It is important to have anatomic reduction and stable fixation of all the fracture fragments. It gives the patient the best chance of restoration of function to the shoulder. The illustrated case below is an example of a highly displaced and multi fragmentary proximal humerus fracture that was fixed with a locking plate and intramedullary fibular allograft. During surgery one of the fragments as indicated by the CT scan below was found be have been"driven" during the injury into the cancellous bone of the humeral head indicating high energy trauma.
Although an anatomic reduction of the fracture was achieved and eventual healing without complication the patient had active forward elevation only to 90 degrees at 12 months after surgery. There is no pain.
This case indicates that other factors may play a role in the functional outcome of this injury that are not related to "how well the fracture is reduced".