Sinus tarsi syndrome:
Associated with compression of lateral column; frequently secondary to excessive chronic calcaneal eversion or following ankle sprain.
Considered to primarily affect the talocalcaneal ligament.
MRI has shown changes consistent with fibrosis and synovitis replacing the normal fat in the sinus tarsi .
Pain (usually chronic) on lateral side of foot – just in front of lateral malleolus, but often poorly localised. Usually worse in morning. Can often palpate pain over lateral sinus tarsi. Forced subtalar joint eversion may be painful. Subtalar joint range of motion may be limited. Patient may have sensation of ‘instability’. Subtalar joint axis is often located more medially located. Local anaesthetic into sinus tarsi should alleviate symptoms.
Peroneal inhibition issues.
MRI has shown loss of fat in sinus tarsi and poor definition of the interosseous ligaments, which may be secondary to oedema or fibrosis
Activity modification; reduce pain and inflammation; subtalar joint mobilisation; inverted orthotic devices seem to be more successful; cortisone injection into subtalar joint.