Surgical anatomy of multipart fractures of the proximal humerus.

The gross fracture anatomy was recorded in a cohort of 22 consecutive patients who underwent open surgery for 3-part and 4-part fractures of the proximal humerus and was compared with preoperative radiographs in a blind manner. It was noted that 8 of the 22 fractures did not correspond to any category of the Neer or AO/Orthopaedic Trauma Association/Jakob classification. These fractures had 3 displaced segments in terms of surgical anatomy, but the humeral head was free of soft tissue. In addition, the soft-tissue attachments to the head were closely related to the articular surface orientation on radiographs (medially oriented or not), rather than to the number of displaced segments or to the grouping of the AO/Orthopaedic Trauma Association/Jakob classification. Thus, in our study population, the current classification systems were inaccurate for realizing the fracture anatomy, particularly humeral head status. They would be accurate if the articular surface orientation was taken into account.