Reduction of Ankle Dislocation

Dislocation of the ankle usually occurs with fractures of the malleoli or of the posterior aspect of the tibia because the ankle’s ligamentous structures are, in most cases, stronger than the osseous architecture.[1, 2] In addition to a strong association with fractures,[3] ankle dislocations are often open because of the thin layer of tissue that lies over the malleoli. Posterior dislocation of the talus is the most common form of ankle dislocation, though medial, anterior, lateral, and superior dislocations have been well described.

Individuals at increased risk for ankle dislocation injuries include those with a history of prior ankle fractures, ankle sprains, weakness of the peroneal muscles, malleolar hypoplasia, or ligamentous laxity such as may occur with Ehlers-Danlos syndrome and other connective tissue disorders.

An ankle dislocation represents a high-force traumatic injury that often occurs in vehicular collisions or sports that involve jumping. The clinician must, therefore, examine the patient thoroughly for additional injuries.

The energy of the traumatic insult usually either forces the ankle into a position of plantarflexion or strikes the ankle while it is already in a resting position of plantarflexion. Once in plantarflexion, all capsular ligaments of the ankle (with the exception of the posterior talofibular ligament) are stretched and, therefore, more susceptible to structural failure. In addition, plantarflexion brings the smaller surface area of the posterior edge of the talus into the mortise of the ankle, which makes translational forces on the talus more likely to dislodge it from the joint.

Injuries that cause subsequent inversion of the ankle lead to posteromedial displacement and tears in the anterior talofibular and calcaneofibular ligaments. Eversion injuries are more likely to produce lateral dislocations and rupture of the talotibial ligament and medial joint capsule. Inversion injuries are more common as a result of axial loads from falls from significant height.

The rupture of the ankle’s capsular structures is often severe, and the risk of infection secondary to open injury is often significant; however, prompt reduction and, when warranted, operative debridement and repair usually lead to excellent functional recovery and long-term prognosis. Immediate recognition and early reduction of the dislocated ankle are essential, in that delayed reduction may lead to subsequent loss of range of motion (ROM) and increased morbidity.

Evaluation of the ankle injury must sufficiently demonstrate that the dislocation is of the ankle joint; subtalar dislocations may have presentations similar to those of dislocated ankles but are reduced with a different method.[4, 5] Applying the ankle reduction technique to a subtalar dislocation may lead to further injury and morbidity, and the two injuries may be clearly differentiated from each other radiographically. In addition to aiding in initial diagnosis, radiography helps to identify the anatomy of the fractures associated with ankle dislocations and should be performed both before and after reduction.[6]

Reduction is indicated for the following:

• Traumatic ankle dislocation that is not associated with neurovascular compromise and that has been elucidated by radiographic views of the ankle - Such dislocations may or may not have an associated fracture and may or may not be open injuries
• Traumatic ankle dislocation that is associated with neurovascular compromise - These injuries may be evidenced by an open or closed ankle deformity with obvious malpositioning of the distal foot; in the context of neurovascular compromise, radiographic studies may be delayed until after the reduction, and in such cases, the clinical presentation must assure the clinician that this is an ankle, rather than a subtalar, dislocation (see Contraindications)

Subtalar dislocations are rare (< 2% of large-joint dislocations) and are the result of high-force mechanisms of injury directed at the forefoot. Of note, 10-20% of subtalar dislocations are irreducible by closed methods and require operative intervention. Radiographs of the ankle, including anteroposterior (AP), lateral, and mortise views, may quickly and reliably differentiate between ankle and subtalar dislocations.

Contraindications include the following:

• Failed attempts at closed reduction despite optimal conditions
• Radiographic evidence of a subtalar, rather than ankle, dislocation ^[4]
• Clinical evidence of a subtalar, rather than ankle, dislocation in the absence of radiographic studies ^[4]

As noted, it is essential to differentiate an ankle injury with dislocation from a subtalar dislocation (see Table 1 below).[4] An attempt to reduce a subtalar dislocation with ankle reduction techniques is likely to be unsuccessful and may lead to further injury of the involved articular structures.

