Extremity CT and ultrasound in the assessment of ankle injuries: occult fractures and ligament injuries.

OBJECTIVE: To assess the rates of fractures and ligament injuries in patients with an acute ankle injury and a normal radiographic examination, and to consider the most appropriate examination protocol. METHODS: Patients with an acute ankle injury who presented to the John Radcliffe Hospital Emergency Department with a normal radiographic examination were eligible for the study. They were invited to receive a cone beam CT and ultrasound examination at a local radiology department within 5 days of their ankle injury. RESULTS: Of the 100 patients recruited to the study, 19 patients were found to have major fractures and 42 patients had small avulsion fractures. Additionally, 42 patients had ankle effusions and there were a large number of soft tissue injuries. There were 83 acute injuries of the anterior talofibular ligament, 19 of the anterior tibiofibular ligaments, 26 of the calcaneofibular ligament, 39 of the deltoid ligament complex, 21 of the talonavicular ligament, 14 of the spring ligament and 3 of the calcaneocuboid ligament. CONCLUSION: Conventional radiographic examination misses significant fractures of the foot and ankle and the presence of an ankle effusion does not relate to the severity of injury. Ultrasound is a useful imaging technique that can supplement clinical practice, but it is unlikely to replace current protocols alone. Cone beam CT is an appropriate alternative to plain radiography, being more sensitive in detecting fractures and delivering a similar dose of radiation. However, neither CT or ultrasound examination can detect all avulsion fractures. Simple anterior process fractures of the calcaneus are associated with talonavicular ligament injuries and the medial ligaments are injured in almost 50% of cases when there is a lateral ligament injury. ADVANCES IN KNOWLEDGE: Fractures in the foot and ankle are detected more precisely with cone beam CT compared to radiographs. Cone beam CT delivers similar doses of to conventional radiographs which is around 10% of that resulting from conventional CT. Ultrasound examination is an effective assessment tool to detect ligamentous injuries. The absence of an ankle effusion does not exclude a major fracture.

Predicting poor outcome from simple ankle injuries: a prospective cohort study.

BACKGROUND: Sprained ankles are common and when there are no signs or evidence of a fracture, conventional management is conservative. At present, there are no clinical markers to identify those that may develop persisting instability and disability that would require rehabilitation or surgery. OBJECTIVES: To investigate the nature and extent of soft tissue ankle injuries, and to consider whether the anatomical severity of injury can predict functional outcome. METHODS: Patients attending a local Accident and Emergency Department in Oxford with an acute ankle injury with no clinical requirement for radiographs, or where radiographs were normal, were invited into the study. Within 5 days, patients underwent a diagnostic ultrasound examination, a cone beam CT study and a disability assessment. Ultrasound and physiotherapy assessments were repeated at 3 and 6 months. RESULTS: 100 patients were recruited and grouped based upon injuries. 58 had simple ankle injuries, 21 complex, 19 had significant fractures and 2 were excluded from further follow up analysis. There were no clinically significant differences in pain, disability or functional outcomes between the groups at all points of the study. CONCLUSION: Medium to long term clinical outcomes were not solely determined by the severity of injury. Some patients with simple injuries were seen to have ongoing problems, whereas some with complex injuries recovered completely in a shorter period. Advances in knowledge: The severity of an ankle injury determined by radiological imaging does not necessarily dictate the severity of a patient's symptoms and the trajectory of their recovery.