Sinus tarsi syndrome
Lateral subtalar impingement syndrome

The sinus tarsi is a kind of tunnel that runs in the foot between the tarsal bones. This tunnel starts just before the lateral malleolus and then runs inward at an angle. If the structures located here cause discomfort, this is referred to as sinus tarsi syndrome.

Description of condition

The sinus tarsi tunnel contains ligaments, blood vessels and nerve branches. Just outside of the sinus tarsi tunnel are found tendons and a joint capsuleas well. When these become excessively strained, symptoms develop.

People with sinus tarsi syndrome suffer from pain on the outside of the ankle. It is experienced as a dull, stabbing or burning pain. It increases when the foot is more heavily strained or when making certain movements with the foot. The ankle may also become stiffer and more unstable.

Cause and history

Sinus tarsi syndrome can occur in various ways. For example, when there is an abnormality of the foot that causes it to tilt strongly inward. This is the case with flat feet, where the structures in and around the sinus tarsi may become excessively strained as a result. Because this happens at every step, chronic irritation or inflammation develops.

The disorder is most common in people who have (repeatedly) sprained their ankle. It is assumed that this is what happened in around 70% of all cases. It is often active sportsmen who get this disorder. But also people who are overweight and who suffer from rheumatoid arthritis are at increased risk.

Signs & symptoms

Symptoms that may occur with sinus tarsi syndrome include:

• Pain on the outside of the foot/ankle (dull, burning, tingling, stabbing).
  
• Aggravation of the symptoms when walking on uneven terrain.- Difficulty walking on uneven terrain.
  
• Pain when moving the foot downward or inward
  

.- Reduction of the symptoms when wearing sturdy, high -sided shoes.

• Stiffness.
  
• Feeling of instability in the foot.
  
• Local swelling.

Diagnosis

If there are symptoms in the area of the sinus tarsi, the doctor or physiotherapist will ask what the symptoms are, and how they developed. This is followed by a physical examination in which pressure on the sinus tarsi causes pain. The position of the feet will also be examined. The focus will mainly be on the inward tilt of the foot and the presence of a flat foot or feet.

When examining the mobility of the foot and ankle, moving the foot downward and inward will be painful. This may also be the case when moving the foot upward and outward.

An X-ray can be taken to see whether there are any visible degenerative abnormalities. This is the case, for example, with osteoarthritis or rheumatoid arthritis. An MRI or CT-scan can clearly show exactly which structures in and around the sinus tarsi are affected.

Treatment

If the foot is misaligned, it can be supported by well-fitting shoes and inserts. A podiatrist can help with this. In addition, it is important to train the stability of the ankle to prevent (repeated) spraining. Stiff joints also need to be mobilized again. If necessary, an injection of an anti-inflammatory and painkiller can help. In order to achieve best results, it is often necessary to combine several of the above treatments.

All of this may not be enough and surgery is required. During surgery, the sinus tarsi is cleaned. After surgery, the patient has to walk on crutches with a special shoe for a fortnight. After that, the weight-bearing on the foot can gradually increase again. This can be done under the supervision of a physiotherapist.

Exercises

You can check your symptoms using the online physiotherapy check or make an appointment with a physiotherapy practice in your locality.

References
Brukner, P. & Khan, K. (2010). Clinical sports medicine. McGraw-Hill: Australia. 3e druk.
Brukner, P. & Khan, K. (2016). Clinical sports medicine (Nederlandse bewerking). 4th edition. Michel van Troost. PreVision, Eindhoven.
Helgeson, K. (2009). Examination and Intervention for Sinus Tarsi Syndrome. North American Journal of Sports Physical Therapy. Volume 4, Number 1. Feb. 2009.
Wees, Ph.J. van der, Lenssen, A.F., Feijts, Y.A.E.J., Bloo, H., Moorsel, S.R. van, Ouderland, R., Opraus, K.W.F., Rondhuis, G., Simons, A., Swinkels, R.A.H.M., Vaes, P., Verhagen, E., Hendriks, H.J.M., Bie, R.A. de (2006). KNGF-richtlijn. Enkelletsel. Jaargang 116. Nummer 5. Update klinimetrie 2017.