Chondromalacia, technically termed chondromalacia patellae, is the most common cause of chronic knee pain. The condition is also called the patellofemoral syndrome.
Softening of the cartilage beneath the knee cap (the patella) results in small areas of breakdown and pain around the knee. Instead of gliding smoothly over the knee, the knee cap rubs against the thigh bone (the femur) when the knee moves. The changes can range from mild to complete erosion of the cartilage.
Chondromalacia commonly occurs in females. Girls in their teens are at elevated risk because the cartilage of the knee is subjected to excessive and uneven pressure due to the structural changes that accompany rapid growth.
Chondromalacia may also occur in adults over age 40 as part of the wear-and-tear process that eventually leads to osteoarthritis of the knee joint. It has informally been called “housemaid’s knee” and “secretary’s knee.”
Chondromalacia may also be related to trauma, overuse, or abnormal forces on the knee joint and can develop in skiers, runners, cyclists, and soccer players, especially if someone is knock-kneed or flat-footed.
The pain of chondromalacia occurs in the front or inside of the knee. The pain is generally worse with activities such as running, jumping, using stairs or kneeling. The pain is also typically worse after prolonged sitting with the knees bent. This pain is called the “theater sign” of chondromalacia.
There may be tenderness of the knee along with a grating or grinding sensation when the knee is extended. X-rays of the knee are generally normal in chondromalacia but may show a slight displacement of the knee cap. (Even if you have symptoms consistent with chondromalacia, your doctor may still order an x-ray to rule out other reasons for your knee pain.)
Nonsteroidal antiinflammatory drugs medications such as ibuprofen (Advil/Motrin) or naproxen (Aleve) are often prescribed both to alleviate pain and reduce the chronic inflammatory processes that increase the structural damage. Icing the knee can also help.
Chondromalacia is usually treated conservatively with exercises designed to strengthen the muscles around the knee and restore normal alignment of the knee cap. These exercises should be carefully designed - a trainer or physical therapist can help - to selectively strengthen the thigh muscles (the quads) and realign the patella.
About 85% of patients with chondromalacia improve with conservative treatment alone and require no further therapy. In about 15% of cases, the pain persists or worsens to the extent that surgical correction of the knee joint may be needed.
Revision date: July 5, 2011
Last revised: by Janet A. Staessen, MD, PhD