Sinus Tarsi Syndrome (Lateral Foot Pain)
Sinus Tarsi Syndrome – from Physio Pedia 2017
Sinus tarsi syndrome is a foot pathology which may follow a traumatic ankle injury. It may also occur if the person has an (over)-pronated foot. This causes compression in the sinus tarsi. Some characteristics are pain at the lateral side of the ankle and a feeling of instability. The pathology is an instability of the subtalar joint due to ligamentous injuries, synovitis and infiltration of fibrotic tissue into the sinus tarsi space.
The sinus tarsi is a tunnel between the talus and the calcaneus that contains structures that contribute to the stability of the ankle and to its proprioception. The subtalar joint is between the talus and calcaneus. It includes 3 facets joints. Ruptures of the intrinsic ligaments allow increased subtalar joint movement that may result in instability. The sinus tarsi maybe a source of nociceptive and proprioceptive feedback that provide information on the movement of the foot and ankle.
Epidemiology/Etiology – Sinus Tarsi Syndrome
The sinus tarsi syndrome occurs after a traumatic lateral ankle sprain with a tear of the interosseous and cervical ligaments. Inflammation and haemorrhage of the synovial recess in the sinus tarsi occur with infiltration of fibrotic tissue into the sinus tarsi space. The sinus tarsi syndrome can occur with compression injury in flat or pronated feet. The talus and calcaneus are pressed together as a result of the deformation.
Characteristics/Clinical Presentation – Sinus Tarsi Syndrome
The characteristics of the syndrome are:
- Pain at the lateral side of the ankle
- Pain worse when standing, walking on uneven ground or during supination and adduction of the foot. I
- Instability (functional instability) will be on the hind foot and allows a greater range of motion to our subtalar joint.
Differential Diagnosis – Sinus Tarsi Syndrome
These common pathologies may give the same pain characteristics or symptoms:
- ankle sprain
- calcaneal fracture
- talar fracture
- peroneal tendonitis
- subtalar joint arthritis
- tarsal tunnel syndrome
Diagnostic Procedures – Sinus Tarsi Syndrome
Diagnosis of the sinus tarsi syndrome is made by excluding other foot pathologies. CT-scans exclude bone fractures but are not specific enough to diagnose STS. MRI findings may include filling of the sinus tarsi space with fluid or scar tissue, alterations in the structure of the ligaments or degenerative changes in the subtalar joint. Localization of pain to the sinus tarsi with the presence of ankle instability is a good indication that the patient has developed STS. The diagnosis of STS has typically been confirmed by the cessation of symptoms upon injection of lidocaine into the sinus tarsi.
An acute ankle injury will present with pain, swelling, ecchymosis, and tenderness in the anterolateral ankle. Because the synovitis and fibrotic tissues associated with STS will take time to develop, athletes with injuries to the subtalar joint may not initially have symptoms that can be localized to the sinus tarsi. Stability of the subtalar joint is assessed with medial and lateral subtalar joint glides performed by moving the calcaneus over a stabilized talus in the transverse plane and with subtalar joint distraction. The range of motion of the ankle may be limited in pronation and supination, but pain over the sinus tarsi at the end range of plantar flexion combined with supination is a typical sign for STS. The subtalar joint may have increased translation mobility if the interosseous and cervical ligaments are disrupted. There may be muscle weakness of the peroneal and plantar flexor muscles.
Medical Management – Sinus Tarsi Syndrome
The treatment of the sinus tarsi syndrome is usually conservative – Physiotherapy, sinus tarsi corticosteroid injections, local gels or drugs. Operative treatment is also very effective if conservative treatment fails.
Physiotherapy Management – Sinus Tarsi Syndrome
Mobilization of a stiff ankle post immobilisation, especially of the subtalar and talocrural joint is necessary. Exercises should be done in pronation and supination at the full range of motion if there is no pain provocation. Ice massage over the lateral ankle may diminish inflammation and pain.
Activities without pain should be started as soon as possible. Reinforce Achilles and Peroneal strength. Flexion of the ankle by standing on the toes on the edge of a stair is good. Eccentric exercises help strength gain. Stability training and proprioceptive exercises are the last stage of the rehabilitation with proprioceptive exercises, taping and bracing, and ortheses.
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