What is a Baker cyst?
A Baker cyst is swelling caused by fluid from the knee joint protruding to the back of the knee. The back of the knee is also referred to as the popliteal area of the knee. A Baker cyst is sometimes called a popliteal cyst. When an excess of knee joint fluid is compressed by the body weight between the bones of the knee joint, it can become trapped and separate from the joint to form the fluid-filled sac of a Baker cyst. The name of the cyst is in memory of the physician who originally described the condition, the British surgeon William Morrant Baker (1839-1896).
What causes a Baker cyst?
Baker cysts are not uncommon and can be caused by virtually any cause of joint swelling (arthritis). The excess joint fluid (synovial fluid) bulges to the back of the knee to form the Baker cyst. The most common type of arthritis associated with Baker cysts isosteoarthritis, also calleddegenerative arthritis. Baker cysts can occur in children withjuvenile arthritis of the knee. Baker cysts also can result fromcartilage tears (such as atorn meniscus), rheumatoid arthritis, and other knee problems
What are symptoms of a Baker cyst?
A Baker cyst may cause no symptoms or be associated with knee pain and/or tightness behind the knee, especially when the knee is extended or fully flexed. Baker cysts are usually visible as a bulge behind the knee that is particularly noticeable on standing and when compared to the opposite uninvolved knee. They are generally soft and minimally tender.
Baker cysts can become complicated by protrusion of fluid down the leg between the muscles of the calf (dissection). The cyst can rupture, leaking fluid down the inner leg to sometimes cause the appearance of a painless bruise on the inner ankle. Baker cyst dissection and rupture are frequently associated with swelling of the leg and can mimic phlebitis of the leg. A ruptured Baker cyst typically causes rapid-onset swelling of the leg.
Rarely, a Baker's cyst bursts and synovial fluid leaks into the calf region, causing:
-Sharp pain in your knee
-Sometimes, redness of your calf or a feeling of water running down your calf
These signs and symptoms closely resemble those of a blood clot in a vein in your leg. If you have swelling and redness of your calf, you'll need prompt medical evaluation to rule out a more serious cause of your symptoms.
How is a Baker cyst diagnosed?
Baker cysts can be diagnosed by the doctor's examination and confirmed by radiological testing (either ultrasound, injection of contrast dye into the knee followed by imaging, called an arthrogram, or MRI scan) if necessary.
How is a Baker cyst treated?
Many times, no treatment is required and a Baker's cyst will disappear on its own.
If the cyst is very large and causes a lot of pain, your doctor may use the following treatments:
Your doctor may inject a corticosteroid medication, such as cortisone, into your knee to reduce inflammation. This may relieve pain, but it doesn't always prevent recurrence of the cyst.
Your doctor may drain the fluid from the knee joint using a needle. This is called needle aspiration and is often performed under ultrasound guidance.
Generally, patients with this condition should diligently follow the R.I.C.E. regime in the first 48 – 72 hours of injury. The R.I.C.E. regime can help to hasten healing and reduce pain and swelling and should comprise of rest from aggravating activities (crutches or a brace may be required), regular icing, the use of a compression bandage and keeping the leg elevated above the level of the heart. Anti-inflammatory medication may also help to hasten healing and recovery by reducing the pain and swelling associated with inflammation.
Patients with a Baker's cyst should perform pain free flexibility and strengthening exercises as part of their rehabilitation to ensure an optimal outcome.
One of the key components of rehabilitation is pain free strengthening of the quadriceps (vastus medialis obliquus muscle – VMO), hamstrings, gluteals and calf to improve the control of the knee joint with weight bearing activities. The treating physiotherapist can advise which exercises are most appropriate for the patient and when they should be commenced.
Physiotherapy treatment may comprise:
-soft tissue massage
-taping or bracing to support the knee
-the use of crutches
-ice or heat treatment
-progressive exercises to improve flexibility, balance and strength (especially the VMO muscle)
-activity modification advice
-the prescription of orthotics
-weight loss advice where appropriate
Typically though, doctors treat the underlying cause rather than the Baker's cyst itself.
