Anterior Mechanical Navigation Device is as Accurate as Lateral Device for Hip Socket Position

Objectives: In total hip arthroplasty (THA), accurate acetabular component position promotes prosthetic hip joint stability and longevity, and minimizes polyethylene wear. Image-based mechanical navigation is known to improve accuracy and reproducibility of accurate cup position intraoperatively via the posterior approach and the superior capsular approach. The purpose of this study was to assess the accuracy of acetabular component position using image-based mechanical navigation via the direct anterior approach (DAA). Methods: We prospectively followed 96 patients who underwent THA with one fellowship-trained arthroplasty surgeon over a nine-month period. Thirty-three patients underwent DAA THA with the anterior HipXpert device (Group 1), and 63 patients underwent posterior approach THA with the lateral HipXpert mechanical navigation device, serving as an operative control group (Group 2). Standard postoperative plain film radiographic measurements of acetabular component inclination and anteversion were assessed. Results: The average inclination angle was 38.6 degrees and 40.6 degrees in Groups 1 and 2, respectively. The average anteversion angle was 27.6 degrees and 30.1 degrees in Groups 1 and 2, respectively. There were no postoperative hip dislocations and no study patients underwent revision THA at an average follow-up of 12 months. There were no patient outliers in Groups I or II with inclination angles or anteversion angles outside 10 degrees of the preoperatively planned values. Conclusion: The anterior HipXpert mechanical navigation device enhances accurate acetabular component position and may reduce outlier component placement. Acetabular socket position is as accurate using the anterior device as it is using the lateral device.