Table 1. Differentiating Features for Ankle Dislocation and Subtalar Dislocation (Open Table in a new window)

Isolated subtalar dislocations have been reported.[7]  Lateral subtalar dislocations are rare but have been reported; these can also occur with bimalleolar fractures.[8]

Anatomy

The ankle is a unique modified saddle joint that, together with the subtalar joint, provides range of motion in several physical planes while maintaining stability. The ankle's complex function as a pivoting structure positioned to bear almost the entire weight of the body leaves it vulnerable to tremendous forces of injury. Pure dislocation without associated fracture was once thought to be very rare[9] ; however, cases of isolated ankle dislocation without fracture have been reported.[10, 11, 12, 13, 14, 15, 16, 3, 17]

The combined movement in the dorsiflexion and plantarflexion directions is greater than 100°; bone-on-bone abutment beyond this range protects the anterior and posterior ankle capsular ligaments from injury. The anterior and posterior ankle capsular ligaments are relatively thin in comparison with the medial and lateral ankle ligaments. (See the image below.) For more information about the relevant anatomy, see Ankle Joint Anatomy.

Anatomy of lateral ankle ligamentous complex and related structures.

Consent for both the procedure and sedation should be obtained from the patient or the patient's representative (eg, a family member).[18] Explanations of the following should be provided:

• Reason for performing the procedure (suspected diagnosis)
• Risks and benefits of the procedure, as well as any alternatives to the procedure
• Risks and benefits of alternatives to the procedure
• Risks and benefits of not undergoing the procedure

Allow the patient the opportunity to ask any questions and address any concerns they may have. Make sure that they have an understanding about the procedure so they can make an informed decision. Ask the patient or the patient’s representative if he or she would like others to be present for the procedure.

In particular, the patient should be counseled about the risks of vascular or neurologic complications, soft-tissue injury, or creation of additional fractures. The patient should also be counseled that the reduction may not be successful and that additional procedures and or surgery may be necessary.

Discuss how the relevant risks can be avoided or prevented (eg, through proper positioning, by ensuring that the patient remains as still as possible during the procedure, or by providing adequate analgesia).

History and physical examination

Obtain and document a thorough preprocedural history, including the following:

• History of prior injuries and surgeries
• Mechanism of trauma
• Amount of time elapsed since the traumatic event
• Description of the presenting symptoms
• Prior medical allergies and reactions
• Any subjective loss of strength or sensation
• Patient’s age in reference to skeletal maturity

Perform and document a thorough physical examination, with particular attention to the following:

• Ecchymoses
• Swelling
• Pallor
• Abrasions and lacerations
• Paresthesias
• Weakness
• Notable deformities of the ankle or foot
• Presence and character of the dorsalis pedis and posterior tibial pulses
• Exact position in which the ankle and distal foot are held
• Comparison examination of the contralateral ankle

Emphasis should be placed on assessing the neurovascular status of the distal foot. Carefully explore all areas of skin overlying the ankle joint for dermal compromise that may make the injury an open dislocation.

If the ankle injury is associated with lacerations of the skin in the area of the ankle joint, the injury is likely an open injury; tetanus prophylaxis and antibiotic coverage of skin flora should be given.

Assess the patient for additional injuries, particularly life-threatening injuries that may have resulted from the high-force trauma that caused the ankle dislocation. Follow Advanced Trauma Life Support (ATLS) protocols, when these are deemed appropriate. Continue management of the ankle dislocation as soon as proper evaluation and resuscitation of the patient have insured hemodynamic stability.

Diagnostic imaging

Obtain radiographs of the patient's ankle, choosing the type of radiograph that may be performed and evaluated in the shortest duration of time. Prereduction films are often a valuable source of information; however, if significant neurovascular compromise is present and radiography would delay the time until reduction can be attempted, prereduction films need not be obtained.

Anteroposterior (AP) and lateral views of the ankle are the most common and efficient means of radiographic assessment. These two views usually provide an excellent depiction of the direction of the dislocated talus and show the presence of most associated fractures. Additional views add little to the initial evaluation of the dislocated ankle and are usually more appropriate in the postreduction setting.

