What is Sinus Tarsi Syndrome?
Sinus Tarsi syndrome(STS) is a painful condition that occurs as a result of trauma or injury to the ligaments in the sinus tarsi area of the foot. The sinus tarsi is a tunnel formed by the talus and the calcaneus bones located in the outer aspect of the hindfoot slightly below and towards the front of the ankle joint. STS can lead to synovitis (inflammation of the joint lining) and infiltration of fibrotic tissue into the sinus tarsi space.
Causes of Sinus Tarsi Syndrome
Common causes of the STS include:
- Trauma or injury in the ankle or foot
- Ankle or foot sprain
- Overuse of the ankle or foot such as long periods of standing or walking
- Conditions such as pes planus or an over-pronated foot
- Inflammation and hemorrhage of the synovial recess
- Talocalcaneal joints synovitis
- Inflammatory arthritis conditions
Symptoms of Sinus Tarsi Syndrome
Some of the common symptoms of STS include:
- Intense pain in the front outer side of the ankle
- Instability of the foot
- Difficulty with walking or standing on unstable surfaces
- Decreased range of motion
- Tenderness and palpation of the sinus tarsi with aggravation on foot inversion and eversion
Diagnosis of Sinus Tarsi Syndrome
Diagnosis of sinus tarsi syndrome is done by your healthcare provider thorough a physical examination and noting your medical history. Further your healthcare provider may order imaging studies to confirm the diagnosis such as:
- X-ray to look for fractures or joint dislocation
- MRI scan to visualize the structures within the sinus tarsi, especially the interosseous and cervical ligaments
- CT scan to look for alterations in the structure of the ligaments or degenerative changes in the subtalar joint
- Bone scan to look for inflammatory changes in the sinus tarsi/subtalar region
Treatment of Sinus Tarsi Syndrome
Treatment of Sinus tarsi syndrome includes:
Sinus tarsi syndrome can often be treated using conservative methods. These include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) which can provide a combination of pain relief and inflammation reduction
- Supportive braces, medical boots, or shoe inserts to support the ankle or foot arch
- Specially made shoes to help better support to the arch, foot, and ankle
- Steroid injections, which can help with inflammation, reducing pain and swelling of the joint
Your doctor may recommend surgical treatment options if your symptoms are severe or if conservative methods fail to resolve the condition. Surgery options include:
- Scar tissue removal: Typically, your surgeon will remove scar tissue using a minimally invasive technique known as arthroscopy.
- Flatfoot surgery: A combination of procedures can be performed by your surgeon to adjust the ligaments, bones, and tendons supporting the arch if the condition occurs due to flat feet.
- Subtalar fusion: If STS occurs due to subtalar arthritis or hindfoot arthritis, then subtalar fusion may be necessary to fuse or lock the joints together.