期刊名称:Journal of Education and Teaching in Emergency Medicine
印刷版ISSN:2474-1949
出版年度:2018
卷号:3
期号:4
页码:1-2
DOI:10.21980/J8PG91
出版社:University of California Press
摘要:History of present illness: A 28-year-old female presented with left ankle pain after a fall down a flight of
stairs. She had normal vital signs. Though her left ankle had an obvious deformity on exam, she was able to
move her toes with mild limitation secondary to pain without sensory deficits. She had 2+ dorsalis pedis and
posterior tibial pulses. Her lower extremity compartments were soft to palpation.
Significant findings: The X-rays were significant for a subtalar dislocation. The calcaneus (red) is laterally
displaced with respect to the talar head (orange), and the white lines indicate the normal articular surface.
Additionally, there was a talonavicular dislocation, asseen in the fourth image: the talus(green) and navicular
bone (purple) overlapping suggests a dislocation. In a normally aligned foot, the boundaries of the two bones
create a point of articulation.
Discussion: Subtalar dislocations arise from both the talonavicular and talocalcaneal joints.1 Talonavicular
dislocations are uncommon and occur due to severe inversion or eversion of the foot that disrupts the
ligamentous structures supporting the joint.2 A thorough physical exam should be performed to assess the
extent of injury. One must also be mindful of concomitant injuries, such as more proximal fractures/dislocations and compartment syndrome. The majority of the blood supply to the talus arises from
the dorsalis pedis artery, and therefore, talonavicular dislocations with subtalar dislocationslead to avascular
necrosis in 40% of cases.2
Proper diagnosis of talonavicular dislocations require obtaining anteroposterior (AP), lateral, and mortise
views of the ankle and foot.3 The utility of computed tomography (CT) in diagnosis has also been discussed.
One study reported that 44% of patients who received CT for subtalar dislocation had a treatment plan
differing from that based on plain film findings.4 Specifically, CT identified fractures that were not visible on
plain films as well as intraarticular debris requiring evacuation in an effort to promote proper healing and
function.
Most dislocations are amenable to closed reduction as first-line treatment.1 Early reduction is crucial as it
decreases the chance of vascular compromise. Closed reduction is performed by applying traction at the
heel with counter-traction at the thigh while the knee is flexed to 90 degrees to relax the gastrocnemius
muscle.5 In the case of a lateral dislocation, a firm eversion of the foot is performed while direct pressure at
the talar head is applied.5 Post-reduction imaging should be obtained for confirmation. Open reduction and
internal fixation (ORIF) is utilized in up to 32% of cases when closed reduction fails.