Disorders of the Subtalar Joint, Including Subtalar Sprains and Tarsal Coalitions


Pathology in the subtalar joint can be debilitating, is challenging to diagnose, and can lead to significant lost time for the athlete. In addition to acute bony or cartilage injuries, instability, ligamentous strain, and congenital coalition may all play a role in generating subtalar pain. Subtalar instability as an isolated phenomenon or in conjunction with lateral ankle ligament instability is often subtle and is frequently overlooked. Sinus tarsi syndrome remains a nebulous diagnosis that can typically be correlated with distinct intraarticular pathology. Additionally, pain along the lateral aspect of the subtalar joint may result from a severe planovalgus position of the foot leading to impingement of the calcaneus against the fibula. Subfibular impingement must be distinguished from true pathology of the subtalar joint. Tarsal coalition, although found in up to 2% of the population as a whole, is commonly symptomatic in the running or jumping athlete/dancer.


The subtalar joint is comprised of three articulating surfaces: the posterior facet, the middle facet, and the anterior facet ( Fig. 17.1 ). Confluence of the anterior and middle facets is present in over 40% of cases. The bony articulations provide inherent stability and soft tissues provide additional stabilization. The lateral soft-tissue stabilizers have been classified into three separate layers. The superficial layer is composed of the lateral root of the inferior extensor retinaculum, the lateral talocalcaneal ligament, and the calcaneofibular ligament (CFL). The intermediate layer consists of the intermediate root of the inferior extensor retinaculum and the cervical ligament. The deep layer consists of the medial root of the inferior extensor retinaculum and the interosseous talocalcaneal ligament ( Fig. 17.2 ).

Fig. 17.1, Variations in the anterior and middle facets of the calcaneus. Conjoined, transitional, and distinct facets are all seen in the population.

Fig. 17.2, The anatomy of the subtalar joint.

The joints move in a triaxial plane, which allows for the motions of flexion/extension, inversion/eversion, and adduction/abduction.

The sinus tarsi is a broadly conical space on the lateral aspect of the foot that lies anterior to the posterior facet between the talus and the calcaneus. It is in continuity with the tarsal canal. The tarsal canal is a narrow opening within the medial subtalar joint and is situated in a posteromedial-to-anterolateral direction. Soft tissues within the sinus tarsi include the artery of the tarsal canal, bursae, nerve endings, and multiple ligaments.

Subtalar Instability

The role that instability of the subtalar joint plays in the patient with lateral ankle instability has been elucidated only recently. Some authors have estimated that 10% to 30% of patients with functional ankle instability marked by a sense of “giving way” of the ankle have evidence of instability of the subtalar joint. It has been suggested that consideration should be given to the concept of global hindfoot instability rather than simply functional instability about the ankle joint.

Instability of the subtalar joint was first proposed in 1962 by Rubin and Whitten. They proposed a series of stress radiographs to further evaluate this disorder. Brantigan et al. were the first to detect radiographic evidence of subtalar instability in their series of three patients. Chrisman and Snook in 1969 were able to document clinical subtalar instability in three of seven patients who were undergoing their tendon transfer procedure for lateral instability. Clanton and Berson described subtalar injuries as a continuum of other injuries in athletes, particularly sprains of the lateral ankle ligaments.

While most cases of subtalar instability are associated with a more global pattern of injury to the lateral ankle ligament complex including the anterior talofibular and calcacaneofibular ligaments, cases of isolated subtalar instability do occasionally present without associated tibiotalar pathology. It is difficult if not impossible to distinguish excess motion on physical examination from the subtalar joint alone from that emanating from the tibiotalar joint or a combination of the two. While stress radiographs have a very limited role in the diagnosis of ankle instability, they may be of utility in diagnosing isolated subtalar instability patterns. Lateral gapping of the subtalar joint on a Broden’s view is typically seen in these cases, although the results must be interpreted with caution. The diagnosis is based upon a combination of radiographic and clinical factors; lateral gapping on stress view may be seen in asymptomatic patients as well.

Clinical Presentation

The typical injury that leads to instability of the subtalar joint is a severe supination or supination-inversion force applied to the hindfoot. This results in a progressive injury to the talonavicular ligament and talonavicular capsule, followed by injury to the calcaneofibular and lateral talocalcaneal ligaments. The presenting complaint often is a sensation of giving way of the ankle. The patient may report pain localized to the region of the sinus tarsi. Athletic activities can exacerbate the symptoms, resulting in a dependence on bracing or taping. Uneven surfaces may cause pain and a feeling of instability.

