Contribution of individual projections alone and in combination for radiographic detection of ankle fractures

OBJECTIVE. We wanted to determine whether the standard three-view ankle rad iographic series could be replaced by a two-view combination, and if so, wh ich two-view combination (anteroposterior with lateral or mortise with late ral) would be superior. MATERIALS AND METHODS. During a 12-month period, we retrospectively reviewe d 556 consecutive ankle radiographic studies consisting of anteroposterior, mortise, and lateral views. One hundred twenty patients with at least one ankle fracture were paired with 140 healthy control subjects. Each image in the three-view examination was separated and sorted by view and studied in dependently; all images were reviewed by two skeletal radiologists and two orthopedic surgeons. Each radiograph was evaluated for fracture of the medi al, lateral, and posterior malleoli and the foot using a five-point confide nce rating. Performance of each view and modeled two- and three-view combin ations of views was evaluated with modified receiver operating characterist ic analysis. RESULTS. The data provide little support for preferring either two-view com bination (anteroposterior-lateral or mortise-lateral) for any type of fract ure. The three-view combination does detect significantly more fractures th an some two-view combinations in some locations, and there is a statistical ly significant cost in diagnostic accuracy for eliminating the anteroposter ior or mortise view. CONCLUSION. Reducing the ankle radiographic series from three to two views would result in a small but significant decrease in the detection of fractu res of the ankle and foot. Both two-view combinations are equivalent for fr acture detection.