Computed tomography (CT) of the ankle, though superior to flat-plate radiography in revealing small fracture fragments, is usually not the test of choice, because it cannot be performed portably and may delay the time to reduction. This test should be considered only if neurovascular compromise is not present and the scan can be quickly performed and evaluated.

Equipment that may be used in reduction of a dislocated ankle includes the following:

• Oxygen supply
• Bag-valve mask
• Oxygen saturation monitor
• Wall suction, suction tubing, and Yankauer suction catheter
• Intravenous catheter (≥20 gauge)
• Medications as needed for procedural sedation
• Normal saline (0.9% NaCl)
• Rolls of 4-in. (10-cm) Webril (3 or 4)
• Stockinette, 5 in. (12.5 cm)
• Rolls of 6-in. (15-cm) plaster (2 or 3)
• Rolls of 4-in. (10-cm) elastic bandage (eg, Ace wrap)

Anesthesia

Anesthesia for reduction of an ankle fracture or dislocation is usually performed by means of procedural sedation, if the reduction is not taking place in the operating room under general anesthesia. Regional ankle blocks should not be attempted because of the difficulty in application in the context of distorted ankle anatomy and the subsequent loss of a reliable neurologic examination.

If possible, one clinician should be responsible only for the procedural sedation and should not take part in the reduction attempt but, rather, ensure that sedation and hemodynamics remain optimal. For more information, see Procedural Sedation.

Intra-articular hematoma block has been studied as an alternative to procedural sedation for closed reduction of displaced ankle fractures.[19]

Positioning

Because of the application of procedural sedation, ankle reduction is usually performed with the patient in the supine position to provide immediate access to the patient's airway for bag-mask ventilation, if needed. The reduction is performed with the ipsilateral knee in a position of flexion, thus relieving tension on the Achilles tendon and making reduction easier.

Proper positioning can be accomplished through the following steps:

• Bring the patient toward the foot of the bed until the knee hangs off in a flexed position; the reduction must then be performed with the clinician sitting at the foot of the bed at the patient's feet
• Have an assistant grasp the ipsilateral leg at the proximal tibia and fibula and bring the knee and hip into a position of flexion (this requires the assistant to hold the leg in this position for the duration of the reduction); the patient may be turned slightly on his or her side so that the ipsilateral leg is not held straight into the air but, rather, is braced against the bed in a position of flexion

Long-term orthopedic follow-up should be arranged in conjunction with the orthopedic specialist who will continue to manage this patient’s case. Many patients require surgical intervention for associated fractures of the ankle, and admission to the hospital may be needed for open fractures. If outpatient management is deemed appropriate, the patient should follow up in the next 2-3 days.

Outpatient instructions should include the following:

• The patient should not bear weight on the affected ankle until instructed otherwise upon follow-up with orthopedics; the ankle should remain in the splint at all times, and instructions as to the care of the splint must be given
• The patient should return for emergency care immediately if pain increases, if the skin color of the distal foot changes, or if the injured leg exhibits any numbness, weakness, or change in temperature
• The patient should understand instructions for pain medicine as deemed appropriate; narcotics, nonsteroidal anti-inflammatory drugs (NSAIDs), or both are usually warranted

Anterior dislocations of the talus are associated with loss of a palpable dorsalis pedis pulse due to impingement from the displaced talus. This represents a vascular emergency, in that the true status of the artery cannot be accurately assessed while the ankle remains dislocated.

Doppler ultrasonography (US) may aid in establishing that some blood flow is present; however, without the presence of a palpable pulse, emergency reduction is required to restore blood flow.

If adequate reduction cannot be achieved, or if reduction has not restored the presence of a palpable pedal pulse, emergency operative management is indicated.

Prepare for and perform procedural sedation. Position the patient as previously described. (See Periprocedural Care.)

