Foot Dislocation Management in the ED

The foot consists of 26 bones and 57 articulations. The foot is composed of 3 functional and anatomic regions. The hindfoot consists of the talus and the calcaneus. The midfoot consists of the navicular, the cuboid, and the 3 cuneiforms. The forefoot contains 5 metatarsals and 14 phalanges.

The foot also contains numerous accessory centers of ossification that are occasionally mistaken for avulsion injuries. The presence of a smooth cortical surface and lack of associated soft tissue edema help to differentiate these normal variants from fractures.

The articulations between the hindfoot and the midfoot are the midtarsal or Chopart joints. These joints are the talonavicular and calcaneocuboid joints. The articulations between the midfoot and the forefoot are termed the Lisfranc joints and consist of 5 tarsometatarsal joints.

The subtalar joint, between the talus and the calcaneus, accounts for most inversion and eversion injuries to the hindfoot. Adduction and abduction of the forefoot primarily occur through the midtarsal joints. Flexion and extension primarily occur at the MTP and IP joints.

All dislocations in the foot (with the exception of simple dislocations of the toes) are uncommon injuries. The most common of these injuries is a dislocation that involves the Lisfranc joint complex. The rarity of these injuries makes diagnosis difficult. A significant proportion of the more subtle dislocations are not diagnosed upon initial presentation. Dislocations through the Lisfranc joint complex are thought to have an incidence of about 1 in 50,000 persons with orthopedic trauma per year, representing less than 1% of all dislocations.

Dislocations of the foot are commonly associated with other significant injuries sustained during falls or MVCs. Delay in recognition of dislocations is common because of the distracting effect of associated injuries or because of the subtle nature of these injuries. Early reduction and immobilization may reduce morbidity.

Many complications, including avascular necrosis, compartment syndrome, and degenerative arthritis, have been reported. Additionally, residual pain and loss of function are common consequences resulting from the complex biomechanics of the foot.

The male-to-female ratio is 6:1. This differential is largely due to the higher number of young males who sustain significant trauma.

Injury may occur at any age, although the more severe forms of dislocation associated with MVCs are more common in young adult males.

Both a detailed medical history and a history of events surrounding the injury or appearance of symptoms are essential in identifying the type of injury and predisposition to complicating factors.

The history should include the following questions.

• What was the exact mechanism of injury?

• Has the patient been able to bear weight since the injury?

• Does the patient have an underlying medical condition, especially a history of diabetes mellitus? People with diabetes mellitus may have denervation of the foot and are prone to develop Charcot joints. Charcot joints are joints that demonstrate a grossly disorganized structure, deformity, edema, extreme hypermotility, and often remarkably little pain. Function is generally good. Early, accurate recognition of foot injury is particularly important in patients with diabetes mellitus, because delayed diagnosis is associated with the development of Charcot joints.

• Does the patient have a history of foot surgery or prior injury to the affected foot? (This may make interpretation of radiographs difficult.)

In general, patients who experience dislocations of the foot have other injuries related to the mechanism of injury. A full history of the event should be obtained from the patient or from prehospital caregivers. Occasionally, these injuries may occur with minimal trauma. This is especially true with athletes. The history in these cases is usually of increasing pain and edema over a few days, resulting in significant limitation in mobility, decreased performance, or both. Often, the patient gives no definitive history of a single traumatic event. The presumed mechanism of injury responsible for each type of dislocation is discussed.

Examination of the foot usually reveals an obvious deformity; however, some dislocations are accompanied by substantial soft tissue edema. The exact nature of the injury may be unclear until radiography is performed.

Neurovascular examination is critical both before and after any reduction.

Assess vascular status. If no pulse is palpable, urgent reduction of the dislocation is required. Confirm the absence of a pulse with Doppler studies in the ED if possible. Mark the position of the pulse on the skin; this simple measure confirms that a pulse was taken and that it was palpable, and it also indicates the ideal anatomic location for reassessment. Loss of a previously palpable pulse is a sign that urgent reduction is needed.

Perform a thorough neurologic examination of the foot.

Check for any breaks in the skin. Check for any tenting of the skin, which may necessitate urgent reduction.

Findings may be subtle and nonspecific in persons who present with foot pain from a Lisfranc dislocation in which no single major traumatic event has occurred.[4] Edema and tenderness are usually noted over the joint. Ecchymoses may develop after a few days. Vascular compromise is rare.

