Clinical results and short-term survivorship of robotic-arm-assisted medial and lateral unicompartmental knee arthroplasty.

PURPOSE: The aim of this multicentre, retrospective, observational study was to determine the incidence of revision and clinical results of a large cohort of robotic-arm-assisted medial and lateral UKAs at short-term follow-up. It was hypothesized that patients who receive robotic-arm-assisted UKA will have high survivorship rates and satisfactory clinical results. METHODS: Between 2013 and 2016, 437 patients (470 knees) underwent robotic-arm-assisted medial and lateral UKAs at two centres. Knee Injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score 12 (FJS-12) and Short-Form Physical and Mental Health Summary Scales (SF-12) were administered to estimate patients' overall health status pre- and post-operatively. Results were dichotomized as 'excellent' and 'poor' if KOOS/FJS-12 were more than or equal to 90 and SF-12 was more or equal to 45. Associations between patients' demographic characteristics and clinical outcomes were investigated. Post-operative complications and pain persistence were recorded. RESULTS: Following exclusions and losses to follow-up, 338 medial and 67 lateral robotic-arm-assisted UKAs were assessed at a mean follow-up of 33.5 and 36.3 months, respectively. Three medial UKAs were revised, resulting in a survivorship of 99.0%. No lateral implants underwent revision (survivorship 100%). On average, significant improvement in all clinical scores was reported in both medial and lateral UKA patients. In medial UKA patients, male gender was associated with higher probability of better scores in overall KOOS, FJS-12 and in specific KOOS subscales. No other associations were reported between biometric parameters and outcome for either medial or lateral UKA. CONCLUSIONS: Robotic-assisted medial and lateral UKAs demonstrated satisfactory clinical outcomes and excellent survivorship at 3-year follow-up. Continued patient follow-up is needed to determine the long-term device performance and clinical satisfaction. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Robotic-arm assisted partial knee arthroplasty: a single centre experience.

BACKGROUND AND AIM OF THE WORK: UKA has proven to be an effective surgical procedure, but its survivorship is still negatively affected by inaccuracy in component component positioning, implant and limb alignment. Robotic surgery has been introduced in order to minimize such technical errors. The aim of the present paper was to evaluate clinical and surgical outcomes after a 3 years' experience of robotic assisted UKA with the Mako Robotic Arm. METHODS: Seventy-three patients undergoing  UKA with robotic instrumentation (65 medial UKAs, 8 lateral UKAs) and with a clinical follow-up of 3 -37 months were included in the present study. A complete clinical evaluation with KOOS, FJS-12 and SF-12 was administered to all patients pre and post operatively. Post-operative HKA angle and surgical time were also recorded. RESULTS: Mean post-operative KOOS score was 81.32 (SD 17.19), while the mean FJS-12 score was 75.51 (SD 30.12) and the mean SF-12 Physical Score 42.25 (SD 9.97). 91% to 88% of post-operative results were considered satisfactory. Only 1 UKA failure was reported (1.3%) caused by peri-prosthetic infection. In medial UKAs mean postoperative HKA angle in extension was 3.9° varus (SD 2.5°), with no case of overcorrection; in lateral UKAs mean postoperative HKA angle in extension was 1.9° valgus (SD 1.9°) with 1 case (13%) of overcorrection. Mean skin to skin surgical time decreased from 83.2 minutes (SD 13.0) to 70.0 minutes (SD 10.9) along the learning curve. CONCLUSIONS: Robotic UKA has provided an improvement both in clinical and technical results, determining satisfactory clinical outcomes and a low risk of post-operative complications.