A Baker's cyst is a fluid-filled swelling that develops at the back of the knee. This swelling can become inflamed, causing pain in the knee and calf. You might find the knee locks or clicks. For some, it may cause no symptoms at all. You’ll get a sharp pain if the cyst bursts. Fluid can leak into the calf, causing swelling and redness. Baker's cyst is more likely to develop in women than men, and people over the age of 40, although it can affect anyone.
Direct injury or trauma to the knee can cause a Baker's cyst to develop. Certain inflammatory joint conditions such as osteoarthritis, gout or rheumatoid arthritis put you at a higher risk of developing a Baker's cyst.
Book a routine appointment with your doctor if you have knee pain that’s not getting better after three or four weeks, or if your knee gives way, locks or clicks in a way that causes pain (painless clicking is not alarming). Your doctor will ask about your symptoms, your medical history and examine your knee to diagnose the condition. If your doctor is concerned that this could be more serious, they will arrange for scans to rule other conditions out.
If the symptoms are not causing you any symptoms, you do not have to do anything. The cyst will usually resolve on its own with time. For pain and inflammation, simple painkillers like ibuprofen or paracetamol are advised. Ice wrapped in a towel and applied to the back of the knee can reduce inflammation. If there are underlying health conditions such as inflammatory arthritis, these need to be managed first in order to help resolve the cyst. If the cyst is not resolving with time or your symptoms are worsening you may be referred to a specialist for drainage of the fluid.
They usually clear up on their own but this can take several months to years. They can be exacerbated by strenuous exercise or activity.