Optimization of components’ positioning in primary total hip arthroplasty Total hip arthroplasty is one of the most important innovations of the 20th century. The aim of this study was to evaluate the anatomical orientation of articular structures of the hip and then to analyze component’s positioning in order to improve the implantation of prosthetic components to minimize dislocation, wear, fracture and pain. The anatomical orientation of transverse acetabular ligament, labrum and horns was studied. Femoral component orientation was assessed with the help of X-rays and CT-scan. We measured femoral anteversion with AP X-rays. Then, we demonstrated that CT-scan was an accurate method to localize femoral head center in comparison with Motion Analysis and Faro. Femoral anteversion and femoral head center were assessed before and after surgery. The goal was to analyze the restoration of femoral anteversion after THA with a straight cementless stem. Some cases of THA dislocations were evaluated with measurement of prosthetic ROM. It allowed us to know whether implant positioning was the risk factor of dislocation. A clinical observation showed that in case of cup malpositioning, the rate of ceramic liner fractures increased.
