A cyst in the knee can be noticed in several shapes and sizes. The swelling is a result of the protrusion of the knee joint fluid. In case of the popliteal cyst, or Baker’s cyst, the swelling is noticed at the back of the knee.
The condition has also been known as semimembranosus burse, gastrocnemio-semimembranosus bursae, synovial cysts and posterior herniae of the knee joint in the past. (1)
The condition is characterized by an inflammation and swelling in the popliteal area of the knee. The swelling is filled with synovial fluid.
The condition was originally described by William Morrant Baker in the 19th century. It is usually noticed when the body weight compresses an excess of knee joint fluid between the bones of the knee joint.
This excess fluid can then become trapped and form a separate fluid-filled sac at the back of the knee.
Baker’s cyst could not have any noticeable symptoms except the swelling. However, in some cases, the condition is associated with pain and tightness around the knee joint.
The average size of such a cyst is usually 3cm. The causes of the condition are commonly an underlying condition such as arthritis or gout.
What are the types of cysts? The swelling noticed in Baker’s cyst is due to the synovial fluid distending the gastrocnemio-semimembranosus bursa.
Most adults over the age of 40 suffer from the secondary type of Baker’s cyst. A secondary type of the condition is indicated due to underlying conditions such as arthritis. A total of 50% of osteoarthritis patients are known to suffer from a popliteal cyst.
Secondary cysts are found to communicate with the knee joint and are more common than the primary cysts. These cysts are said to be caused due to a combination of factors such as internal pathology, valvular opening between the knee joint and bursa, and a weakness of the knee joint.
A primary cyst is usually noticed in younger people and is most commonly noticed to be benign with no noticeable symptoms. Studies report that primary cysts are not known to communicate directly with the knee joint.
It is a fairly common condition, with a study stating that up to 38% of MRIs of the symptomatic knee indicated Baker’s cyst. (2)
The treatment techniques are fairly simple and involve self-care therapies and exercises to stretch the hamstrings. With the help of self-care remedies, the condition can be managed well and the healing time is around two weeks. (3)
Anatomy of the Popliteal Bursa
The posterior side of the knee consists of four bursae, which are located as follows.
- Between posterior tibia and fibula and the popliteus tendon. It is known to communicate with the synovial cavity
- Between the lateral head of gastrocnemius and the capsule.
- Between semimembranosus and the medial head of gastrocnemius
- Between the capsule and medial head of gastrocnemius. (4)
When noticed in children, the cyst’s communication with the joint is infrequent. However, intra-articular pathology is common in adults. A high recurrence possibility is present if the joint pathology is not taken into consideration.
The knee contains several bursae, which help in circulation of the synovial fluid. The fluid is necessary for the proper movement of the knee.
The popliteal bursa is located at the back of the knee. The bursa and the knee joint are linked with a valve-like system to regulate the synovial fluid circulation. (5)
What is the Popliteal Fossa? It is a diamond shaped area located at the posterior side of the knee.
The four borders include semimembranosus, biceps femoris, medial head of the gastrocnemius, and the lateral head of the gastrocnemius and plantaris.
The fossa’s roof consists of the popliteal fascia and the skin, while the floor consists of the posterior surface of the femur and the knee joint capsule. (6)
A cyst in the posterior side of the knee presents itself as a soft-tissue swelling. Usually, the location of Baker’s cyst is noticed to be distal to the popliteal crease below the medial head of the gastrocnemius muscle.
Baker’s cyst is known to be of two types – bursal and hernia. The bursal type is characterized by the development of cysts in the gastrocnemius-semimembranosus bursae.
In the case of hernia cysts, the protrusion is noticed as lying outside the body.
A study reports that most abnormalities of the popliteus bursa are linked with a torn meniscus. Compression and narrowing were among the common changes noticed in patients with a meniscal tear injury. (7)
What Causes Baker’s Cyst?
The accumulation of the excess synovial fluid in the popliteal bursa leads to this condition. The most common cause of this knee joint is an inflammation.
