Even thought this is versing towards medical comments about knees may I add my .02,,, It is only my opinion and it what has worked for me. I am not offering advice but perhaps my experience might work for others:
I have had knee trouble for years. The injection shots only went so far. MRI confirmed degenerative arthritis due primarily due to age but not enough to cause the excruciating pain when recreating. Strong pain killers allowed me movement but I did not want to constantly take medication.
Doctor prescribes Physical Therapy because of
Iliotibial band syndrome- AKA: IT Band Syndrome. Even though this condition is largely associate with runners, the doc said it can be a very common cause of knee pain for a lot of folks and the causes of it are many. ITBS does not always necessitate surgery to correct.
Basically the outside of my legs were stronger than the insides which caused a physiological imbalance of the lower extremities that would affect the weakest point first which for me were the knees.
For me, strengthening abductors and quads and massage therapy on the IT bands to loosen them up allowed my patella to return to a more normal position. Exercise, PT and dropping a few pounds did wonders for my knees.