Hemiarthroplasty for three- and four-part proximal humerus fractures.

Displaced three- and four-part proximal humerus fractures are among the most challenging shoulder conditions to manage. Because of the risk of symptomatic malunion, nonunion, and humeral head osteonecrosis, surgical management is preferred. Locking plate technology has provided an alternative to hemiarthroplasty for certain three- and four-part fracture patterns, even in the setting of osteopenic bone. Prosthetic humeral head replacement has been advocated for head-splitting fractures and fracture-dislocations as well as four-part fractures with significant initial varus displacement (>20°). Technical challenges, including obtaining proper humeral head height, retroversion, and optimal positioning and fixation of the tuberosities, have a substantial effect on patient outcomes.