FEA of Proximal Humerus Locking Plate Using Bone and Implant Model

Abstract

<p>Finite element analysis (FEA) of orthopaedic implants has become a common tool for evaluating the mechanical performance for various implant designs. While these models have been very useful, the application of forces directly to the implant limits our ability to accurately model the interaction of the implant with the bone. Our goal in this work has been to create modeling of both the bone and the implant simultaneously with forces applied to entire system so that the interaction forces between the two can be more accurate. A recent study in our lab by Schumer et al of proximal humerus locking plates was done on cadaveric humeri to compare the use of smooth pegs versus threaded screws for fixation. Cyclic torsion testing was done at ±2 Nm for 3000 cycles with results around 1.5 degrees of displacement and at ±5 Nm for 3000 cycles with results around 5 degrees of displacement. Load to failure testing was also done with results around 1300 N of load at failure. Our current study is now using finite element modeling to recreate these physical tests. Computed tomography (CT) images of the humeri and implants have been used to create models with Mimics® software (Materialise, Ann Arbor, MI, USA). The FEA of these models is being done in Abaqus FEA software (SIMULlA, Providence, RI, USA) to simulate the physical testing. The modeling results will be compared to the physical results. Eventually, we hope to supplement the physical tests with these modeling tests for cases where physical tests are limited by resources, such as the number of cadaveric bones available.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010</p>