My mri results for left kneew reveals: mild thinning of the cartilage along the lateral femoral condyle with out full thickness defect or underlying reactive change. there is mild to moderate thinning of the medial compartment cartilage w/out full thickn

You : You have several reasons for pain based on this report. Where is your pain? Along the inside, front, or back of the knee. Based on the fact that there is mild to moderate thinning of the articular (joint surface) cartilage in the medial (inside) compartment, i assume your partial menisectomy in 2000 was on the inside (medial) aspect of your knee. If that is the case, you have done very well for the past 12 years considering that you are a runner only to have mild thinning! grading of arthritis in an MRI (where most likely you were laying down) is sometimes a little artificial so it is a little hard to tell how bad it really is. You definitely have thinnning, and it is probably a little more advanced in the medial(inside) compartment than for age, although basing this on a report is very subjective. The baker's cyst is located in the back of the knee, so if your pain is in the back, then this is the most likely the culprit. That being said, the baker cyst is a direct result of the joint being irritated, either from the medial meniscus tear or arthritis. Pain from the current meniscus tear should be along the inside of the knee, and it may be associated with instability, locking or catching. Based on this report, you should see a sports medicine professional to discuss your options. Good luck!.