SURGICAL NECK FRACTURES OF THE PROXIMAL HUMERUS - A LABORATORY EVALUATION OF 10 FIXATION TECHNIQUES

Objective: A biomechanical cadaver study was performed to compare the stability and ultimate strength of ten standard fixation techniques us ed for the treatment of surgical neck fractures of the proximal humeru s. Design: One hundred twenty (60 fresh frozen, 60 embalmed) proximal humerus specimens were selected and divided into two groups: fresh fro zen specimens represented a nonosteopenic group and embalmed specimens an osteopenic group. Simulated fractures were created at the level of the surgical neck, reduced, and randomly assigned to one of ten metho ds of fixation (six fresh frozen and six embalmed specimens per fixati on group), These constructs were then mechanically tested with the hum eri oriented to create primarily shear loading of the fixation. Result s and Conclusions: The T-plate and screws provided significantly stron ger fixation (p < 0.005) in the fresh frozen specimens than all other methods, The Ender nails/tension band construct was the second stronge st fixation technique, providing significantly stronger fixation (p < 0.01) than all the remaining techniques, Four Schanz pins with one pin placed through the greater tuberosity followed by the T-plate and scr ews provided the strongest fixation in embalmed specimens, Tension ban d fixation in both humeral groups was shown to provide the least effec tive fixation.