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Basics ⬇

Author(s): JeremySchmitz, MD, ABFM and Kenneth P.Barnes, MD, MSc, CAQSM, FACSM

Description

  • Any fracture involving the most distal portions of the fibula or tibia, commonly known as the lateral and medial malleoli, respectively
  • Synonyms: ankle fracture

Epidemiology

  • Very common: ~170 ankle fractures per 100,000 people each year (1)
  • Fractures to ankle or midfoot occur in <15% of ankle sprains.
  • Most ankle fractures are malleolar fractures: 70% are unimalleolar (lateral being most common), 20% are bimalleolar, and 10% are trimalleolar (medial, lateral, and posterior malleoli) (1).

Risk-Factors

  • History of prior ankle injury
  • Inadequate rehabilitation of injury
  • Skeletal immaturity
  • Weakness in dynamic (muscles) and/or static (ligamentous) stabilizers of the ankle
  • Abnormal gait and/or foot biomechanics
  • Foot and ankle proprioceptive dysfunction (dysfunction in the ability of the foot and ankle to adapt to uneven terrain)
  • Cigarette smoking
  • Obesity

Commonly Associated Conditions

Diagnosis ⬆ ⬇

History

  • Elicit mechanism: inversion versus eversion and external versus internal rotation of the ankle and foot
  • Most frequent injury is inversion.
  • Occasionally caused by direct blow to the affected malleolus
  • Patient may hear or feel a “pop.”
  • Immediate, disabling pain and difficulty bearing weight
  • Acute onset of swelling
  • Development of ecchymosis
  • Assess for neurovascular symptoms.

Physical Exam

  • Swelling and/or deformity about the ankle
  • Ecchymosis
  • Limited range of motion of the ankle
  • Tenderness to palpation over the affected malleolus
  • Difficulty or inability to bear weight and/or ambulate
  • May note instability of the ankle joint on examination
  • Check for signs of neurovascular compromise (pulses/sensation in the foot).

Differential Diagnosis

  • Contusion
  • Ankle sprain
  • Tear of ankle retinacular structures
  • Syndesmosis injury (“high ankle sprain”)
  • Foot fracture
  • Posttraumatic subluxation of peroneal tibialis posterior tendons

Diagnostic Tests & Interpretation

  • Ottawa Ankle Rules are used to determine whether x-rays are necessary. Obtain x-rays for pain in the malleolar zone associated with any of the following:
    • Bony tenderness along distal 6 cm of posterior tibia or fibula or at medial or lateral malleolar tip
    • Inability to bear weight (four steps) on ankle immediately after injury and at time of evaluation
  • The Ottawa Ankle Rules have a sensitivity for fracture near 100% and a modest specificity (2)[A].
  • Ottawa Ankle Rules have been validated for children 10 yr and older (3)[A].
  • X-rays include anteroposterior (AP), lateral, and mortise (AP with foot in 15 degrees of adduction) views.
  • Some ankle fractures may not be initially seen. Presence of a large ankle effusion on the lateral radiograph may indicate an occult fracture and the need for further evaluation (4)[C].
  • On the mortise view, the joint space between the talus and lateral malleolus and the distal tibia and medial malleolus should be equal. Inequality should raise suspicion of an unstable ankle injury.
  • Computed tomography (CT) not indicated in most ankle fractures; however, it is performed when an occult fracture is suspected or to further evaluate pilon (comminuted distal tibial fracture), triplane (tibial fracture in sagittal, coronal, and axial planes), or suspected talar fractures.
  • When performed, order thin-cut CT in case coronal or sagittal reconstructions are required.

Treatment ⬆ ⬇

General Measures

  • Acetaminophen at recommended age- or weight-based dosages every 6 to 8 hr as needed
  • Consider nonsteroidal anti-inflammatory drugs (NSAIDs), although controversy exists as to their effect on bone healing.
  • Narcotics as needed for severe pain only
  • Cryotherapy applied 20 to 30 min every 2 to 4 hr for the first 24 to 48 hr after injury. Use caution to avoid thermal injury to the skin.
  • Relative rest and elevation of affected limb for first 48 to 72 hr
  • Isolated lateral malleolar fractures with 2 mm or less of displacement do not need reduction. Refer to orthopedist for >2 mm displacement (5)[C].
  • Isolated medial malleolar fractures with any displacement other than small avulsion injuries should be referred to an orthopedist. Do not attempt to reduce.
  • Check neurovascular status of foot postreduction.
  • Postreduction x-rays are same views as initial films.
  • Non–weight-bearing in stirrup or posterior splint, with ankle in neutral position, for 3 to 5 days
  • Isolated, minimally displaced lateral malleolar fracture: short leg walking cast with ankle in a neutral position or fracture boot with (e.g., controlled ankle motion [CAM] walker) or without adjustable ankle range of motion for 4 to 6 wk
  • Isolated simple avulsion fracture of the medial malleolus: Stirrup splint or CAM walker can be used short term for comfort, typically 2 to 4 wk.

