Age and Racial Disparities in Manipulation Rates Following Total Knee Arthroplasty: An 11-Year Review

Manipulation under anesthesia (MUA) is a recognized intervention for early postoperative stiffness following total knee arthroplasty (TKA). Although a restricted preoperative range of motion is a known risk factor for postoperative stiffness, the impact of many patient-related factors remains unclear. To our knowledge, no previous investigations have directly evaluated the effect of employment status on MUA incidence. Similarly, the impact of marital status/social support and the presence of language barriers remains incompletely assessed. The primary aim of this investigation was to evaluate how such patient-related parameters may impact MUA incidence following primary TKA. We performed a retrospective review of a prospectively gathered multicenter institutional database from July 1, 2012, through December 3, 2023, comprising cases from 23 surgeons at seven surgical sites. Patients undergoing a primary TKA with subsequent MUA within 16 weeks of the index procedure were included. Demographic variables, employment and marital status, primary language, and Area Deprivation Index (ADI) were collected. Variances in MUA frequency were then identified using two-sample t-tests for continuous data and Pearson's chi-square tests for categorical data. To model MUA risk and eliminate potential confounding, multivariate and matched case-control logistic regression analyses were performed. Statistical significance was defined as p < 0.05. Among 6,110 primary TKA patients, 265 (4.3%) underwent MUA within 16 weeks. The MUA cohort was significantly younger than the non-MUA cohort (median age: 67 years vs. 73 years, p < 0.001). Self-identification as Black or African American was associated with an increased incidence of MUA (10.3% vs. 4.3% overall, p < 0.001). Gender, marital status, employment status (except "disabled"), other racial designations, primary language, and ADI did not significantly impact MUA incidence. Younger age and Black/African American race were independently associated with significantly higher rates of MUA following TKA. Further investigation is warranted. These results may help guide physician and patient postoperative expectations and support resource allocation to promote successful outcomes for all patients undergoing knee replacement.