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. Here we explain the injury as well as treatment, strapping and exercises.
On this page:
- Symptoms & diagnosis
- Causes & anatomy
- Patella taping
Chondromalacia patella symptoms
Symptoms are similar to that of patellofemoral pain syndrome with 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.
Chondromalacia patella causes & anatomy
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 is 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 & rehabilitation
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. The taping techniques used for patellofemoral pain syndrome are the same as for chondromalacia patella.
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 require strengthening. The aim is to encourage the patella to track in the proper position spreading the forces throughout the joint.
Begin the exercises as soon as they can be performed without pain. It may be necessary to tape the knee while performing exercises so they can be done pain-free. The
The main aim here is to strengthen the Vastus Medialis Oblique muscle on the inside of the knee. This should help pull the kneecap inwards and allow it to track normally in the groove of the knee joint.
Chondromalacia patella exercises should start with learning to contract these muscle whilst sitting with the leg straight. This can be progressed to standing, and them maintaining a strong contraction whilst performing progressively harder exercises.
It is important that the athlete can feel the Vastus Medialis Oblique muscle contracting during strength exercises. Beginners may need to actually feel the muscle with their hand as it contracts. Strengthening exercises for the hip abductor muscles such as Gluteus
This is suitable for the athlete that has pain and is unable to perform standing exercises. The athlete sits on the floor with a foam roller or rolled up towel under the knee so that it is slightly bent. The hand is placed on the vastus medialis muscle (just above and to the inside of the knee cap) so the athlete can feel it contracting.
It is essential that the athlete learns to isolate the vastus medialis muscle and feel it being used for strengthening to be effective. Turning the foot outwards may increase the load on the VMO. A muscle stimulator or tens machine can help in the early stages. Contact the muscles, hold for 3 to 5 seconds, relax and repeat 10 times. The foot should lift up off the floor as the knee straightens. This exercises should be performed 3 to 5 times a day if pain allows.
Heel drop exercises
A more advanced exercise than a static contraction. Again it should be emphasized that the knee should be kept pointing forwards throughout the exercise and the athlete should be aware that it is the vastus medialis on the inside that is working.
The athlete drops down off the step as far as is comfortable (this does not always need to be all the way down) and returns to the starting position. Repeat 10 times and aim to perform a number of sets throughout the day.
Lay on your side with the knees bent to 90 degrees and feet in line with your spine. Lift the top knee away from the bottom knee. Make sure you keep the lower back and pelvis still and don’t rock backwards. You should start to feel the Gluteus Medius muscle at the back, top of the hip working. Start with 2 sets of 10 repetitions and gradually increase to 3 sets of 15-20.
This exercise should be started as soon as pain will allow. Tape the knee if necessary to avoid pain. Stand one foot in front of the other, the injured knee forwards. Bend the front knee enough to feel the vastus medialis is working. Aim to keep the knee pointing forwards – don’t let it fall inwards. Return to starting position and repeat. Aim for 3 sets of 10 repetitions. Again it may be better to perform a number of sets throughout the day, especially in the early stages of rehabilitation or for a particularly weak muscle.
Exercises to stretch the outside of the knee should be done. Tight lateral structures will not allow the kneecap to track naturally. Stretching the ITB, Quads, Hamstrings,
You may be referred for x-rays to help confirm the diagnosis. However, standard x-rays are often normal in this condition, although they may rule out other injuries. An MRI scan may be ordered instead of an x-ray as this is more likely to confirm the diagnosis.
The tight structures of the knee such as the lateral retinaculum need to be stretched and mobilized. The athlete sits with the knee slightly bent. The kneecap is glided (pulled) towards the inside of the knee and help for 20 to 30 seconds.
Hold the foot of the leg to be stretched and gently pull up behind. It can be done in the standing position (most common) or lying down as shown. Aim to keep the knees together and pull the leg up straight not twisted. The athlete should feel a stretch at the front of the leg. It should not be painful. Hold stretches for 20-30 seconds. Repeat 3-5 times. Important – if this stretch is painful for the knee then do not do it.
Iliotibial band stretch
Place the leg you want to stretch behind the other one. Put your weight onto your back leg, hold onto something to lean on if necessary. Hold for 20-30 seconds, repeat 3-5 times and do this at least three times a day. It is a lot of stretching but it is worth it in the end if you want to be rid of this injury. Never bounce when stretching, always ease into it gently and try to relax. If it is painful you are not doing it properly
Long adductor stretch
To stretch the long groin muscles which cross the knee joint stand with the feet wide apart. Bend the knee that you don’t want to stretch and lean away from the one you are stretching. Hold for 20-30 seconds and repeat 3-5 times, at least 3 times a day.
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