Robotic-arm assisted lateral unicompartmental knee arthroplasty: 5-Year outcomes & survivorship.

INTRODUCTION: Robotic-arm assisted unicompartmental knee arthroplasty (RA-UKA) has demonstrated accurate component positioning and excellent outcomes for medial components. However, there is a paucity of literature on lateral compartment RA-UKA. The purpose of our study was to assess the midterm clinical outcomes and survivorship of lateral RA-UKA. METHODS: This study was a retrospective review of a single-center prospectively maintained cohort of 33 patients (36 knees) indicated for lateral UKA. Perioperative, and postoperative two- and five-year Knee injury Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC), and Forgotten Joint Score (FJS) patient reported outcome measures were collected. Five-year follow-up was recorded in 29 patients (32 knees). RESULTS: Mean follow up was 5.1 ± 0.1 years. Mean age and BMI was 70.9 ± 7.2 years and 29.0 ± 4.2 kg/m2, respectively. At discharge, mean distance walked was 273.4 ± 70.4 feet, and mean pain score was 2.0 ± 2.5. At 2-year follow up, mean KOOS, WOMAC, and FJS were 75.1 ± 13.5, 15.0 ± 7.2, and 81.0 ± 23.3, respectively. At 5-year follow up, mean KOOS, WOMAC, and FJS were 75.3 ± 14.6, 14.9 ± 5.0, and 75.8 ± 27.4, respectively. Mean change in KOOS and WOMAC were 35.6 ± 27.1 and 11.7 ± 13.4 (p< .001 and p< .001). 94% of patients were very satisfied/satisfied, 3% neutral, and 3% dissatisfied. 91% met activity expectations, and 59% were more active than before. Survivorship was 100% at 5 years. DISCUSSION: In this study, lateral RA-UKA demonstrated significantly improved clinical outcomes, high patient satisfaction, met expectations, and excellent functional recovery at midterm follow up. Comparative studies are needed to determine differences between robotic-assisted and conventional lateral UKA, as well as TKA.

5-Year Survivorship and Outcomes of Robotic-Arm-Assisted Medial Unicompartmental Knee Arthroplasty.

Purpose: While unicompartmental knee arthroplasty (UKA) has demonstrated benefits over total knee arthroplasty (TKA) in selected populations, component placement continues to be challenging with conventional surgical instruments, resulting in higher early failure rates. Robotic-arm-assisted UKA (RA-UKA) has shown to be successful in component positioning through preop planning and intraop adjustability. The purpose of this study is to assess the 5-year clinical outcomes of medial RA-UKA. Methods: This study was a retrospective review of a single-center prospectively maintained cohort of 133 patients (146 knees) indicated for medial UKA from 2009 to 2013. Perioperative data and 2- and 5-year Knee injury Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC), and Forgotten Joint Score (FJS) outcome measures were collected. Five-year follow-up was recorded in 119 patients (131 knees). Results: Mean follow-up was 5.1 ± 0.2 years. Mean age and BMI were 68.0 ± 8.1 years and 29.3 ± 4.7 kg/m2, respectively. At 2-year follow-up, mean KOOS, WOMAC, and FJS were 71.5 ± 15.3, 14.3 ± 7.9, and 79.1 ± 25.8, respectively. At 5-year follow-up, mean KOOS, WOMAC, and FJS were 71.6 ± 15.2, 14.2 ± 7.9, and 80.9 ± 25.1, respectively. Mean change in KOOS and WOMAC was 34.6 ± 21.4 and 11.0 ± 13.6, respectively (p < 0.001 and p < 0.001). For patient satisfaction at last follow-up, 89% of patients were very satisfied/satisfied and 5% were dissatisfied. For patient activity expectations at last follow-up, 85% met activity expectations, 52% were more active than before, 25% have the same level of activity, 23% were less active than before, and 89% were walking without support. All patients returned to driving after surgery at a mean 15.2 ± 9.4 days. Survivorship was 95% (95% CI 0.91-0.98) at 5 years. One knee (1%) had a patellofemoral revision, two knees (1.3%) were revised to different partial knee replacements, and five knees (3.4%) were converted to TKA. Conclusion: Overall, medial RA-UKA demonstrated improved patient-recorded outcomes, high patient satisfaction, met expectations, and excellent functional recovery. Midterm survivorship was excellent. Longitudinal follow-up is needed to evaluate long-term outcomes of robotic-arm-assisted UKA procedures.

Robotic-arm assisted bicompartmental knee arthroplasty: Durable results up to 7-year follow-up.

BACKGROUND: The purpose of our study was to investigate the mid-term clinical and functional outcomes of robotic-arm assisted Bicompartmental knee arthroplasty (BiKA). METHODS: This study reviewed a single-centre prospectively maintained cohort of 50 patients (53 knees) who underwent BiKA (patellofemoral and medial compartment) at 5- and 7-year postoperative follow-up. RESULTS: Mean follow-up was 7.1 ± 0.1 years (range, 7.0-7.3). Kaplan-Meier survivorship rates at 5 and 7 years were 96% and 93%, respectively. At 7-year follow-up, patient satisfaction was 76% satisfied, 13% neutral, and 11% not satisfied. Mean KSS-FS was 80.5 ± 15.8 (range, 30-100) with 82% of patients reporting walking more than 10 blocks, 89% reporting walking without support, and 100% able to go up and down stairs with 61% requiring use of a rail. Three patients (four knees) underwent revision surgery. CONCLUSIONS: Our study reported excellent survivorship and functional outcomes, and good-excellent satisfaction at mid-term follow-up for robotic-arm assisted BiKA.