The underlying knee inflammation could be caused due to an injury or other medical conditions. Understanding the underlying causes is important to treat and manage the condition.
Secondary cysts are caused because of a problem in the knee joint. This could be in the form a meniscal tear or knee inflammatory conditions.
The problems in the knee joint result in too much synovial fluid being produced in the joint, which then increases the pressure inside the knee. As the pressure increases, the joint capsule has a stretching effect and bulge out at the back of the knee. (8)
Cartilage tears are known to result in swelling in the knee resulting in Baker’s cyst. This is commonly noticed in athletes but is also common in older people.
The lateral meniscus and medial meniscus consist of thick cartilage lining the knee. An injury to the meniscus is usually observed during sports such as football, skiing, and rugby.
A sudden twist of the knee could result in a meniscal tear and cause swelling in the knee. The swelling is noticed gradually post the injury.
However, with age, the meniscus starts to degenerate with everyday activities. This makes it more susceptible to tear with kneeling, squatting, and lifting heavy objects.
Self-care techniques, exercises, and protective braces are useful tools to manage this condition. (9)
Osteoarthritis is a painful joint condition. It is more common in women and the risk of being affected by this condition increases with age.
The knee joint is able to deal with the constant pressure of everyday activities as the body is able to repair the damage to the joint, if any.
However, when a break-down of the protective cartilage on the end of the bone occurs due to wear and tear, it can cause osteoarthritis.
As the condition results in damage and loss of cartilage, the knee movement is affected. Osteoarthritis is also known to result in a mild inflammation of the tissues and bony growths around the edges of the knee joint.
It is known as a degenerative form of arthritis, affecting around 13% of women and 10% of men over the age of 60 in the US. However, younger people are known to suffer from this condition post a traumatic injury.
One of the complications arising from osteoarthritis is Baker’s cyst.
The condition is characterized by pain and difficulty in knee movements. Managing this condition involves exercise and pain relieving techniques.
The muscle can weaken gradually, therefore, it is important to implement stretching exercises to keep the joints flexible.
This type of arthritis is a long-term condition characterized by swollen and painful joints. It is an autoimmune disease, where the immune system attacks the cells of the knee joint.
The attack of the immune system on the lining of the knee joint results in inflammation. This condition is different from the wear-and-tear associated arthritis.
Rheumatoid arthritis is seen to be more common in women than men, with adults over the age of 40 more prone to suffer from it. A total of 1% to 2% of the global population is said to be affected by this condition.
An early diagnosis of rheumatoid arthritis is important. Over time, the condition could result in damage to the knee joint as well as the cartilage and the adjacent bone.
The condition is also known to serve as a risk factor for other medical conditions such as an increased risk of heart attacks.
A common symptom is the morning joint stiffness along with knee pain, loss of appetite, and fever. These symptoms are intermittent and they become more severe with every flare-up episode.
The proper management of this condition is focused on alleviating the pain and discomfort. Exercises and a healthy diet are known to help patients. (10)
Knee gout is a result of excess uric acid in the blood. This excessive rise in the uric acid levels in the body could result in urate crystals building up in the knee joint.
The condition results in severe pain and inflammation. Recurring episodes of gout could lead to damage to the cartilage and bones.
It is more common in men and menopausal women. Gout symptoms are quite similar to other knee conditions. However, diagnostic tests to evaluate the presence of uric acid crystals is to extract fluid from the affected knee.
In cases of chronic gout, the sufferers are able to notice tiny lumps called as tophi. These uric acid crystal concentrations cause pain and stiffness in the knee.
However, a formation of these tophi deposits in the kidneys could result in kidney stones.
The risk factors for gout include obesity, alcohol consumption, certain medications, and genetics.
Treating mild cases are fairly simple and involve an incorporation of a healthy lifestyle. It is advised to reduce the consumption of high-purine content food.
Additionally, in order to avoid a ketosis condition in the body, it is essential to avoid low-carbohydrate diet for gout sufferers. Ketosis can result in a rise in the uric acid levels in the blood. (11) (12)
Hemophilia is a rare inherited bleeding disorder caused by a complete absence or a congenital deficiency of coagulation factor VIII or IX resulting in hemophilia A and hemophilia B respectively.
A study reports the prevalence of hemophilia in most countries to be 13 to 18 among 100,000 men. Hemophilia A is more common, with a ratio of 4:1 between hemophilia A and hemophilia B.1
If left undiagnosed and untreated, it could cause life-altering disabilities and chronic diseases. The prevalence of the condition is higher with a family history, however, new mutations account for around 30% of newly diagnosed cases of hemophilia.
Earlier prophylaxis is ideal as it increases the likelihood of preventing joint damage in the future. (13)
Other underlying causes include septic arthritis, reactive arthritis, psoriasis, and lupus.
Symptoms of Baker’s Cucst
In some cases, the condition can present itself without any symptoms of pain. The cyst could be small enough to not be noticed by patients.
However, the following are the signs of a popliteal cyst.
Swelling: The most noticeable sign of the condition is swelling at the back of the knee. It can be confirmed by standing straight and comparing it to the other knee.
As the swelling is filled with fluid, it can feel tender to touch.
Knee Pain: The pain associated with this condition is localized to the back of the knee. It is known to get worse with activity.
Knee Instability: The inflammation could lead to locking or buckling of the knee.
Other signs include calf pain and fluid accumulation around the knee. A ruptured cyst could lead to fluid leaking down into the calf causing swelling, pain, and redness in the calf.
The leaking of the fluid down the inner leg can also result in a discoloration around the ankle. (14)
Backer’s Cyst Diagnosis
Baker’s Cyst is diagnosed on the basis of a physical examination and medical history.
Physical examination will usually check for tenderness and pain in the knee. A swelling distal to the popliteal crease is an indication of Baker’s cyst.
The swelling is more prominent when the knee is extended and is seen to disappear when the knee is in flexion mode. The flexion mode for the knee is described as the position where the posterior surfaces of the thigh and leg come close. (15)
The medical history is important to understand if an underlying cause is responsible. Diagnostic tests are sometimes considered to rule out other conditions such as a tumor or an aneurysm.
Imaging techniques such as MRI, CT, and ultrasound scans are known to be effective techniques. MRI is considered as the standard for diagnosis as it helps in determining the composition of the cyst and underlying causes such as osteoarthritis, meniscal tears, and ligament tears.
When compared to ultrasound, MRI is able to differentiate Baker’s cysts from meniscal cysts.
However, ultrasound is widely used as a screening method at the onset of symptoms. (16)
A differential diagnosis is important to check if the symptoms are a result of some other medical condition.
A differential diagnosis should check for the following conditions.
- Deep vein thrombosis
- Septic arthritis
- Popliteal artery aneurysm
- Meniscal cyst
- Ganglion cyst
- Gastrocnemius muscle tear
- Benign soft tissue tumor
A blood clot behind the knee could also cause swelling. Therefore it is necessary for a doctor to examine the swelling to check if the cause is a clot or a cyst.
Backer’s Cyst Treatment
Treatment options includes self-care therapy, treating the underlying causes, non-invasive approach by using injectables and invasive therapy to remove cyst surgically.
The treatment therapies include self-care techniques as well as non-invasive surgical methods to relieve the symptoms.
In most cases, benign cysts could get resolved on its own without any medical intervention. However, some self-care techniques can help alleviate the pain and discomfort.
The following techniques can be used to reduce pain and inflammation at the onset of symptoms.
Making an icepack and applying it on the cyst location can reduce inflammation. It is important to note that the ice is not directly applied to the skin.
Patients who are experiencing discomfort in the knee can benefit from resting and avoiding strenuous activities.
One of the symptoms include knee instability, therefore it is essential to take support when climbing stairs.
It is advised for the patient to rest and avoid excessive pressure on the knees through physical activities. Also, it is important to check for knee strength before resuming physical activity.
Knee stretching exercises can help flexibility in the knee, post which activities can be resumed.
Patients can also keep their leg elevated while lying down to get some relief from the pain.
It will also help to reduce an inflammation.
