ACE Inhibitor Use Does Not Significantly Affect Occurrence of Manipulation Under Anesthesia Following Total Knee Arthroplasty

Abstract

Introduction Common medications may attenuate fibroblast proliferation and scar tissue formation. This study aims to evaluate the association between angiotensin converting enzyme inhibitor (ACEI) use and post-operative stiffness assessed by rate of manipulation under anesthesia (MUA) and change in range of motion (ROM) following total knee arthroplasty (TKA). Methods Patients undergoing primary TKA January 2014 - September 2019 were identified. Demographic information, use of ACEI medications, occurrence of MUA in the 6 months following surgery, and ROM was determined by chart review. MUA was indicated upon failure to achieve 90° ROM at 1-month follow-up. Demographics were analyzed using Student’s t-test and Chi-Squared tests. SPSS (version 24, IBM) multivariate regression calculated odds ratios for MUA controlling for age, BMI, American Society of Anesthesiologist’s class, and gender. Results 1590 primary TKA’s were identified. 274 patients (17.3%) were taking ACEI medications. 46 patients required MUA (2.9%). Five patients (1.8%) taking an ACEI required MUA, versus 41 of the 1316 control patients (3.1%). No significant difference in MUA rates between the ACEI and control cohorts (odds ratio 0.670, 95% CI: 0.259 – 1.735, p=0.410) was identified. Change in ROM was not significantly different between cohorts at 1 and 3 month intervals. At 1-year, improvement in ROM was significantly less in patients taking ACEIs (+6.54° vs. +9.90°, p=0.035) and significantly fewer ACEI cohort patients achieved 118° flexion (56.9% vs. 68.4%, p=0.013). Conclusions This study supplies evidence that ACEIs do not reduce post-operative stiffness following TKA. Additionally, patients taking ACEI medications have significantly less improvement in ROM 1 year post-operatively.