Robotic-assisted total knee arthroplasty leads to a higher proportion of better Kujala score and global patient-reported outcomes measurements compared to conventional surgery after a minimum of two years of follow-up.

Abstract

Introduction: Total knee arthroplasty (TKA) is a widely adopted surgical intervention for individuals with severe knee osteoarthritis. The integration of robotic assistance in TKA (R-TKA) has been proposed to enhance surgical precision and patient outcomes. Specifically, R-TKA has demonstrated enhanced consistency in radiological outcomes. However, consistent improvements in clinical results remains to be proven, as existing reports are heterogeneous, necessitating further investigation. This study compares patient-reported outcome measurements (PROMs) for TKA performed with conventional (C-TKA) versus R-TKA. Specifically, it evaluates the frequency of patients achieving Patient Acceptable Symptom State (PASS), Threshold for Improved Satisfaction (TIS), and Threshold for Improved Failure (TIF) for Western Ontario and McMaster Universities Arthritis Index (WOMAC), Kujala, and Knee Injury and Osteoarthritis Outcome Score quality of life (KOOS-QoL) questionnaires.

Methods: A retrospective analysis was conducted using institutional data from 2016 to 2021, involving 149 TKA cases (41 R-TKA, 108 C-TKA) with a minimum follow-up of two years. Patients completed validated PROMs, including WOMAC, Kujala, and KOOS-QoL. Propensity score matching adjusted for variables including age, sex, surgeon, side, and patellar resurfacing. The primary outcome was the proportion of patients surpassing PASS and TIS thresholds for WOMAC pain, WOMAC function, Kujala and KOOS-QoL.

Results: A total of 117 patients were contacted. Patients who underwent R-TKA showed a significantly higher proportion of favorable outcomes compared to those with C-TKA. Specifically, 30% more patients in the R-TKA group surpassed the Kujala threshold (95% CI: 18% to 45%; 1-β = 0.97), and 29% more met all thresholds simultaneously, indicating a successful TKA (95% CI: 13% to 45%; 1-β = 0.84); both were associated with moderate to large effect sizes. Although differences in PASS achievement for WOMAC pain (+5%), WOMAC function (+6%), and KOOS-QoL favored R-TKA and reached statistical significance, the study lacked sufficient statistical power to confirm these findings with high confidence CONCLUSIONS: Compared to C-TKA, R-TKA achieves a significantly higher proportion of patients with Kujala scores of 70 or above, as well as a higher proportion of patients meeting all targeted PROMs thresholds at the two-year follow-up. These findings underscore the potential for R-TKA to optimize outcomes.

Level of evidence: Clinical study, Level III.