Orthopedics Hip & Knee Meniscus Injuries An Overview of Meniscal Cysts By Jonathan Cluett, MD Jonathan Cluett, MD LinkedIn Twitter Jonathan Cluett, MD, is a board-certified orthopedic surgeon with subspecialty training in sports medicine and arthroscopic surgery. Learn about our editorial process Updated on December 12, 2021 Medically reviewed by Oluseun Olufade, MD Medically reviewed by Oluseun Olufade, MD LinkedIn Twitter Oluseun Olufade, MD, is a board-certified orthopedist. He teaches as an Assistant Professor of Orthopedics at Emory School of Medicine in Atlanta, Georgia. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Symptoms Causes Diagnosis Treatment The meniscus cartilage is the joint pad inside the knee. A meniscal cyst is a collection of joint fluid caused by a tear within the meniscus cartilage. Joint fluid is also called synovial fluid. Some people with meniscal cysts do not have any symptoms. Others may have pain, swelling, or problems moving the knee. This article looks at meniscal cysts and their symptoms, causes, diagnosis and treatment. Verywell / Tim Liedtke Symptoms of a Meniscal Cyst Meniscal cysts do not always cause symptoms. When they do, the most common are: Pain in the knee when standingTenderness directly along the jointA bump or lump at the cyst site, usually near the outside of the kneeA bump that becomes more visible as the knee straightens, though the bump itself may be painlessA bump that changes size (though it may also remain seemingly unchanged)Swelling or locking of the knee joint Recap Your cyst may not have any symptoms. If you do have symptoms, they may include pain, a lump or bump, and swelling or locking of the knee joint. What Causes a Meniscal Cyst? Meniscal cysts are most common in 20- to 30-year-old males. They are usually associated with a type of meniscal tear called a horizontal cleavage tear. This kind of tear may be caused by over-rotation of the knee. It can also be caused by direct impact to the front or side of the knee. Disproportionate force on the knees, such as when you run on an uneven surface, can also cause this type of injury. Cysts may also be caused by degeneration of the meniscus. This is usually related to age or osteoarthritis. Meniscal Tears and Osteoarthritis A tear in the meniscus allows joint fluid to leak out of the joint. This is what causes the cyst. A meniscal cyst is not a true cyst. Instead, it is made up of displaced joint fluid. When fluid escapes the joint, it can collect in a pouch. This pouch is the cyst. The cartilage tear can act as a one-way valve. Fluid can escape the joint into the cyst, but it can't go back into the joint. Because of this, the cyst will continue to collect fluid. Risk factors for meniscal cysts include: Knee injury or meniscal injury Participation in contact sports or any sport where there is twisting of the knee joint, like football, soccer, rugby, or tennis Increasing age or osteoarthritis Ligament injuries, such as a torn anterior cruciate ligament (ACL) Recap Meniscus cysts happen when a tear in the meniscus allows joint fluid to escape. This can happen after a knee injury or as a result of osteoarthritis. Diagnosis of Meniscal Cysts A healthcare provider will ask you questions about: Knee painPopping soundsRecent injuries or impact to the knee This will help determine if you have a meniscal tear. A meniscal cyst can usually be palpated, which means a doctor can feel it. Range of motion tests can confirm there are no torn pieces of cartilage in the joint. There are a few tests doctors use to assess meniscal tears and other knee injuries. These include: The McMurray test The Apley test The Stienmann I test The Payr's test Childress' sign The Ege's test These are motion, weight-bearing, and pressure tests that can help doctors identify a tear. They can also help a doctor decide if the tear needs surgery. Diagnosis may be confirmed by a magnetic resonance imaging (MRI) scan or ultrasound. An MRI is a test that creates images of your knee using a magnetic field and radio waves. An ultrasound creates images using sound waves. These tests will help your doctor see both the cyst and the tear. Meniscal Cysts vs. Baker's Cysts Meniscal cysts are similar to popliteal or Baker's cysts. Baker's cysts, however, are located in the back of the knee joint. Baker's cysts are seen with many types of knee joint problems that lead to fluid accumulation. They can occur with meniscus tears, but also with arthritis, ligament injuries, and other problems that cause knee swelling. Recap Your doctor will ask questions about your pain and any injury that may have occurred. Meniscal cysts can often be palpitated. An imaging test can confirm the diagnosis. Treatment of Meniscal Cysts Pain caused by a meniscal cyst can be treated with ice. Anti-inflammatory medications can also help. The cyst may be drained with a needle in a doctor's office. Unfortunately, the cyst will usually return unless the meniscal tear is treated or heals itself. Surgery Meniscal tears don't always need surgery. When they do, the most common surgery is a minimally invasive arthroscopic surgical approach. This is where a surgeon uses instruments passed through small incisions to operate on the joint. Once the tear has been repaired, the cyst will usually go away. While it is possible for the cyst to come back, it is unlikely. Removing the actual cyst is not necessary. The better treatment is to address the cause of the cyst. Physical Therapy for a Meniscus Tear Summary Meniscal cysts don't always cause symptoms. When they do, symptoms may include pain, a bump on the knee, and swelling or locking of the joint. Meniscal cysts are caused by tears in the meniscal cartilage. This can happen after injury or because of degeneration of the meniscus. A meniscal cyst is a pouch of joint fluid that drains from the joint. A doctor may be able to feel it, and the diagnosis can be confirmed through a number of different tests. Meniscal cysts can be drained, but the best treatment is to repair the tear. A Word From Verywell Though it is called a cyst, a meniscal cyst is really just a pouch of dislocated joint fluid. It is not a growth or a tumor. It is simply a collection of normal joint fluid in an abnormal location. If you don't have pain, you may resume normal activities right away. If you do feel some pain, swelling, or locking of the knee, your doctor can help you find the right treatment. 5 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Chen H. Diagnosis and treatment of a lateral meniscal cyst with musculoskeletal ultrasound. Case Rep Orthop. 2015;2015:432187. doi:10.1155/2015/432187 Crowell MS, Westrick RB, Fogarty BT. Cysts of the lateral meniscus. Int J Sports Phys Ther. 2013;8(3):340-348. Ercin E, Kaya I, Sungur I, Demirbas E, Ugras AA, Cetinus EM. History, clinical findings, magnetic resonance imaging, and arthroscopic correlation in meniscal lesions. Knee Surg Sports Traumatol Arthrosc. 2012;20(5):851-856. doi:10.1007/s00167-011-1636-4 Demange MK. Baker's cyst. Rev Bras Ortop. 2015;46(6):630-633. doi:10.1016/S2255-4971(15)30317-7 Cowden III CH, Barber FA. Meniscal cysts: treatment options and algorithm. J Knee Surg. 2014;27(02):105-12. doi:10.1055/s-0033-1353995 Additional Reading Gupta Y, Mahara D, Lamichhane A. McMurray's test and joint line tenderness for medial meniscus tear: Are they accurate? Ethiop J Health Sci. 2016;26(6):567–572. doi:10.4314/ejhs.v26i6.10 Washington Orthopaedics & Sports Medicine. Meniscal cyst. 2019. By Jonathan Cluett, MD Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit