This seems to me to be a rehab issue. For every injury, there's a way to rehab it. The trick is to figure out what that is. My first instinct would be to try walking, just plain walking. We are built to walk. Try around the block, then gradually longer up to say 3 miles. Depending on the injury, this might be a little uncomfortable to start with, but might loosen up and feel fine after maybe 1/2 mile - or not. Sometimes I'll do deep unweighted squats to loosen up and strengthen knee tissues. Play around with various things.
__________________
Results matter