AUTHOR AND EDITOR INFORMATION

Section 1 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

INTRODUCTION

Section 2 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Background

Ankle dislocations occur when significant force applied to the joint results in loss of opposition of the articular surfaces. Because of the large amount of force required and the inherent stability of the joint, dislocation of the ankle joint is rarely seen without an associated fracture.

Pathophysiology

The ankle joint is designed for a balance of stability and flexibility, particularly the former. Joint stability is provided by close articulation of the talus with the tibia and fibula. The mortise design further enhances the stability of the configuration.

The talus is trapezoidal in shape, with the greater width anteriorly. As the joint moves into plantar flexion, the talus becomes narrower, resulting in a decrease in stability. During normal walking, the ankle joint bears 3-5 times the body weight. This factor increases several fold during running and jumping activities. As weight is applied on heel strike, the fibula descends to increase stability of the ankle joint.

Mortality/Morbidity

• Associated fractures are the rule rather than the exception with ankle dislocations.
• Ligamentous disruption varies according to the type of dislocation.
• Neurovascular injury is the principal concern, as with any dislocation. Vascular compromise may result in avascular necrosis of the talus if not promptly reduced. Tented skin may be subject to ischemic necrosis.

Sex

• Dislocations of the ankle are seen more frequently in young males than in any other group. This presumably is related to their increased risk overall for traumatic injury.
• Postmenopausal women are at higher risk for associated fractures. Increased fracture risk probably is related to osteoporotic changes in this subset of patients.

Age

Children and adolescents have the most ankle dislocations.

CLINICAL

Section 3 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

History

A detailed history regarding the mechanism of injury often helps predict the type of injuries to expect. Furthermore, an understanding of the injury mechanism aids treatment, since an opposite force is required in reduction of the joint. Four types of dislocations are seen around the ankle joint.

• Posterior
• • A posterior dislocation in the most common type of ankle dislocation. The talus moves in a posterior direction in relation to the distal tibia as force drives the foot backward. The wider anterior talus wedges back, resulting in forced widening of the joint.
  • This must be accompanied by either a disruption if the tibiofibular syndesmosis or a fracture if the lateral malleolus. This occurs most commonly when the ankle is plantar flexed.
• Anterior
• • Anterior dislocations result from the foot being forced anteriorly at the ankle joint.
  • Typically, this occurs with the foot fixed and a posterior force applied to the tibia or with forced dorsiflexion.
• Lateral
• • These dislocations result from forced inversion, eversion, or external or internal rotation of the ankle.
  • They are associated uniformly with fractures of either or both the malleoli or the distal fibula.
• Superior
• • Diastasis occurs when a force drives the talus upward into the mortise. These dislocations usually are the result of a fall from a height.
  • In such cases, the patient should be evaluated carefully for concomitant spine injury and fracture of the calcaneus.

Physical

• Inspection of the ankle reveals significant edema with deformity ranging from trace to obvious. Tenting of the skin by the malleoli may be noted.
• Palpation of the joint reveals tenderness along the joint line, corresponding to areas of capsular or ligamentous disruption.
• In associated fractures, tenderness, deformity, or tenting proximal to the joint may be seen.

DIFFERENTIALS

Section 4 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Other Problems to Be Considered

In cases of superior ankle dislocations, concomitant spine injury and fracture of the calcaneus should be sought.

WORKUP

Section 5 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Imaging Studies

• Routine radiographic examination of the ankle includes the following views:
• • Anteroposterior
  • Lateral
  • Mortise or oblique views: These are taken with an internal rotation of 10-20 degrees. This places both the medial and lateral malleoli in the same horizontal plane, which provides optimum viewing of the tibial plafond and talar dome.
• Obtain prereduction and postreduction films.

Procedures

• Reduction of the ankle joint
• • In patients with obvious or complete neurovascular compromise, perform reduction prior to radiographic studies. Prompt reduction is important in reducing the risk of complications related to neurovascular compromise.
  • Reduction is accomplished with the knee in flexion to reduce tension on the Achilles tendon. With one hand on the heel and another on the dorsum of the foot, apply traction while maintaining countertraction at the knee. Entrapment of the tibialis posterior tendon (or of a fracture fragment within the joint space) may result in an irreducible dislocation.
  • Anesthesia includes Bier block, spinal block, conscious sedation with narcotics and/or benzodiazepines, or general anesthesia. Bier block is the preferred method because of its efficacy and risk profile, although time may not permit in cases of vascular compromise.

