Often called "runner's knee", chondromalacia patella is a common condition causing pain in the kneecap. The patella is covered with a layer of smooth cartilage, which normally glides across the knee when the joint is bent. The pain is caused by an irritation of the undersurface or patella of the kneecap as the kneecap rubs against one side of the knee joint, irritating the cartilage surface.
Symptoms of chondromalacia include knee tenderness and pain that increases after sitting for a prolonged period of time, using stairs or getting out of a chair. There may also be a grating or grinding sensation when the knee is straightened. It may also cause pain during or after vigorous activities.
Cause and Risk Factors
Chondromalacia usually affects young, athletic otherwise healthy individuals as a result of overuse, injury or too much stress on the knee. It affects women more often than men because women experience greater lateral pressures on the patella. People who have had a dislocation, fracture or other injury to the kneecap are more prone to chondromalacia than other individuals.
A physician will examine the knee for signs of tenderness or mild swelling. The kneecap may also not be perfectly aligned with the thigh bone (femur). Applying pressure to the kneecap when it is extended may cause pain, which aids in diagnosis. X-rays usually do not show the damage caused by chondromalacia, although magnetic resonance imaging (MRI) may.
Unlike the damage to cartilage caused by arthritis, damage caused by chondromalacia can often heal. Conservative treatment is usually recommended first since rest and physical therapy may eliminate the symptoms.
First, the inflammation caused by chondromalacia must be allowed to subside. Non-steroidal anti-inflammatory medication may be prescribed to reduce the discomfort of the condition. For several weeks, patients should avoid activities that cause knee pain. Then, activity can be gradually increased.
During this time, low-impact activities, such as swimming, can help an athlete keep in shape, while avoiding running or activities that stress the knee. Once the inflammation has subsided, physical therapy can focus on strengthening and increasing the flexibility of the quadriceps and hamstring muscle groups.
If conservative treatment for several months fails, surgery may be recommended. A surgeon can look into the knee to assess cartilage damage by using an arthroscope (a surgical instrument for the visual examination of the interior of a joint). The physician can also determine if there is an anatomic misalignment that needs to be surgically corrected. If the tissue on the outside of the kneecap is too tight, it can make the patella track abnormally. Lateral release, a surgical procedure where the tight lateral ligaments are cut thus allowing for the patella to move normally, may be recommended. In rare cases, more extensive surgery may be required.