Baker’s cyst is one of the many causes of knee swelling and pain and seen regularly at Pure Physiotherapy. The location of the problem normally exists most commonly in the back of the knee but can present pain or swelling in the calf, front and sides of the knee.
A cyst is a membranous sac or cavity of abnormal character in the body, containing fluid. Approximately 5% of the population has a ‘Baker’s cyst’ (Demange, 2015). Like many problems in the body, an abnormality can be found and cause no problems at all and not generate pain. A Baker’s cyst is an example of this and can be found on an MRI scan quite commonly.
Sometimes when there is another problem such as a meniscus tear, this allows the fluid to escape as the congruence or the way the joint fits together has been compromised slightly. The fluid inside of the synovial joint capsule may pool to form a cyst in the back of the knee. The synovial joint capsule is located inside the knee joint and surrounds the knee joint. Less commonly, there can be complications in which the ‘cyst’ can rupture, leaking fluid into the calf – this can cause sharp pain and redness in the calf (Kornaat et al. 2006).
More women than men are generally affected by this problem. This is likely because osteoarthritis affects women more, meaning they may be pre-disposed to Baker’s cyst. It can affect any age, although it is most common in those over 40.
See a physiotherapist if you have a cyst that’s causing problems and does not clear up on its own. They’ll usually be able to confirm diagnosis of a Baker’s cyst by examining the back of your knee and asking about your symptoms. Your physiotherapist will ask you whether you have any associated health conditions, such as arthritis.
Physiotherapists at Pure are highly trained to detect whether more serious conditions may be present. If your physiotherapist would like to rule out other rare and more serious conditions, such as a tumour, an aneurysm (bulge in a section of a blood vessel) or deep vein thrombosis (a blood clot in one of the deep veins of the body) they will refer you to your GP. Not usually, but sometimes you may need an ultrasound scan or a magnetic resonance imaging (MRI) scan (NHS, 2018).
If you have an underlying condition that’s causing your cyst, it’s important that the condition is properly managed. The cyst may disappear when the condition causing it has been treated. Mainly your physiotherapist will prescribe you a tailored exercise programme to correct any muscle imbalances or to increase joint mobility. This combined with manual therapy to reduce swelling and increase blood flow to the affected area, can be very helpful in promoting healing and facilitating movement.
Treatment will not usually be necessary if you have a Baker’s cyst that is not causing any symptoms. Painkillers such as paracetamol and ibuprofen can be used to reduce the swelling and relieve any pain, but it is important you check with your GP that it is safe for you to take these. Bandages or an ice pack may also help. A bag of frozen peas wrapped in a tea towel works well as an ice pack.
In some cases, it may be required to drain the cyst, aspirating the fluid with a needle by your doctor. Sometimes it may not be possible to drain the cyst. Not often but sometimes surgery may also be needed to repair any significant damage around the knee joint.
NHS Information on Baker’s Cyst – click here.
Demange, M. K. (2015). Baker’s cyst. Rev Bras Ortop, 46(6), pp.630-633.
Kornaat, P. R., Bloem, J. L., Ceulemans, R. Y., Riyazi, N., Rosendaal, F. R., Nelissen, R. G., … & Kloppenburg, M. (2006). Osteoarthritis of the knee: association between clinical features and MR imaging findings. Radiology, 239(3), 811-817.