MRI Ankle Although MRI may be used for occult injuries or suspicion for ligamentous tears in inversion injuries [29], it is not the first imaging study for the evaluation of acute trauma to the ankle with positive OAR. Radiography Ankle Radiographs are indicated in patients who meet OAR criteria as the initial imaging study. Studies demonstrate between 92% and 99% sensitivity for detecting ankle fracture using these guidelines, with <2% of those who are negative for fracture using the OAR actually having a fracture [13-15,30]. The OAR are validated in children >5 years of age and should not be used in patients meeting the exclusionary criteria listed above [8]. Typical radiographic protocols should include 3 standard views: anteroposterior, lateral, and mortise views to include the base of the fifth metatarsal bone distal to the tuberosity [31]. Although foot and ankle radiographs have been performed together in clinical settings in the past, in a retrospective study of 243 patients with both radiographs performed, no foot fractures other than the base of the fifth metatarsal were noted. In the presence of inversion injury or fracture of the ankle, foot or knee radiographs should not be performed owing to low yield [32,33]. Weight-bearing radiographs, if possible, provide important information, particularly with fractures of uncertain stability, because the most important criterion in treatment of malleolar fractures is stability. A medial clear space of <4 mm should confirm stability. Increased incidence of fracture and instability is noted with medial tenderness, bruising or swelling, fibular fracture above the syndesmosis, bi- or trimalleolar fractures, open fracture, or high- energy fracture injury [34]. Special scenarios that warrant special mention and additional views include: Acute Trauma to the Ankle US Ankle Ultrasound (US) may be useful but is not typically considered the first line of imaging for the evaluation of acute trauma to the ankle with positive OAR [41].
Acute Trauma to the Ankle. MRI Ankle Although MRI may be used for occult injuries or suspicion for ligamentous tears in inversion injuries [29], it is not the first imaging study for the evaluation of acute trauma to the ankle with positive OAR. Radiography Ankle Radiographs are indicated in patients who meet OAR criteria as the initial imaging study. Studies demonstrate between 92% and 99% sensitivity for detecting ankle fracture using these guidelines, with <2% of those who are negative for fracture using the OAR actually having a fracture [13-15,30]. The OAR are validated in children >5 years of age and should not be used in patients meeting the exclusionary criteria listed above [8]. Typical radiographic protocols should include 3 standard views: anteroposterior, lateral, and mortise views to include the base of the fifth metatarsal bone distal to the tuberosity [31]. Although foot and ankle radiographs have been performed together in clinical settings in the past, in a retrospective study of 243 patients with both radiographs performed, no foot fractures other than the base of the fifth metatarsal were noted. In the presence of inversion injury or fracture of the ankle, foot or knee radiographs should not be performed owing to low yield [32,33]. Weight-bearing radiographs, if possible, provide important information, particularly with fractures of uncertain stability, because the most important criterion in treatment of malleolar fractures is stability. A medial clear space of <4 mm should confirm stability. Increased incidence of fracture and instability is noted with medial tenderness, bruising or swelling, fibular fracture above the syndesmosis, bi- or trimalleolar fractures, open fracture, or high- energy fracture injury [34]. Special scenarios that warrant special mention and additional views include: Acute Trauma to the Ankle US Ankle Ultrasound (US) may be useful but is not typically considered the first line of imaging for the evaluation of acute trauma to the ankle with positive OAR [41].