Avaliação tridimensional das extremidades inferiores de crianças e adolescentes utilizando um sistema biplanar de radiografia de baixa dose

Abstract

Objectives: To evaluate three-dimensional (3D) measurements of the lower extremity using a biplanar low-dose X-ray device in children and adolescents. Methods: In the first part of this study, 3D measurements of eight dried bones were analyzed by a biplanar low-dose X-ray device(LDX) using stereoscopic software and compared with 3D Computed Tomography (CT). In the second part, 47 lower limbs of children and adolescents were studied using LDX two-dimensional (2D) and 3D measurements. Both parts evaluated: femoral and tibial lengths, femoral and tibial mechanical angles, frontal and lateral knee angulations, and the femoral neck-shaft angle. Results: The 3D specimen comparison between LDX and CT measurements showed no significant differences: femoral length (p: 0.069), tibial length(p: 0.059), femoral mechanical angle (p: 0.475), tibial mechanical angle (p: 0.067), frontal knee angulation (p: 0.198), lateral knee angulation (p: 0.646) and femoral neck-shaft angle(p:0.068). The comparison between LDX 2D and 3D measurements in patients showed significant differences in tibial length (p: 0.003), femoral mechanical angle (p<0.001) and femoral neck-shaft angle (p: 0.001); other parameters were unremarkable. Conclusions: The 3D LDX system presented accurate measurements compared with 3D CT. Differences between LDX 2D and 3D measurements were noted in the femoral mechanical angle, femoral neck-shaft angle and tibial length. Moderate to good interobserver agreement for the 3D LDX measurements were found.