Humeral Fracture Fixation Techniques: a Fea Comparison of Locking and Compression Techniques with Cadaveric Pullout Comparison of Cortical Compression and Internal Locking Screws

Title of Document: HUMERAL FRACTURE FIXATION TECHNIQUES: A FEA COMPARISON OF LOCKING AND COMPRESSION TECHNIQUES WITH CADAVERIC PULLOUT COMPARISON OF CORTICAL COMPRESSION AND INTERNAL LOCKING SCREWS. Aaron Johnson, MS Mechanical Engineering, 2007 Directed By: Professor, Donald Barker, Mechanical Engineering Locking and non-locking humeral repair techniques provide different mechanical constructs for securing fractures, and consequently could generate different strain fields at the callus. The purpose of this study was to investigate the strain field callus, and to compare to determine if one construct offers a healing advantage over another. An FEA analysis was conducted using ABAQUS, with all contact surfaces modeled as friction interfaces; additionally, a pretension was applied to the non-locking construct to simulate the effect of installation. The models were subjected to axial tension loads, and results were compared with existing cadaveric and synthetic experimental loading. Additional validation involved screw pullout testing conducted on cadaveric humeri. Results showed that the strain fields at the fracture site showed no significant variation in distribution, shape, or magnitude, therefore concluding that the locking plate offered no biomechanical healing advantage. HUMERAL FRACTURE FIXATION TECHNIQUES: A FEA COMPARISON OF LOCKING AND COMPRESSION TECHNIQUES WITH CADAVERIC PULLOUT COMPARISON OF CORTICAL COMPRESSION AND INTERNAL LOCKING SCREWS.