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

Abstract

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 (alpha), sagittal (beta), and axial tilt (gamma) angles of the fracture plane. Both alpha and beta 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 alpha, beta, and gamma were 62 degrees [95% confidence interval (CI), 59-64], 69 degrees (95% CI, 65-72), and 36 degrees (95% CI, 34-38). Both alpha and beta 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.