Biomechanical Analysis of Hip Replacement Stem Design: A Finite Element Analysis

The hip joint is one of the largest joints of the body, which plays an important role in bearing the body's weight. When arthritis progresses to its higher levels, arthroplasty is performed to reduce pain and increase joint range of motion. This surgery is a common treatment worldwide, the quality of which depends on several factors. One of the critical factors is the geometry of the stem, which is implanted into the femur bone and receives support from it. For this aim, in this study, the geometry of three available stems in the orthopedic devices market was investigated by the finite element method (FEM). An accurate model of the proximal part of the femur was generated, and after modeling each stem, the final model was assembled. After developing the FE model, three loading conditions were applied to the stems. Maximum values of stress were observed in the middle part and neck of the stem. Moreover, it was observed that thickness is a key parameter in addition to the offset and neck shaft angle parameters and their effect on the amount and distribution of stress in the implant and bone. The results of this study can help improve the design of hip joint stems.