TREATMENT

Section 6 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Prehospital Care

• Prehospital personnel should immobilize the joint following standard procedure for any extremity injury.
• If neurovascular compromise is identified in the field by examination, revealing a cold, discolored, and pulseless or insensate foot, the joint should be realigned unless transport time is brief. This is accomplished by in-line traction with countertraction. Traction or splinting should be maintained en route to the hospital.
• Intravenous opioids should be administered to make the patient comfortable and especially if traction is applied to reduce the dislocation en route. If intravenous opioids are unavailable, intravenous benzodiazepine medications can be used as an alternative.

Emergency Department Care

• Early reduction is essential since delay may increase risk of neurovascular compromise or damage to articular cartilage. In patients with vascular compromise, perform reduction prior to radiologic examination.
• Postreduction radiographs should confirm proper joint alignment. Appropriate pain management is the greatest contribution an emergency physician can make to the patient's care. Postreduction splinting is discussed below.

Consultations

Dislocations of the ankle are, by definition, unstable due to accompanying disruption of the lateral or medial ligaments or the tibiofibular syndesmosis. These require an immediate orthopedic consultation for internal fixation of any associated fractures and repair of capsular or ligamentous tears.

MEDICATION

Section 7 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Drugs used to treat the pain associated with dislocations include analgesics and anxiolytics.

Drug Category: Analgesics

Pain control is essential for 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.

Drug Category: Anxiolytics

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

FOLLOW-UP

Section 8 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Further Inpatient Care

• Patients with ankle dislocations should be admitted to the orthopedic surgery service for further evaluation and possible intraoperative repair.

Transfer

• In hospitals without an orthopedic surgeon, transfer the patient to an appropriately staffed facility for operative intervention. The joint should be reduced and splinted prior to transfer.

Complications

• Nonunion or malunion
• Synostosis
• Entrapment of the tibialis posterior tendon or of a fracture fragment
• Cartilaginous injury
• Osteochondral fractures of the talar dome
• Joint stiffness and decreased range of motion
• Arterial injury (anterior and posterior tibial, peroneal)
• Compartment syndrome (rare)

Prognosis

• Dislocated ankles should not be expected to return to premorbid function.
• The amount of force and level of capsular disruption required to dislocate the inherently stable joint results in significant injury with lasting effects. To a limited extent, prompt intervention can reduce the risk of complications.

Patient Education

• For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article Ankle Fracture.

REFERENCES

Section 9 of 9

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

• Daffner RH. Ankle trauma. Semin Roentgenol. Apr 1994;29(2):134-51. [Medline].
• Daffner RH. Ankle trauma. Radiol Clin North Am. Mar 1990;28(2):395-421. [Medline].
• Distefano S, Divita G. A case of pure dislocation of the ankle joint. Ital J Orthop Traumatol. Mar 1988;14(1):133-7. [Medline].
• Finkemeier C, Engebretsen L, Gannon J. Tibial-talar dislocation without fracture: treatment principles and outcome. Knee Surg Sports Traumatol Arthrosc. 1995;3(1):47-9. [Medline].
• Graeme KA, Jackimczyk KC. The extremities and spine. Emerg Med Clin North Am. May 1997;15(2):365-79. [Medline].
• Greenbaum MA, Pupp GR. Ankle dislocation without fracture: an unusual case report. J Foot Surg. May-Jun 1992;31(3):238-40. [Medline].
• Griffiths HJ. Trauma to the ankle and foot. Crit Rev Diagn Imaging. 1986;26(1):45-105. [Medline].
• Krishnamurthy S, Schultz RJ. Pure posteromedial dislocation of the ankle joint. A case report. Clin Orthop Relat Res. Dec 1985;(201):68-70. [Medline].
• Merianos P, Papagiannakos K, Hatzis A, Tsafantakis E. Peritalar dislocation: a follow-up report of 21 cases. Injury. Nov 1988;19(6):439-42. [Medline].
• Moehring HD, Tan RT, Marder RA, Lian G. Ankle dislocation. J Orthop Trauma. 1994;8(2):167-72. [Medline].
• Mooney JF, Naylor PT, Poehling GG. Anterolateral ankle dislocation without fracture. South Med J. Feb 1991;84(2):244-7. [Medline].
• Schuberth JM. Diagnosis of ankle injuries: the essentials. J Foot Ankle Surg. Mar-Apr 1994;33(2):214. [Medline].
• Wilson AB, Toriello EA. Lateral rotatory dislocation of the ankle without fracture. J Orthop Trauma. 1991;5(1):93-5. [Medline].
• Wroble RR, Nepola JV, Malvitz TA. Ankle dislocation without fracture. Foot Ankle. Oct 1988;9(2):64-74. [Medline].

Article Last Updated: Aug 13, 2007