The influence of femoral ball size on the range of motion that fulfills the criteria of safe zone orientation acetabular cup

Abstract

Dislocation and edge loading are significant issues highlighted due to the acetabular component orientation during total hip replacement(THR). This study aims to define the optimum acetabular cup orientation with the most suitable femoral ball size, thus eliminating the possible issue that may arise during postoperative surgery. A numerical approach by creating a single function that enables the calculation of the cup inclination (a) and the cup anteversion (β) with respect to range of motion are developed by using a programming language namely Matlab®. Three separate studies were done by having a head neck ratio of 2.33, 2.67 and 3.0, respectively. From these data, it is clear that the size of femoral head affects the area under range of motion at the bearing surfaces. A wide area under the graph resulted in a better and greater number combination of acetabular cup thus reducing the risk of dislocation and edge loading.