How To Unlock Locked Knees?

I am 61 years, heart (RCA) stented 3 months back, 5 feet 3 Inches, 73 kg. I have a complex miniscus tear and Osteoarthrites (MRI scan) in my right knee. At the moment it unlocks with little movement of the leg. I have to travel to USA for one month. What to do if my knee gets locked during travel or in USA and does not unlock? I am very worried. Is there a sure way to unlock it somehow and travel back to India and consult doctor here. Medical treatment in USA is out of bound. Thanks and I shall be indebted for any guidance.