Sinus Tarsi Syndrome – Causes & Treatment

The sinus tarsi is the cavity on the lateral (outer) side of the foot in front of the ankle. The sinus tarsi space is filled with many connective tissues that contribute to the stability and the proprioception of the ankle (proprioception is the unconscious perception of movement and spatial orientation arising from stimuli within the body itself).

In sinus tarsi syndrome, the ligaments around the sinus tarsi—the interosseous and cervical ligaments—are injured, causing instability of the subtalar joint. This joint allows inversion and eversion of the foot, which is the ability to move the foot in toward the body (pronation) or out away from the body (supination).

With instability of the subtalar joint, these movements are exaggerated. This causes stress across the sinus tarsi tissues, which leads to inflammation and anterolateral ankle pain characteristic of sinus tarsi syndrome.

Injury to the ligaments around the sinus tarsi can occur in athletes such as runners and dancers whose chosen sports require a lot of jumping or sudden, quick movements and sudden stops. Sinus tarsi syndrome is thought to occur after a single traumatic event or a series of ankle sprains.

Sinus Tarsi Syndrome Symptoms To Know About

Athletes with sinus tarsi syndrome often have two symptoms:

  • Deep, sharp, or pinching pain along the top and/or outer side of the foot and ankle when the foot is dorsiflexed, such as when walking up stairs; the pain may increase with time on the feet and be relieved by rest.
  • A feeling of unsteadiness when walking on uneven surfaces.

Affected athletes may report having a previous ankle injury or one or more ankle sprains. An athlete with recurrent ankle sprains may have sinus tarsi syndrome.

What Causes Sinus Tarsi Syndrome?

The most common cause of sinus tarsi syndrome is trauma (in 70 percent of cases); inflammatory conditions, ganglion cysts, and foot deformities are responsible for the remaining 30 percent of cases.

The exact reason why sinus tarsi syndrome develops is a matter of debate. One theory suggests that scar tissue, which is part of the natural healing process, causes thickening of the joint capsule. The thickened joint capsule becomes pinched between the bones in the ankle, leading to chronic inflammation.

It has also been suggested that sinus tarsi syndrome develops after ankle inversion sprains that are not treated properly. If the sensory receptors responsible for proprioception in your ankle do not heal well after a sprain, they may not regain their pre-injury ability to sense changes in ankle position.

How Is Sinus Tarsi Syndrome Diagnosed?

Your doctor will examine your foot and perform several tests to assess the stability of the subtalar joint and surrounding joints, including the talocrural joint. You will be asked to stand so that your posture can be assessed.

Some athletes with sinus tarsi syndrome may appear to have pes planus (flat feet) due to pronation, or inward leaning, of the ankle. Your doctor will manually move your foot to test passive range of motion of the ankle and subtalar joint.

This test may reveal excessive motion or looseness of the joint. A typical sign of sinus tarsi syndrome is pain in the sinus tarsi when your foot is turned in or turned out, or if you feel pain on palpation of the area.

The muscles that cross the ankle joint will also be assessed to see whether there is any loss of strength. The unaffected foot will be evaluated to compare the differences in joint mobility between both feet and to determine whether you might have instability.

Stability of the subtalar joint can be assessed in a few ways. Your doctor may hold onto your forefoot with one hand while applying an inversion and internal rotational force to your heel with the other hand.

Or you may be asked to stand on the affected foot while keeping the other foot raised and perform rotating motions of the leg and foot to reproduce symptoms.

You may be referred for imaging studies. These may include radiographs of the foot, computed tomography, magnetic resonance imaging (MRI), or stress fluoroscopy—a method of visualizing the motions of the subtalar joint in real time using low-level radiation.

MRI is considered the best method to visualize the structure within the sinus tarsi, especially the interosseous and cervical ligaments. Ankle arthroscopy can also be used to evaluate the sinus tarsi for damaged tissue.

Sinus Tarsi Syndrome Treatment Options

After your doctor has evaluated you and a diagnosis of sinus tarsi syndrome has been confirmed, conservative treatment of sinus tarsi syndrome can be administered at home. Such treatment involves:

  • RICE (Rest, Ice, Compression, and Elevation) to reduce inflammation and swelling in the ankle
  • Identifying and eliminating the activity that may be exacerbating your subtalar joint injury to decrease the tension and thickening of the joint capsule
  • Muscle-strengthening exercises to restore proper ankle proprioception

Your doctor may recommend anti-inflammatory medications, stable shoes, an ankle sleeve or brace, and over-the-counter orthotics. If your symptoms persist after conservative treatment, you may need a course of oral corticosteroids, a series of corticosteroid injections into the joint, physical therapy, or custom orthotics.

Surgery is rarely indicated, although it may be considered for patients whose symptoms do not improve after corticosteroid injections.

Most patients have two options: open surgery (through an incision for reconstruction of the subtalar joint) or closed surgery (via arthroscopic exploration).

When to Return to Play After Sinus Tarsi Syndrome

You should be able to resume your normal activities within a few days, depending on your ability to move in all directions and at appropriate speeds. You may need further treatment if symptoms return, however, in order to prevent chronic inflammation of the sinus tarsi tissues.

All about Sinus Tarsi Syndrome


Clinical disorder characterized by specific symptoms and signs localized to the sinus tarsi (known as the “eye of the foot”), which refers to an opening on the outside of the foot between the ankle and heel bone.


