Biomechanical Evaluation of a Minimally Invasive Fixation Method for Length Unstable Limb Injuries

INFIX instrumentation has provided an alternative treatment option for anteriorly unstable pelvic injuries. In this study, we explore the biomechanical feasibility of using an INFIX construct in an unstable longbone model and present a unique clinical case of its use. The external fixation, locked plate and spinal implant constructs (n = 5 each) were applied to lengthunstable fracture models and tested under various loads. Analysis of variance and pairwise Ttests were performed with levels of significance adjusted by Bonferroni correction to account for multiple comparisons. The biomechanical stiffness of the INFIX was found to be intermediate between the other two constructs in axial loading and torsion and was equivalent to one of the other constructs in sagittal and lateral bending. It was never the most compliant construct in any testing mode. This study and case report demonstrate the biomechanical feasibility of using INFIX to treat limb injuries. (Journal of Surgical Orthopaedic Advances 29(1):1825, 2020).