Fluoroscopy Computer Navigation Versus Manual Fluoroscopic Acetabular Positioning in Direct Anterior Total Hip Arthroplasty: Safe Zone Compliance and Learning Curve Analysis

Background Fluoroscopy is commonly leveraged in direct anterior approach total hip arthroplasty (DAA-THA). Computer-navigation systems provide real-time guidance aiming to enhance component positioning, but their learning curves and component accuracy remains incompletely characterized. This study evaluated the learning curve and safe zone compliance after implementation of computer navigation in DAA-THA. Methods This retrospective cohort study analyzed 200 consecutive primary DAA-THA cases performed by a single high-volume surgeon: 100 manual and 100 computer-navigated cases using the Velys Hip Navigation system. Acetabular component inclination and anteversion were measured on postoperative standing radiographs. Safe zone compliance was assessed using surgeon-defined, Lewinnek, and Callanan criteria. Learning curve analysis utilized segmented linear regression and cumulative sum methods. Operative time, fluoroscopy exposure, and component safe zone compliance were compared between groups. Results Operative time stabilized after 6 cases ( P < .05), while significant breakpoint was identified for radiation exposure Computer navigated cases had shorter operative time (76.1 ± 16.4 vs 82.3 ± 17.0 minutes, P < .05) without increased fluoroscopy exposure (28.3 ± 6.6 vs 28.8 ± 9.8 seconds, P = .25). Safe zone compliance was significantly higher with navigation for surgeon-defined (98.9% vs 91.6%, P = .04), Lewinnek (86.3% vs 68.4%, P = .01), and Callanan criteria (68.4% vs 49.5%, P = .01). Conclusions Fluoroscopic based computer navigation was associated with higher safe zone compliance in DAA-THA with a rapid 6-case learning curve and reduced operative time, without increasing radiation exposure.