Comparison of cup setting angle accuracy between computed tomography-based and computed tomography-free navigation in the same patients with crowe’s classification i or ii hip dysplasia

Abstract

Background: In total hip arthroplasty, the cup setting angle may affect the postoperative results. In recent years, both computed tomography-based navigation and computed tomography-free (imageless) navigation have been reported to produce high accuracy in cup installation; however, no direct comparison between these two methods has been performed. The present study aimed to directly compare the cup installation angle accuracy between computed tomography-based navigation and computed tomographyfree navigation in patients with Crowents with Crowetive results. In recent years, both computed tomography-basthe factors affecting the cup installation accuracy.Methods: Using both navigation systems for the same technique, primary total hip arthroplasty was performed by the same surgeon in 36 patients. A cup was installed using computed tomography-based navigation, and the installed cup was measured again using computed tomography-free navigation. We compared the error between the target angle and the intraoperative installation angle for each navigation method by performing statistical analyses. Results: For computed tomography-based navigation, errors in the inclination and the anteversion angles compared to the target angle were 3.14d ± 1.55 were 3.14d ± 0.99 were 3.14d to the target  vigation, errors in the inclinathe inclination and anteversion angle errors were significantly larger, i.e., 6.84n ± 4.78 errors were± 5.22 errorpectively (p < 0.01). The inclination and anteversion angles of computed tomography-free navigation were correlated, and there were no significant factors influencing the error. Conclusions: Computed tomography-based navigation is more accurate for cup installation than computed tomography-free navigation. When using computed tomography-free navigation, it is necessary to add technical schemes before and during surgery to improve the cup installation accuracy.