Strength of Titanium Intramedullary Implants vs Traditional Miniplate Fixation of Mandibular Condyle Fractures

Abstract

Objective: Test the strength of internal fixation of mandibular condyle fractures repaired with titanium miniplates vs titanium intramedullary implants. Method: Condylar osteotomies were created in 40 urethane hemimandible models and 24 human cadaveric specimens. Half of the samples in each group were repaired with traditional miniplates and the other half were repaired with intramedullary titanium pins. Anteroposterior and mediolateral loads were applied and the displacement across the fracture site was calculated. Results: When subjected to physiologic and supraphysiologic loads, titanium intramedullary implants provided more resistance to bone fragment displacement than traditional miniplates. This was true for both the urethane model and the cadaveric mandible experimental groups. Mechanical failures in the miniplate groups were due to plate bending and/or screw extrusion. However, a 1.65 mm diameter titanium intramedullary pin did not mechanically fail in any of the cases. Intramedullary implantation failures were due to secondary fracture of the adjacent cortical bone under high forces or rotation of the smooth pin implant. Conclusion: Mechanical failures which were encountered under physiologic forces with miniplate fixation were not seen with titanium intramedullary implants. These intramedullary implants provide stronger and more durable fixation of mandibular condyle fractures than traditional miniplates in both urethane and cadaveric laboratory models.