Q+A: Why do my knees click when I run?

Q Every time I run, my knee clicks loudly but painlessly. It’s annoying rather than painful. The noise comes from below and outside the kneecap. Is it, or the cartilage, damaged? I broke my kneecap when I was 12 – could this be a cause?

A Your problem with a ‘clicking’ knee is actually quite common among active people. The joint is a mechanical structure, and can be prone to some form of clicks, cracks and other sounds. Occasional clicking is entirely normal, and is usually caused by soft tissue passing over a bony prominence or the surface of two bones moving over one another. The knee joint commonly presents some form of mild crepitus in people over 30. This is referred to as ‘normal wear and tear’ and occurs as we get older and continue to use our joints. However, if the clicking becomes more persistent, uncomfortable or associated with a specific movement, the underlying cause needs to be examined.

It’s unlikely that you have suffered a cartilage injury, as you say that there is no pain, and don’t mention any excessive swelling following training – both of which you would expect with damaged cartilage.

There are therefore two probable explanations for your problem. Tightness in the soft tissue around the knee or weakness in certain muscle groups can cause problems with the tracking of the patello-femoral joint (where the kneecap and thighbone meet). If this occurs, clicking would be the usual symptom, particularly when you start to bend the knee.

The second cause could be tightness in your iliotibial band. This will tend to pull the kneecap excessively to the outside and worsen any alignment problem (such as that described above). Iliotibial tightness can also cause increased friction and subsequent clicking as it passes over the outside of the femur.

Over the long term, these problems will tend to increase patello-femoral wear, and can lead to further injury without proper treatment. Seek the advice of a chartered physiotherapist. They can tell you what stretches and exercises may be required.

Despite all this, your problem has quite a simple explanation and you definitely don’t have to hang your trainers up just yet.

Andy Caldwell, chartered physiotherapist