Wearing away and/or softening of the articular cartilage, which is a connective tissue that covers and protects the underside of the patella, the bottom end of the femur, and top end of the tibia. It absorbs stress to the knee joint and allows the patella to track smoothly in its femoral groove.

Excessive running or similar activity can wear down the articular cartilage over time. This can occur due to the patella not tracking smoothly in its femoral groove.

Pain around the patella (kneecap), usually occurring on the medial (inner) side and below.

R.I.C.E. Rest, Ice, Compression, Elevation. Reduce activity to promote healing. Avoid downhill runs especially. Strengthen surrounding muscles with a professionally recommended program. Apply Ice for 10-15 minutes after each workout to reduce inflammation and pain. A proper stretching routine is highly recommended pre and post workouts. As with any orthopedic injury, a consultation with a sports medicine professional is recommended.