The MUA has disrupted a lot of things inside your leg, and yes, it will take time for it to settle down. Don’t force your bend or extension and don’t let any PT force it either. That will hinder healing. It’s not exercising that gets our range of motion back, it’s Time: Time to recover. Time for pain and swelling to settle. Time to heal. Our range of motion is right there all along just waiting for that to happen so it can show itself. In the general run of things, it doesn't need to be fought for, worked hard for or worried about. It will happen. Exercise as in strength training is counter-productive and in the early weeks does more harm than good. Normal activity is the key to success.