Evaluation of the deformity of congenital proximal radioulnar synostosis by using a digital technique

Abstract

Purpose: To find out the influence factors of the “forearm rotation angle” (FR) which related to the severity of CRUS. Methods: We established 48 digital three-dimensional forearm bones models of 48 patients with congenital radioulnar synostosis (CRUS) classified as Cleary and Omer type 3. In total, 10 independent deformities involved in the CRUS complex deformity were measured. Pearson correlation analysis for each deformity was performed and multivariate linear regression analysis was also performed with FR as the dependent variable and the other deformities as the influential factors. Results: The “dorsal angle of radius” (DAR) had the strongest correlation with the FR (0.601, P<0.01), the internal rotation angle of the radius (IRAR) has a moderate correlation with FR (0.552, P<0.01). A forearm deformity equation was established: FR=35.896+0.271 DAR+0.989 IRAR. Conclusion: The results of this study and the forearm deformity equation may be significant in guiding clinical practice. Level of Evidence: Level 4 Evidence.