Robotic‐assisted total knee arthroplasty improves aseptic survivorship compared to conventional total knee arthroplasty: A minimum 15‐year follow‐up

Abstract

PURPOSE: This study aimed to compare long-term clinical and radiographic outcomes, as well as implant survivorship, between robotic-assisted and conventional total knee arthroplasty (TKA) using a posterior cruciate-retaining prosthesis. METHODS: A retrospective analysis was conducted on 150 patients who underwent robotic-assisted TKA and 147 patients who underwent conventional TKA for knee osteoarthritis between March 2005 and December 2008, with a minimum follow-up of 15 years. Radiographic assessments included the hip-knee-ankle (HKA) angle, coronal and sagittal alignment of the femoral and tibial components, and alignment outliers, based on full-length standing and lateral radiographs. Kaplan-Meier survival analysis was performed to estimate implant survivorship, with endpoints defined as revision for any reason (septic or aseptic) or mechanical failure. RESULTS: Both groups demonstrated significant clinical improvement, with no significant differences in clinical scores between them (all p > 0.05). However, the robotic-assisted group had significantly fewer alignment outliers for the HKA axis and sagittal component positioning compared to the conventional group (all p < 0.05). The robotic-assisted group also exhibited a significantly lower rate of revision due to aseptic mechanical failure (0.6% [1/150] vs. 4.8% [7/147]; p = 0.029). Kaplan-Meier analysis using aseptic failure as the endpoint estimated a 17.3-year survival rate of 98.7% in the robotic-assisted group and 95.2% in the conventional group (log-rank test; p = 0.032). Cox proportional hazards regression identified younger age (HR 0.908, p = 0.032), postoperative varus malalignment (HR 1.296, p = 0.004), and femoral component varus malpositioning (HR 1.499, p = 0.003) as significant risk factors for mechanical failure. CONCLUSIONS: Robotic-assisted TKA may be associated with fewer alignment outliers and improved aseptic implant survivorship compared to conventional TKA at a minimum follow-up of 15 years. However, these findings should be interpreted with caution due to the retrospective design and high rate of loss to follow-up. LEVEL OF EVIDENCE: Level III, therapeutic.