Accuracy of Image-based Computer Assisted Surgery in Acetabular Cup Placement for Supine Two-incision Total Hip Arthroplasty

Introduction: Supine patient positioning in conjunction with twoincision minimally invasive surgery (MIS-2 incision) total hip arthroplasty (THA) increases difficulty of accurate and repeatable cup orientation in accordance with pre-operative planning. Investigators have suggested advantages of utilizing computer assisted orthopaedic surgery (CAOS) to successfully eliminate extreme outlying acetabular shell placement positions (Saxler et al., 2004). The current study examines the effects of CAOS on accuracy and consistency of acetabular cup placement in supine position MIS-2 THA. The authors hypothesize that improved accuracy of cadaver cup placement will be observed with the use of CAOS in comparison to traditional mechanical guides described for this MIS-2 THA in the supine patient position, with actual cup orientation assessed by post-implantation computed tomography (CT) study.