Imaging Studies
Plain-film radiography
Ottawa foot rules are a tool that predicts significant midfoot fractures. They are guidelines used to determine whether radiographs are necessary. [12] If any of the following are present, a radiograph is required: point tenderness over the base of fifth metatarsal; point tenderness over the navicular bone;iInability to take 4 steps, both immediately after injury and in the ED.
Although developed and validated in adults, the Ottawa foot rule also appears to be a reliable tool to exclude fractures in children 5 years of age and older. [16] When performed, a systematic approach to reading foot radiographs is important and reduces the risk of missing important injuries. [17]
In a study by Pires et al, the Ottawa ankle rules showed a high reliability for determination of when to take radiographs in patients with foot or ankle sprains. Weight-bearing inability was found to be the most important isolated item to predict the presence of a fracture (69.4% sensitivity, 61.6% specificity, 63.1% accuracy, 21.9% positive predictive value, and 93% negative predictive value). Orthopedic surgeon subjective analysis had a 55.6% sensitivity, 90.1% specificity, 46.5% positive predictive value, and 92.9% negative predictive value. The general orthopedic surgeon opinion accuracy was 85.4%. The Ottawa ankle rules presented 97.2% sensitivity, 7.8% specificity, 13.9% positive predictive value, 95% negative predictive value, and 19.9% accuracy. [18]
Other imaging modalities
Bone scanning, CT scanning, MRI, and ultrasonography may help diagnose certain foot fractures that are occult on plain film radiography. [19, 20] Although recent anecdotal reports and small diagnostic trials suggest that ultrasonography may someday have a role in routine assessment of acute foot fractures, [21, 22] second-line imaging studies generally do not need to be performed while the patient is in the ED and are usually ordered only after consultation with a foot surgeon.
Bedside ultrasonography in addition to Ottawa Foot and Ankle Rules (OFAR) in acutely injured patients was found to reduce the number of ordered x-rays and length of stay in ED in patients 18 years and older. The sensitivity of US in detecting foot and ankle fractures was 100%, and the specificity of OFAR increased from 50% to 100% with the addition of US. The negative predictive value and positive predictive value were both 100%. [23]
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Fractures, foot. Proximal fifth metatarsal avulsion fracture (also termed pseudo-Jones, tennis, or dancer fracture).
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Fractures, foot. Jones fracture of the fifth metatarsal.
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Fractures, foot. Lisfranc fracture-dislocation.
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Fractures, foot. Calcaneal fracture with intraarticular involvement and joint depression.
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Fractures, foot. Calcaneal fracture with intraarticular involvement and joint depression with Böehler angle imposed. Reduced angle of 16 degrees is pathologic.
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Fractures, foot. Subtle fracture of the first cuneiform at the Lisfranc joint. Another fracture at the base of the first metatarsal is not seen here but was found on subsequent computed tomography.
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Fractures, foot. CT scan showing fracture of first cuneiform and proximal first metatarsal.
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Fractures, foot. Spiral fracture of the shaft of the fifth metatarsal. This fracture was treated conservatively with immobilization.
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Fractures, foot. Minimally displaced fracture of the distal fifth metatarsal. This fracture was treated conservatively with immobilization in a rigid flat bottom shoe.
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Fractures, foot. Two fractures of the proximal phalanx of the great toe. The fracture at the base is obvious, but the fracture at the head is more subtle. Make certain to examine every bone on the radiograph to avoid being distracted by obvious finding.
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Comminuted navicular fracture in a young drunk driver involved in a motor vehicle crash. The patient sustained no other injuries and was discharged in a plaster splint with strict nonweightbearing. The patient subsequently had a computerized tomography (CT) scan and underwent open reduction and internal fixation 9 days after the injury. A standard anteroposterior (AP) view is shown here.
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An added oblique view of this same patient with a navicular fracture was performed in the ED to help verify the absence of other significant fractures. Obtaining views that are not part of the routine foot series can be helpful and should be added when needed.