First described by Denis O’Connor in 1957. He also described a surgical procedure to address this problem (called the O’Connor procedure) that involves removal of all or a portion of the contents of the sinus tarsi.


Cause can be due to an inversion (rolling out) ankle sprain (70-80% of the time) or can be due to a “pinching” or impingement of the soft tissues in the sinus tarsi due to a very pronated (rolling in) foot (20-30% of the time).

Clinical Presentation:

Patients present with localize pain to the sinus tarsi region with a feeling of instability and aggravation by weight bearing activity. These patients do poorly on uneven surfaces, i.e., grass and gravel. Physical examination reveals pain to palpation of the sinus tarsi with aggravation on foot inversion (turning in) or eversion (turning out). Looseness and instability of the ankle and foot joints may be present as well.

Diagnostic Testing:

May include x-rays, bone scan, CT scan and MRI evaluation. Injection with local anesthetic is diagnostic for localizing this problem to the sinus tarsi. Many times this is a diagnosis make by excluding other common problems in the foot as definitive diagnostic findings are rarely present. MRI is probably the one best test to shoe changes in the tissues of the sinus tarsi involving either inflammation or scar tissue from previous injury. Ankle arthroscopy may also be beneficial to directly evaluate the sinus for damaged tissue.


After a diagnosis is established conservative treatment can be initiated which is generally very effective in eliminating the problem. Treatment may include anti-inflammatories, stable shoes, period of immobilization, ankle sleeve and over-the-counter orthoses. Resistant cases may require a course of oral steroids, series of steroid injectionss, physical therapy or custom orthoses. Rarely is surgery indicated and if needed open surgery (through an incision) or closed surgery (via arthroscopy) can be considered. Excellent results should be expected but surgery is not a panacea and should be considered as a last resort.


STS is a problem that can occur commonly after an ankle sprain or in someone who has a severly pronated foot. Diagnosis is critical as this will dictate appropriate treatment which can differ significantly from other common problems seen in the foot and ankle. Conservative treatment is usually effective and surgery is rarely needed and should be considered after an adequate and thorough trial of conservative treatment.

The important treatment of sinus tarsi syndrome

Rest from all painful activities. Continuing to train on a painful ankle will make the injury worse or at least prevent healing. Apply ice or cold therapy to reduce pain and inflammation. Cold can be applied for 10 to 15 minutes every hour initially if the injury is very painful but reducing later to 3 or 4 times a day as required.

A doctor may prescribe NSAID’s or non steroidal anti inflammatory drugs such as ibuprofen (dont take if you have asthma). Electrotherapy such as ultrasound may help reduce inflammation and swelling caused by sinus tarsi syndrome.

Ankle mobilizationMobilization of the subtalar joint is and important part of treatment and rehabilitation. A professional therapist or trainer should be able to help with ankle mobilizations for sinus tarsi syndrome. Correction of any biomechanical problems such as over pronation. Over pronation is when the foot flattens or rolls in too much. This could change the way the ankle bones move restricting the space in the sinus tarsi channel. A podiatrist or similar can prescribe orthotic insoles which go in shoes to correct biomechanical foot problems. It is important to have the correct running shoes for your type of feet also.

Wobble board exercisesStrengthening exercises for the ankle especially proprioceptive exercises such as use of a wobble board. If you have been out of training on an injured ankle then the proprioception or co-ordination of the ankle will be disrupted. Balancing exercises and using a wobble board can strengthen the proprioception and make re-injuring the ankle less likely.

Stretch the calf muscles at the back of the lower leg. Tight calf muscles may affect the biomechanics of the ankle.


Recommendations for rehabilitation of STS include balance and proprioceptive training, muscle strengthening exercises, bracing, taping, and foot orthosis. No random control trials for the efficacy of a rehabilitation program for STS are available. Instability of the talocrural joint or chronic ankle instability (CAI) is a similar and associated entity to subtalar joint instability and STS. Numerous studies of the effects of balance and proprioceptive training for CAI have been conducted, with improvements found in athletes’ balance, joint position sense, and functional abilities.

Athletes with STS have developed a chronic inflammatory process that results in a synovitis and inflammation of connective tissues and may benefit from a trial of nonsteroidal anti-inflammatory medication to help control their symptoms and inflammation. Cryotherapies, especially the use of ice massage over the lateral ankle, may also be useful for diminishing local inflammation and pain associated with this condition. Athletes with STS may have limited joint mobility at the talocrural and mid tarsal joints that can be addressed with specific joint mobilization techniques. Precautions should be made not to place excessive stress across the subtalar joint with these techniques. Muscular stiffness of the gastrocnemius, posterior tibialis, or peroneal muscles may also be found in athletes with STS, but stretching activities for these muscles should be carefully provided or avoided as excessive forces across the subtalar joint may be detrimental.


Stability of the subtalar joint may be initially improved with the use of an orthosis. Ankle braces intended for CAI may be useful for some athletes with STS, but the overall design of these braces may not significantly improve the stability of the subtalar joint during athletic activities. Foot orthosis have also been recommended as a method for limiting motion at the subtalar joint and reducing symptoms associated with STS. The types of shoes the athlete is using for training, practices, and competition should also be considered, as well constructed shoes can restrict excessive rearfoot movements.

