Range-of-Motion Predictors for Repeat Manipulation Under Anesthesia and Revision Surgery for Stiffness After Total Knee Arthroplasty.

Introduction: Manipulation under anesthesia (MUA) is a first-line treatment for stiffness after total knee arthroplasty (TKA), but predicting outcomes after MUA can be difficult.

Purpose: We sought to determine the association between pre-MUA range-of-motion (ROM) and the risk of repeat MUA and revision in patients who underwent primary TKA.

Methods: We conducted a retrospective review of 543 MUAs for stiffness at a single institution. Mean age was 62.5 years, and 64% were female. Second MUA or revision TKA were considered failures of treatment. Penalized logistic regression models were used to assess risk factors for failures. The Kaplan-Meier survivorship was used to examine survivorship free from second MUA or revision.

Results: Before and after MUA, there was significant improvement in knee flexion (78.0° vs 112.8°, respectively) and extension (4.1° vs 0.8°, respectively); 6.4% of patients required repeat MUA and 5.3% required revision TKA. Survivorship free of second MUA was 90.9%, revision for stiffness was 92.4%, and all-cause revision was 88.2% at 2 years post-MUA. Patients with pre-MUA flexion contracture of ≥5° were more likely to undergo second MUA revision for stiffness and any revision. There were significant improvements in patient-reported outcomes postoperatively.

Conclusions: This retrospective chart review suggests that MUA is an effective treatment for post-TKA stiffness, with good early survivorship, and that worse pre-MUA ROM is associated with MUA failure and need for repeat MUA or revision. This information may have implications for patient counseling and management.