Sinus Tarsi Syndrome (STS)… a differential diagnosis for your severe/frequent ankle sprains!
STS consists of localised pain and tenderness at the anteriolateral side of the foot between the talus and calcaneus… also known as the ‘eye of the foot’… palpate it for a feel why.
WHO GETS IT?
Patients following one single or a series of ankle sprains, especially those which have concurrent talocrural interosseous ligament injury.
Ligaments of the sinus tarsi can be sprained or torn causing an increase of mobility, decrease of stability, blood vessel haemorrhage or inflammation. This can then cause irritation during pro/supination movements resulting in SYNOVITIS & SCAR TISSUE formation (in the sinus tarsi).
Patients with obesity, flatfoot and hyperpronation deformities and athletes who perform frequent jump/land activities.
– These cases are ‘compression injuries’ from the talus and calcaneus getting pressed together as a result of the deformation. This causes bone to bone contact of the talus and calcaneus, with inflammation or arthritis in the sinus.
The diagnosis is confirmed if an anesthetic injection given into the painful sinus tarsi results in relieving pain and restoring normal function. Also by MRI.
NSAIDS, an initial period of immobilization, ice and orthoses. Non steroidal injections are frequently given by podiatrists for instant relief and treatment.
Once remodelling phase has started, physios can consider mobilising the subtalar and talocrural joint.
The sural nerve passes the sinus tarsi laterally, and some branches of it may run through the tarsi.