Outcomes of robotic-arm-assisted medial unicompartmental knee arthroplasty: minimum 3-year follow-up.

The purpose of this study was to determine implant survivorship, complications, and re-operation rates, after robotic arm-assisted unicompartmental knee arthroplasty (UKA) at intermediate follow-up. Patient satisfaction and clinical outcome were further investigated, in addition to an analysis of restoration of knee alignment. Fifty-one patients, who received a robotic arm-assisted medial UKA, were prospectively studied, and followed for a minimum of 3 years (mean 51.4 ± 4.5 months). Survival of implants, complications, reoperations, and patients' overall satisfaction were evaluated. WOMAC scores, as well as knee flexion, varus deformity and flexion contracture were further analyzed, before and after surgery. No implant failure or implant-related complication was recorded, and no revision surgery was performed at the last follow-up in any patient. Overall satisfaction was excellent; 96.1% of patients, at the latest follow-up, was satisfied or very satisfied, while none was dissatisfied or very dissatisfied. Total WOMAC score and each score's component was significantly improved after surgery. Knee alignment was significantly improved, as flexion increased, varus decreased, and flexion contracture also decreased. In conclusion, robotic-arm-assisted UKA, through accurate implant positioning, significantly improves range of motion and coronal plane alignment, in appropriately selected patients. Excellent overall satisfaction rates and clinical outcomes can be expected, at intermediate follow-up, along with excellent survival of implants and minimal to none surgery-related morbidity.