Posterior talus dislocations are reduced by performing the following steps (see the video below):

• Hold the foot in a position of plantarflexion, thus recreating the position of the initial injury
• Apply axial traction to the ankle by having an assistant grasp the distal foot and provide constant force to fatigue the musculature of the extremity
• Grasp the distal tibia with one hand, and create posterior traction proximal to the dislocation; at the same time, place the other hand on the posterior heel of the foot, distal to the injury, and create persistent anterior pressure; this maneuver effects reduction after a few moments

Anterior talus dislocations are reduced by performing the following steps (see the video below):

• Hold the foot in a position of plantarflexion, thus recreating the position of the initial injury
• Apply axial traction to the ankle by having an assistant grasp the distal foot and provide constant force to fatigue the musculature of the extremity
• While anterior traction is being applied to the distal tibia, grasp the foot at a point distal to the injury and create both axial traction and a posterior force; this posterior pressure effects reduction after a few moments

Lateral talus dislocations are reduced by performing the following steps:

• Hold the foot in a position of plantarflexion, thus recreating the position of the initial injury
• Apply axial traction to the ankle by having an assistant grasp the distal foot and provide constant force to fatigue the musculature of the extremity
• Grasp the distal tibia with one hand and create lateral traction proximal to the dislocation; at the same time, place the other hand on the posterior heel of the foot, distal to the injury, and create persistent medial pressure; this maneuver effects reduction after a few moments

Medial talus dislocations are reduced by performing the following steps:

• Hold the foot in a position of plantarflexion, thus recreating the position of the initial injury
• Apply axial traction to the ankle by having an assistant grasp the distal foot and provide constant force to fatigue the musculature of the extremity
• Grasp the distal tibia with one hand and create medial traction proximal to the dislocation; at the same time, place the other hand on the posterior heel of the foot, distal to the injury, and create persistent lateral pressure; this maneuver effects reduction after a few moments

After each reduction attempt, repeat the neurovascular examination to ensure that blood flow has been maintained and no new sensory or motor compromise has occurred.

If reduction has been achieved but neurovascular compromise is apparent after reduction, emergency operative management is indicated.

If neurovascular compromise is present but reduction has not been achieved, operative management may be needed to reduce the injury, and limited future attempts should be made. If reduction cannot be accomplished after two or three attempts under optimal conditions, operative management should not be delayed further.

Once reduction is achieved and the neurovascular status of the limb is stable, apply a long leg posterior splint with a sugar-tong component, which immobilizes the joint in a position of 90° of flexion. All efforts should be made to avoid applying any material that may become constricting to the ankle; remarkable swelling may take place in the postreduction period. The distal foot and toes should be left open to allow serial neurovascular checks.

Repeat radiography may now be performed to assess the adequacy of the reduction and document any associated fractures. Flat-plate radiography may consist of repeat anteroposterior (AP) and lateral views at a minimum; a mortise or additional view may be added to further describe the condition of the joint. Computed tomography (CT) of the ankle may provide additional information as to the presence of smaller fractures and the position of fracture fragments.

Irreducible dislocation

Osseous fragments, capsular ligaments, and ruptured tendons, as well as foreign bodies, may all become interposed in the anatomic joint space and make closed reduction impossible. Repeat forceful attempts at reduction can cause additional soft-tissue injury and iatrogenic fractures and can convert a closed injury into an open injury if the skin around the ankle is ruptured. Concurrent fracture of the anterior calcaneal process may make closed reduction of a subtalar dislocation impossible.[20]

Need for surgical intervention

Surgical intervention should be considered in the following scenarios:

• Failure to reduce the injury despite two or three attempts under optimal conditions
• Increasing tension or tenting of the skin in a closed injury during reduction attempt
• The presence of multiple other intra-articular fractures or subtalar dislocation demonstrated by radiography, in a neurovascularly intact injury
• Amputation of the foot distal to the injury

Conversion of closed injury to open injury

During closed reduction, if the skin over the ankle joint is ruptured (particularly over the malleoli), the injury has been converted into an open injury. Tetanus prophylaxis and antibiotic coverage of skin flora should be administered. If necessary, the wound should be surgically debrided.