General recommendations for shoes include those with a straight last, a firm heel counter, and rigid material through the midsole. Shoes should also be assessed for wear, as materials within a shoe will be begin to break down before the external material show signs of deterioration. The use of a foot orthosis with an athletic shoe should be considered together, as the effect of an orthosis can be inconsistent. An ongoing assessment of shoe and orthosis use is needed to provide adequate support of the foot and ankle throughout an athlete’s cycle of training and competition.

Taping or strapping has also been used to specifically limit movements of the subtalar joint and the midfoot. Wilkerson et al have described a taping procedure that combines a closed basket weave with a subtalar sling to control movements at the talocrural and subtalar joints. Viczenzio et al have described a modified Low-Dye taping method that uses a calcaneal sling intended to provide support to the medial longitudinal arch of the foot (Figure 3). This method could be used to control or reduce the amount of pronation through the subtalar joint during walking and running activities. Taping techniques have been used as a precursor for the use and selection of specific types of shoes and foot orthotics.

Figure 3.

Taping for stabilizing the rearfoot. These taping methods can be used in addition to an closed ankle basket weave or a foot Low-Dye method. Figure on the top shows a calcaneal sling with a long strip to control rearfoot pronation, figure on the bottom

Stability Training

Training programs to improve the stability of the subtalar joint and lower extremity function will be the hallmark of treatment plans for STS. Joint stability relies on passive joint structures, dynamic muscular responses, and neurological control. Because tears or ruptures of the interosseous and cervical ligaments of the subtalar joint are believed to be the essential lesions that lead to STS, the dynamic muscular responses and neurological control of the rearfoot will need to be emphasized to compensate for the loss of passive stability.

The muscles that cross the subtalar joint are important for maintaining stability, as they act as force transducers to guide and control the pronation and supination motions of the subtalar joint. The relative strength of these muscles is important, but their reaction time to joint perturbations and the ability to work in a coordinated fashion is even more important for the rehabilitation of STS. Dynamic stability will also rely on the proprioceptive information from the muscle spindles and Golgi tendon organs of these muscles to compensate for the lack of proprioceptive information from the stabilizing ligaments of the joint. The endurance of the muscles will also be important to maintain stability during long bouts of exercise or sports activities.

Training programs to improve joint stability have been described as multiphase processes that start the athlete at an appropriate level of activity and progresses to higher levels of activities while maintaining joint stability. To help the athlete understand this process the progression of three phases are called: Attain, Maintain, and Sustain. The Attain phase will determine postures or positions the athlete is able to attain in a stable fashion. The Maintain phase will develop coordinated isometric and eccentric muscle contractions of the muscles crossing the joint. The Sustain phase will involve integrating all of the neuromuscular subsystems needed for stability during sports specific activities (Table 1).

Table 1:

Progression through three stages of stability training.


The Attain phase for subtalar joint instability is usually started with the athlete in standing positions. Single leg standing, with the contralateral limb held in approximately 30 degrees of hip flexion and 90 degrees of knee flexion, will emphasize ankle balance strategies. The clinician should closely observe the arch of the foot and rear-foot to assess the athlete’s ability to attain a stable position for the subtalar joint while avoiding excessive pronation movements (Figure 4). The Attain phase begins with the eyes open and attempting to hold the single leg position for 30 to 60 seconds with minimal alterations in body position. Once the athlete is able to hold a single leg standing position consistently, a progression to eyes closed conditions can be made.

Figure 4.

Foot held in an excessive pronated position.


The second phase, Maintain, is performed with perturbations to the single leg positions. Perturbation forces are imparted near the level of the athlete’s center of gravity to replicate the type of forces that produce subtalar joint instability during athletic activities. The perturbating forces are intended to facilitate rapid isometric and eccentric contractions of the stabilizer muscles of the ankle. Perturbations to standing balance are begun with movements from the contralateral hip starting in the sagittal and coronal planes of motion, progressing to transverse plane motions. Observations of the athlete’s rearfoot and hip stability will indicate his/her ability to maintain this position. The clinician needs to insure that the athlete is not using excessive compensatory motions at the rearfoot or hip to maintain a single leg standing position.

The star excursion balance test activities can also be used in this phase, with the athlete in the single leg standing position and touching different lines drawn on the floor in a star pattern. Standing heel raises and lowering exercises can be performed at a slow speed in double leg and single leg standing. Emphasis is placed on promoting controlled concentric and eccentric muscle contraction of the ankle plantarflexors and subtalar joint pronator muscles. External perturbations can be imparted with the athlete holding a two-foot length of theraband. With both hands in front of the umbilicus, the therapist can then pull on the theraband with oscillating motions. Catching and throwing a small ball or medicine ball while in single leg standing can also be used for perturbations in multiple directions and different timing.

The Sustain phase will begin with the athlete learning to “close the chain” meaning moving from an open kinematic chain to a stable closed kinematic chain position. The emphasis is on developing the feedforward motor control of the lower extremities. This activity can be started by having the athlete perform lunging steps and then stepping down from a 4 or 8 inch step onto the involved extremity into a single leg standing position. Progression can be to lateral lunge steps and lateral step downs. Observations of the athlete’s overall control of motion through the lower extremities with an emphasis on alignment of the knee and foot will insure that excessive subtalar joint motion is not occurring.

