Manipulation Under Anesthesia After Total Knee: Who Still Requires a Revision Arthroplasty?

Stiffness after total knee arthroplasty (TKA) is a multifactorial complication involving patient, implant, surgical technique, and rehabilitation, occasionally necessitating manipulation under anesthesia (MUA) or revision. Few modern databases contain sufficient longitudinal information of all factors. We characterized MUA after primary TKA and identified independent risk factors for revision TKA after MUA from the American Joint Replacement Registry.

We retrospectively reviewed primary TKAs for American Joint Replacement Registry patients ≥65 years from January 1, 2012 to 31 March, 2019. We linked these to the Centers for Medicare and Medicaid Services database to identify MUA and revision TKA procedure codes. We compared groups with chi-squared testing, identifying independent risk factors for subsequent revision with binary logistic regression presented as odds ratios with 95% confidence intervals.

Of 664,604 primary TKAs, 3918 (0.6%) underwent MUA after a median of 2.0 ± 1.0 months. Revision surgery occurred in 131 (3.4%) MUA patients after a median of 9.0 months. Timing of MUA was not different between revision and no revision patients (P = .09). Patients undergoing MUA compared to no MUA were older (age 71.5 vs 70.7, P < .01), predominantly female (63.9% vs 61.2%, P < .01), current/former tobacco users (24.2% vs 13.3%, P < .01), with osteoarthritis diagnoses (98.0% vs 84.3%, P < .01). Independent risk factors for revision after MUA were male gender (1.56, 1.09-2.22).

The incidence of MUA after primary TKA is low (0.6%) in Medicare patients ≥65 years of age; 3.4% progress to revision after a median of 9 months. Being male was significantly associated with revision TKA after MUA.