Analysis of Fracture Distribution in the Surgical Neck Region of the Proximal Humerus: a 3D Bone Cortical Thickness Mapping Study

Abstract Objection: Among the many studies on the proximal humerus, few have focused on cortical bone distribution around the surgical neck region and its relationship with the epiphysis. Materials and methods: Ninety-five surgical neck fracture patients with available plain X-rays and CT scans were enrolled. In addition, 38 normal subjects were also included to illustrate the cortical thickness of the diaphysis, cortical change region and greater tuberosity.Results: The fracture lines were mainly distributed in the cortical change region. Significant differences were found in cortical thickness between the diaphysis, surgical region and greater tuberosity in men and women. The thickest cortex was noted in the diaphysis, and the thinnest cortex was noted in the greater tuberosity. No significant differences were observed in the width of the cortical change region in man and women.Conclusion: The surgical neck region had decreased cortical thickness. It was concluded that the epiphysis connection region had an effect and acted on the proximal humeral fracture pattern in adults; therefore, the surgical neck fracture was identified as an epiphyseal relative fracture.