Progressions of the Sustain phase can be performed with the athlete jumping or hopping in place and then into hopping in different directions. Running activities can begin by acceleration and deceleration with forward and backward motions. Athletes needing to perform pivoting or cutting maneuvers can begin these activities at a slow speed maintaining good alignment of the foot and leg and avoiding excessive motions through the rearfoot.

Return to play criteria is based on the athlete’s ability to move in all directions and at appropriate speeds. Athletes performing cutting and jumping maneuvers on firm surfaces, such as basketball and volleyball players, should be returned to full activities over a period of days to insure their tolerance to these stressful maneuvers. A progression of the athletic activities should be assessed with the athlete in his or her normal practice or competitive environment. The athlete’s anterolateral ankle symptoms will need to be well controlled to insure that the return to competition will not create chronic inflammation of the sinus tarsi tissues.


Athletes who fail a course of rehabilitation may need an arthroscopic exploration and reconstruction of the subtalar joint in order to return to their athletic pursuits. Arthroscopy of the subtalar joint has allowed for a more precise examination of the subtalar joint and the sinus tarsi. A synovectomy of the subtalar joint along with an arthrotomy of the subtalar joint can be used to remove chronic synovitis and arthrofibrosis that is commonly found in STS. Surgical reconstructions of the cervical and interosseous ligaments are made by splitting the tendon of the peroneus brevis and routing the graft through bone tunnels made through the calcaneus and the talus. Patients with instability of the talocrural and subtalar joints may require a tri-ligamentous reconstruction of the anterior talofibular, calcaneofibular, and cervical ligaments. Patients who present with significant joint degeneration or continue to have persistent symptoms even after ligamentous reconstruction may require an arthodesis resulting in an isolated fusion of the subtalar joint.

Athletes who have undergone ligamentous reconstructions will commonly be immobilized for a 6-week period, followed by a rehabilitation program to regain normal ankle mobility, strength, and balance. Return to athletic activities usually begins at 4 to 6 months post-operatively. Common post-operative problems are transient loss of sensation of the lateral ankle and foot and persistent peroneal weakness



Athletes with STS usually describe a history of a traumatic ankle injury, typically with a supination/inversion mechanism of injury. Athletes involved with jumping sports may incur an injury to the subtalar joint after coming to an abrupt stop after a jump or a fall. This mechanism is thought to create a “whiplash injury” to the rearfoot with the talus moving anteriorly over the calcaneus. This mechanism may result in a sprain to the ligaments of the talocrural joint as well. Physical therapists should also be cautious with athletes who have an extended history of talocrural joint instability even after undergoing reconstruction of the lateral ankle ligaments, as these procedures are intended to improve stability of the talocrural joint and may not improve stability at the subtalar joint.

An acute ankle injury will typically present with pain accompanied by 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 (Figure 1). Athletes with STS will typically describe a feeling of instability of the foot and ankle that is provoked upon walking over uneven ground, stepping off a curb, or running or sprinting activities. Athletes involved with cutting and jumping activities on firm surfaces will have the greatest difficulty with subtalar instability as these activities will cause excessive movements of the subtalar joint to the end ranges of pronation and supination.

Figure 1.

Symptoms associated with STS are usually described as deep in the ankle and can be localized by athlete pointing to the sinus tarsi space.


Assessment of standing posture in athletes with STS may demonstrate a pes planus posture or an asymmetry of the rearfoot angle with the leg, but these are not typical findings. Passive range of motion of the ankle and subtalar joint may not reveal excessive motion, but pain over the sinus tarsi at the end range of ankle plantarflexion with foot supination is typical of STS. Muscles that cross the ankle joint should be assessed for any loss of strength, especially the plantarflexor muscles.

Before examining the subtalar joint, a careful assessment of the talocrural joint should be performed. Anterior and posterior glides of the talus on the tibia and a talar tilt test that produces movement of the talus in the frontal plane are recommended for assessing talocrural joint stability. Mobility of the contralateral ankle and foot joints should be assessed to determine if the athlete has increased joint mobility that will make them susceptible to developing an instability.

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. Therman et al described a stability test that is thought to recreate instability of the subtalar joint (Figure 2). The test is performed with the athlete in supine with the ankle in 10 degrees of dorsiflexion to keep the talocrural joint in a stable position. The fore-foot is first stabilized by the examiners hand, while an inversion and internal rotational force is applied to the calcaneus. Then an inversion force is applied to the forefoot. The examiner assesses for an excessive medial shift of the calcaneus and a reproduction of the athlete’s complaint of instability and symptoms.

Figure 2.

Clinical test for reproduction of subtalar instability. The forefoot is first stabilized by the examiners hand, while an inversion and internal rotational force is applied to the calcaneus.

Reproduction of the athletes feeling of instability or giving way may be reproduced by having the athlete single leg stand on the affected side and perform rotating motions of the leg and foot that may reproduce their symptoms. Therapists may also want to assess the athlete during functional activities of walking, running, stepping down from a step, and hopping on the affected extremity. Activities that produce feelings of instability should be assessed for the relative position of the rearfoot and leg for any compensation through the lower extremity the athletes makes when the instability is produced. The activity levels of athletes with STS can be assessed using the Ankle Disability Index, which includes the athlete’s rankings of sports related activities.


