Less inflammation and early functional recovery after total hip arthroplasty performed with robotic arm assistance than with computed tomography-based navigation: a propensity score-matched comparative study.

PURPOSE: It remains unclear whether robotic arm-assisted total hip arthroplasty (RA-THA) or computed tomography-based navigation THA (CN-THA) is clinically superior. This study compared post-operative inflammatory responses, pain, functional recovery, and clinical benefits between RA-THA and CN-THA. METHODS: This retrospective study included 496 consecutive hips that underwent RA-THA or CN-THA via an anterolateral supine approach between 2020 and 2024. After propensity score-based matching, the sample size was 158 hips in each group. Single reaming was performed in RA-THA, whereas multiple reamings were performed in CN-THA. Demographics, C-reactive protein (CRP) levels, ten-point numeric rating scale (NRS) pain scores, functional recovery, and complications were recorded. RESULTS: CRP on post-operative days (POD) 1 and 7 (1.8 ± 1.3 mg/dL vs 2.7 ± 1.8 mg/dL, 2.1 ± 1.2 mg/dL vs 3.8 ± 2.5 mg/dL, p < 0.001), NRS pain scores on PODs 1, 3 and 14 (2.4 ± 0.3 vs 2.6 ± 0.4, 2.4 ± 0.2 vs 2.6 ± 0.2, 1.4 ± 0.8 vs 2.0 ± 0.7, respectively, all p < 0.001), and days to independent walking (9.0 ± 2.3 days vs 10.7 ± 2.7 days, p < 0.001) were significantly lower in the RA-THA group. The incidence of asymptomatic deep vein thrombosis (DVT) was significantly lower in the RA-THA group (4.4% vs 10.8%, p = 0.03). Other complications did not significantly differ between the two groups. CONCLUSION: RA-THA was associated with reduced post-operative CRP, pain, and the incidence of DVT, while also contributing to early functional recovery. Single reaming may have contributed to decreased inflammatory responses and early functional recovery.