A small bony canal that is present between the talus and the calcaneum is called sinus tarsi. It contains structures that contribute to stability and proprioception of the joint. Damage to the sinus tarsi can be caused from overuse or an ankle sprain.
Sinus tarsi syndrome mostly occurs after a lateral ankle sprain or recurrent ankle sprains which consequently results into injuries of the interosseous and cervical ligaments present in sinus tarsi.
As a result of injury to sinus tarsi ligaments, an inflammation of the synovial recess in the sinus tarsi occurs. This happens in 70% of the cases of recurrent lateral ankle sprain cases.
The sinus tarsi syndrome can also occur as a compression injury in patients with people flat feet. The talus and calcaneum are pressed together as a result of the deformation. This causes bone to bone contact of the talus and calcaneum, with inflammation or arthritis in the sinus.
It is difficult to pinpoint the exact location of paint by the patient. The usual area of pain is on the outer aspect of ankle near the lateral malleolus. Tenderness can be elicited at the sinus tarsi opening near the outer side of the ankle.
Inversion of ankle may reproduce the pain.
To confirm the diagnosis an anesthetic injection can be administrated into sinus tarsi which will relieve the symptoms and allowing normal function if not than some other structure is at fault.
The pain is most severe when standing, walking on uneven ground or during the movements of supination and adduction of the foot’.
People suffering from the sinus tarsi syndrome also have a feeling of instability (functional instability) in the hind foot.
Moreover the loss of stability in the ankle will allow a greater range of motion to the subtalar joint.
The common pathologies that may give the same pain characteristics or symptoms are:
- Ankle sprain
- calcaneal fracture
- talar fracture
- peroneal tendonitis
- subtalar joint arthritis
- tarsal tunnel syndrome
Diagnosis of the sinus tarsi syndrome is usually made by excluding other foot pathologies.
MRI is the best method to visualize the structure within the sinus tarsi, especially the interosseous and cervical ligaments. The MRI findings may also include alterations in the structure of the interosseous and cervical ligaments and degenerative changes in the subtalar joint.
The initial treatment can be abbreviated as PRICE – protection, Rest, Ice, Compression and Elevation.
The patient may have a painful limp, so the patient needs to be rested from complete weight-bearing activities.
Ice can be applied to reduce pain and swelling. Apply for 10-15 minutes every 3 to 4 hours during the initial inflammatory phase.
Anti-inflammatory medication may help reduce pain and swelling. Supportive crepe bandage can be applied to restrict ankle movement.
Other helpful physiotherapy modalities and techniques can be used to reduce pain.
Mobilization of the joints of ankle and foot especially subtalar joint is important part of treatment. A specialized manual therapist should be able to mobilizations the foot and ankle joint appropriately for sinus tarsi syndrome.
Correction of biomechanical problems such as overpronation should be done. This may help relief the narrowing of the sinus tarsi canal. An orthotic insole to correct biomechanical foot problems may be needed. It is important to have correct supportive running shoes.
Stretching and strengthening exercises for the ankle to normalize the muscle balance around the ankle is very important to regain complete range and strength of ankle.
Proprioceptive and balance exercise on a wobble board to enhance joint sense of patient. If an individual/ athlete have been out of training because of injured ankle then the proprioception or co-ordination of the ankle will be disrupted. Balancing exercises and using a wobble board can strengthen the proprioception and reduce the chances of re-injury.