Painful Knees & Baker’s Cyst

William Morrant Baker (1838-1896) was a surgeon who first described this condition. It’s not even a true cyst. It is in fact a swollen bursa.

I wish he had never described them. The diagnosis often causes patients anxiety that this condition will cause permanent and increasing pain, dysfunction, distress and worry. This is not necessarily so and most patients should not consider their knee will be “ruined”.

The knee joint is surrounded by a tough capsule, the inside of which secretes a fluid called synovia (Latin = white of an egg). This lubricates the joint to prevent friction between the joint bearing surfaces of the knee.

At the back of the knee there is a bursa (Latin = small sack) that communicates with the joint capsule of the knee. A Baker’s Cyst is simply a swelling in this bursa caused by increased swelling in the knee joint capsule proper. So in fact, a Baker’s Cyst is a swollen knee and not a separate condition of its own.

Swelling in the knee can be caused by injury, wear and tear, weakened quadriceps, arthritis or any condition of the knee that can cause a build-up of fluid (effusion), which triggers the Baker’s Cyst. Occasionally a Baker’s Cyst can develop in children for no obvious reason. These should always be thoroughly investigated.

The best management for this condition is to remove the cause of the swelling. A thorough physiotherapy/rehabilitation program over several weeks will treat the underlying cause and restore the knee into optimum condition. This removes the underlying irritation which causes the build-up of fluid in the knee joint. This usually takes 6-12 weeks to be successful.

Occasionally, treatment options can include Cortisone injections, but rehabilitation must still be undertaken to obtain maximum benefit.

Aspiration, or drawing off the fluid with a needle, seldom is successful as it does not get rid of the cause of the swelling and the fluid returns.

To find out how this condition can be overcome, contact Southside Physiotherapy & Sports Injury Centre (Cronulla) and talk to one of our experienced physiotherapists on how best to overcome this condition.