Robotic-assisted TKA Reduces Postoperative Alignment Outliers and Improves Gap Balance Compared to Conventional TKA

TLDR

Mechanical alignment is known to influence total knee arthroplasty outcomes. The study aimed to determine whether robotic‑assisted TKA improves clinical outcomes, mechanical alignment, gap balance, and reduces complications, drainage, and operative time compared to conventional TKA over a minimum 3‑year follow‑up. A randomized trial of 100 patients compared robotic‑assisted versus conventional TKA, evaluating postoperative ROM, WOMAC, HSS scores, mechanical axis alignment, flexion/extension gap balance, complications, drainage, and operative time. At a mean 65‑month follow‑up, robotic‑assisted TKA produced no mechanical axis outliers versus 24% in the conventional group, achieved better flexion‑extension gap balance, required 25 minutes longer but yielded less drainage, and showed no difference in ROM, WOMAC, HSS scores, or complications.

Abstract

Several studies have shown mechanical alignment influences the outcome of TKA. Robotic systems have been developed to improve the precision and accuracy of achieving component position and mechanical alignment.We determined whether robotic-assisted implantation for TKA (1) improved clinical outcome; (2) improved mechanical axis alignment and implant inclination in the coronal and sagittal planes; (3) improved the balance (flexion and extension gaps); and (4) reduced complications, postoperative drainage, and operative time when compared to conventionally implanted TKA over an intermediate-term (minimum 3-year) followup period.We prospectively randomized 100 patients who underwent unilateral TKA into one of two groups: 50 using a robotic-assisted procedure and 50 using conventional manual techniques. Outcome variables considered were postoperative ROM, WOMAC scores, Hospital for Special Surgery (HSS) knee scores, mechanical axis alignment, flexion/extension gap balance, complications, postoperative drainage, and operative time. Minimum followup was 41 months (mean, 65 months; range, 41-81 months).There were no differences in postoperative ROM, WOMAC scores, and HSS knee scores. The robotic-assisted group resulted in no mechanical axis outliers (> ± 3° from neutral) compared to 24% in the conventional group. There were fewer robotic-assisted knees where the flexion gap exceeded the extension gap by 2 mm. The robotic-assisted procedures took an average of 25 minutes longer than the conventional procedures but had less postoperative blood drainage. There were no differences in complications between groups.Robotic-assisted TKA appears to reduce the number of mechanical axis alignment outliers and improve the ability to achieve flexion-extension gap balance, without any differences in clinical scores or complications when compared to conventional manual techniques.