Comparative study of acetabular center axis vs anterior pelvic plane registration technique in navigated hip arthroplasty.

There is significant variation in registering the anterior pelvic plane (APP) among experienced navigated hip arthroplasty surgeons, reflecting negatively on the accuracy of determining inclination and anteversion. Whether it is variation in pelvic anatomy or improper positioning, this inaccuracy emphasizes the need for alternative methods of registration, of which the acetabular center axis (ACA) is proposed. Data collected from ACA and APP registration were compared with postoperative computed tomography (CT) images of the pelvis in 34 cases. Findings showed ACA software to be comparable with CT in its accuracy in determining the inclination and version angles of the acetabulum and cup implant.