Does the level of the supracondylar humerus fractures affect the stability of pinning configurations? A biomechanical study.

Abstract

Objective: Supracondylar humerus fractures (SHFs) are prevalent injuries in pediatric orthopedics and often necessitate surgical management to restore elbow function and prevent long-term complications. The study aimed to evaluate the biomechanical effects of different fracture levels relative to the olecranon fossa and the efficacy of different pin configurations.

Methods: Synthetic humerus bone models were used to standardize the fracture patterns and simulate surgical interventions. Pin configurations, including lateral divergent and cross-pin configurations, were applied using 3D-printed custom guides. Bending and torsional tests were conducted to assess biomechanical stability, with stiffness values calculated for each fixation method. Statistical analysis was performed to compare outcomes between the groups.

Results: Distinct biomechanical responses to bending and torsional loads at various fracture levels and fixation configurations were observed. Lower-level fractures demonstrated greater stability in bending forces (low cross bending-high cross bending, P = .025; low divergent bending-high divergent bending, P = .004), with cross-pin fixation providing advantages in torsional forces compared with lateral divergent pinning (low divergent torsion-high divergent torsion, P = .001). Conversely, no significant biomechanical superiority was observed in higher-level fractures. Statistical analysis highlighted significant differences in maximum forces and stiffness values between the fixation groups, indicating the selection of optimal fixation strategies based on fracture characteristics.

Conclusion: Results showed that distal SHFs were biomechanically more stable under bending forces, with cross-pin fixation providing an advantage in torsional forces for lower-level fractures. However, no significant biomechanical superiority was found for high fractures. These findings contribute to the understanding of fracture fixation strategies and highlight the importance of tailored approaches based on the fracture level. Further clinical studies are warranted to validate these biomechanical findings and to assess their impact on patient outcomes.   Cite this article as: Kaymakoğlu M, Ramazanov R, Güneş Z, Aksoy T, Yılmaz G. Does the level of the supracondylar humerus fractures affect the stability of pinning configurations? A biomechanical study. Acta Orthop Traumatol Turc. 2026; 60(4), 0352, doi: 10.5152/j.aott.2026.25352.