Influence of the diameter and the material type on the contact pressure in the acetabular component of a total hip prosthesis

The hip joint is often affected by diseases that lead to its failure and consequent need of replacement by an artificial joint. In this case, the total hip arthroplasty is the most common medical procedure to substitute the natural joint. The total hip prostheses are available on a wide range of sizes and materials. In this work, it is develop a computational model to compute the contact pressures on the joint surfaces of the prosthesis. This model is able to analyze the most commercialized diameters and the different material combinations used on the hip prosthesis. The model, based on the Finite Element Method, is developed in the finite element software ABAQUS ® . Firstly, the geometric model of the three components of the hip joint, corresponding to the external cup, the liner and the femoral stem’s upper part, the head, is built and discretized using a suitable finite element mesh. Then, the stress on the interface between the head and the liner are computed solving a quasi-static contact problem. The finite element mesh is composed of 8 node hexahedral elements. The load cycle used to simulate the contact pressures on the acetabular component was measured In Vivo by Bergmann, using instrumented hip prosthesis. The results were analyzed in a way to promote the study of the effects of the different diameters and material type combination on the contact pressure. These results are in agreement with results obtained in previous studies and can be an important factor on the decision of which type of prosthesis to implant.