A 3-Dimensional Analysis of the Fracture Planes in Pediatric Lateral Humeral Condyle Fractures for Image-Based Pin Positioning During Fixation.

Objective: To determine the 3-dimensional morphology of pediatric lateral condylar physeal fractures using 3-dimensional computed tomography (3D-CT) and to identify optimal pin positions for percutaneous pinning.

Design: Prospective case series of consecutively treated patients.

Setting: Tertiary university hospital setting.

Patients: Preoperative 3D-CTs in pediatric surgical candidates diagnosed with lateral condylar physeal fractures.

Intervention: Closed reduction and percutaneous pinning was performed.

Main Outcome Measures: Reconstructed images of the distal humerus were aligned accordingly to determine the coronal (α), sagittal (β), and axial tilt (γ) angles of the fracture plane. Both α and β were also measured on plain radiography. Image-based position of the 2 pins was calculated preoperatively using 3D-CT, based on anteroposterior and lateral views. Final angle of pins was measured on postoperative radiographs.

Results: A total of 29 fractures were assessed. 3D-CT reconstruction images of fractures showed a posterolateral fracture fragment with reference to the long axis of the humerus. The mean α, β, and γ were 62 degrees [95% confidence interval (CI), 59-64], 69 degrees (95% CI, 65-72), and 36 degrees (95% CI, 34-38). Both α and β measured on plain radiography were not significantly different from 3D-CT measurements (P = 0.6712, 0.6218). Average postoperative pin angles were 144 degrees (95% CI, 140-147) and 161 degrees (95% CI, 158-165) for the proximal pin, and 118 degrees (95% CI, 114-122) and 115 degrees (95% CI, 110-120) for the distal pin, on anteroposterior and lateral views, respectively, resulting in similar trajectories to the preoperatively calculated pin positions.

Conclusion: Our study adds to the current knowledge by providing an image-based angular reference of the fracture configuration in pediatric lateral humeral condyle fractures, which may be used during percutaneous pinning.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.