Manipulation Under Anesthesia (MUA) After Knee Replacement . While most patients progress well with physical therapy, some may develop limited range of motion that requires additional intervention. Manipulation Under Anesthesia (MUA) is a non-surgical procedure where your surgeon gently moves your knee while you’re under anesthesia to break up scar tissue (adhesions) that may be limiting your movement, like pressing the “reset button” on your knee’s mobility: - Most effective when performed with