Looking for some answers(knee problems)

I have ongoing knee problems, for about 20 years now. I am wondering what would be the best fit for me, employment-wise? PT? Restrictions? I am 6 ft tall, 200 lbs and 42 years old. My knee is always sore, and sometimes very unstable. Here is my MRI report;

CLINICAL HISTORY

NOV/86 Lateral retinacular release. Lateral osteochondral fragment removal.
Aug/01 Arthroscopic shaving of patella.
Fairly constant left knee pain since 1986. Has gotten worse over time.
History of significant arthitis left patella.

MRI REPORT

DEC/O5

MRI SEQUENCES
- Axial T2*
- Sagittal dual echo SPIR, dual echo, dual echo ACL
- Coronal PD SPIR, T2 STIR

MRI FINDINGS

The menisci, collateral ligaments and cruciates are intact. There is a 4mm
rounded lesion of intermediate signal intensity seen within the medial femoral
condyle in a subchondral location at the junction of the middle and posterior
third of the condyle. This is located immediately adjacent to a contour
abnormality along the articular surface of the condyle. This may possibly
represent a small neovascular chondral defect.
There is no evidence of joint effusion.

Degenerative changes are seen within the patellofemoral joint involving the
hyaline cartilidge. This is more pronounced within the medial articular surface
of the patellofemoral joint.

IMPRESSION

Degenerative hyaline changes noted in the patellofemoral joint, particularly
within the medial aspect of the joint.

3 mm small osteochondral lesion within the medial femoral condyle, most
likely representing a healed osteochondral defect.
--------------------------------------------------------------------------------------

I appreciate any and all feedback!!

Thanks,
Steve

I am a 22 year old male. I worked in a warehouse for 2 years from age 18-20. Never had any previous knee pain or injury. For those 2 years for 8 hours a day, 40 hours a week all i did was squats to pick up cases of various items ranging from 1-80lbs. About a year into the job, i started have knee pain in both knees with the left being the worse of the two. My knees would turn red on the lower half of them(no swelling though), very painful. If i put my hand on my knee while sitting down and straighten it from 90 degrees i feel a crack. And if i am just sitting down and put my hand on my knee and wag it side to side i feel it grinding. There were nights when i left work i could barely walk, and i could barely press the clutch in on my car me knee was so sore. I was forced to give that job up. Since i gave it up i would still get the knee pain but not as bad unless i was doing some strenuous on my knees.

Now i have a job where i am on my feet for about 4 hours each day. Nothing strenuous, just on my feet. And i am going through the same thing. Knees turning red, painful clicking. My knees become very stiff. 2 years ago i went to the dr. and she sent me for x-rays which came back good. She mentioned something about the patella femoral syndrome. Anybody have any advice? Think her diagnosis was right? And if so, what can i do about treating it because it is becomming very debilitating. PLEASE HELP!!