Study of Stress Distribution at the Inner Surface of Uncemented Total Hip Replacement (THR)

Uncemented total hip replacement (THR) is a reconstructive surgery to improve the function of the diseased femoral hip. This replacement relies of press-fit technique which it is the most crucial part. This replacement is said to be successful by achieving the primary fixation which consequently lead to the secondary fixation through osseointegration. However, aseptic loosening often reported case for this replacement where many patients need to have revision. There are reasons to believe that the high stress distribution at the bone inner surface leads to the implant failure. Therefore, this study aims to determine the stress distribution at the inner surface of the implanted femoral bone. A standardized femoral bone was generated from Initial Graphics Exchange Specification (IGES) format file. The bone model was then implanted and analyzed by using ANSYS Workbench (V15) Software. The femoral bone was having Young’s modulus of 14, 200 MPa and Poisson’s ratio of 0.3. Meanwhile, the material of the hip prosthesis used was Titanium (Ti-6A1-4V) which having Young’s modulus of 100, 000 MPa and Poisson’s ratio of 0.3. The implanted bone was subjected to walking load case. The results of the stress distribution for whole inner surface of the implanted bone were 56.02 MPa which below the failure stress.