What is Baker's knee cyst? Baker's cyst is the most common cause of swelling, pain and stiffness behind the knee. Behind the knee, there is a small fluid-filled sac called the popliteal bursa, which is placed between the tendons of the hamstring muscle and the knee bones and reduces friction. Inflammation of the popliteal bursa, which is also called semimembranous bursitis or popliteal cyst, was first discovered in the 19th century by Dr. William Morant Baker, and his name was also placed on this cyst. Popliteal cyst is more common in people over 40 and affects women more than men. In the following, we will examine the causes and classic symptoms of Baker's cyst, the best treatment options, and how to prevent inflammation from returning in the future. What is the cause of Baker's knee cyst? Baker's cyst is caused by the accumulation of excess fluid in the knee joint. With the swelling of the joint, excess synovial fluid leaves the joint and goes to the popliteal bursa. As the liquid enters this area, the bursa starts to swell and as a result, bursitis occurs. Several things, including the following, can cause swelling of the knee, resulting in a Baker's cyst: - **Arthritis:** Abrasion of bones and tearing of knee cartilage leads to an increase in fluid in the knee joint. 50% of people with arthritis experience Baker's cyst at some point. Arthritis is by far the most common cause of Baker's cysts. - **Knee injury:** Any type of injury that causes swelling inside the knee joint increases the risk of popliteal bursitis. Cartilage tears are the most common injury that causes a Baker's cyst. - **Inflammatory arthritis:** Several types of inflammatory arthritis, the most common of which is gout, increase the risk of developing a Baker's cyst. Types of Baker's knee cysts Baker's cyst is formed in two ways. ### Primary Baker's cyst This type of cyst, sometimes called primary Baker's cyst or idiopathic cyst, occurs just behind the healthy knee joint and usually affects younger people and children. It is thought that in this type of disease, there is a connection between the knee joint and the popliteal bursa behind the knee. As a result, the synovial fluid from inside the joint goes to the popliteal bursa and Baker's cyst is formed. Read more: Is knee meniscus tear surgery good? ### Secondary Baker's cyst In some cases, Baker's cyst is caused by an underlying problem such as arthritis inside the knee or a tear in the meniscus cartilage that is inside the knee joint. This type of cyst is called secondary Baker cyst. In cases of secondary Baker's cyst, the underlying problem in the knee joint causes excessive production of synovial fluid in the joint, resulting in increased intra-knee pressure and stretching of the joint capsule. The joint capsule bulges at the back of the knee and forms a Baker's cyst, which is filled with synovial fluid. Baker's knee cyst symptoms A small bump on the back of the knee that looks like a small balloon or soft orange is the first symptom that patients experience. Sometimes there is only a small amount of swelling, and usually a Baker's cyst is so small that you don't even notice it. However, in some cases, the popliteal cyst becomes very large and causes pain and stiffness in the back of the knee, especially when you bend and straighten the knee. The average size of Baker's cyst is 3 cm, and the pain is aggravated by activity or standing for a long time and decreases with rest. Read more: Leg pain from the knee down + symptoms and diagnosis Physiotherapy for the treatment of Baker's cyst of the knee Physiotherapy treatment is essential to speed up the healing process and ensure the best outcome in all patients with Baker's cysts, and is recommended for all patients regardless of whether they have had surgery or not. Physiotherapy treatment will include the following: - Soft tissue massage - Electrotherapy - Using a band or brace to support the knee - Mobilization - Dry needling - Hydrotherapy - Using a cane - Application of ice or heat - Progressive exercises to improve flexibility, balance and strength (especially quadriceps). - Modify activity - Education - Biomechanics correction - Orthosis prescription - Anti-inflammatory recommendations - Lose weight if necessary - Ultrasound to evaluate and retrain the inner quadriceps muscle - Gradual return to activity program In patients for whom surgery is recommended to remove Baker's cyst, physical therapy and rehabilitation should begin before surgery. This treatment method will include techniques to reduce pain and swelling, electrotherapy, strengthening exercises and range of motion, use of compression bandages and crutches. Physiotherapy and rehabilitation after surgery will speed up the healing process and you will get better results with confidence. In the final stages of rehabilitation, the physiotherapist designs a suitable program for all patients to return to sports or activities. Returning to sports too quickly or not participating in rehabilitation activities can lead to knee swelling and re-injury. Despite appropriate physical therapy management, some patients with Baker's cysts do not improve either conservatively or after surgery. In such a situation, the doctor or physiotherapist will recommend the best treatment including further research, drug intervention, corticosteroid injection or surgery. Suitable exercises for the treatment of Baker's knee cyst The following exercises are usually prescribed for patients with Baker's cyst. Before starting these exercises, you should talk to a physiotherapist about their suitability. In general, these exercises should be done 3 times a day and only if they do not cause or increase symptoms. ### Bending and straightening the knee Bend and straighten the knee as much as possible without increasing pain 20 times. This movement helps to restore the normal movement of the knee. ### Static quadriceps contraction Press and tighten the front of the thigh muscle (quadriceps) towards the towel. Place your fingers on the quadriceps muscle to feel the muscle tighten during the contraction. Stay in this position for 5 seconds and if the symptoms do not worsen, repeat the movement 10 times with maximum possible intensity.