Using a compression bandage can support the knee and reduce inflammation.
Such bandages can be worn during the recovery period to improve the healing process.
Medicines such as NSAIDs can help reduce pain and inflammation. Ibuprofen is the most commonly used medication to treat Baker’s cyst.
The condition can be treated and properly managed by knee stretching exercises. The popliteal bursa can also be impacted by extra pressure from tight hamstrings.
Stretching the hamstrings can improve the healing process and avoid recurring episodes.
Stretch 1: While sitting on the edge of a chair, keep the good knee bent. Place the other knee towards the front with a slight bent and lean forward till you feel a light stretch. Hold the position for 30 seconds and repeat.
Stretch 2: While lying down on the back, bend the knee and pull it towards yourself with the help of your hands. Place your hands on the thighs and stretch it. Hold the stretch for 30 seconds and repeat.
It is important to note that these stretches should be focused on the hamstrings and not the knees. Proper posture is important for getting the benefits. A pressure on the knee while performing these stretches could aggravate your injury. (16)
Treating Underlying Causes
If the cyst is a result of an underlying condition, it is important to treat the condition along with Baker’s cyst to prevent recurring episodes.
Since arthritis and gout are known to be associated with Baker’s cyst, it is essential to ensure proper management of the underlying cause.
Knee inflammation resulting from arthritis and gout can be managed with a healthy lifestyle and weight management techniques.
Cysts that form because of gouty arthritis are known to respond to an antigout treatment program. Those that are caused by rheumatoid arthritis and osteoarthritis are effectively managed with medical treatment regimens.
In case of an infected cyst, antibiotics can be prescribed once the cyst has been surgically drained.
These therapies are usually considered if the self-care techniques have not shown any improvements.
Knee pain and inflammation can be reduced with corticosteroid injections.
However, the effect is said to be short-lived and is effective for immediate relief.
Aspiration to drain the excess fluid with a needle and syringe can reduce inflammation and pain.
Invasive Treatment Option
Surgery to remove the cyst is usually a rare occurrence and is considered when excessive knee joint damage is associated.
An arthroscope is used through a small incision to surgically remove the cyst and repair the joint.
In case of injury-related cysts, arthroscopic treatment focussed at meniscal tears and cruciate ligament tears could improve the success of the recovery.
However, surgical intervention is considered as the last resort and is used rarely. It is considered only when the other treatment options have not reduced the pain and inflammation.
Surgery is highly recommended if the condition is causing life-altering disabilities. (17)
Some home remedies involving herbs and essential oils can bring relief to the inflamed knee.
Using a good quality cold pressed castor oil on the cyst can substantially reduce the size and also provide relief from the pain. The oil can be used three times a day.
Herbs and Spices
Several herbs and spices are known to possess anti-inflammatory properties.
It is essential to include them in your daily cooking or incorporate them in a smoothie to increase its effectiveness.
You can incorporate ginger, garlic, cinnamon, turmeric, celery seed, and cayenne pepper in your diet.
Apple Cider Vinegar
Prepare a drink of 1 tablespoon of apple cider vinegar with a teaspoon of honey in warm water. Drinking this three times a day can remove the fluid from the cyst and reduce inflammation.
A warm bath with Epsom salt can offer relief from pain and inflammation. The magnesium-rich salt can help improve the healing process and enhance circulation.
Soaking tea bags in milk and placing in on the affected area can reduce the size of the cyst. Tea bags are known to have anti-inflammatory properties. (18) (19)
The healing process for a Baker’s cyst depends on the cause of the condition and the measures used to treat it. If left untreated and without any severe complications, it can resolve in up to four weeks. Self-care techniques can help treat it in about two weeks.
The recovery period post a surgery could be longer and will include a physical therapy program.
Backer’s Cyst: Risk Factors
Gender: Females over the age of 40 are prone to suffer from the condition.
Arthritis: People who suffer from arthritis are known to be susceptible.
Other risk factors include knee gout, obesity, and autoimmune disorders.
