Wow, yikes...that sounds very ominous.

I've been recently finding that for my hip, I get a lot more mobility out of it if I do basic exercises in all the planes of motion it can move in.
1. Start facing the ground on all fours (knees on the ground, hands on the ground)
2. Lift it up to the side
3. Pick up the leg and lift forward
4. Pick up the leg and lift backwards
5. Kick up the leg behind me

The idea as I understand it is to:
1. Get the muscles around the hip moving in all different directions and break up any stickiness in ways they can't move
2. Flush fluids through the joints in the hips, which causes the body to do a much better job at rebuilding and repairing the tissue/etc in the joint

Does this help you? I have no idea. You might be able to do something similar with the knee or you might not. It's just a suggestion. I'm also going to the gym and doing weight machines, but at the very lowest weight that I can feel. Like say I could probably do 80lbs on the machine with my legs, I'm only doing 30lbs. Just enough to flush some blood through the muscles.

No idea if this is relevant to your situation, but it's been an enormous help to me when I injured my hip. The body is sorta...lazy (aka "efficient") at repairing muscles/ligaments/etc in way they aren't being used. If you can use it (nothing big and heavy just enough to kick your body into realizing the area is being used and needs to be repaired) you can sometimes get it to kick in and repair the area. My dad (I'm in my 30's, he's in his late 50's) started to have one of those issues with not being able to raise his arms above his head, his doctor said surgery, but he was able to fix it by doing lightweight lat pulldowns until his body kicked in and cleared away whatever buildup was causing the impingement.

Again, I'm not sure if this is relevant to your situation, just a though on something I've been finding benefit from recently.