Locking plate fixation for proximal humeral fractures: initial results with a new implant.

Treatment of proximal humeral fractures remains controversial, with multiple reported techniques and variable results. Recently, locking plates have become available for fixation of osteopenic and comminuted fractures. This study reports our initial experience with a new locking plate designed specifically for proximal humeral fractures. We observed 16 patients until union or revision with a mean of 12 months' follow-up. Of the 16 patients, 9 had high-energy injuries. There were nine 3-part, five 2-part, and two 4-part fractures. Twelve of sixteen patients healed without complications. There were 4 nonunions; all occurred in patients with 3-part fractures with metadiaphyseal comminution, 3 of whom were heavy smokers. In patients with united fractures, mean elevation was 132 degrees and mean external rotation was 43 degrees, with mean internal rotation to T11. Locking plate fixation achieved union in 75% of patients in this series. Risk factors for delayed union or nonunion included comminution, smoking, and 3-part fractures. These fractures remain challenging despite the availability of locked plating systems.