The Baumann Angle: An Analysis from Theory to Practice

Objective  To analyze how the Baumann angle (BA) is affected by inadequate radiographic inclinations. Methods  The study was performed from radiographs of the distal humerus of children aged 3 to 10 years. The BA measurements performed by five observers were compared, and each radiograph was evaluated for its quality as "adequate" or "inadequate." The correlation between radiographic quality and the normality of the angles was evaluated. Results  Sample was composed of 141 patients, 44% between 3 and 6 years of age and 56% between 7 and 10. We observed the BA between 52.01 and 89.82 degrees, with about 16% of the measurements outside the normal limits of the literature. A total of 33.3% of the evaluated radiographs were classified as "inadequate". On the BA measurements outside the normality parameter, we observed that its proportion was higher among images with inadequate radiographic quality (31.1 vs. 6.2%), and this difference was significant ( p  < 0.001). Conclusions  The BA is a very variable measurement and, alone, it is unreliable for the evaluation of angular deformities of the pediatric elbow, with radiographic quality proven to be an important causal factor of this variability.