Finite Element Analysis to Quantify the Effect of Surgery in Proximal Femur

Abstract

Stress shielding and subsequent implant loosening is a very common challenge in a total hip arthroplasty (THA) and hip resurfacing surgeries. Load path in the bone altered by implant need to be studied carefully to develop implants having long term success. Stress distribution in the proximal femur is found to produce mechanical stimuli which activate the mechanotransduction pathways to induce bone remodeling in surrounding region. In current study, Computer aided (CAD) model of intact femur, implanted femur and femur bone with resurfacing cup were modeled to represent pre and post operating geometry. Finite element analysis was performed by imposing 3D muscle forces and hip contact force during normal activity. The von mises stress distribution in the geometries was calculated. Study reveals that the stress distribution in the proximal femur is strongly affected by the patient activity and surgical procedure. Predominant stress shielding was observed in implanted femur, especially in lateral region of trochanters. Resurfaced cup model found to retain the physiological load transfer across the femur.