High ankle sprains: Easy to miss, so follow these tips
Misdiagnosis can result in increased loss of play time and chronic ankle dysfunction. Here are the physical exam maneuvers and imaging options to consider.
PRACTICE RECOMMENDATIONS
› Maintain a high level of suspicion for syndesmotic injury in any athlete describing an external rotation or hyper-dorsiflexion ankle injury. A
› Obtain weight-bearing anteroposterior- and mortise-view ankle x-rays in all cases of suspected syndesmotic injuries. A
› Consider stress x-rays of the affected ankle, contralateral ankle x-rays for comparison views, or advanced imaging with magnetic resonance imaging (MRI) or computed tomography if initial x-rays are unrevealing. A
› Treat stable syndesmotic injuries with conservative measures and rehabilitation. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
A thorough examination of the ankle, including palpation of common fracture sites, is important. Employ the Ottawa Ankle Rules (see https://www.theottawarules.ca/ankle_rules) to investigate for: tenderness to palpation over the posterior 6 cm of the posterior aspects of the distal medial and lateral malleoli; tenderness over the navicular; tenderness over the base of the fifth metatarsal; and/or the inability to bear weight on the affected lower extremity immediately after injury or upon evaluation in the physician’s office. Any of these findings should raise concern for a possible fracture (see “Adult foot fractures: A guide”) and require an x-ray(s) for further evaluation.13
Perform range-of-motion and strength testing with regard to ankle dorsiflexion, plantar flexion, abduction, adduction, inversion, and eversion. Palpate the ATFL, CFL, and PTFL for tenderness, as these structures may be involved to varying degrees in lateral ankle sprains. An anterior drawer test (see https://www.youtube.com/watch?v=vAcBEYZKcto) may be positive with injury to the ATFL. This test is performed by stabilizing the distal tibia with one hand and using the other hand to grasp the posterior aspect of the calcaneus and apply an anterior force. The test is positive if the talus translates forward, which correlates with laxity or rupture of the ATFL.13 The examiner should also palpate the Achilles tendon, peroneal tendons just posterior to the lateral malleolus, and the tibialis posterior tendon just posterior to the medial malleolus to inspect for tenderness or defects that may be signs of injury to these tendons.
An associated Weber B or C fracture? Trauma causing ankle syndesmosis injuries may be associated with Weber B or Weber C distal fibula fractures.7 Weber B fractures occur in the distal fibula at the level of the ankle joint (see FIGURE 1). These types of fractures are typically associated with external rotation injuries and are usually not associated with disruption of the interosseous membrane.
Weber C fractures are distal fibular fractures occurring above the level of the ankle joint. These fractures are also typically associated with external ankle rotation injuries and include disruption of the syndesmosis and deltoid ligament.14
Also pay special attention to the proximal fibula, as syndesmotic injuries are commonly associated with a Maisonneuve fracture, which is a proximal fibula fracture associated with external rotation forces of the ankle (see FIGURE 1).1,2,4,11,14,15 Further workup should occur in any patient with the possibility of a Weber- or Maisonneuve-type fracture.
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