The Early Outcome of Robotic-Assisted Functional Versus Mechanical Alignment in Total Knee Arthroplasty: A Prospective Randomized Control Trial.

Abstract

The objective of the study was to compare the early clinical outcomes of functional alignment (FA) with mechanical alignment (MA) in robotic-assisted total knee arthroplasty (R-TKA). Prospectively randomized into two groups, FA R-TKA (n = 50) and MA R-TKA (n = 49), 99 patients were scheduled for R-TKA. We compared surgical parameters between FA and MA techniques, encompassing limb alignment, gap balance, soft-tissue release, and operative time. In addition, we assessed clinical outcomes at three weeks, six weeks, three months, and six months postoperatively. Compared to the MA technique, the FA technique demonstrated a notable reduction in both the frequency and extent of soft-tissue release (P < 0.05). Compared with MA R-TKA patients, at the 6-month postoperative, the FA R-TKA group displayed noteworthy enhancements in Knee Injury and Osteoarthritis Outcome Score (KOOS)-Pain, KOOS-Daily Living, KOOS-Quality of Life, and forgotten joint score-12 scores (P < 0.05). In addition, there were significantly lower Pain visual analog scales scores when climbing up stairs at three and 6 months postoperatively (P < 0.05). Stratified analysis showed that in the obese subgroup, the FA R-TKA group had significantly higher KOOS-Total and 2011 Knee Society Score than the MA R-TKA group at six months postoperatively (P < 0.05). Compared to MA, the FA technique reduces soft-tissue release, shortens the duration of the procedure, reduces postoperative pain, and improves early clinical outcomes for patients. In particular, the obese population and patients who have more varus deformity benefit more from the FA technique.