Chondromalacia patella (CMP) is damage to the articular cartilage under the kneecap. Symptoms are similar to patellofemoral pain as the kneecap rubs on the bone underneath causing swelling and pain.
Chondromalacia patella symptoms
- Symptoms are similar to that of patellofemoral pain syndrome.
- Pain and swelling at the front of the knee, especially over and around the kneecap or patella.
- It is often worse when walking downstairs or after sitting for long periods, known as movie-goers knee or theatre knee.
- A grinding or clicking feeling called crepitus can be felt when bending and straightening the knee.
What is Chondromalacia patella?
CMP results from damage to the cartilage which covers the back of the patella or kneecap. This smooth hard cartilage is known as hyaline cartilage or articular cartilage and its purpose is to allow smooth movement of the patella over the femur or thigh bone in the knee. There are different stages or grades of injury depending on how much of the surface has been damaged.
The cause can be either acute from a sudden impact or from a long-standing overuse injury. Acute injuries normally occur when the front of the kneecap suffers an impact, such as falling directly onto it or being hit from the front. This results in small tears or roughening of the cartilage. In overuse cases, the cause of the damage is usually repetitive rubbing of part of the cartilage against the underlying bone.
In a healthy knee, the movement of the Patella across the knee is a smooth gliding movement. In individuals with CMP, the kneecap rubs against the part of the joint behind it, resulting in inflammation, degeneration, and pain.
This can be for a number of reasons but is usually due to the position of the patella itself. The most common feature of CMP is patella mal-tracking. Usually, the patella moves sideways towards the outside of the knee due to muscle imbalances. The quadriceps muscles and other tissues such as the retinaculum are too tight on the outside of the knee and the vastus medialis oblique muscle is weak on the inside of the knee.
Other structural problems include Patella Alta, which refers to a high patella and patella Baja which refers to a low patella.
Chondromalacia patellae are common in young athletes who are often otherwise injury-free. Its incidence is also highest in women due to their higher Q angle. It is also more common in those who have experienced previous traumatic knee injuries such as fractures and dislocations.
CMP is often confused with Patellofemoral Pain Syndrome (PFPS) as CMP is often a result of PFPS. However, they can both occur in isolation.
Chondromalacia patella treatment
The aims of Chondromalacia patella rehabilitation are to decrease pain and inflammation, strengthen weak muscles of the knee and hip, stretch tight muscles and gradually return to full fitness. Patella taping is often a key part of CMP treatment and rehabilitation.
Reducing pain and inflammation
- Rest from activities that aggravate the injury. As a general rule, if it hurts or is made worse by an activity then don’t do it! Running and jumping activities are usually out along with cycling
- Apply cold therapy or ice (Do not apply ice directly to the skin as this may cause ice burns). Ice may be applied for 15 minutes every hour initially reducing to every 2 to 3 hours after a day or so.
- Compression, particularly in conjunction with cold therapy can help in reducing swelling. Apply a compression bandage after cold therapy. Tight compression bandages should only be applied for 10 minutes at a time in order to prevent tissue damage from restricting blood flow.
Chondromalacia patella taping
- Taping the kneecap can have an instant effect in relieving pain as the kneecap is pulled away from the site causing pain.
- The purpose of taping is to reduce pain and allow muscle strengthening exercises to be done.
- If the athlete has pain on normal daily activities then taping should be applied all day until there is no pain on normal activities.
- If there is pain only on sports-specific activities or muscle strengthening exercises then tape only for those exercises.
Go to Patella taping.
Exercises for rehabilitation of Chondromalacia patella
It is usually the vastus medialis obliques on the inside of the thigh near the knee and the gluteus medius muscle on the outside of the hip that requires strengthening.
The aim is to encourage the patella to track in the proper position spreading the forces throughout the joint. Exercises are the same as those for Patellofemoral pain.
Surgery is not common although can be a last resort if exercise rehabilitation has not worked. Surgery is via an arthroscopy or keyhole surgery where the damaged cartilage is removed or shaved off.
Return to fitness and prevention
- Return to full fitness should be gradual and sports specific training should only begin when there is no pain.
- Full strengthening exercises should have been done to restore the muscles to full and balanced strength.
- It may be necessary to tape the knee or wear
a supportwhilst returning to sport, but do not get to rely on it long term unless specified by your therapist.
- Any biomechanical abnormalities (e.g. pronation) should be corrected to prevent the injury returning.