Following a thorough history and physical examination, including application of the Ottawa Ankle Rules, ED clinicians not only should provide a diagnosis but should rate the severity of soft tissue injuries, or the stability of fractures and dislocations, which are the pivotal decision points in guiding ED treatment, specialist referral, and the follow-up plan.[5]

Risk factors for dislocation of the foot are the same as those for any major trauma (ie, youth, alcohol intake, drug intake). However, dislocation of the foot can result from an apparently simple fall (eg, twisting one's foot in a hole in the ground when jogging).

Numerous different types of dislocations of the foot are recognized.

Subtalar or peritalar dislocation

Subtalar or peritalar dislocation is a simultaneous dislocation of the talocalcaneal and talonavicular joints. Note that the talus remains in the ankle mortise. This type of dislocation typically is caused by falls from a height, MVCs, and severe twisting injuries (eg, basketball players who land on an inverted and plantar-flexed foot).[6]  

Subtalar dislocation is seen with both high- and low-energy trauma. Sporting activities, commonly basketball, are often the cause of low-energy injuries. A majority of subtalar dislocations are accompanied by fractures of the hindfoot, including osteochondral fractures, calcaneus fractures, and fractures of the posterior process and tubercles of the talus. The diagnosis of subtalar dislocation is usually made on AP, lateral, and oblique radiographs of the foot or ankle. The nature of the deformity often limits radiographic positioning.[7]

These dislocations are typically medial or lateral (rarely anterior or posterior), although medial dislocation is more common (80%). Posterior dislocation may result from hyperplantar flexion.[8] Inversion injuries result in medial dislocation, and eversion injuries result in lateral dislocation. The navicular bone and the forefoot are displaced medially with a medial subtalar dislocation and laterally with a lateral dislocation. These dislocations are frequently associated with fractures of the involved bones, and a small percentage are open.

The effect of the direction of dislocation on long-term prognosis remains controversial.[2, 9, 10]

Total talar dislocation

A rare dislocation, this injury typically results from very high energy trauma. The talus is completely out of the ankle mortise and is rotated such that the inferior articulation points posteriorly and the talar head points medially.

These dislocations are commonly open and often result in avascular necrosis of the talus, loss of ankle motion due to traumatic arthritis, and ischemic skin loss from underlying skin pressure.

Talar dislocation with associated distal fibular fracture (Weber C) has been reported.[11]  When total talar dislocation injuries occur with an open wound, the talus often has associated fractures with remaining soft tissue attachments. Initial radiographs are often obtained with nonconventional positioning. After initial reduction, CT is performed to further characterize associated injuries.[7]

Lisfranc dislocation

Dislocation fractures of the tarsometatarsal joints are referred to as Lisfranc injuries. This type of dislocation is caused by several mechanisms, including rotational forces about a fixed forefoot, axial loading in a plantarflexed foot, and crush injuries. These injuries may also be a manifestation of a developing neuropathic or Charcot joint arthropathy.

Although it was first described in the 1800s, the Lisfranc injury remains one of the most controversial topics in foot and ankle surgery. From the basic anatomy of the ligament complex to optimal diagnostic and management methods, new research both sharpens and confounds our understanding of this unique injury.[2]

Tremendous energy is usually required to subluxate or dislocate the Lisfranc joint complex. This energy frequently results in extensive soft tissue injury. Occasionally, minor rotational injuries may cause this problem. This is particularly well described in athletes and in older patients.[12]  The clinician must be careful to not miss these injuries.

Evaluate the alignment of the metatarsal bones with their corresponding tarsal bones on radiographs. The first, second, and third metatarsals should line up with the medial, middle, and lateral cuneiforms, respectively. The fourth and fifth metatarsals should line up with the cuboid.

A good starting point for evaluation is to inspect the medial aspect of the middle cuneiform to confirm that it is directly in line with the medial aspect of the second metatarsal. Any disruption is indicative of a dislocation that may have spontaneously reduced.

Lisfranc dislocations are classified according to the direction of injury in the horizontal plane; these classifications include the following.