The subtalar joint is a superficial joint formed by the articulation of the talus and the calcaneus. Inflammation can make inversion and eversion of the foot uncomfortable (as opposed to pain with dorsiflexion and plantar flexion in the true ankle joint). In inflammatory arthritis, the subtalar joint may communicate with the ankle joint and obviate the need for injection. Injection is challenging because this joint is small and difficult to access.

The sinus tarsi is a conical space on the lateral foot formed between the talus and calcaneus. It is enclosed by the extensor retinaculum and contains portions of the neighboring joint capsules and the interosseous talocalcaneal ligament. Injury to this ligament is implicated in the characteristic pain of sinus tarsi syndrome.

Sinus tarsi syndrome often is associated with subtalar instability after an inversion sprain of the ankle. It also may be seen in inflammatory conditions of the foot and ankle, including rheumatoid arthritis, ankylosing spondylitis, and gout.

Persistent pain resulting from inversion sprains of the anterior talofibular ligament—the principal lateral stabilizer of the ankle—may be confused with sinus tarsi syndrome. Alleviation of pain with injection of anesthetic may be diagnostic of sinus tarsi syndrome and help differentiate it from the pain of inversion sprains.

Suggested supplies

• 3-mL syringe with 15 mg of prednisone equivalents (we prefer 10 mg of methylprednisolone for both the subtalar joint and sinus tarsi) and 1 mL of 1% lidocaine.
• A 25-gauge needle for the subtalar joint and a 1- or 1.5-inch 22-gauge needle for the sinus tarsi.
• Alcohol wipes, povidone-iodine, or chlorhexidine for sterilization.
• Local anesthetic: ethyl chloride topical spray or 1% lidocaine (optional).
• Needle cap or ballpoint pen to mark the site of insertion.
• Nonsterile gloves.
• Gauze pads and bandage.

Surface anatomy

• For injection of the subtalar joint, a lateral approach is preferred because visualizing and entering the joint with this approach is easier. Place a mark just inferior and posterior to the tip of the lateral malleolus. Estimation of the joint line may be further facilitated by putting the foot through inversion and eversion.
• To access the sinus tarsi, palpate and mark the soft recess just distal to the lateral malleolus on the foot.

Patient position

• For either injection, the patient should be asked to lie supine and try to be comfortable. To enlarge  the sinus tarsi, the foot should be inverted.


Subtalar joint: After sterilization and application of local anesthetic, advance the needle at an angle perpendicular to the skin (See Figure 1 enlarged).

subtalar joint injection just inferior to lateral malleolus

Figure 1 – An approach to subtalar joint injection is shown on a cadaver model. The point of entry is just inferior to the lateral malleolus.

Sinus tarsi: Advance the needle toward the medial malleolus (See Figure 2 enlarged). The needle will not meet bony resistance; therefore, once the needle is roughly ¹/2 to 1 inch deep, infuse the anesthetic and corticosteroid.

sinus tarsi injection

Figure 2 – An approach to sinus tarsi injection
is shown on a cadaver model.


• Infusing corticosteroid ¹/2 to 1 inch deep into the sinus tarsi increases the chances of success. In addition, the risk of skin hypopigmentation is reduced.

Sinus Tarsi Syndrome

What?What?Whaat the…is that? I know, another funny name to add to this blog “sinus tarsi syndrome“. Let´s start from the beginning, let´s define sinus tarsi for those who don´t know what it is, although I am sure that if you were searching on google and you found this article it is because you were an unlucky person who got injured.

Sinus tarsi is a cavity located exactly where you usually get pain when you get the most common ankle sprain, lateral ankle sprain. For those who know a bit of anatomy, this cavity is located between the calcaneus and the talus bones. In this cavity there are many structures as ligaments, tendons, vessels or joint capsule.

Now, let´s go to the point, what is sinus tarsi syndrome? As usual, I think that the best way to explain what an injury is about is by telling you what the different words that name it mean.

Sinus: it is a cavity within a bone or other tissue.

Tarsi: it is the plural form of tarsus, tarsus being a set of seven bones located between the lower leg bones  (fibula and tibia) and the metatarsus.

Syndrome: it is the association of symptoms and signs of a condition, the cause of which can be known or not. The reality is that this term is used very often to name injuries or conditions of unknown cause.

Sinus tarsi syndrome


Video by BodyParts3D is made by DBCLS. (Polygon data is from BodyParts3D) [CC BY-SA 2.1 jp ], via Wikimedia Commons

Yes, I know, so far you have no idea what sinus tarsi syndrome is. Well, sorry, it is necessary to know the basics to get to know the injury.

Sinus tarsi syndrome is a condition characterized by anterolateral ankle pain that occurs when you have had traumatic injuries to the ankle. By traumatic injuries, I mean ankle sprains or repetitive strain due to an excessive stress in the area as result of, for instance, using wrong footwear.

The sinus tarsi is filled with many connective tissues which contribute to the stability and proprioception of your ankle. When these tissues are damaged, mainly the ligaments, this will result in talocrural joint instability ( joint where the foot and the leg meet and which movements are plantarflexion and dorsiflexion of the foot). Also, according to research, when you get talocrural joint instability, this might be associated to subtalar joint instability (joint between talus and calcaneus bones, also called talocalcaneal joint/articulation, which movements are eversion and inversion of the foot).

