High-quality knee-specific evidence includes a 2024 multicenter randomized controlled trial (Abdel et al.) in which MUA produced an immediate mean improvement in range of motion (ROM) of 46° (from a pre-MUA ROM of 72–118°) and similar ROM and clinical outcomes between randomized groups at 6 weeks and 1 year. Systematic reviews and meta-analyses from 2018 through 2024 consistently report clinically meaningful improvements in ROM after MUA for postoperative knee arthrofibrosis following TKA, with some reviews noting better gains when MUA is performed earlier (within roughly 12 weeks) and reporting mean ROM improvements in the range of ~20–41° depending on the analysis.
The systematic reviews (2022–2024) supporting knee MUA note important limitations: many included studies are nonrandomized, heterogeneous in definitions and timing of arthrofibrosis and MUA, often lack comparison groups, vary in physical therapy regimens, and overall the evidence quality is low to moderate. A 2024 systematic review/meta-analysis comparing early versus delayed MUA found similar post-MUA flexion but greater mean gains and fewer complications with earlier MUA; pooled analyses were limited by variable reporting.
For non-knee joints (spine, TMJ, toe, ankle and others), the evidence is limited, inconsistent, or low quality. Spine and spinal manipulation under anesthesia (SMUA) studies show negligible or uncertain benefits and are limited by small samples, high risk of bias, and inconsistent controls. TMJ, toe, and ankle reports are small case series or retrospective reviews with mixed results and methodological limitations. Professional guidance (AAOMS) includes specific recommendations for TMJ disease in select contexts, but overall the policy characterizes MUA for these other joints as having limited or insufficient evidence of efficacy and potential risks that do not consistently favor the procedure.
Policy administrative updates relevant to the evidence summary include revisions to the Clinical Evidence and References sections effective 04/01/2025 and an entry on 06/01/2025 adding Idaho and Kansas to the states where the medical policy does not apply; these are documentation/administrative changes rather than changes to the substantive coverage rationale.