Partial femoral head replacement: A new innovative hip-preserving approach for treating osteonecrosis of the femoral head and its finite element analysis

Abstract

Abstract Background Controversy remains regarding the optimal treatment for stage III Osteonecrosis of the femoral head (ONFH). This study presents, for the first time, the precise treatment of stage III ONFH using the "substitute the beam for a pillar" technique and performs a comparative finite element analysis with other hip-preserving procedures. Methods A formalin-preserved femur of male cadavers was selected to obtain the CT scan data of femur. The proximal femur model was reconstructed and assembled using Mimics 20.0, Geomagic, and UG-NX 12.0 software with four different implant types: simple core decompression, fibula implantation, porous tantalum rod implantation, and partial replacement prosthesis. The finite element simulations were conducted to simulate the normal walking gait, and the stress distribution and displacement data of the femur and the implant model were obtained. Results The peak von Mises stress of the femoral head and proximal femur in the PRFH group were 22.8 MPa and 37.4 MPa, respectively, which were 3.1–38.6% and 12.8–37.4% lower than those of the other three surgical methods. Conclusions After partial replacement of femoral head, the curvature of prosthetic head and femoral head is the same, and the stress conduction mode is the same as that of normal hip joint. However, stress concentration occurs at the joint between prosthetic head and stem, and the choice of materials with higher strength should be considered.