Objective: To evaluate the outcome of open reduction and internal fixation of displaced proximal humerus fractures using a new locking plate.

Design: Prospective.

Setting: Level I university center.

Patients: Twenty-eight women and 22 men (mean age, 62.9 ± 19.l years). Twenty-nine patients were 65 years of age or older (mean age, 76.8 years). Fractures were classified according to AO/OTA as 11-A2 (n=3), A3 (n=12), B1 (n=4), B2 (n=18), B3 (n=1), C1 (n=1), and C2 (n=11). Mean follow-up was 19.8 months (range, 12 to 39 months).

Intervention: Open reduction and internal fixation with a proximal humerus locking plate.

Main Outcome Measurements: Raw and adjusted (sex and age) Constant score.

Results: Forty patients were available for follow-up. The mean raw Constant score was 66.6 (adjusted, 82.0). In patients under 65, the raw Constant score was 78.2 (adjusted score, 86.7). In patients over 65, the raw Constant score was 56.1 (adjusted score, 77.8). An excellent or good result was found in 72.5% overall. There was no secondary loss of position or implant cut-out. Seven patients (17.5%) developed avascular necrosis (AVN), 6 in C2 fractures in the older group. Their mean adjusted score was 60.7, as compared to 86.6 ± in those without AVN (p = 0.001).

Conclusions: The outcome was equally good in the younger and older age groups of patients, except in those who developed avascular necrosis. While the latter might be due to the nature of the fracture, it is also possible that surgical technique plays a role.