Patellofemoral pain syndrome is a term used to describe pain at the front of the knee and around or behind the kneecap (patella). It is one of the most common disorders of the knee. It can occur in all age groups but is particularly common in teenage girls.
- Patellofemoral pain syndrome usually involves pain in or around the kneecap and usually comes on gradually.
- People tend to notice the pain particularly when going up or down stairs, squatting, kneeling or running. It is often known as “runner’s knee”.
- It may also be aggravated by long periods of sitting with the knees bent, and this symptom is known as ‘movie-goers knee’.
- Swelling is not a major feature of this condition.
In this syndrome, the pain is usually the result of the kneecap not tracking smoothly in the groove of the femur (the underlying thighbone) when the leg is being bent and straightened. Kneecap pain can be caused by any imbalance or dysfunction of the stabilising forces that keep the kneecap tracking smoothly in this groove, or by damage to the back surface of the kneecap.
A combination of factors may result in the kneecap not tracking smoothly, including:
- Overly tight thigh (hamstring or quadriceps) muscles;
- Tightness of the iliotibial band (the strong band of thick tissue running down the outside of the thigh), which pulls the kneecap outwards;
- Weakness of the inner thigh muscles (adductors);
- Weakness of one of the buttock muscles which stabilise the pelvis, called the gluteus medius;
- Weakness or delayed contraction of one of the large quadriceps muscles, such as the vastus medialis obliquus;
- Faulty biomechanics, such as excessive pronation (rolling in of the foot during the walking cycle;
- Swelling of the joint, due to an injury or wear and tear in the joint, will also cause reduced function in the quadriceps muscles, and this can result in anterior knee pain; and
- Osteoarthritis of the patellofemoral joint may cause anterior knee pain.
Often the pain develops as an overuse injury seen in long-distance runners or cyclists, or it may be initiated by a twisting injury to the knee, or even as a result of lunging or squatting.
- Initial treatment may involve taping of the kneecap to hold it in a more ideal position to relieve pain. A sports doctor or physiotherapist will be able to show you how to tape the knee correctly to pull it back into alignment.
- Simple pain relief medicine such as paracetamol and sometimes a non-steroidal anti-inflammatory drug (NSAID) may also help.
- When the symptoms first develop they are best treated by icing the knee for 10-20 minutes after activity.
- It is also advisable to avoid any activities that exacerbate the pain.
- Rehabilitation involving stretching and strengthening exercises for specific muscles to achieve correct balance of the stabilising muscles around the kneecap.
- Strengthening of stabilising buttock muscles, that when activating properly, enable the muscles about the knee to function more effectively.
- Orthotics are useful for those with biomechanical abnormalities, particularly excessive pronation of the foot (rolling in).
- Your doctor or physiotherapist may design an individual exercise programme for you. Such a programme will include a graded increase in activity. It is important to do these exercises on a daily basis to maximise the chance of recovery, which will generally take about 6 weeks.
- If there is significant swelling of the knee, further assessment and investigation will be needed.