knee snaps when lowering to sit or use car clutch

by p.
(virginia)

While on vacation I was pushed over by a wave and my leg was pushed outward when I fell. When I was helped up up I thought I was OK but swelling and pain started almost immediately. Not wanting to ruin the next 10 days of vacation I slowly hobbled with knee straight up and back to the beach.

It improved slowly but after 3 mo. I have a click/snap near the center of knee cap seems permanent. It is even audible. I experience some pain on ascending stairs, irritation when using the stick shift (which I avoid!) random shooting pains.I still cannot crouch with that knee. What's happening in there?

Thanks.
P. 57 yr. old