Manipulation under anesthesia following total knee arthroplasty: a comprehensive review of literature

Introduction: The etiology of the stiff knee after total knee arthroplasty (TKA) is largely unknown, although excessive scar tissue due to arthrofibrosis is an important reason for a limited range of motion (ROM) after this procedure. Persistent limited ROM after TKA results in poor patient-reported outcomes and is increasingly becoming a more prominent reason for TKA revision surgery. Methods: A narrative review of current literature on manipulation under anesthesia (MUA) after TKA analyzing etiology and risk factors for stiffness after TKA, effectiveness of MUA and what is known about rehabilitation after MUA. Results: Literature describes numerous risk factors for insufficient knee ROM after TKA, but a comprehensive valid risk model is lacking. MUA is an effective treatment option with evidence suggesting better outcomes if performed within the first 3 months after TKA. The wide variety in both the indication and timing for MUA, and the lack of scientific evidence on how to rehabilitate patients after MUA, complicates the interpretation of available literature. This is even more so the case on the reporting of one versus two or more MUAs after TKA. Conclusion: Future comparative trials, preferably with a randomized study design, should be conducted to elude more clear indications for MUA, to give clinical guidance on correct timing for MUA and on how to rehabilitate patients afterward. © 2018, Istituto Ortopedico Rizzoli.