Imageless ROSA® Robotic Arm-Assisted Total Knee Arthroplasty Is Associated With Improved Accuracy Compared to Conventional Techniques.

Background The purpose of this study was to compare conventional and robotic-assisted total knee arthroplasty (TKA) using the imageless Robotic Surgical Assistant (ROSA®) Knee System. Methods This prospective study consecutively analyzed 23 patients undergoing conventional TKA against 27 patients undergoing robotic-assisted TKA and followed them for 20.8±2.0 and 17.6±1.3 months, respectively. All procedures were performed by a single surgeon, and radiographic measurements were taken by two observers. Results There were no major differences between the cohorts for age (p=0.40), sex (p=0.59), and body mass index (p=0.23). The groups were similar for length of stay (p=0.76), patellar resurfacing (p=0.27), cementation (p=0.23), and posterior cruciate ligament (PCL) resection (p=0.39). The robotic cohort more often used a thicker polyethylene bearing (p=0.01). Surgery was longer in the robotic cohort (78.3±2.0 versus 70.1±1.8; p=0.01). Differences were noted in radiographic alignment in coronal and sagittal planes, with the robotic cohort more frequently meeting criteria for functional alignment versus the conventional group (90.1% versus 34.9%, respectively; p=0.001). The intra-class correlation coefficient was excellent (0.75-1.00) for most recorded values. However, there did not appear to be meaningful differences between groups in terms of range of motion (ROM) and patient satisfaction. Conclusions The robotic cohort was found to be superior to the conventional cohort in terms of radiographic alignment in all planes, but similar in ROM and patient satisfaction.