• Homolateral, in which all 5 metatarsals move in the same direction

• Partial, or isolated, in which 1 or 2 metatarsals are displaced from the others

• Divergent, in which the first metatarsal displaces medially, with 1 or more of the other metatarsals displaced laterally

Some studies have estimated that 20% of Lisfranc injuries are missed upon initial presentation to the ED. Subtle injuries to the Lisfranc joint do occur and may be difficult to diagnose. Slight widening (2-5 mm) of the space between the first and second metatarsals may be seen, as well as widening of the space between the middle and medial cuneiforms.

Lisfranc injuries are rare, are often missed, and may cause permanent structural deterioration of the tarsometatarsal joint, despite optimal management. Consequently, a Lisfranc injury may lead to disruption of the biomechanics of the normal foot during walking and may alter the plantar pressure distribution, which is essential for proper gait mechanics. Despite surgical management of Lisfranc injuries, the injured foot does not regain functional, radiologic, or pedobarographic levels as compared to the uninjured foot for 57 months or longer.[13]

Metatarsophalangeal (MTP) and interphalangeal (IP) dislocations

First MTP dislocations, although rare given the inherent stability of the joints, typically result from large forces.[14] These dislocations are typically dorsal and are often open.

Dislocations of the other metatarsophalangeal joints are not unusual and typically are caused by trauma. These dislocations most frequently involve lateral or dorsal displacement of the digit on the metatarsal head.

IP dislocations are less common than MTP dislocations. Most occur in the first toe as a direct result of axial loading.

Other dislocations

Although very rare, other dislocations in the foot have been described.

Isolated fracture dislocation of the navicular on the talus may occur following a fall from a height and is usually treated with open reduction and internal fixation.

Cuboid and cuneiform fractures are sometimes associated with tarsometatarsal dislocations, but they may present as isolated fracture dislocations. They are frequently unstable and often require open reduction internal fixation (ORIF). An exhaustive inspection of these injuries is recommended through analysis of radiographs, CT scans, or magnetic resonance images, especially with unexposed lesions, with the goal of applying appropriate treatment and helping the patient achieve prompt recovery.[15]

Routine radiography of the foot should include 3 views: AP, lateral, and 45º internal oblique.

• The hindfoot is assessed via the lateral projection, and the midfoot and the forefoot via anteroposterior and oblique projections.

• Any identified hindfoot injury should prompt standard imaging of the ankle.

• Additional views, such as the Harris (axial) view to evaluate the subtalar joint and calcaneus, can be obtained to enhance imaging of certain areas of the foot.

• Weightbearing views may reveal subtle Lisfranc abnormalities.

Increasingly, CT scanning is being used to help evaluate fractures and dislocations in the foot, in particular calcaneal and talar fractures.

MRI is often used to diagnose stress fractures and to evaluate the various tendons and ligaments of the foot.

Lisfranc injuries range from sprain to fracture dislocation. Radiologists must have a thorough understanding of anatomy, mechanisms, and patterns of these injuries to diagnose and help clinicians assess treatment options and prognosis. The initial imaging evaluation of patients with a suspected Lisfranc injury consists of non-weight-bearing radiographs. With high-energy injuries, the diagnosis is straightforward, and patients usually undergo CT for surgical planning. For patients with low-energy injuries, when findings on initial radiographs are equivocal, further evaluation is performed with weight-bearing radiographs, CT, or MRI. Stable injuries are treated conservatively, whereas all other injuries require surgical intervention.[1]

Up to 20% of Lisfranc fracture dislocations are misdiagnosed or missed during initial evaluation.[16]  Individuals with Lisfranc injuries typically present to the ED with pain, particularly on weight-bearing, with swelling and a characteristic description of the mechanism of injury. The injury is diagnosed via clinical examination and radiologic investigation, typically with plain radiographs and CT scans.[17] Sensitivity and specificity of MRI identification of Lisfranc injuries have been reported to be as high as 94% and 75%, respectively.[18]  Ultrasound is now also being used to evaluate Lisfranc injuries.[19]

Injuries to the ankle and foot are common in the young athlete, especially with increasing participation and high levels of competitiveness in youth sports programs. Knowledge of normal development of the foot and ankle is crucial if one is to understand age-specific injury patterns, because acute or chronic/repetitive stress to the developing skeleton results in injuries that differ from those seen in adults. Congenital abnormalities may also predispose children to increased risk of injury and pain. Radiologists must be aware of these distinctions to diagnose and classify injuries correctly for optimal treatment.[20]

Reduction of some foot dislocations, especially isolated dislocations of the talus or some of the more complex dislocations of the Lisfranc joint complex, can be very difficult and is inadvisable in the ED. In these cases, consulting an orthopedic specialist is always wise. Closed reduction is frequently insufficient, and open reduction internal fixation (ORIF) is required.

