Patello femoral pain

The patella is the kneecap bone. It lies within the quadriceps tendon. This large tendon from the powerful thigh muscles (quadriceps) wraps round the patella and inserts into the top of the lower leg bone (tibia). The quadriceps muscles straighten the leg. The patella acts like a fulcrum to increase the force of the quadriceps muscle.The back of the patella is covered with smooth cartilage. This helps the patella to glide over the lower part of the thigh bone (femur) when you straighten your leg.

What causes patellofemoral pain?

It is probably due to a combination of different factors which put extra strain on the knee joint and on the surrounding muscles and ligaments.

Situations where this can occur include:

• • Overuse of the knee, such as in certain sports - particularly at times of increased training.

  • Some people may have a slight problem in the alignment of the knee. This may cause the patella to rub on rather than glide over the lower femur. It may be due to the way the knee has developed. Or, it may be due to an imbalance in the muscles around the knee - for example, the large quadriceps muscle above the knee. If one side of the quadriceps muscles pulls harder than the other side, then the patella may not glide 'true' and may rub on one side.

  • A combination of an alignment problem (as above) and overuse with sports, may be the commonest reason for getting patellofemoral pain.

  • Foot problems can play a part. For example, where the feet do not have strong arches ('flat feet'). This makes the foot roll inwards ('pronate'), which means the knee has to compensate for the inward movement. Also, shoes where the soles are hard rather than springy, put more strain on the knee.

  • Injury to the knee - including repeated small injuries or stresses due to sports, or due to slack ligaments ('hypermobile' joints).

  • Reduced muscle strength in the leg can contribute, as the leg muscles will be less able to absorb stresses on the knee.

Who gets patellofemoral pain?

Almost anyone - it can occur in children from about age five onwards, and in adults. It is a common cause of knee pain.

What are the symptoms of patellofemoral pain?

• • Pain around the knee. The pain is felt at the front of the knee, around or behind the knee cap. Often, the exact site of the pain cannot be pinpointed; instead the pain is felt vaguely at the front of the knee.

  • The pain comes and goes. It is typically worse when going up or down stairs or with certain sports. Also, it may be brought on by sitting still for long periods. For example, after going to the cinema or a long drive.

  • There may be a grating or grinding feeling or noise when the knee moves. This is called 'crepitus'.

  • Sometimes there is fullness or swelling around the patella.

How is patellofemoral pain diagnosed?

The diagnosis is made from your symptoms, the history of the problem, plus a doctor's examination.

Tests such as X-rays or scans cannot diagnose patellofemoral pain and are not helpful - though they may sometimes be used to look for other conditions.

What is the treatment for patellofemoral pain?

In the short term:

• • Avoid strenuous use of the knee - until the pain eases. Symptoms usually improve in time if the knee is not over used. Aim to keep fit, but to reduce the activities which cause the pain.

  • Painkillers - paracetamol and/or anti-inflammatory painkillers such as ibuprofen. Anti-inflammatory painkillers are often helpful for this type of pain.

In the longer term, treatment aims to treat some of the underlying causes. For example, by strengthening muscles and helping with foot problems:

• • Physiotherapy - improving the strength of the muscles around the knee will ease the stress on the knee. Also, specific exercises may help correct problems with alignment and muscle balance around the knee. For example, you may be taught to do exercises which strengthen the inner side of the quadriceps muscle. You may also be taught exercises to stretch tight ligaments. The physiotherapist can give advice tailored to your individual situation.

  • Suitable footwear - for example, arch supports if you have 'flat feet'; suitable shoes if you are running; springy soles which reduce strain when walking.

Other possible treatments are:

• • Taping of the patella - is a treatment which may reduce pain. This is where adhesive tape is applied over the patella, to alter the alignment or the way the patella moves. Some people find this helpful. Some physiotherapists can offer patellar taping treatment.

  • A special brace is another option which may help reduce pain.

  • Surgery is not often used for patellofemoral pain. However, it may be helpful in certain situations. For example, to correct the alignment of the patella by releasing a tight ligament.

What is the outlook?

The outlook is good. Most people get better with simple treatments such as physiotherapy. However, it may take 4-6 months for full recovery, and meanwhile you may need to reduce activities such as sports training.

References

• • Labotz M. Patellofemoral syndrome. The physician and sportsmedicine July 2004.

  • Potter, JP. Patellofemoral syndrome. emedicine, updated March 2006.

  • Heintjes E, Berger MY, Bierma-Zeinstra SM, et al; Pharmacotherapy for patellofemoral pain syndrome. Cochrane Database Syst Rev. 2004;(3):CD003470. [abstract]

  • Heintjes E, Berger MY, Bierma-Zeinstra SM, et al; Exercise therapy for patellofemoral pain syndrome. Cochrane Database Syst Rev. 2003;(4):CD003472. [abstract]

  • D'hondt NE, Struijs PA, Kerkhoffs GM, et al; Orthotic devices for treating patellofemoral pain syndrome. Cochrane Database Syst Rev. 2002;(2):CD002267. [abstract]

  • Aminaka N, Gribble PA; Patellar taping, patellofemoral pain syndrome, lower extremity kinematics, and dynamic postural control. J Athl Train. 2008 Jan-Mar;43(1):21-8. [abstract]