Robotic‐arm‐assisted lateral unicompartmental knee arthroplasty leads to high implant survival and patient satisfaction at mean 10‐year follow‐up

Abstract Background There is a lack of literature reporting on long‐term outcomes following robotic‐arm‐assisted lateral unicompartmental knee arthroplasty (UKA). This study assessed the long‐term survivorship, patient‐reported satisfaction and pain scores following robotic‐arm‐assisted lateral UKA for lateral compartment osteoarthritis (OA). Methods A single surgeon's database was reviewed to identify all patients who underwent robotic‐arm‐assisted lateral UKA with a cemented, fixed‐bearing prosthesis prior to May 2015. Patients were contacted to determine implant survivorship, satisfaction and pain. Kaplan–Meier models were applied to analyse survival. Results A total of 77 knees (70 patients) with a mean follow‐up of 10.2 ± 1.5 years (range: 8.1–13.3) were included. Five knees were revised, corresponding to a 10‐year survivorship of 96.1% and estimated survival time of 12.7 ± 0.3 years (95% confidence interval: 12.2–13.2) with all‐cause revision as the endpoint. Unexplained pain (40.0%) and progression of OA (40.0%) in contralateral compartments were the most reported reasons for revision. Among patients without revision, 94.4% were either satisfied or very satisfied with their lateral UKA and the average pain score was 1.1. Conclusion Robotic‐arm‐assisted lateral UKA led to high implant survivorship and patient satisfaction, and low pain scores at long‐term follow‐up. Progression of OA in contralateral compartments and unexplained pain were the most frequent reasons for revision. These findings support the continued use of robotic‐arm‐assisted lateral UKA for lateral compartment OA; however, its clinical value over conventional techniques remains to be established in prospective comparative studies. Level of Evidence Therapeutic Level IV.