It is difficult to differentiate lateral ankle instability from subtalar instability on the basis of patient history. A thorough clinical and radiographic workup can help define the source of the athlete’s complaints, but the differentiation still can be elusive.

Physical Examination

The most notable finding on physical examination is increased inversion of the subtalar joint. This should be compared with the presumably uninjured opposite limb. The increased inversion can result from subtalar instability or a combination of subtalar and ankle instability. It is not possible to detect the location of increased inversion by examination. In addition to increased inversion of the hindfoot, an increased translation of the calcaneus in the medial direction has been noted by Thermann et al. In their test, a valgus stress was applied to the calcaneus, followed by an abrupt internal rotation stress. Stress radiographs showed a medial shift of the calcaneus in relation to the talus or an opening of the talocalcaneal angle in patients with subtalar instability.

Following an acute injury, there may be swelling, bruising, and tenderness laterally. In the more chronic setting, increased inversion and lateral tenderness are more likely. It is easier to detect instability clinically in the chronic setting because the athlete will be less apt to guard because of pain.

Radiographic Evaluation

The initial radiographic workup of the patient with subtalar instability involves a weight-bearing anterior-posterior (AP), lateral, and mortise view of the affected ankle, as well as weight-bearing AP, lateral, and oblique radiographs of the affected foot to rule out evidence of bony pathology.

Plain radiographs often are negative, and further investigation must be carried out to arrive at the diagnosis. There have been multiple investigations into the use of stress radiographs in the workup of subtalar instability ( Fig. 17.3 ). In a series of three patients, Brantigan et al. were able to radiographically demonstrate subtalar instability. They attributed the instability to an injured CFL. Heilman et al. sequentially sectioned ligaments in cadaver limbs and then obtained lateral and Broden’s radiographs. They found that sectioning of the calcaneofibular joint caused a 5-mm opening of the subtalar joint. With subsequent sectioning of the interosseous ligament, the joint opened up to 7 mm.

Fig. 17.3, Stress radiographs. (A) Stress anterior-posterior (AP) radiograph with subtalar tilt. (B) Stress Broden view showing subtalar instability.

The utility of stress radiographs has been called into question by multiple authors. Harper reported a wide range of subtalar tilt with stress radiographs in his group of asymptomatic patients. Louwerens et al. examined 33 patients with chronic ankle instability and 10 control patients who were asymptomatic. Broden’s views were checked under fluoroscopy and they detected no difference between symptomatic and asymptomatic feet with regard to subtalar tilt or medial shift. Van Hellemondt et al. examined both stress radiographs and stress computed tomography (CT) scans in 15 patients with unilateral chronic ankle instability with suspected subtalar instability. Although three of the symptomatic feet and one of the asymptomatic feet had increased subtalar tilt on plain films, there was no significant difference between the symptomatic and asymptomatic sides. None of the patients had increased subtalar tilt on the stress CT scans. The authors therefore doubted that a Broden’s stress examination reveals the true amount of subtalar tilt. Frost and Amendola reviewed the collective literature on both talar tilt and anterior drawer stress radiographs for ankle instability and found no normative values and little agreement between studies. Nevertheless, a markedly positive stress radiograph remains the only definitive means to demonstrate the presence of subtalar instability.

It is most accurate to state that a positive stress radiograph, either in a clinic or operating room setting, is a necessary but not sufficient condition to clearly make the diagnosis of isolated subtalar instability. The false-positive rate is high, and the radiographic findings must be correlated with the physical examination and history.

Nonoperative Treatment

In an acute injury, the standard treatment regimen for lateral ankle sprains will suffice for subtalar ligamentous injuries as well. Rest, ice, compression, and elevation (RICE) are part of a good protocol, as well as immobilization and physical therapy, when needed. The same can be said for management of chronic subtalar instability. The routine nonoperative regimen used for chronic lateral ankle instability is initiated. This may include proprioceptive training, peroneal strengthening, and bracing or strapping. With bracing, it is important to understand the delicate balance in providing an athlete with enough support without impeding his or her performance. Taping by an athletic trainer before participation can be effective. Wilkerson examined a modification of the standard method of ankle taping with the incorporation of a “subtalar sling.” He found that addition of the sling enhances the protective function of taping but cautioned that it may impede performance of certain activities.