Subtalar joint of the ankle

Subtalar joint

Photo from Wikipedia under CC BY-SA 3.0 Unported license

As for many other injuries, there are many things we don´t know about sinus tarsi syndrome. There are some authors that relate sinus tarsi syndrome with subtalar joint instability. In this article by Keefe DT et al. you can find more information about subtalar joint instability.

Symptoms and signs of sinus tarsi syndrome

Sinus tarsi syndrome is usually characterized by:

  • Instability of the foot and ankle when walking on uneven ground, running and  with sprinting activities.
  • Possible talocrural joint instability.
  • Deep anterolateral ankle pain.
  • Pain over the sinus tarsi at the end of range of foot supination with ankle plantarflexion (inversion).
  • Possible loss of strength of the muscles involved (calf muscles: gastrocnemius, soleus, tibialis posterior, peroneal muscles-peroneus longus and brevis-; tibialis anterior, among others)
  • Poor proprioception which will mean poor control, due to the fact that ligaments are affected.
  • Cutting and jumping activities on hard surfaces will be very difficult.

Ankle: Sinus tarsi syndrome (STS)

This is a term used to refer to condition in which a patient experiences pain over the lateral opening of the sinus tarsi (outside of the ankle/foot), which is eliminated by local anesthetic injection into the area (to confirm the location of the pain causing lesion). This is the definition of the condition used, and it is not a precise diagnosis. In other words there are a number of conditions that can cause “sinus tarsi syndrome”. It is not a single diagnostic entity.

It may be associated with a feeling of hind-foot instability.

The cause of the problem or pain, is not well understood and there are a number of theories. It is likely that precise cause is not the same in all patients with this problem.

Causes that have been found include:

    scarring and increased tension in the ligaments in this area

    partial or complete tear of these ligaments

    synovial hyperplasia (inflammation of the lining of adjacent subtalar joint)

    post-traumatic fibrosis (scarring following previous sprains or other other injuries)

    other pain producing disorders (more unusual causes)


The term STS is not an accurate diagnosis, and it based primarily on the clinical assessment. It describes the symptoms and signs, rather than the pathology.

Investigations, such as MRI, may allow a more precise diagnosis and these should be used when available.


Of those available, only MRI really adds to the accuracy of the diagnosis, but this is not always accurate, and the final diagnosis is often only possible if the problem does not settle with non-operative treatment, and the patient ends up having an operation. At surgery it is possible, in most cases, to see the precise pathology and hence to make a true diagnosis.

MRI demonstrating a partial tear of the interosseous talocalcaneal ligaments, and intra-operative photograph below shows the partial tear at the time of surgery

Above left is an MRI demonstrating a partial tear of the cervical ligament. Below left is an intra-operative photograph of the lesion

MRI and intra-operative photograph of synovitis within the sinus tarsi


This usually consists of a combination of non-steroidal inflammatory tablets, and/or panadol, relative rest or avoidance of the painful activities, physical therapy to improve ankle/foot strength and stability, the use of a ankle braces and sometimes the fabrication of orthoses.


If the non-operative treatment has failed, and the patient is comfortable with the fact that the precise cause of the pain may not be certain until after surgery, surgery may become warranted.

The procedure involves either arthroscopic (“key-hole”) or open surgical exploration of the sinus tarsi, and treatment of the pathology found.

The procedure is performed with the patient under a general anesthetic in a sterile operating theatre environment. The patient is given intra-venous antibiotics before the commencement of surgery. A tourniquet is placed on the leg to control bleeding and facilitate visualization at the surgical site.

The incision or incisions are placed over the location of the sinus tarsi (the site of pain). The surgeon will carefully dissect down the level of the bones and the joints between the bones (that is the sinus tarsi proper, between the talus and the calcaneus). Once in the appropriate area, the surgeon will explore all the potential sources of pathology and pain in the sinus tarsi, and address these problems as they are encountered. This is usually a matter of removing the pathologically scarred, thickened and/or impinging tissues.

In most cases this involves the debridement a degenerate and thickened ligament, other scar tissue, thickened synovial tissues or capsule (joint lining), or excision of bone outgrowths.

Once the source of the pain has been confirmed and dealt with, the wounds are closed (usually with dissolving sutures) and the foot and ankle placed in a heavy crepe bandage. Sometimes the foot and ankle have to be placed in a short below knee back slab (half cast).

The patient is discharged home on the day of surgery in most cases.

The patient is usually asked to only partially weight-bear until the first post-operative reviews, 7-10 days post surgery. At this appointment the bandages are removed, the wounds checked and physical therapy organized. The surgeon will monitor your recovery from the procedure with the assistance of the physiotherapist.


Over 90% of patients report a good to excellent outcome following this surgical procedure.


These are some general guidelines, however if there are any significant deviations from them you will be informed of this by your surgeon.

If at any stage you experience severe pain (not controlled with the analgesia you were given), fevers, chills, night-sweats, shortness of breath, chest pain, or any symptom about which you are concerned please make immediate contact with your surgeon, your anesthetist, the hospital where your surgery was performed, or (if after hours) your local emergency department (they will be contact your surgeon or manage the problem themselves).

