Cubitus varus deformity following paediatric supracondylar humeral fracture remodelling predominantly in the sagittal direction: A three-dimensional analysis of eighty-six cases

Purpose Three-dimensional (3D) capacity for remodelling in cubitus varus deformity (CVD) after paediatric supracondylar humeral fractures (PSHFs) remains unelucidated. This study investigated remodelling patterns after PSHFs by examining 3D deformity distribution over time after injury. Methods Computed tomography (CT) data of 86 patients with CVD after PSHFs were analysed. The 3D deformity angles in the sagittal, coronal, and axial directions were assessed and correlated with the duration between the age at injury and CT evaluation. For the subgroup analysis, we performed the same correlation analysis in a younger (< 8 years old) and an older group (>= 8 years old); we categorized the duration into early (< 2 years), middle (>= 2 to < 5 years), and late periods (>= 5 years) and compared the deformity angles of each direction among the three groups. Results Sagittal deformity showed a moderate correlation with the duration of deformity (r = -0.54; P < 0.001), while coronal and axial deformities showed a negligible correlation. Sagittal deformity showed moderate correlations with the duration in the younger group (r = -0.62; P < 0.001) and weak correlations in the older group (r = -0.37; P = 0.091). In the sagittal direction, the deformity angle in the early period was significantly larger than those in the mid and late periods (P < 0.001). However, there were no significant differences among the three groups in the coronal and axial directions. Conclusion Sagittal deformities in CVDs are capable of remodelling, especially in the early period and at a younger age, whereas coronal and axial deformities are less likely to undergo remodelling.