A cyst is a fluid filled cavity. This collection of fluid (Baker's cyst) is found behind the knee joint. It is often found on imaging of the knee joint (eg ultrasound or MRI scans). Most often in adults it is an indication of a problem within the knee joint (such as arthritis or cartilage damage), rather than a problem behind the knee.

While many cause no symptoms, Baker’s cysts may result in a feeling of fullness or discomfort behind the knee, large ones may cause tightness or difficulty flexing (bending) the knee joint. Baker’s cysts under pressure may rupture, although this is not usually dangerous, many patients complain that it is quite uncomfortable or painful. If this happens it is treated with pain killers, ice packs, and gentle exercises to mobilise the knee joint.

Because they often indicate a problem within the knee joint in adults, the treatment is aimed at diagnosing the internal knee joint problem and treating it. Aspirating the cyst directly is less likely to work and the aspirated cysts often re-occur, and surgically dissecting out the cyst is not necessary. Dr Ihsheish can assess the cyst clinically and radiologically and discuss with you the findings and relevant treatment options.