Immediately post-surgery

•You will wake up in recovery with your operated leg in a heavy crepe bandage and/or short (below knee) cast, depending upon the findings at surgery

•The bandage and/or cast should be left intact until seen in surgeons rooms for your first post-operative review. Phone the surgeons rooms to confirm the date and time of this appointment if not sure.

•The wound will be closed with dissolving sutures which do not require removal but the wounds must be kept clean and dry until review.

•The nurses will administer pain killers as required

•You will be encouraged to move the knee and hip on the operated side

•When you have recovered from the anesthetic, you will be allowed to mobilize with the assistance of crutches

•You are usually allowed to partially bear weight on the operated side

•The surgeon will see you before you leave and explain the surgical findings and the procedure performed and let you know if you are allowed to weight bear.

From discharge until 2 weeks post surgery

•Although you are allowed to mobilize as indicated above, when not moving around try to keep the ankle above the level of the heart to reduce the amount of swelling and pain.

•You are encouraged to move the operated knee and hip often, and for at least 10 minutes every 3-4 hours during waking hours.

•If your ankle is in a heavy bandage only you will be asked to begin some simple ROM exercises with the bandage in place.

You may notice some bruising appearing in your toes, days to weeks following your surgery. This is bleeding from the operation site that has tracked distally under the influence of gravity and should not cause alarm.

First post-operative review (2 weeks)

•The surgeon will remove the bandage and/or cast, check the wound and place you in an appropriate brace (will vary with type of surgery performed, the stability of the repair etc.)

•You will also be referred for physiotherapy to supervise and monitor your rehabilitation

2-6 weeks

•You will be allowed to weight bea as tolerated with the brace on, and this can be with or without crutches. You should be able to walk without crutches within 2-4 weeks of the surgery.

•Physiotherapy sessions will concentrate on restoring the normal range of movement in the dorsi-plantar flexion and eversion-supination directions. The physiotherapist will also instruct you in strengthening exercises in each of these directions. No inversion-supination movements are allowed until 6 weeks post surgery. You will also perform balancing exercises.

Second post-operative review

•The surgeon will see you for your second post-operative review at about 6 weeks post surgery. He will check the quality of the repair and healing

•At this stage he will usually recommend weaning yourself off the use of the brace for activities of daily living, but it should be worn for all sporting activities until told otherwise.

•It should also be worn whenever working on, or walking over, uneven ground

6-8 weeks

•You should be able to swim and cycle with or without the brace on. An air cast stirrup may be recommended for these activities.

8-12 weeks

•You should be able to return to running (even surfaces) wearing the air-cast stirrup.

12-26 weeks

•Over this period you should be able to make a graded return to full sports activity, aiming for unrestricted sports participation within 6 months.

Air-cast stirrup

•This should be worn until the ankle has regained full stability and is similar to the other (uninjured) ankle. However, for high-risk activities, such as volley-ball, basketball, netball, touch foot ball, orienteering etc. it is recommended that you continue to wear the air-cast brace or a lace-up ankle brace indefinitely.

Subtalar Impingement Syndrome

Subtalar impingement syndrome is a somewhat common problem that causes pain on the outer side of the ankle area.  The problem has also been referred to as sinus tarsi syndrome.

Patients with subtalar impingement syndrome will often complain of pain with walking, running, or other weight-bearing activities that are felt in an area just below and in front of the ankle bone on the outer side of the ankle (called the sinus tarsi).   The pain can be sharp and stabbing at times, but is often achy and deep.  The pain generally grows worse throughout the day, as weight-bearing activities are performed.

The source of the pain is the joint below the ankle joint, called the subtalar joint.  The subtalar joint separates the heel bone (calcaneus) from the bone that rocks up and down within the ankle joint (talus).  The pain originates when the subtalar joint repetitively jams (impinges) while performing weight-bearing activities.  Most commonly, the mechanism that causes the repetitive jamming is a foot that pronates excessively (a foot where the arch flattens and rolls in as the heel rolls out).  The problem usually develops without an acute injury.

Besides feeling pain with weight-bearing activities at the area just below and in front of the ankle bone on the outer side of the ankle (sinus tarsi), you may note swelling in this area and tenderness when you push your finger into this area.  X-rays are usually not helpful to make the diagnosis; although in more severe cases may show some degenerative arthritis of the subtalar joint.

Subtalar impingement syndrome usually resolves with non-surgical treatment in 2-8 weeks, depending on the duration and severity of the condition at the beginning of treatment.  It is essential to properly support your foot if this condition is to resolve.  In some cases, the condition takes longer to resolve, and in rare cases, non-surgical treatment fails.  Surgery may be effective in the rare case that does not resolve with non-surgical treatment.

What can I do for myself?

