Fracture displacement and screw cutout after open reduction and locked plate fixation of proximal humeral fractures [corrected].

Background: Fixation of proximal humeral fractures is challenging. Locking plate technology offers mechanical advantages for treating unstable fractures in weak bone. In this study, we assessed the radiographic and clinical results of a single surgeon's experience treating proximal humeral fractures with a locked proximal humeral plate.

Methods: Fifty-three adult patients with a displaced proximal humeral fracture were treated with a proximal humeral locking plate over a forty-five-month period. A standard postoperative rehabilitation regimen was followed. Radiographs were made at two weeks, six weeks, three months, six months, and one year and were examined for fracture alignment, fracture displacement, hardware position, and healing. Postoperative outcomes were collected with questionnaires.

Results: Fifty-two (98%) of the fifty-three fractures healed by six months. Nineteen patients (36%) had radiographic signs of a complication, including screw cutout with intra-articular displacement in twelve (23%), substantial (>10 degrees ) varus displacement in thirteen (25%), and osteonecrosis in two (4%). These radiographic signs of a complication occurred in twelve (57%) of twenty-one patients older than sixty years of age and in seven (22%) of thirty-two patients under sixty years of age (p = 0.0015). Screw cutout occurred in nine (43%) of the twenty-one patients older than sixty years. Patients with a complication had worse functional outcomes as measured with the Short Musculoskeletal Function Assessment (p < 0.05) and the Quick Disabilities of the Arm, Shoulder and Hand (p < 0.001) questionnaires. We were unable to demonstrate a relationship between fracture type and complications. Revision surgery was performed in seven (13%) of the fifty-three patients. There were no cases of infection, nerve injury, or hardware failure.

Conclusions: The use of locking plates in the surgical treatment of proximal humeral fractures is associated with an unexpectedly high rate of screw cutout and revision surgery, especially in patients older than sixty years who have a three or four-part fracture. The indications for open reduction and internal fixation in these patients require continued analysis.