Softening of the knee cartilage.

Alternative Names

Patellae - femoral grinding

Causes, incidence, and risk factors

Chondromalacia patella occurs in adolescents and young adults, more frequently in women. The cause is thought to be related to overuse, trauma and/or abnormal forces on the knee. Many affected adolescents have a mildly abnormal alignment of the patella (knee cap) and femur. Affected people of all ages have knee pain and a grating or grinding sensation when they extend their knee.

Signs and tests

A physical examination of the knee is not specific but may suggest the diagnosis. The knee may be tender and mildly swollen. The kneecap may not be perfectly lined up with the femur (thigh bone) underneath. X-rays are usually normal.

Treatment

Temporary rest or immobilization of the affected joint and nonsteroidal anti-inflammatory drugs may be effective in relieving pain. Physical therapy, especially quadriceps strengthening and hamstring stretching, is helpful. Participation in sports or strenuous activity should be limited until the pain has resolved. Surgery is beneficial if there is a problem with the alignment of the patella that cannot be corrected with therapy. Depending on the nature of the misalignment, the surgery may be arthroscopic or open.

Expectations (prognosis)

The condition usually improves with therapy and non-steroidal anti-inflammatory medications. For the few people that need it, surgery is successful about 90% of the time.

Complications

Failure of treatment to relieve pain is the primary complication. When surgery is necessary, surgical complications include infection, failure to relieve pain, and worsening pain.

Calling your health care provider

Call for an appointment with your health care provider if symptoms of this disorder develop.

Prevention

Avoid trauma or abnormal stress on the knee.Keep the leg muscles strong and flexible, especially the quadriceps and the hamstrings.