You should use as many of these treatments as possible concurrently:

  • Wear supportive shoes.  Add a good arch support or orthotic in your shoe.  The following is the recommended option: green Superfeet.  You can purchase this item at the Depot Store Map (located in the reception area of the Foot and Ankle Surgery Department).
  • Avoid standing or walking barefoot or in unsupportive footwear like slippers or sandals.  (Instead, you should be in supportive shoes with Superfeet orthotics as much as possible every day.)
    Perform calf stretching exercises for 30-60 seconds on each leg at least two times per day.  (Stand an arm’s length away from the wall, facing the wall. Lean into the wall, stepping forward with one leg, leaving the other leg planted back. The leg remaining back is the one being stretched. The leg being stretched should have the knee straight (locked) and the toes pointed straight at the wall. Stretch forward until tightness is felt in the calf. Hold this position without bouncing for a count of 30-60 seconds. Repeat the stretch for the opposite leg.)
  • Lose weight .
  • Modify your activities.  (Decrease the time that you stand, walk, or engage in exercise that put a load your feet.  Convert impact exercise to non-impact exercise – cycling, swimming, and pool running are acceptable alternatives.)
  • Use an oral anti-inflammatory medication. (We recommend over-the-counter ibuprofen.  Take three 200mg tablets, three times per day with food – breakfast, lunch, and dinner.  To obtain the proper anti-inflammatory effect, you must maintain this dosing pattern for at least 10 days.  Discontinue the medication if any side effects are noted, including, but not limited to: stomach upset, rash, swelling, or change in stool color.  IF YOU TAKE ANY OF THE FOLLOWING MEDICATIONS, DO NOT TAKE IBUPROFEN: COUMADIN, PLAVIX, OR OTHER PRESCRIPTION OR OVER-THE-COUNTER ORAL ANTI-INFLAMMATORY MEDIACTIONS.  IF YOU HAVE ANY OF THE FOLLOWING HEALTH CONDITIONS, DO NOT TAKE IBUPROFEN: KIDNEY DISEASE OR IMPAIRMENT, STOMACH OR DUODENAL ULCER, DIABETES MELLITUS, BLEEDING DISORDER.)
  • See your doctor if you have failed to respond to the above regimen after a two month trial.

What can my doctor add?

  • Administer cortisone injections.  (Injection of cortisone is a potent way to reduce inflammation and expedite the recovery process.  Cortisone does not replace the need for supportive shoes, foot orthoses, calf stretching, and other physical measures.  Cortisone is typically injected at 2 month intervals, until the condition resolves or 3 injection have been administered, whichever comes first.  The risks of cortisone injections for subtalar impingement syndrome are: increased pain for 24-72 hours following the injection (30%), infection (<0.1%), and arthritis (<1%).  Systemic side effects of this type of injection are extremely rare.)
  • Prescribe physical therapy. (Ultrasound and interferential electric current therapy can be useful methods of reducing inflammation.)
  • Refer you for custom-made foot orthotics. (Custom foot orthoses are not a covered benefit of the Kaiser Permanente Health Plan.  However, custom foot orthoses are available at the Santa Rosa Kaiser Permanente facility on a fee for service basis through a non-Kaiser Permanenteprovider.  The fee is currently $275.)
  • Perform surgery.  (Surgery involves fusing the subtalar joint.  The anesthesia is usually general or spinal.  The surgery is usually done on an inpatient basis with discharge to home occurring in 1-3 days after the surgery.  A below-knee cast is used for 3 months.  The first two months requires absolutely no weight-bearing, while in the 3rd month, weight-bearing is allowed.  Recovery takes 4-12 months.  The success rate is about 80%.  About 15% are better, but still have some problems.  About 5% are no better or worse.  Risks include, but are not limited to: delayed or non-healing of the fusion site, infection, nerve injury or entrapment, tendon injury, wound healing or scar problems, prolonged recovery, incomplete relief of pain, no relief of pain, worsened pain, limp, chronic swelling, and transfer of pain, callus, or arthritis to other area of the foot or ankle.)

Keys To Patient Education And Accurate Diagnosis Of Sinus Tarsi Syndrome

A patient has been having pain on the outside of his ankle for some time and you tell him he might have sinus tarsi syndrome. The patient’s puzzled look does not surprise you and you proceed to explain what might be the cause of his pain.

What is the sinus tarsi? Explain to patients that the sinus tarsi is an anatomical depression on the outside aspect of the foot that is filled with soft tissue structures: ligaments, muscle, nerves, blood vessels and fat.

What causes the pain? While there are a variety of possible etiologies, acute injury to the ankle or chronic ankle sprains seem to be the most common culprits. Pain is related to possible ligamentous injury and instability at the subtalar joint. Inflammation ensues and the sinus tarsi region may fill with synovial fluid and fibrotic tissue.

Other possible causes of sinus tarsi pain may include: cysts, degenerative changes and injury to the extensor digitorum brevis muscle.

What are the clinical symptoms? These symptoms may include pain along the anterolateral ankle, a feeling of instability in the foot or ankle, swelling and ecchymosis. There must be tenderness within the sinus tarsi for diagnosis.

What about diagnostic studies? X-rays are not the best imaging technique for diagnosis. Magnetic resonance imaging (MRI) is the better choice due to its ability to assess soft tissue structures. Positive MRI findings include abnormal fluid collection within the sinus tarsi (increased signal intensity), synovitis within the subtalar joint (increased signal intensity) and possible disruption of ligamentous structures.

Differential diagnoses include osteochondral defect, ligamentous injury, arthritis and tarsal coalition.

Conservative treatments for sinus tarsi syndrome include:
• steroid injection within the sinus tarsi;
• physical therapy with a focus on balance and proprioceptive training along with muscle strengthening;
• bracing/taping; and/or
• orthoses.

Conservative care is the mainstay of treatment. Alternately, one may perform exploratory surgery to inspect the subtalar joint and remove any osteophytes that may be in the area.