What is sinus tarsi syndrome?
Sinus tarsi syndrome is the medical term for injury to the ligaments and joint capsule that pass through the sinus tarsi, a small cavity between two of the bones on the outside of the ankle.
The ankle joint is made up of one strong capsule that forms around the joint, enclosing it and preventing either boney ends of the lower leg and foot from connecting or impacting. The ankle is, in fact, made up of two joints in order to allow it a lot of movement and flexibility. The point where the lower leg connects to the foot is through the Tibiotalar Joint (the joint between the tibia and the talus), this joint allows the foot to point downwards and upwards. The second joint is the Subtalar Joint (the joint between the talus and calcaneus), this joint allows the ankle to bend from side to side. There is a small cavity between the talus and calcaneus called the sinus tarsi. Ligaments, blood vessels, tendons and part of a joint capsule pass through this cavity. Any pain from injury or damage to these structures is classed as sinus tarsi syndrome. The two ankle joints are encompassed by the one strong capsule. The capsule itself is filled with a small amount of thick fluid called synovial fluid which acts as a cushion and there is a protective layer of articular cartilage that covers each boney surface. The cartilage, fluid and strong capsule allow the joint to move in a smooth, flexible manner. Ligaments that surround the joint are made of thick, tough, fibrous tissue, they overlap the joint and work in co-ordination with the strong lower leg muscles to provide protection and stability for the ankle.
Why & when does sinus tarsi syndrome happen?
Sinus tarsi syndrome is a relatively common condition and affects people of all ages, it is most often seen in people who have hypermobile or weak ankles and who suffer from repetitive ankle sprains. It is also commonly seen in people whose arches have fallen and have very flat feet. These weaknesses mean that the normally sturdy Subtalar joint is allowed to tilt to the side more often and with less control, repetitively narrowing the sinus tarsi cavity and compressing its structures. Either through one single traumatic compression (an ankle sprain) or repetitive compression the structures become damaged and inflamed.
What does sinus tarsi syndrome feel like?
Sinus tarsi syndrome can cause a very intense, immediate sharp pain or dull ache around the outside of the ankle. The pain can at times radiate up into the lower leg or further down into the foot. The pain will be accompanied by local swelling and possibly bruising and will be incredibly tender to touch. Pain levels will be aggravated by any side to side foot movements and in particular walking and running on uneven surfaces. Stiffness and dull aches are normally experienced during the night and are most intense early in the mornings easing with movement.
How will sinus tarsi syndrome be diagnosed?
Your GP or therapist will be able to diagnose you by both listening to your history and examining you. No X-rays or further investigation should be needed to confirm the diagnosis.
What treatment options are available for sinus tarsi syndrome?
Your GP will most likely prescribe anti-inflammatory medication to reduce any swellingand painkillers for pain relief. You will be advised to follow the R.I.C.E protocol. The R.I.C.E protocol involves Resting your ankle, try not to walk about on it too much and most importantly avoid all ankle eversion movements. Ice, applying a covered ice pack to the area may also significantly hasten the healing process by reducing the pain and swelling. Make sure the ice pack is covered to prevent any ice burn and for best results use the icepack regularly for 10-15 minutes with intervals of 30 minutes. Compression, try and keep the elastic bandage on during the day to limit the swelling and make sure to take it off at night. Elevation, keep your foot raised on cushions or a stool to help limit the swelling.
Your GP or therapist will be able to provide you with exercises to strengthen the ankle ligaments and stretch the surrounding muscles to aid the healing process and prevent reoccurring injury. Many people find massage therapy helpful to loosen the affected muscles. Manipulative therapies such as physiotherapy, chiropractic and osteopathy are thought to help through mobilisation treatment of the ankle, working to reduce any stiffness levels and return the joint back to its normal movement.
If your GP has mentioned or if in fact, you feel that there is some element of foot or ankle dysfunction that has predisposed you to this injury then it is very important that you see a podiatrist who can fully examine your feet and determine whether you need orthotics for your shoes. Often inappropriate and unsupportive running shoes are a factor in the development of ankle or foot tendinitis. The failure to do this may result in recurring cases of sinus tarsi syndrome.