Robot-assisted surgery in total knee arthroplasty: trauma maker or trauma savior? A prospective, randomized cohort study

BACKGROUND: Robotic assistance has been increasingly employed to improve the operative precision in modern knee surgery. The purpose of the study was to evaluate the trauma effect of one of the first domestically developed orthopedic surgical robots in China in a clinical trial of robot-assisted total knee arthroplasty (RA-TKA). METHODS: A total of 33 patients who underwent unilateral TKA for end-stage osteoarthritis were randomized to receive RA-TKA (17 cases) or conventional manual TKA (CM-TKA) in our institution in 2020. The trauma effects of the 4 main indicators with 48 sub-indicators in terms of subsectional operative time, inflammation and coagulation markers, physical and radiographical analyses of osteotomy deviation, and postoperative comfort were analyzed. RESULTS: Subsectional operative time analysis showed that the times for bone cutting and gap balancing with RA-TKA were 5.3 and 2.2 min shorter than those with CM-TKA (p = 0.010, p = 0.02), respectively. Arterial blood gas indicators (partial pressure of carbon dioxide, partial pressure of oxygen and SO(2)) 24 h after RA-TKA, as well as the white blood cell count and neutrophil ratio, were significantly lower than those after CM-TKA (p < 0.05). Inflammatory markers at 72 h after surgery showed the increments of C-reactive protein, erythrocyte sedimentation rate and D-dimer of RA-TKA declined by 180.7, 22.0 and 1050.0% (p < 0.05), respectively, referenced to the preoperative baseline values, as compared to CM-TKA. Mechanical deviation distribution exhibited percentages of region I errors for RA-TKA and CM-TKA of 76.5% and 27.1% (p = 0.000), respectively, and the success rates of one-time osteotomy were 94.1% and 62.5% (p = 0.039), respectively. Radiographical verification showed RA-TKA was more conducive to achieving mechanical alignment and ideal tibial component azimuths. Postoperative efficacy showed that patients were more comfortable after RA-TKA in terms of reduced administration of tranexamic acid, hydrocortisone and the utilization rate of temporary intensive opioid analgesics. No statistical difference in patient-reported outcome measures and complications were recorded between the two groups during continuous observation. CONCLUSIONS: Compared with CM-TKA, RA-TKA decreases rather than increases trauma. It might shorten the time required for bone cutting and gap balancing, reduce mechanical errors related to the osteotomy and prosthesis position, and improve the accuracy of the mechanical alignment reconstruction. RA-TKA is also favorable in promoting postoperative comfort and minimizing inflammatory response and drug consumption. TRIAL REGISTRATION: The Chinese Clinical Trial Registry (ChiCTR2000031282) approved registration on 26 March 2020.