Morphological Analysis of Fractures of the Proximal Humerus by the Fracture Mapping Technique

Fractures of different parts of the proximal humerus may lead to different postoperative functional deficits, but there are few studies on the morphology and related functions of the proximal humerus. The purpose of this study was to analyze the fracture pattern of the proximal humerus by the three-dimensional (3-D) fracture mapping technique and to further evaluate its clinical utility.

Patients with proximal humeral fractures admitted to Pudong Hospital, Fudan University, from January 2018 to December 2020, were analyzed. Three surgeons divided the fractures into groups according to the 3-D CT imaging technique and mapped the fractures on a 3-D template according to the fracture line of each fracture. Finally, the humeral head inversion angle and the functional score were recorded in different fracture types.

A total of 312 cases of humeral fractures were included. Among them, there were 90 patients (28.8%) in the simple greater tuberosity + lesser tuberosity + medial cortex group, with typical fracture features of surgical neck fractures of the humerus + greater tuberosity fractures. Eighty-seven patients (27.9%) in the greater tuberosity + isolated fragment lesser tuberosity + medial cortex group had typical "four-part fractures." There were 45 patients (14.4%) in the greater tuberosity + lesser tuberosity + medial isolated fragment group. Moreover, more patients in this group had medial comminution due to varus displacement of the femoral head. There were 66 patients (21.1%) in the isolated greater tuberosity group, 21 patients (6.7%) in the greater tuberosity + lesser tuberosity group, and three patients (1.0%) in the greater tuberosity + medial cortex group. In addition, the humeral head inversion angle and other statistical differences were observed in the greater tuberosity + lesser tuberosity + medial isolated fragment group.

This morphological study helps to further identify the characteristics of proximal humerus fracture patterns, which may be closely related to different clinical outcomes. Further relevant studies are needed to verify the reliability of their clinical application and the potential value in surgical planning and postoperative functional rehabilitation.