Olgar BIRSEL, Bugra GULLU, Ilker EREN, Mehmet DEMIRHAN
Cerrahpaşa Medical Journal - 2026;50(1):1-5
Objective: Variable angle locking plates were developed to allow flexible screw trajectories and broader fixation within the humeral head in proximal humerus fractures, where fixation failure remains a common challenge. Whether this theoretical advantage is utilized in clinical practice remains unclear. Methods: This retrospective radiographic study evaluated 43 patients treated with locking plate fixation for proximal humerus fractures between 2015 and 2023. Eighteen patients received variable angle plates and 25 fixed angle plates. Screw trajectories were assessed on early postoperative radiographs and intraoperative fluoroscopy. Vertical screw distribution was measured as the percentage of anatomical neck coverage in the coronal plane, and axial screw spread was defined as the angle between the 2 most divergent screws on lateral fluoroscopic images. Results: Screws placed through variable angle plates covered a smaller proportion of the anatomical neck compared with fixed angle constructs. In the axial plane, fixed angle plates demonstrated a mean screw divergence of 40 derece, whereas variable angle plates showed significantly narrower spread, with a mean divergence of 15.4 derece (P < .001). Variable angle screws were therefore placed in a more convergent configuration despite the availability of angular freedom. Conclusion: Despite their intended design, variable angle proximal humerus plates demonstrated a consistent tendency toward convergent screw placement in clinical practice, resulting in reduced humeral head coverage compared with fixed angle constructs. Further clinical studies are required to determine whether this radiographic mismatch has clinical relevance and whether deliberate screw divergence influences fixation durability and outcomes.
