PurposeCurrently, there is limited information regarding the utilization of pin-less augmented reality (AR) assistance in total hip arthroplasty (THA). This preliminary study aimed to evaluate the precision of acetabular cup placement in THA utilizing the AR Navigation “Pin-less” System (Pin-less AR navigation, prototype). MethodsA total of 72 consecutive primary THAs in 58 patients were categorized into two groups: the Pin-less AR navigation group and the conventional group. All THAs were conducted via the direct anterior approach. First, the absolute value of difference between the intra-operative and post-operative angles (absolute difference) was calculated in the Pin-less AR navigation group. Second, the absolute value of error between the post-operative angles and the target angles (absolute target error) was assessed both in the Pin-less AR navigation group and the conventional group. ResultsThe absolute difference in inclination and anteversion angles was 2.2 ± 1.4° and 2.4 ± 1.5°, respectively. The absolute target error in the Pin-less AR navigation group versus the conventional group was 1.9 ± 1.5° versus 4.2 ± 2.7° in inclination (P < 0.001) and 2.3 ± 1.5° versus 3.1 ± 2.1° in anteversion (P = 0.092). The percentage of acetabular cups placed within ±5° from the target angles was significantly higher in the Pin-less AR navigation group (90.3%) compared with the conventional group (52.6%) (P < 0.001). ConclusionsThis study demonstrates that Pin-less AR navigation yielded generally accurate acetabular cup positioning, surpassing the conventional method. Further research is warranted to thoroughly evaluate Pin-less AR navigation.