PLAIN RADIOGRAPHIC INTERPRETATION IN TRIMALLEOLAR ANKLE FRACTURES POORLY ASSESSES POSTERIOR FRAGMENT SIZE

Twenty-five patients with trimalleolar ankle fractures were evaluated using both conventional radiography and computed tomography (CT) to de termine the size of the posterior fragment along with other fracture c haracteristics. Plain radiograph measurements indicated very poor inte r- and intraexaminer reliability. When compared to the CT scan measure ment, 54% of the plain radiographic readings revealed >25% error. Plai n radiographic interpretations erred in most cases by overrating the s ize of the fragment, but major underestimations also occurred. The lar ger size fragments showed more error than the smaller ones. This infor mation confirms our clinical suspicion that the lateral radiograph is unreliable in assessing the posterior fragment size.