Augmented reality hip navigation system versus the Naviswiss system in cup alignment during total hip arthroplasty using the posterolateral approach.

Aims: No studies have compared two portable navigation systems, including augmented reality (AR) hip navigation and the Naviswiss system, to improve the accuracy of acetabular component alignment during total hip arthroplasty (THA) in the posterolateral approach. We investigated the difference in cup placement accuracy between the two systems.

Methods: We retrospectively compared THAs performed using the AR hip navigation (n = 32) and those performed using Naviswiss (n = 41) from June 2021 to April 2023. All patients underwent THA in the posterolateral approach. The primary endpoint includes radiological inclination (RI) and radiological anteversion (RA) measured on postoperative radiographs, and the absolute value error of radiological inclination (δRI) and radiological anteversion (δRA) between the final cup alignment displayed on the navigation screen at final cup fixation and cup alignment measured on postoperative radiographs.

Results: No significant differences in the mean RI and mean rRA and δRI and δRA were found between the two groups. The percentage of cases with both δRI and δRA of < 3° were 31% and 24% in the AR hip and Naviswiss groups, respectively, with no significant difference. The percentage of cases in both δRI and δRA of < 5° was 66% and 90% in the AR hip and Naviswiss groups, respectively (p = 0.009). No cases demonstrated both δRI and δRA of > 5°.

Conclusion: No significant differences were found between the two systems. The Naviswiss system demonstrated a higher percentage of errors within 5° than the AR navigation system, indicating that Naviswiss reproduced functional pelvic plane more accurately.