Baker's Cysts (named after the doctor who discovered them in 1877) are a relatively common knee problem.
Otherwise known as popliteal cysts, the Baker's cyst is a fluid filled sac out-pouching at the back of the knee.
The cysts can be small pea sized lumps or can grow to the size of a grapefruit.
They are uncomfortable and can be painful. The cysts usually only form on one knee but can form on both at the same time.
The knee joint is surrounded and enclosed by a fibrous capsule lined by a layer of tissue called the synovium. This structure secretes a fluid called synovial fluid which is a viscous substance involved in lubricating and cushioning the joint surfaces, bathing them and keeping them healthy. The Baker's cyst will form when too much fluid is produced and the compression of the joint during weight bearing will squeeze it out into the capsule and out of the back of the knee.
There are 2 types of cyst:
Primary cyst - Happens in young people for no particular reason. A fluid filled sac at the back of the knee called a bursa is often thought to be in communication with the synovuim and this allows the movement of synovial fluid into that space.
The lump formed will be soft to palpate and there is very often no change in skin colour.
Secondary cyst - These develop as a result of trauma or degeneration within the knee such as cruciate ligament tears, meniscal cartilage damage or osteoarthritis. These conditions can irritate the synovium and cause excessive fluid production. There may be pain and the whole knee can look swollen too. The joint may feel tight and there will be restriction in flexion/bending of the leg.
Baker's cysts can sometimes rupture, causing the fluid inside to drain down into the calf muscle space, causing swelling, pain and irritation. Diagnosis must, at this stage, exclude DVT, phlebitis (vein inflammation) or other lower leg conditions.
Treatments -
Most cysts are best left alone and will eventually reabsorb, particularly if they are of the primary type.
For secondary cysts, it is wise to begin treating the underlying cause such as repairing cartilage, ligaments and assessing arthritis.
Doctors can put a needle in and drain the cyst if it gets too big and painful.
An injection of cortisone into the joint will reduce inflammation but may not be curative.
Physical therapy will include ice, compression wrapping, reduction of weight bearing and exercises to maintain and improve range of motion at the knee joint and hip.
It is a good idea to strengthen the muscles around the knee when the pain has subsided and swelling is down.
Use of over-the-counter pain relief is advised and you may wish to elevate the leg when resting.
If in doubt visit your GP who will be able to advise you of the best course of treatment.
For osteopathy in High Wycombe and beyond call Lucy from OsteoFusion on 07833 321604 or visit www.osteofusion.co.uk
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