The whole leg radiograph (WLR), the standard technique for determining axial alignment, is usually taken in a standing position, although some prefer the supine position. To determine the difference between these two positions, we performed a standing and a supine WLR in 20 patients with a varus alignment. We found an average of 2 degrees more varus deviation in the standing position than in the supine position.,
Acta Orthopaedica Scandinavica
Erasmus MC: University Medical Center Rotterdam

Brouwer, R., Jakma, T., Bierma-Zeinstra, S., Ginai, A., & Verhaar, J. (2003). The whole leg radiograph: standing versus supine for determining axial alignment. Acta Orthopaedica Scandinavica, 74(5), 565–568. doi:10.1080/00016470310017965