Do we medialise the hip centre of rotation in total hip arthroplasty? Influence of acetabular offset and surgical technique.

Acetabular offset (AO) is the distance between the centre of the femoral head and the true floor of the acetabulum. We quantified the AO in normal hips and compared the displacement of the centre of rotation of the hip (CRH) after conventional and anatomical cup implantation during THA. 100 CT-scans of normal hips were analysed before and after simulating implantation of the acetabular component.

Should the acetabular cup be medialised in total hip arthroplasty.

Background: During total hip arthroplasty (THA), medialisation of the cup decreases the lever arm of body weight and is considered to be beneficial. Theoretically it should be compensated by an equivalent increase of the femoral offset in order to maintain global offset.

Goal Of The Study: We investigated via a numerical model the forces on each bundle of the abductor muscles and the loading forces at the head-cup interface.