Ultrasound imaging-based procedure to integrate the dynamic behavior of the pelvis in Total Hip Arthroplasty planning

One of the main constraint in total hip arthroplasty (THA) is to optimize the position of the acetabular implant in order to avoid postoperative instability. The best orientation of the cup has been studied by several authors in order to avoid it, but for most of them, they don´t take into account the dynamic behavior of the pelvis during daily activities. This dynamic acts on the orientation of the acetabulum and therefore, not taking into account this behavior can lead to postoperative instability of the implant in some positions (sitting, standing or supine position). To assess the dynamic of the pelvis and the effects on the acetabular orientation, a rapid, accurate and easy new method has been developed. A functional parameter representing the pelvic flexion is first measured in different position (sitting, standing and supine position). Then, a software allowing us to assess the behavior of an acetabular implant in these positions is used. A study on twenty healthy patients has been carried out and shows that taking into account this method during THA planning might be very crucial to improve postoperative results.