Fracture line and comminution zone characteristics, and rotator cuff footprint involvement in OTA/AO 11C3-type proximal humeral fractures: complex proximal humerus fracture map.

PURPOSE: To identify fracture characteristics and zones of comminution as well as the relationship with anatomic landmarks and rotator cuff footprint involvement in OTA/AO 11C3-type proximal humerus fractures. METHODS: Computed tomography images of 201 OTA/AO 11C3 fractures were included. Fracture lines were superimposed to a 3D proximal humerus template, created from a healthy right humerus, after fracture fragment reduction on 3D reconstruction images. Rotator cuff tendon footprints were marked on the template. Lateral, anterior, posterior, medial, and superior views were captured for the interpretation of fracture line and comminution zone distribution as well as to define the relationship with anatomic landmarks and rotator cuff tendon footprints. RESULTS: A total of 106 females and 95 males (mean age = 57.5 ± 17.7 [range 18-101] years) with 103 C3.1-, 45 C3.2-, and 53 C3.3-type fractures were included. On the lateral, medial, and superior humeral surfaces, fracture lines and comminution zones were distributed differently in 3 groups. Tuberculum minus and medial calcar region were significantly less severely affected in C3.1 and C3.2 fractures than C3.3 fractures. The supraspinatus footprint was the most severely affected rotator cuff footprint area. CONCLUSIONS: Specifically defining the certain differences for repeatable fracture patterns and comminution zones in OTA/AO 11C3-type fractures and the relationship between the rotator cuff footprint and the joint capsule may contribute to the decision-making process of surgeons.