Urgent reduction of a dislocation in the ED is often necessary to prevent further vascular or neurologic compromise. Whenever possible, adequate analgesia should be ensured; conscious sedation may be required. The joint should be reduced via gentle traction, and the limb should then be immobilized. Further therapy or operative intervention may be required after this initial reduction.

If the dislocation is open, antibiotics are essential.

When the dislocated foot is seen as one of numerous injuries in a patient with major trauma, management of other potentially life-threatening injuries takes priority. When the dislocation is an isolated injury, immobilize the limb to make the patient as comfortable as possible. Control bleeding with direct pressure, and cover any open dislocation with a sterile dressing.

Immediate management may be dictated by concomitant injuries. Assess the neurovascular status of the foot as part of the secondary survey. Consider urgent reduction of any dislocation that causes significant neurovascular compromise.

In cases of isolated injury, assess and record neurovascular status. Radiographs should be urgently obtained. Make arrangements for referral to an orthopedic specialist for reduction of the dislocation and further management as appropriate.

Remember the possibility of compartment syndrome after severe injuries to the foot. Often, signs of compartment syndrome may be initially masked by severe pain related to the injury. Failure to diagnose this problem can result in serious long-term sequelae for the patient, including contractures, deformities, and chronic pain. A high index of suspicion for this complication is required, and measurement of compartment pressures in the foot should be instituted if any findings suggest that this complication is present.

Any open dislocation with or without an associated fracture typically should not be reduced in the ED. Appropriate prophylactic antibiotics should be administered, and the tetanus status of the patient should be updated. Sterile dressings should be applied.

Treatment of subtalar and total talar dislocations consists of the following.

• Most subtalar dislocations can be treated with closed reduction with the patient under appropriate analgesia and sedation.[21] The interposition of soft tissues may prevent reduction, necessitating open reduction. Consider urgent reduction if significant neurovascular compromise is evident.[22]

• Total talar dislocations are often open and, as such, should not be reduced in the ED. If a closed injury is present, or if urgent reduction is necessary secondary to neurovascular compromise, reduction may be attempted, ideally with appropriate consultation available.

• With the knee flexed, apply longitudinal traction at the foot. Initial accentuation of the injury followed by reversal of the deformity with pressure over the talus may result in reduction. For example, after distraction, apply an abduction force for a medial dislocation.

Injury to the tarsometatarsal joint complex, also referred to as a Lisfranc injury, is a relatively uncommon presentation in the ED; however, accurate diagnosis is vital to prevent the risk of long-term disability. Clinicians must use a broad range of clinical skills to manage patients' injuries effectively. A high level of suspicion, recognition of the clinical manifestations of Lisfranc injury, and attainment of appropriate radiographic images are required to formulate a correct diagnosis.[23]

Lisfranc dislocations frequently require operative reduction. An orthopedic surgeon should be involved in the care of patients with these injuries. ED care typically involves appropriate analgesia, ice, and elevation.[24]

In a study of 31 patients with dislocations and fracture dislocations of the Lisfranc joint over a 10-year period, outcomes were evaluated based on the Baltimore Painful Foot Scale (PFS) score and the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot scoring scale. Among surgical treatments, internal fixation with screws received the highest scores. Eight patients (25.8%) developed posttraumatic arthritis of the tarsometatarsal joints.[25]  However, a case series at a Level I trauma center found that functional outcomes after Lisfranc fracture are most dependent on the quality of anatomic reduction, rather than on the choice of fixation implant used.[26]

Dislocations of the toes often can be reduced in the ED with simple longitudinal traction and the patient under local anesthesia (digital block). Dislocation of the first toe may be difficult to reduce.

Urgent ED orthopedic consultation is indicated for subtalar, total talar, and Lisfranc dislocations. Additionally, first metatarsophalangeal (MTP) and interphalangeal (IP) joint dislocations that are open or are not reducible require orthopedic consultation. Most other MTP and IP dislocations are easily managed by the ED physician.

One of the major complications of dislocation of the foot involves failure to make the diagnosis. Some of these dislocations can be subtle, especially those around the Lisfranc joint complex. These dislocations often are missed, resulting in significant morbidity.

