Runner's knee or chondromalacia is more commonly known by doctors as patellofemoral pain syndrome. The knee joint is formed from three bones that are connected by tendons and ligaments: the femur (thighbone), the tibia (shinbone), and the patella (kneecap).
Patellofemoral pain syndrome is pain in the area where the patella and femur meet. It is often caused by overuse of the knee. Although it is often noticed while doing rigorous activities such as running or jumping, a person may also experience pain while squatting, walking up stairs, or even when sitting for long periods of time. Runner's knee can usually be treated without surgery, often with a combination of rest and anti-inflammatory medications.
See also Kneecap Conditions (Patella)