Sinus Tarsi Syndrome and Arthroscopic (Subtalar) Treatment



What is Sinus Tarsi?

Sinus is an area surrounded by bone or soft tissue, it can be explained with the term dead end in Turkish. It is necessary to perceive the sinus structure in three dimensions and to evaluate it together with the structures it contains. The syndrome was first described by Dr O’Conor and published in the Bone and Joint magazine in 1958. (J Bone Joint Surg 1958 40 (3) 720-726)

The sinus is between the two main bones … the talus (forms the ankle base transfers the load to the heel and the arch of the foot) and the calcaneus (heel bone). The boundaries are defined by the bony grooves (Sulcus Tali-Sulcus Calcaneus) we call Sulcus. While the lower and upper surfaces of the sinus structure are covered with cartilage, the other surfaces are limited by ligaments and muscle tendon packages. Adipose tissue (contains abundant mesenchymal cells) instead of synovial membrane as a typical joint.


Nerve Tarsi in Midfoot Blood and Nerve Box that makes a predicament

The inner surface is the Talocalcanel interosseous ligament. Ligamentum Cervicalis, which adheres to the neck of the talus bone in front, is the most important ligament parts of the sinus. The retinaculum structure, which packs the tendons of the extensor muscles in the back, completes the main walls.

The vascular neural structures within the sinus structure must be well known to understand the character of the symptoms. The deep branch of the peroneal artery is the main artery that supplies the bones and ligaments that make up the midfoot.

The pressure increase in the sinus will affect the perfusion of this artery, causing necrosis of all relevant structures of the foot. The main artery Arteria dorsalis pedis lateral branch on the dorsum of the other foot joins the network within the sinus tarsi and provides anastomosis with the deep peroneal branch.

This anastomosis means that the two arteries leading to the sole of the foot use the sinus tarsi to spread blood exchange. In this case, the dorsalis pedis, which is blocked due to forefoot problems, diabetes or other vascular diseases, is of great importance in terms of providing collateral to the irrigation area.

In this respect, the sinus tarsi is the anatomical structure that should be evaluated very well in diabetic patients.

The sensory transmission of the structures around the sinus tarsi is provided by the deep branch of the fibular nerve. In case of damage to this nerve branch, the plantar nerve (tibial nerve) that contains deep sensation of the interosseous ligament structures comes into play. It creates burning style pains on the sole of the foot. This option should be investigated in sinus pain that cannot be localized.

In fact, sinus tarsi pains can be well localized in the anterior outer ankle.


Sinus Tarsi Syndrome Causes

We can classify it as Acute and Chronic. Acute causes are traumatic. As a result of the mild sprain of the ankle, the lateral talocalcaneal ligaments are quite strong and do not load the sinus structures. However, in severe torsional traumas, mostly during the injuries accompanied by lateral ligament ruptures, the sinus tarsi joint facets are loaded.

When torsional injury affects the sinus boundaries, surrounding ligament structures may cause problems up to rupture depending on the strength of the force. Sinus boundaries may disappear, surrounding bones may be broken, fragments in cartilages may break off and remain as intra-articular free bodies.

Scar tissue formed after trauma may contain fibrotic, cartilage or even bone tissue, depending on the severity of the injury and the structures involved. Since the Talus-Calkeneus bones are joints in the sinus structure, it is clinically important to think and approach like a joint.

Among the chronic causes, rheumatic inflammatory diseases involving the joints and ligaments, tumors and aneurysms and neurinomas of the vascular and nerve structures located in / around the sinus are responsible.



A good physical examination is essential for diagnosis. I do not recommend online diagnosis in this regard, but it may be possible in late cases with radiological definite reports.

During the examination, subtalar instability eversion provocation and laterally localized pain should be evaluated carefully. Feeling defect or tarsalgia in the forefoot and sole may be accompanied by metatarsalgia. Direct radiography is the lateral oblique sinus tarsi radiography.

With tomography and MRI, the sinus can be exposed in three dimensions and the problems in its content can be examined. Simultaneous radiology with clinical examination sometimes facilitates the diagnosis by scintigraphy.



It is very important to distinguish between acute and chronic causes of sinus tarsi syndrome. In the acute and subacute stages, in inflammations caused by chronic diseases, anti-inflammatory treatments can be applied orally or by local injections. There may be PRP, Orthocaine, Collagen and hyaluronic acid viscosupplementation applications in local injection contents.

Surgical treatment includes removal of scar tissue, tumor or free bodies in the sinus tarsi. Open surgery leaves the option to Sinus tarsi Subtalar arthroscopy over time. Subtalar arthroscopy is an effective solution for removing the tissues in the sinus tarsi without damaging the surrounding structures. Likewise, a minimally invasive option should be considered as a suitable option in subtalar arthrodesis where the dysfunctional sinus is removed.