Surgical Treatment

Patients with residual symptomatic instability despite an adequate program of nonoperative management will require a surgical stabilization of their subtalar joint. If both ankle and subtalar instability exist and require surgery, both problems should be corrected at the time of surgery. Surgical stabilization involves direct ligament repair or lateral tendinosis procedures to substitute for the irreparable ligaments.

Many techniques have been described to concurrently stabilize the ankle and subtalar joint ( Fig. 17.4, A through C ). Many require some form of extraarticular tendon transfer to provide stability. Kato and Pisani described techniques focused on the subtalar joint involving intraarticular ligament reconstruction of the interosseous ligament between the calcaneus and talus.

Fig. 17.4, (A) Chrisman-Snook modification of Elmslie procedure. (B) Triligamentous reconstruction. (C) Larsen procedure. (D) Lateral ankle ligament reconstruction. (E) Reinforcing repair with inferior extensor retinaculum.

A less invasive technique that, according to Clanton and Berson and Gould et al., provides a good treatment for subtalar instability is the Brostrom-Gould reconstruction technique for lateral ankle instability ( Fig. 17.4, D and E ). With the reconstruction of the CFL and anterior talofibular ligament (ATFL) buttressed by the inferior extensor retinaculum, subtalar stability is effectively restored. There is no significant drawback to its routine inclusion in lateral ankle ligament reconstruction; doing so may obviate any concern over subtle subtalar instability in many cases. When the extensor retinaculum and the fibular periosteum are sufficient to hold suture, the Gould modification of the Brostrom procedure should be performed.

No clear criteria exist to guide the use of allograft or autograft reconstruction of the lateral ankle ligaments. In patients with a previous failed reconstruction, documented history of Ehlers-Danlos syndrome, or failed contralateral reconstruction, augmentation of the repair is warranted. The technique originally described by Colville utilizes a split peroneus brevis tendon to recapitulate the ATFL and CFL in an anatomic fashion. Rather than split a normal native tendon, O’Neil and Guyton recently described a method of reconstruction utilizing a combination of semitendinosis allograft and a braided suture construct to provide both new tissue and early strength to difficult cases with poor soft-tissue envelopes.

The use of the braided suture anchored with interference screws has also recently been described for lateral ankle ligament reconstruction. The primary utility of the suture construct is immediate strength of the ATFL portion of the reconstruction to allow early mobilization. That same rigidity can create the hazard of limited subtalar motion if it is used across the path of the CFL. While routine use of the suture construct across the ATFL reconstruction may have significant benefit for early mobilization, extension across the subtalar joint is not necessary in most cases.

Sinus Tarsi Syndrome

Symptoms of sinus tarsi syndrome may overlap with those associated with subtalar instability. Some authors consider this syndrome simply a variant of subtalar instability. Sinus tarsi syndrome simply describes pain localized to the region of the sinus tarsi. Characteristic findings on clinical and radiographic examination have not been well defined. Likewise, the pathologic changes found at the time of surgery are unclear. The most widely reported description of the pathologic anatomy associated with this condition is degenerative changes to the soft tissues of the sinus tarsi. The majority of cases are posttraumatic but also may be related to inflammatory arthropathies, gout, ganglion cysts, and structural foot abnormalities.

The term sinus tarsi syndrome is typically used to refer to pathology emanating from the subtalar joint . It must be distinguished from extraarticular impingement of the fibula against the lateral calcaneus in a fixed or dynamic planovalgus deformity. The pain in the case of subfibular impingement is more typically located underneath the fibula and may only be present with weight bearing. The condition typically does not respond even transiently to injection of the subtalar joint, as the impingement is extraarticular. Magnetic resonance imaging (MRI) may be helpful in making the diagnosis in subtle cases; edema in the lateral talus, distal fibula, or lateral calcaneus is often present.

Clinical Presentation

The typical complaint is pain over the lateral and anterolateral ankle and hindfoot centered in the region of the sinus tarsi. The patient may report a sensation of mild hindfoot instability. It has been estimated that as many as 70% of patients with sinus tarsi syndrome have had a previous inversion injury to the hindfoot.

Excessive motion of the subtalar joint may result in temporary impingement against the fibula in the athlete participating in a cutting activity. The symptoms in these cases are transient and localized to the sinus tarsi or lateral calcaneus. The diagnosis of this entity is based primarily upon the same criteria as for subtalar instability. As in subfibular impingement, edema in the distal fibula or lateral calcaneus may be present on MRI.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here