Beacker’s Cyst Prevention
Understanding the risk factors associated with the condition can help a person decrease their chances of developing Baker’s cyst.
Are You at Risk Because of a Specific Activity?
Athletes are known to be prone to suffer from injury-related Baker’s cysts. This is common in sports such as football, skiing, and rugby.
If your activity involves the possibility of direct blows to the knee or a tackle, it is important to wear protective braces to support the knee.
Injuries are common in everyday activities too, therefore, being cautious about the knee movements could prevent this condition.
Meniscal tears are also associated with this condition. Understanding the causes and signs of such injuries could result in an early diagnosis of the condition.
What’s Your Medical History?
Your medical history plays an important role in preventing the condition. Knee inflammation conditions such as arthritis and gout make you more prone to suffer from this condition.
Knowing your medical history is important to treat knee ailments. Certain medications are also known to cause knee conditions.
In such cases, it is imperative to discuss with a physician if the medicine can be changed or of the dose could be reduced.
Proper management of these conditions could reduce the probability of Baker’s cyst.
What’s Your Lifestyle?
Obesity and a lack of exercise can cause many knee inflammatory conditions. These can lead to Baker’s cyst.
Following a healthy lifestyle can prevent this condition as well as other serious medical conditions.
It is known that walking 10,000 steps a day can reduce the risk of heart diseases. Maintaining a healthy nutritional diet is more important than limiting calories.
When considering diet changes, it is essential to note that excess uric acid in the body can cause gout. This can be avoided by maintaining a healthy lifestyle.
You can implement anti-inflammatory food into your daily diet. Some food items are listed below.
- Fruits and Vegetables: Include more kale, spinach, cabbage, broccoli, cherries and blackberries in your diet.
- Fish: Consumption of tuna or salmon at least twice a week could provide the body with substantial omega-3 fatty acids to fight the inflammation.
- Nuts: A handful of nuts consumed daily provides the body with a healthy kind of fat to stop inflammation.
- Whole Grains: Include more fiber-rich grains such as brown rice, oatmeal, and whole-wheat bread.
- Herbs and Spices: Turmeric and garlic are known to be rich in antioxidants.
- Onions: They are also high in antioxidants.
The food items that should be avoided in case of inflammation in the body are listed below.
- Processed Meat: sausages and hot dogs
- Processed snack food: Chips and biscuits
- Alcohol: Excessive consumption of alcohol
- Refined Carbohydrates: white bread and white pasta
- Certain Oils: Soybean and corn oil
- Trans Fats: Food with partially hydrogenated ingredients
- Desserts: Ice cream and candy (21)
Prevention techniques also involve the following.
- Wear proper shoes to ensure that weight distribution is balanced.
- Avoid sudden increase in duration and intensity of activities.
- Support sleeves and braces to protect the knee.
Baker’s cyst is a common occurrence in adults with an underlying knee condition. Usually, the condition is not associated with any symptoms and does not need any treatment.
In some cases, it does lead to pain and inflammation at the posterior side of the knee and can also cause knee instability. As knees perform various functions in everyday activities, certain activity modifications could be required.
A cautious approach to activities with the use of support in the form of railings and braces could help improve the recovery period. The healing process can be aggravated by ignoring the pain and continuing the same level of activity.
Knee pain can cause discomfort, however, it is important to keep the body flexible with some form of exercise. Hamstring stretches work very well for relieving Baker’s cyst conditions.
While performing stretching exercises in the presence of knee pain, it is essential to not put the pressure on the knee. This could cause more damage and increase the recovery period.
Baker’s cyst is commonly noticed because of the presence of other knee problems in an individual. There is an increased risk of suffering from it if you have arthritis. Managing your underlying condition could help you prevent Baker’s cyst.
However, if the pain descends to the calf, it could be because of a ruptured cyst. In this case, there could be calf pain or a discoloration around the ankle.
Treatment therapies involving RICE techniques and medications to reduce pain and inflammation should be the first course of action.
Fluid drainage is also considered if the symptoms are not alleviated. Surgery is recommended in rare cases when no other treatment options have shown success.