Issues for Referral

  • Any open fracture or fracture associated with neurologic or vascular deficits requires emergent surgical evaluation.
  • Ankle injuries that are unstable or incongruent should be evaluated by an orthopedic surgeon.

Additional Therapies

  • Patients should seek attention immediately for pain that is increasing, new or worsening numbness, or skin pallor/duskiness distal to the fracture or splint/cast.
  • Repeat x-rays at 2 wk to ensure maintained alignment and at 6 wk to assess bony healing (6)[C].
  • Repeat x-rays every 2 wk if not healing.
  • Total healing time: 6 to 8 wk; may take months to see complete radiographic healing
  • Athletes should cross-train while healing to maintain fitness.
  • Proper rehabilitation of these injuries with a home instructional program or with formal physical therapy guidance is crucial to successful healing and return to full function.
  • After period of immobilization is complete, start standard ankle rehabilitation range of motion exercises, strengthening exercises, and proprioceptive training.
  • The shorter the period of immobilization, the easier it should be for the patient to regain ankle motion and strength.
  • Follow up every 2 to 3 wk to assess progress of rehabilitation.

Surgery/Other Procedures

The following injuries are frequently managed with surgical intervention:

  • Disrupted mortise joint
  • Fracture-dislocations
  • Bimalleolar fractures
  • Trimalleolar fractures
  • Unimalleolar fracture with contralateral ligament rupture
  • Lateral malleolar fractures with >2 mm displacement
  • Lateral malleolar fractures above the tibiotalar joint line (as they are frequently associated with syndesmotic disruption)
  • Medial malleolar fractures with >2 mm displacement (5)[C]
  • Posterior malleolus fractures involving >25% of the articular surface or >2 mm displacement (5)[C]
ALERT
  • 5% of all fractures in pediatrics with a higher incidence in children with an increased body mass (7)
  • Physis are vulnerable, and ligamentous structures are robust (7).
  • Salter-Harris (SH) type II is the most common (7).
  • SH III and IV may damage the reserve zone and are at a higher risk of causing physeal growth disturbance (7).
  • Long-term treatment is to minimize angular deformity and leg length discrepancy, to achieve normal ankle function, and to avoid posttraumatic arthritis (7).

Admission, Inpatient, and Nursing Considerations

Admission criteria:

  • Open fracture
  • Fracture-dislocations in which adequate reduction is not achieved with manual manipulation
  • Evidence of or concern for neurovascular compromise (severely comminuted pilon fracture, compartment syndrome)

Additional Reading ⬆ ⬇

  • Eiff MP, Hatch RL. Fracture Management for Primary Care. 3rd ed. Philadelphia, PA: WB Saunders; 2011.
  • RockwoodCA, GreenDP, BucholzRW, et al, eds. Rockwood and Green’s Fractures in Adults. 4th ed. Philadelphia, PA: JB Lippincott; 1996.

References ⬆ ⬇

  1. Elsoe R, Ostgaard SE, Larsen P. Population-based epidemiology of 9767 ankle fractures. Foot Ankle Surg. 2018;24(1):34–39.
  2. Derksen RJ, Knijnenberg LM, Fransen G, et al. Diagnostic performance of the Bernese versus Ottawa Ankle Rules: results of a randomised controlled trial. Injury. 2015;46(8):1645–1649.
  3. Halai M, Jamal B, Rea P, et al. Acute fractures of the pediatric foot and ankle. World J Pediatr. 2015;11(1):14–20.
  4. Clark TW, Janzen DL, Ho K, et al. Detection of radiographically occult ankle fractures following acute trauma: positive predictive value of an ankle effusion. AJR Am J Roentgenol. 1995;164(5):1185–1189.
  5. Michelson JD. Fractures about the ankle. J Bone Joint Surg Am. 1995;77(1):142–152.
  6. Goost H, Wimmer MD, Barg A, et al. Fractures of the ankle joint: investigation and treatment options. Dtsch Arztebl Int. 2014;111(21):377–388.
  7. Su AW, Larson AN. Pediatric ankle fractures: concepts and treatment principles. Foot Ankle Clin. 2015;20(4):704–719.

Clinical Pearls ⬆

  • 70% are unimalleolar with lateral being the most common.
  • Ottawa Ankle Rules have been validated for 10-yr-olds and older.
  • Any open fracture or fracture with neurologic or vascular compromise requires emergent surgical evaluation.
  • In pediatrics, ligamentous structures are more robust than the physis.