Other complications include the following.

• Infection as a result of compound dislocations or, occasionally, as a postoperative complication

• Long-term stiffness of the foot

• Foot pain not specifically localized to one area

• Secondary osteoarthritis

• Avascular necrosis, especially of the talus, after a total talar dislocation

• Damage to the medial plantar nerve with associated wasting of the intrinsic muscles of the foot (rare)

Compartment syndrome injuries are associated with long-term morbidity in a significant proportion of patients.

In one study, by Perron et al, 48% of patients with midfoot dislocations (Chopart and Lisfranc joints) had a fair or poor result at follow-up 20-56 months after the injury. Fair or poor in this classification indicated substantial limitation of activities.[27]  The quality of the initial reduction was the major determinant for obtaining an excellent long-term result. When treating midfoot trauma, it is important for the clinician to fully understand the injury pattern, as this dictates the principles and techniques of fixation. Identification and knowledge of injury patterns will aid surgeons in future management of these injuries and may improve treatment outcomes.[3]

Administer analgesia as appropriate. Ensure adequate coverage against tetanus. If dislocation is compound, broad-spectrum intravenous antibiotics are required. Generally, a cephalosporin is the drug of choice. Dirty wounds may need the addition of an aminoglycoside to target gram-negative organisms. Injuries heavily contaminated with soil or farmyard waste require penicillin to protect against Clostridium perfringens.

Class Summary

Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. Many analgesics have sedating properties that benefit patients who have sustained injuries.

Fentanyl citrate (Duragesic, Sublimaze)

More potent narcotic analgesic with a much shorter half-life than morphine sulfate. Drug of choice (DOC) for conscious sedation analgesia.

With short duration (30-60 min) and easy titration, excellent choice for pain management and sedation. Easily and quickly reversed by naloxone.

After initial dose, subsequent doses should not be titrated more frequently than q3h or q6h.

Oxycodone and acetaminophen (Percocet)

Drug combination indicated for relief of moderately severe to severe pain. DOC for aspirin-hypersensitive patients.

Oxycodone and aspirin (Percodan)

Drug combination indicated for relief of moderately severe to severe pain.

Hydrocodone bitartrate and acetaminophen (Vicodin ES)

Drug combination indicated for relief of moderately severe to severe pain.

Class Summary

Patients with painful injuries usually experience significant anxiety. Anxiolytics allow the clinician to administer a smaller analgesic dose to achieve the same effect.

Midazolam (Versed)

DOC for procedural sedation to aid in reduction of anxiety associated with fractures or dislocations. Provides antegrade amnesia. Dose q1-2h.

Class Summary

Procedural sedation for reductions may require a sedative-hypnotic.

Propofol (Diprivan)

Phenolic compound. Sedative-hypnotic agent used for induction and maintenance of sedation or anesthesia.

Class Summary

Prophylaxis is given to patients with compound dislocations.

Cefazolin (Ancef, Kefzol, Zolicef)

First-generation semisynthetic cephalosporin that binds to 1 or more penicillin-binding proteins, arrests bacterial cell wall synthesis, and inhibits bacterial replication. Primarily active against skin flora, including Staphylococcus aureus. Total daily dosages are the same for IV and IM routes.

Gentamicin (Gentacidin, Garamycin)

Aminoglycoside antibiotic used for gram-negative bacterial coverage. Commonly used in combination with both an agent against gram-positive organisms and one that covers anaerobes.

Used in conjunction with ampicillin or vancomycin for prophylaxis in patients with compound dislocations. Dosing regimens numerous and adjusted based on CrCl and changes in volume of distribution. May be given IV or IM.

Vancomycin (Vancocin)

Potent antibiotic directed against gram-positive organisms and active against enterococcal species. Used to treat septicemia and skin structure infections. Used in conjunction with gentamicin for prophylaxis in patients with penicillin allergy with compound dislocations. Dosage may need adjustment for patients with renal impairment.

Ampicillin (Omnipen, Marcillin)

Used along with gentamicin for prophylaxis in patients with compound dislocations. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. Given in place of amoxicillin to patients unable to take PO medication.

Penicillin G (Pfizerpen)

Interferes with synthesis of cell wall mucopeptide during active replication, resulting in bactericidal activity against susceptible microorganisms.