A Baker’s cyst, or popliteal cyst, is a fluid filled swelling that develops on the back of a person’s knee. Baker’s cysts can sometimes rupture, potentially leading to pain and swelling.

Baker’s cysts are benign, meaning that they are noncancerous and do not spread.

They can occur due to certain health conditions or as a result of injury to the knee. Inflammation from disease or damage to tissue can cause the knee to produce excess fluid. This fluid then travels to the back of the knee, where it can build up and form a Baker’s cyst.

Learn more about Baker’s cysts here.

The American Academy of Orthopedic Surgeons notes that Baker’s cysts often go away on their own in time. However, on rare occasions, a Baker’s cyst can rupture.

This article discusses the symptoms of a ruptured Baker’s cyst. It also explains what happens when a Baker’s cyst ruptures and lists the next steps a person should take.

A leg with a heat pack to treat a ruptured baker's cyst.Share on Pinterest
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According to the United Kingdom’s National Institute for Health and Care Excellence, up to 80% of ruptured Baker’s cysts cause no symptoms. However, in other cases, the symptoms of a ruptured Baker’s cyst can include:

  • sharp pain in the knee and calf
  • swelling of the calf
  • itching
  • bruising on the inner ankle
  • the sensation of water running down the calf
  • thrombophlebitis, which is when blood clots form in the leg veins

A ruptured Baker’s cyst can lead to various complications, such as:

  • a trapped nerve in the leg
  • blocked arteries
  • weakness of the toes
  • compartment syndrome, which occurs when pressure builds inside enclosed muscle spaces

If a person experiences symptoms of a ruptured Baker’s cyst, they should speak with a doctor.

Ruptured Baker’s cysts can have similar symptoms to deep vein thrombosis (DVT). DVT is a blood clot that forms in a vein deep within a person’s body, and it can be life threatening without treatment.

A person who presents with a ruptured Baker’s cyst may have to undergo tests to determine the cause of their symptoms. A doctor may want to rule out DVT as a possible cause, particularly as DVT can occur alongside a ruptured Baker’s cyst.

DVT can sometimes lead to pulmonary embolism, which is a blood clot within the lungs. If a person experiences any of the following symptoms, they should seek medical attention immediately:

  • shortness of breath
  • sudden chest pain
  • coughing
  • spitting up or vomiting blood

Learn more about deep vein thrombosis here.

As a 2019 case study in the Journal of General and Family Medicine shows, a doctor may perform an ultrasound to diagnose a ruptured Baker’s cyst. Additionally, they may look for bruising on a person’s inner ankle.

Baker’s cysts contain synovial fluid, which the body produces to cushion joints and reduce friction during movement.

A Baker’s cyst can rupture if it fills with synovial fluid too quickly, leading to a buildup of pressure that causes the membrane to tear. When the cyst ruptures, it releases this fluid into the person’s calf.

According to the U.K.’s National Health Service (NHS), about 5⁠–10% of Baker’s cysts will rupture.

Most cases of ruptured Baker’s cysts will clear up over time. A doctor may recommend that a person speed the healing process by elevating the affected leg as much as possible or applying heat packs to the area. They may also prescribe pain medication.

The NHS also recommends keeping the leg raised to treat a ruptured Baker’s cyst, as well as resting as much as possible. It notes that the body can reabsorb the fluid from a ruptured Baker’s cyst within a few weeks.

Following treatment for a ruptured Baker’s cyst, a doctor may place an elasticated bandage around a person’s knee to keep it compressed.

A study from 2020 found that draining fluid from the ruptured Baker’s cyst and then injecting corticosteroids into the cyst was an effective treatment option. However, the study only included 42 people, so further research may be necessary to confirm this finding.

Treatment before a rupture

A doctor can use various methods to treat a Baker’s cyst before it ruptures, including:

  • observing the cyst to look for any changes
  • suggesting that a person refrain from engaging in high impact activities
  • recommending or prescribing pain relievers
  • administering steroid injections
  • draining the cyst

Baker’s cysts can return after treatment. A case study from 2018 reported on an individual who had to undergo treatment for a second time only a week after receiving their initial treatment for a ruptured Baker’s cyst.

If a person has a Baker’s cyst that keeps returning after a doctor has drained it, they may require surgery to remove it. Additionally, a person may require treatment for any underlying conditions that could be causing the Baker’s cyst.

Baker’s cysts are fluid filled swellings that form behind a person’s knee. Occasionally, a Baker’s cyst can rupture, possibly leading to pain and swelling, among other symptoms.

The symptoms of a ruptured Baker’s cyst can be very similar to those of DVT. It is, therefore, important that people speak with their doctor if they notice any symptoms of a ruptured Baker’s cyst. Additionally, a person who experiences any symptoms of a pulmonary embolism should seek immediate medical attention.

A doctor can treat a ruptured Baker’s cyst in several ways. However, most ruptured Baker’s cysts will clear up within a few weeks of a person resting and keeping their leg elevated.

Baker’s cysts can return after treatment, and a person may sometimes require surgery to remove them. Additionally, a person may require treatment for any underlying conditions that could lead to a Baker’s cyst forming.