locking bolt hole than normal walking. The conclusion can be drawn that non-removal of PFNA after healing may result in high fractural risk near locking bolt on femoral shaft. Meanwhile, stair climbing should be avoided during healing.