Range of Motion at Discharge Predicts Need for Manipulation following Total Knee Arthroplasty

Stiffness following total knee arthroplasty (TKA) is a common complication that can result in unsatisfactory outcomes. Manipulation under anesthesia (MUA) has been widely employed to treat this problem. It is uncertain whether an association exists between range of motion (ROM) at discharge and need for MUA following primary TKA.A retrospective review of an institutional joint registry identified cases of primary TKA performed by three surgeons at a single institution over a 22-month period. A logistic regression model was used to examine the association between ROM at discharge and subsequent MUA controlling for confounding variables related to patient demographics and perioperative details. Of the 1,546 cases identified, 113 (7.3%) cases underwent subsequent MUA. As discharge ROM increased, manipulation rates decreased. Patients with discharge flexion <65 degrees were more likely to undergo MUA than those with flexion >90 degrees (odds ratio [OR] = 17.57, 95% confidence interval [CI] [7.97, 38.73], p < 0.0001). The largest differential in odds of MUA was observed between the <65 degrees at discharge group (OR = 17.57) and the 65 ≤ 75 degrees at discharge group (OR = 7.89). At discharge ROM of 80 ≤ 90 degrees of flexion, patients had more than a twofold increase in odds of MUA relative to those in the >90 degrees group (OR = 2.22, 95% CI [1.20, 4.10], p = 0.011). The results of this study suggest that there is an association between lower ROM at discharge and greater risk of MUA post primary TKA. Counseling patients in regard to discharge ROM and associated risk of MUA may optimize gains in ROM during recovery.