What Is Sinus Tarsi?

Sinus tarsi is painful inflammation of the joint below the ankle known as the subtalar joint. This joint allows the foot to move from side to side.  


A common cause or sinus tarsi is flatfoot deformity. With flatfoot deformity, the arch of the foot drops and the two bones on the outside portion of the subtalar joint pinch against each other. This leads to inflammation of the joint lining. This syndrome also can occur because of arthritis or as a result of injury. 


Sinus tarsi syndrome commonly leads to pain over the outside portion of the foot. Swelling over the hollow between the ankle bone and the heel bone can develop. The swelling can enlarge so that it can be mistaken for a cyst or tumor.  


This syndrome is usually diagnosed by a foot and ankle orthopaedic surgeon's exam. Your surgeon will see swelling over the outside of the joint below the ankle and tenderness over a specific area of the foot. X-rays can be helpful in diagnosis. On X-rays, your doctor may see collapse of the arch or arthritis.  


There are non-surgical and surgical treatment options available. In most cases, non-surgical treatments will be attempted first. Anti-inflammatory medications may decrease the inflammation in the sinus tarsi. A steroid injection may be tried if other medicines do not relieve the pain. An arch support can be used to relieve the pinching of the subtalar joint. A brace can be applied to the ankle and hindfoot to support and rest the subtalar joint.

Surgical treatments include removal of inflammation and scarring of the sinus tarsi. This can be done in an open or arthroscopic technique.  


If surgery is performed, the recovery involves limited weightbearing until the stitches are removed and a fracture boot is placed on the foot. Weightbearing is allowed at that time. Usually, physical therapy is ordered to help regain range of motion and strength. A boot may be used for several weeks to aid walking.

Risks and Complications

All surgeries come with possible complications, including the risks associated with anesthesia, infection, damage to nerves and blood vessels, and bleeding or blood clots.


Are there things that make people more likely to develop sinus tarsi syndrome?
People with flat feet and those who participate in activities that require cutting maneuvers can be more prone to this syndrome. Also, repetitive activities on uneven surfaces can make someone more likely to develop symptoms.

How often is surgery necessary to treat sinus tarsi syndrome?
Surgery is not necessary in most patients who develop sinus tarsi syndrome. Non-surgical treatment can be very successful in relieving pain and swelling.

The American Orthopaedic Foot & Ankle Society (AOFAS) offers information on this site as an educational service. The content of FootCareMD, including text, images, and graphics, is for informational purposes only. The content is not intended to substitute for professional medical advice, diagnoses or treatments. If you need medical advice, use the "Find a Surgeon" search to locate a foot and ankle orthopaedic surgeon in your area.