Understanding Sinus Tarsi Syndrome

Are you active in sports or into any physical activity that requires you to move about? You might have experienced a painful sensation around your foot or ankle. The pain usually shoots up whenever you point your foot towards your body or when you walk up the stairs. The condition you have may be a sinus tarsi syndrome. Now is the time to know its nature, causes, course of treatment and prevention.

What is sinus tarsi syndrome?
This is a clinical disorder that affects the sinus tarsi or “eye of the foot”, which is a soft indentation between the ankle and the heel bone. The space in the tarsal sinus contains lots of nerve endings, fat, ligaments and joint capsule.

Sinus tarsi syndrome was first described in 1957 by Denis O’Connor as a syndrome that occurs after trauma to the lateral hind foot. The development of tarsal sinus syndrome is not completely known, but it was theorized that the joint capsule in the sinus thickens due to deposition of scar tissue. The thickening of the capsule makes it prone to get pinched between the bony structures in the foot and ankle causing it to be inflamed. The inflammation triggers pain and discomfort as well as a bigger likelihood for it to get pinched again and get worse.

What causes sinus tarsi syndrome?
The disorder commonly develops after ankle inversion sprains. So how does it happen? The structures in the tarsal Understanding Sinus Tarsi Syndromesinus play a significant role in the proprioception and stability of the ankle. Inversion sprains need to be treated and/or rehabilitated properly for the damaged sensory receptors to fully heal and regain their pre-injury state.

If not healed properly, the ankle will not be able to sense changes in foot and ankle position. This will result in a feeling of unsteadiness or instability when walking on uneven ground. This may even result to more ankle sprains which may aggravate the condition.

Moreover, the normal healing process of the ankle sprain may predispose thickening of the joint capsule thus leading to a sinus tarsi syndrome.

What are the symptoms?
Patients usually experience localized pain in the sinus tarsi region or in their ankles. This is accompanied by a feeling of instability especially on uneven surfaces like grass and gravel. The feeling of unsteadiness is also made worse by weight bearing activities.

Physical assessment reveals pain of the tarsal sinus region upon palpation or with certain range-of-motion (ROM) exercises such as turning in of the foot (inversion) and/or turning out of the foot (eversion). In some cases, looseness of the ankle or foot, ligament tears, and joint injuries may be present.

How is sinus tarsi syndrome diagnosed?
Radiologic exams may be done such as x-rays, bone scan, computed tomography (CT) scan and MRI evaluation. Plain radiographs may be used but it is not definitive because certain conditions like degenerative arthritis may be confused with the results.

MRI is deemed to be the best test to fully display the changes in the structures of the tarsal sinus including inflammation and presence of scar tissue sustained injury. Ankle arthroscopy is done to evaluate the ankle for damaged tissue.

How is sinus tarsi syndrome treated?

  1. Non-surgical management
    The disorder is first treated conservatively – decreasing inflammation present and decreasing tension and thickening of the capsule. Tissue injury usually extends to blood vessels that result to bleeding at the injury’s site. The bleeding leads to the five cardinal signs of inflammation: redness, heat, pain, swelling, and impairment in function.
    Inflammation can be addressed through the following:

    • Protect – protect the ankle from undue stress that may hamper the healing process. Appropriate splint can be used such as the Aircast ankle brace and other customized orthopedic devices as appropriate.
    • Rest – it is important to let the injured area to rest to reduce its energy requirements and avoid unnecessary upsurge in blood flow which can aggravate the inflammation. If activity cannot be avoided, use crutches to help shift the weight away from the injured ankle.
    • Ice – ice can be used to constrict the blood vessels so that swelling can be controlled. This can also help in reducing the accumulation of scar tissue. Crushed ice must be placed in a damp towel and applied immediately after injury for a maximum of 20 minutes every 3-4 hours.
    • Compression – compression bandages can also be applied to the area making sure that it is not too tight to impede circulation.
    • Elevation – lowers the pressure and flow of blood in the area thereby limiting bleeding and inflammation.

    The patient is also advised to wear confortable and stable shoes as well as undergo recommended exercises. These methods can be combined with pharmacologic treatments in order to address sinus tarsi syndrome.

  2. Pharmacologic management
    Inflammation and pain are addressed with analgesics, anti-inflammatory medications and steroids.
  3. Surgical management
    Open debridement – This surgical procedure is done by the excision of the entire content of the tarsal sinus, including the interosseous talcocalcaneal ligament. This procedure is reported to have very favorable results for most of patients, effectively removing pain and discomfort cause by the syndrome.
    Arthroscopy – This is a closed surgery performed through the use of a scope. It was noted that 94% of the patient who have undergone this procedure experienced positive results.

How is Sinus Tarsi Syndrome Prevented?
Sometimes, biomechanical problems of the feet can be the cause of frequent ankle sprains which can lead to the disorder. These problems can be corrected with the appropriate use of shoe inserts and/or orthotics.

For those without biomechanical errors of the feet, it is imperative to wear suitable footwear that is shock absorbent. Also consider shoes that have the correct grip for the different types of surfaces that you will play or train on. If you engage in sports, it is important that you warm up sufficiently so that you do not overexert yourself.

Your feet take you places so you should give them the attention and care that they most certainly deserve. Equip yourself with the knowledge and prevent sinus tarsi syndrome from happening to you!

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