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

Abstract

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. 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. 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. 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 III, therapeutic.