Perioperative comparison between robotic-assisted and freehand total knee arthroplasty : a quasi-randomized controlled trial

Abstract

Background

The advent of navigation, followed by robotics in knee prosthetic surgery aims, among other things, to enhance the alignment of components and to improve the control of stress forces (i.e., weight, gravity, and static and dynamic stabilizers) on the bearing surface throughout the range of motion; however, the benefits of robotic-assisted total knee arthroplasty (TKA) are debated. Objective

This quasi-randomized controlled trial (RCT) compares robotic-assisted and conventional TKA, focusing on surgical duration, hospital stay and serum markers. It aims to address current gaps in the literature and clarify potential advantages. Material and methods

All patients who received a TKA at the Department of Orthopedic Surgery of the Eifelklinik St. Brigida in Simmerath, Germany, between 2021 and 2025 were prospectively invited to participate in the present clinical trial. All patients followed the same clinical, imaging, and anesthesiological presurgical and postsurgical pathways irrespective of their allocation. All surgeries were performed using a standard medial parapatellar approach and a functional alignment philosophy. Both groups received the same implants, and patients followed the same postoperative physiotherapy program. Deviation from the planned surgical procedure and rehabilitation protocol warranted exclusion from the study. For patients allocated to robotic-assisted TKA, the CORI system (Smith & Nephew plc, Watford, United Kingdom) was used. Results

A total of 1099 patients completed the study, 59% (649 of 1099) of the patients were women and 50% (547 of 1099) of TKAs were performed on the left side. The mean body mass index (BMI) was 30.2 ± 4.9 kg/m2, and the mean age was 66.9 ± 8.2 years. Comparability was found between the two cohorts regarding the number of women, side of surgery, mean BMI, age, hemoglobin, hematocrit and leucocyte count at admission. Robotic-assisted TKA was associated with a longer surgical time of 1.6 min (p = 0.04) and a lower C‑reactive protein level at both the first (p = 0.0003) and fifth (p = 0.003) postoperative days. No other difference between groups was found. Conclusion

Robotic-assisted TKA was associated with lower serum C‑reactive protein levels. No difference was found in the length of hospitalization and erythropoietic function in serum. Although the surgical execution of conventional TKA was statistically significantly faster, the clinical relevance of the endpoint surgical duration is negligible.