Chondromalacia patellae is damage to the cartilage at the back of the kneecap (patella). The usual treatment advised is to avoid overuse of the knee and to have physiotherapy, which is effective in most cases.
The patella, or kneecap, can be a source of knee pain when it fails to function properly. Alignment or overuse problems of the patella can lead to wear and tear of the cartilage behind the patella. Chondromalacia patella is a common knee problem that affects the patella and the groove it slides in over the femur (thigh bone). This action takes place at the patellofemoral joint.
Chondromalacia is the term used to describe a patellofemoral joint that has been structurally damaged, while the term patellofemoral pain syndrome(PFPS) refers to the earlier stages of the condition. Symptoms are more likely to be reversible with PFPS.
Your kneecap (patella) sits over the front of your knee joint. As you bend or straighten your knee, the underside of the patella glides over the bones that make up the knee.
Strong tendons help attach the kneecap to the bones and muscles that surround the knee. These tendons are called:
- The patellar tendon (where the kneecap attaches to the shin bone)
- The quadriceps tendon (where the thigh muscles attach to the top of the kneecap)
Anterior knee pain begins when the kneecap does not move properly and rubs against the lower part of the thigh bone. This may occur because:
- The kneecap is in an abnormal position (also called poor alignment of the patellofemoral joint)
- There is tightness or weakness of the muscles on the front and back of your thigh
- You are doing too much activity that places extra stress on the kneecap (such as running, jumping or twisting, skiing, or playing soccer)
- You have flat feet
Anterior knee pain is more common in:
- People who are overweight
- People who have had a dislocation, fracture, or other injury to the kneecap
- Runners, jumpers, skiers, bicyclists, and soccer players who exercise often
- Teenagers and healthy young adults, more often girls
Other possible causes of anterior knee pain include:
- Pinching of the inner lining of the knee during movement (called synovial impingement or plica syndrome)
Anterior knee pain is a dull, aching pain that is most often felt:
- Behind the kneecap (patella)
- Below the kneecap
- On the sides of the kneecap
One common symptom is a grating or grinding sensation when the knee is flexed (when the ankle is brought closer to the back of the thigh).
Symptoms may be more noticeable with:
- Deep knee bends
- Going down stairs
- Running downhill
- Standing up after sitting for awhile
Exams and Tests
The health care provider will perform a physical examination. The knee may be tender and mildly swollen, and the kneecap may not be perfectly lined up with the thigh bone (femur).
When you flex your knee, you may feel a grinding sensation below the kneecap. Pressing the kneecap when the knee is straightening out may be painful.
X-rays are usually normal, although a special x-ray view of the kneecap may show signs of arthritis or tilting.
MRI scans are rarely needed.
Resting the knee for a short period of time and taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen, or aspirin may help relieve pain.
Other treatments or self-care for anterior knee pain include:
- Changing the way you exercise
- Learning and performing exercises to both strengthen and stretch the quadriceps and hamstring muscles
- Losing weight (if you need to)
- Special shoe inserts and support devices (orthotics — for people with flat feet)
- Taping to realign the kneecap
- Wearing the correct running or sports shoes
Surgery for pain behind the kneecap (anterior knee pain) is rarely needed. During the surgery:
- Kneecap cartilage that has been damaged may be removed.
- Changes may be made to the tendons to help the kneecap move more evenly.
Anterior knee pain often improves with a change in activity, exercise therapy, and the use of NSAIDs.