Accuracy of cup placement compared with preoperative surgeon targets in primary total hip arthroplasty using standard instrumentation and techniques: a global, multicenter study.

Background: Acetabular cup positioning in total hip arthroplasty (THA) is closely related to outcomes. The literature has suggested cup parameters defined by the Lewinnek safe zone; however, the validity of such measures is in question. Several studies have raised concerns about the benefits of using the Lewinnek safe zone as a predictor of success.

Spinopelvic challenges in primary total hip arthroplasty.

There is no universal safe zone for cup orientation. Patients with spinal arthrodesis or a degenerative lumbar spine are at increased risk of dislocation. The relative contributions of the hip (femur and acetabulum) and of the spine (lumbar spine) in body motion must be considered together.

Contemporary, non-navigation, cup orientation techniques improve accuracy and eliminate differences seen between the anterior and posterior approach in THA.

Background: This study aimed to: (1) Determine the ability to achieve the surgeons' desired cup orientation, without navigation, using contemporary measures with the anterior- (AA) and posterior- approaches (PA); and (2) assess whether surgical approach is associated with cup orientation accuracy, as previously reported, when contemporary measures are used.

Methods: A prospective, 2-centre, multi-surgeon study of 400 THAs (200 AA; 200 PA) was performed. Intraoperative radiographs were obtained with the AA.