Vigdorchik JM, Sculco PK, Inglis AE, et al. - This study was carried out to assess the registration accuracy of an imageless navigation device during total hip arthroplasty (THA) performed in the lateral decubitus position. Researchers performed a prospective, observational study including a total of 94 patients who had undergone a primary THA with imageless navigation assistance. They compared navigation measurements of cup position for each plane to measurements from postoperative radiographs. Using a plane approximating the long axis of the body, patient registration provided a frame of reference that accurately measured intraoperative cup position. As per the results, registration using a plane approximating the hip-shoulder axis; nevertheless, provided the most accurate and consistent assessment of acetabular component position.