The Influence of Radiograph Obliquity on Böhler's and Gissane's Angles in Calcanei

Abstract

In calcaneal fractures, Böhler's and Gissane's angles are considered important parameters to guide treatment strategy and provide prognostic information during follow-up visits. Therefore, lateral radiographs have to be accurate. The aim of this study was to evaluate the effect of craniocaudal and posteroanterior angular variations (i.e., simulate lower leg malposition) from the true lateral radiograph on Böhler's and Gissane's angles. In this radioanatomical study, 15 embalmed, skeletally mature, human anatomic lower limb specimens were used. Using predefined criteria, a true lateral radiograph (i.e., 0° angular variation) was obtained. Angular variations from this true lateral radiograph were made from –30° to +30° deviation in the craniocaudal and posteroanterior direction at 5° intervals. Böhler's and Gissane angles were independently assessed by 2 experienced trauma surgeons. Böhler's angle decreased with increasing caudal angular variations (maximum –4.3° deviation at –30°). With increasing of the posterior angular variations, Böhler's angle increased (maximum 5.0° deviation at +30°) from the true lateral radiograph, but all deviations were within the measurement error. The deviation of the angle of Gissane was most pronounced in the cranial direction, with the mean angle decreasing by –8.8° at +30° angular variation. Varying angular obliquity in the caudal and posteroanterior direction hardly affected Gissane's angle. Foot malpositioning during the making of a lateral radiograph has little influence on Böhler's and Gissane's angles. If used for clinical decision-making in initial treatment and during follow-up of calcaneal fractures, these parameters can reliably be obtained from any lateral radiograph.