Pain and swelling over the space on the outside lower edge of the ankle that connects the heel bone and the foot. This area is called the sinus tarsi. The pain is usually worst when the ankle is turned, pressed on or bearing weight.
A podiatrist will diagnose this condition by doing a physical exam and using imaging tests like X-rays or an MRI scan. A diagnostic injection with a local anesthetic may also help confirm the diagnosis.
Diagnosis
Often, sinus tarsi syndrome arises as a result of a previous ankle sprain and is associated with flat feet or over-pronation (inward turning of the foot and ankle). It may also occur in people who have inflammatory conditions like rheumatoid arthritis. Diagnosis is made through a history, physical examination and imaging studies. MRI provides excellent definition of the structures in and around the sinus tarsi and enables early detection of abnormalities, such as ligament tears and altered tarsal canal anatomy.
The sinus tarsi is a tunnel-like space in the ankle bone (talus) and heel bone (calcaneus). It allows you to tilt your ankle from side to side. This area of the ankle contains important ligaments, blood vessels and nerves that help you move and control your foot. If this area becomes inflamed or compressed, it can affect your ability to walk, run and perform other physical activities. Pain and tenderness on the outside of your ankle are the most common symptoms of sinus tarsi syndrome. Your podiatrist can evaluate this condition with a careful history, physical examination and imaging studies, such as X-rays and MRI scans. They will be able to determine the cause of your ankle pain and recommend appropriate treatment. The goal is to reduce your ankle pain and restore normal foot function. Symptoms typically resolve over time, but it is important to get medical treatment right away if your ankle is hurting.
Symptoms
The symptoms of sinus tarsi syndrome are pain and tenderness in the lower outside portion (lateral side) of your ankle. The pain may come and go. It is usually worse with activity and relieved by rest. This is due to irritation and inflammation of the space between your ankle bone (talus) and heel bone (calcaneus), called the subtalar joint. This joint lets you tilt your foot from side to side. The space in between the two bones is called the sinus tarsi, and it houses several key ligaments that support your rearfoot. It also houses a nerve and some adipose tissue.
A single injury, most often an inversion ankle sprain, can damage or stretch the ligaments in this area. Repeated ankle sprains, especially in people with poor ankle stability, can lead to instability in this area and chronic irritation of the ligaments that support the subtalar joint.
In some cases, this injury leads to a buildup of scar tissue or fluid in the space between your ankle and heel bones. This can make the joint feel tight and painful, and it can cause other issues in the foot and ankle. If your symptoms are not getting better with conservative treatment, your doctor may recommend a corticosteroid injection. This can reduce the swelling, decrease the inflammation and break the pain cycle. Surgery is typically only considered as a last resort after conservative treatments have failed.
Treatment
If you are experiencing pain in the ankle or foot and think you may have sinus tarsi syndrome, see one of our board-certified podiatrists for an evaluation. Upon taking your history, a physical examination and imaging studies will be done to determine if you have this condition and if so, the underlying cause. Treatment options will focus on alleviating symptoms and improving stability of the foot and ankle.
Sinus tarsi syndrome is a common injury in the foot and ankle that causes pain over the outside lower edge of the ankle. The pain is felt when you move or put weight on the ankle. The area around the sinus tarsi is very sensitive and often becomes inflamed and swollen, and can look like a cyst on x-rays.
This is usually caused by a traumatic ankle sprain, especially an inversion ankle sprain (rolling your ankle away from the center of the body). This can irritate or stretch ligaments that make up the sinus tarsi. The condition can also develop with repetitive stress on the ankle due to activities that require frequent turning of the foot, such as sports or work, or over-pronation of the feet.
Some people are more prone to developing this condition than others, such as those who have flat feet or participate in high impact activities on uneven surfaces. Treatment of this condition typically begins with reducing inflammation and includes using orthoses to improve your biomechanics and lower limb alignment, which will reduce stress on the sinus tarsi area and relieve pain and swelling. Exercises, such as toe curls with a towel on the floor and balance exercises that involve standing on one leg can help strengthen the arch muscles and promote stability of the ankle.
Prevention
Any injury to the ankle or subtalar joint that damages or irritates the sinus tarsi ligament can lead to pain and limited movement in the area. It is often the result of an inversion ankle sprain or chronic ligament instability in this area, which some refer to as “the eye of the foot.” To prevent this condition, it is important to warm-up and stretch before physical activity, to wear proper footwear and to avoid playing through pain.