To evaluate the stress distribution and displacement of femoral and implant models after partial femoral head replacement by finite element analysis.

A healthy adult volunteer was selected to obtain the full-length CT scan data of femur. Mimics 20.0 software, Geomagic software and UG NX 12.0 software were used to establish the model of femoral head ischemic necrosis. The femoral head prosthesis was designed and developed after bone tunnel resection. The finite element simulation was conducted to simulate the one-leg standing environment, and the stress distribution and displacement data of the femur and the implant model were obtained.

The femoral stress distribution mainly concentrated on the lower part of the femoral neck and both sides of the femoral shaft cortical bone, the maximum stress was 48.25 Mpa, the maximum displacement was 10.98mm. The stress of the implant model was mainly distributed under the main structure of the metal implant, with a maximum stress of 147.2 Mpa and a maximum displacement of 9.58mm.

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.