Patellofemoral Pain Syndrome

(including CMP or Chondromalacia Patellae)

What is Patellofemoral Syndrome?

Patellofemoral syndrome is the term used to describe pain on and around the patella or kneecap. A common cause is damage to the surface underneath the kneecap. It can be started by an impact or it gradually comes on from rubbing on the bone underneath. The injury is often referred to as chondramalacia patellae, patella pain syndrome or runner's knee.

The injury is common among girls aged 10 - 20 years. Correct rehabilitation is essential for this injury along with taping. Do not ignore this injury because if it gets very bad it is extremely difficult to treat.

• Patellofemoral Pain Syndrome is the term used to describe pain in or around the kneecap (patella). It is also known as PFJ (patellofemoral joint) syndrome and anterior knee pain. Pain results from the abnormal movement of the patella on the femur (thigh bone) during bending of the knee joint.
• Chondromalacia is sometimes used to describe this injury. However this is a common misconception as chondromalacia refers specifically to the softening of the articular cartilage on the underside of the patella.

When the knee is bent from being outstretched, a number of muscles and ligaments that are attached to the patella function to move it medially (towards the inside surface of the knee) to sit in the intercondylar notch of the femur (bit in the middle where the patella sits).

In general, patellofemoral pain syndrome occurs when the patella does not move or 'track' in a correct fashion when the knee is being bent. This movement can lead to damage of the surrounding tissues, such as the cartilage on the underside of the patella itself, which can lead to pain in the region. This injury is quite common in people who do a lot of sport, in particular women of an adolescent age. Correct and immediate rehabilitation is vital for this injury as, if ignored it becomes very difficult to treat.

There are a number of causes that can lead to abnormal movement of the patella:

• Overloading - Bending the knee increases the pressure between the patella and the femur. Thus sports such as running, where repeated weight-bearing occurs, may result in PFJ syndrome.
• Pronating Feet - Pronating or 'flat' feet lead to an increased biomechanical stress on the knee joint. This may affect the alignment of the patella particularly during movement.
• Muscle imbalance - The quadriceps muscle group are responsible for the movement of the patella itself. If the lateral (outer) fibres are stronger or tighter than the medial fibres, or if the iliotibial band (ITB) is very tight this can lead to problematic patella tracking.
• Q-angle - Some people have a larger than normal femoral angle (known as the Q-angle)and may have 'knock-kneed' appearance (genu valgum). When the person straightens their leg, the patella will be forced to the outside of the knee. With repeated bending and loading, this motion may lead to damage of the underlying structures and cause pain.

What are the symptoms of patellofemoral syndrome?

• Aching pain occurs in the knee joint, particularly at the front, around and under the patella.
• Pain under the patella when bending and straightening the knee.
• Tenderness along the inside border of the kneecap.
• Usually swelling is present.
• Is often worse when walking up or down hills or stairs.
• A clicking or cracking sound may be present on bending the knee.
• Sitting for long periods may be uncomfortable. This is known as the theatre sign.
• What other signs may be present with patellofemoral syndrome?
• Temporary loss of function.
• Wasting (atrophy) of the quadriceps muscles.
• A Q-angle greater than 18 to 20 degrees.
• Tight muscles including calf muscles, hamstrings, quadriceps (especially vastus lateralis on the outside) and iliotibial band.

Who is most at risk from patellofemoral syndrome?

• You are more prone to this if you have a small kneecap or one that sticks out
• If your feet roll in or pronate.
• If you have weak quadriceps muscles.
• Athletes who do a lot of long distance running or hill running.
• Those who have had a previous knee dislocation

What can the athlete do to prevent patellofemoral syndrome:

• Apply RICE (Rest, ice compression and elevation) to the injured knee. This will help reduce swelling.
• Rest until there is no pain (this is very important).
• Use a knee support or heat retainer (with a hole).
• See a sports injury professional who can advise on treatment and rehabilitation.

A Sports Injury Specialist or Doctor could:

• Prescribe anti-inflammatory medication e.g. ibuprofen. Use electrotherapy equipment such as ultrasound, laser and electrical stimulation.
• Prescribe a comprehensive rehabilitation programme in conjunction with taping techniques.
• Investigate the possibility of a synovial plica.
• Operate in chronic cases.
• Vastus Medialis Obliquus (VMO) strengthening exercises combined with iliotibial band (ITB) stretches.
• Provide orthotic foot supports.

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