Robotic-assisted ligament-guided unicompartmental knee arthroplasty for medial compartment osteoarthritis: Current...

Despite theoretical advantages over total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) has historically been underutilized due to concerns regarding durability and registry-reported revision rates. Robotic-assisted, ligament-guided medial UKA, designed to restore medial collateral ligament isometry and estimated pre-arthritic alignment, has emerged as a technique intended to improve technical reproducibility and survivorship. Contemporary multicenter investigations demonstrate durable outcomes across short-, mid-, and long-term follow-up, including survivorship of 98.8% at a mean of 2.5 years, 97.0% at 5.7 years, and 91.7% at 10 years, with patient satisfaction consistently exceeding 90%. In a matched comparative study comparing robotic-assisted medial UKA to TKA, UKA was associated with fewer stiffness-related interventions at 2 years (0 vs. 6 manipulations under anesthesia, p = 0.03), lower reoperation burden, faster recovery, and superior joint awareness measured by the Forgotten Joint Score (FJS; 90.5 vs. 79.5, p < 0.001). At the 5-year follow-up, robotic-assisted UKA maintained superior outcomes compared with TKA across all patient-reported measures, including joint awareness (FJS: 87 vs. 59, p < 0.001), function (Knee Society Score (KSS): 88 vs. 75, p < 0.001), and satisfaction (37.2 vs. 32.5, p < 0.0001), with 100% survivorship free from component revision compared with 98% for TKA. Contemporary evidence further demonstrates that conversion of failed conventional UKA to TKA yields outcomes comparable to primary TKA, preserving future reconstructive options. Remaining limitations include the absence of long-term randomized controlled trial data directly comparing robotic-assisted UKA with TKA, the need for refined patient selection criteria, and limited return-to-sport data. Robotic-assisted ligament-guided medial UKA represents a durable and reproducible treatment strategy in appropriately selected patients. LEVEL OF EVIDENCE: Level V.