Does Use of Technology Affect Manipulation Under Anesthesia Rates in Total Knee Arthroplasty?

Abstract

Arthrofibrosis can be a major source of dissatisfaction for patients undergoing total knee arthroplasty (TKA). Manipulation under anesthesia (MUA) may be offered to improve motion in selected cases. Advancements in computer-navigated and robotic-assisted technology have been championed to improve component positioning with fewer soft tissue releases. We sought to investigate whether these technologies impact MUA rates. An institutional retrospective review was conducted on 18,815 patients who underwent a primary, elective, unilateral TKA between January 2010 and December 2022. Patients were stratified into conventional (C-TKA; n=12,659), computer-navigated (N-TKA; n=4,071), or robotic-assisted (R-TKA; n=2,085) cohorts. Patient demographics and implant data, including mode of fixation and level of constraint (cruciate-retaining [CR] vs posterior-stabilized [PS]) were collected. MUA rates were the primary outcome. Data was analyzed using ANOVA with Tukey post hoc testing and multivariate logistic regression analysis. We report a 1.7% overall MUA rate, with a rate of 1.6% for conventional and 1.5% for navigated TKA, which were significantly lower than robotic-assisted TKA at 3.2% (p<0.001). However, on multivariate analysis, there was no difference in MUA rates for navigated and robotic-assisted when compared to conventional techniques. Cementless and hybrid fixation and CR implant designs were higher with robotic-assisted compared to conventional and navigated TKA. Multivariate regression revealed that TKA with fully cementless (OR: 1.80 [95%CI: 1.16-2.78] p=0.008) or hybrid fixation (OR: 2.92 [95%CI: 1.77-4.81] p<0.001) increased the risk for future MUA. Constraint also significantly influenced MUA rates, with CR designs yielding higher MUA rates (OR: 1.51 [95%CI: 1.16-1.96] p=0.002). When controlling for confounding factors, navigated and robotic-assisted TKA generated comparable odds for MUA when compared to conventional techniques. However, robotic-assisted TKA were more likely to utilize cementless or hybrid fixation and CR implant constraint, each of which were independently associated with increased odds of MUA. These operative factors should be considered when risk-stratifying and counseling patients on the likelihood of MUA.