If your doctor determines that a cartilage tear is causing the overproduction of synovial fluid, he or she may recommend surgery to remove or repair the torn cartilage.
Baker's cysts associated with osteoarthritis may stay swollen even if you're receiving arthritis treatment. You and your doctor may discuss surgery to remove the cyst if it doesn't resolve and it affects your joint movement. Baker's cyst removal may be an option for a cyst that repeatedly refills after you have it drained with a needle.
What Are The Best Exercises?
There are a number of different ways of stretching the Hamstrings to help your Bakers Knee Cyst recover.
1) Standing Hamstring Stretch
Starting position: Find a stool or object that is about 50cms / 1 ½ foot high. Leave one foot on the floor and rest the other foot on the stool with the knee slightly bent (about 15°)
Action: Lean forwards and down, keeping your back straight, until you feel a stretch in the middle of the back of the thigh. Hold for 30 secs
Repetition: Repeat 3 times, 2x daily, and before and after exercise
Alternatives: If you do not feel much of a stretch, lean slightly to the side of the leg being stretched as well as forwards and you may feel more of a stretch
2) Lying Hamstring Stretch
Starting position: Lie flat on your back. Bend the knee on the leg to be stretched and hold the back of your thigh with one hand and the back of your calf with the other
Action: Use your hands to pull the leg towards you keeping the knee bent about 20° until you feel a strong stretch in the middle of your thigh (at the back). Hold for 30 secs
Repetition: Repeat 3 times, 2x daily, and before and after exercise
Alternatives: If you can’t reach your leg to pull it, hook a towel around your leg and pull that instead to achieve the same stretch
3) Seated Hamstring Stretch
Starting position: Sit on the edge of a chair with your good leg bent. Put your bad leg out in front of you with the knee very slightly bent
Action: Lean forwards (keeping your back straight and your head up) until you feel a stretch in the back of your thigh. Hold for 30 secs
Repetition: Repeat 3 times, 2x daily, or before and after exercise
4) Knee Bend to Straighten
Bend and straighten your knee as far as possible without increasing your pain. This helps to restore your normal knee movement. Repeat 20 times.
5) Static Quadriceps Contraction
Tighten the muscle at the front of your thigh (quadriceps) by pushing your knee down into a towel (figure 3). Put your fingers on your inner quadriceps to feel the muscle tighten during contraction. Hold for 5 seconds and repeat 10 times as hard as possible without increasing your symptoms.
Knee joints are prone to injury during sporting activities. Preventing knee trauma can reduce the risk of Baker’s cyst developing in the first place or recurring after treatment. Suggestions include:
-Warm up the knee joints and soft tissue by gently going through the motions of your sport or activity and stretching the muscles.
-Wear supportive footwear appropriate to your activity.
-Try to turn on the balls of your feet, rather than through your knees.
-Cool down after sport by performing gentle and sustained stretches.
-If you injure your knee, stop your activity immediately, apply ice packs to treat the swelling and seek medical advice.
Prognosis of a Baker's cyst
Most patients with a Baker's cyst heal well with appropriate physiotherapy and can often return to sport or activity in a number of weeks. Many cases may require no specific treatment.
In rare cases of this condition where patients experience significant discomfort and ongoing symptoms despite appropriate physiotherapy treatment, surgery may be indicated with a lengthy rehabilitation period to follow, lasting weeks to months.
· A Baker cyst is swelling caused by fluid from the knee joint protruding to the back of the knee.
· Baker cysts are not uncommon and can be caused by virtually any cause of joint swelling (arthritis).
· A Baker cyst may cause no symptoms or be associated with knee pain and/or tightness behind the knee, especially when the knee is extended or fully flexed.
· Baker cysts can rupture and become complicated by protrusion of fluid down the leg between the muscles of the calf (dissection).
Baker cysts can be treated with medications, joint aspiration and cortisone injection, and surgical operation, usually arthroscopic surgery.