The mandible is the most fractured bone of the face and has estimated annual treatment and rehabilitation costs of >$5 million in the USA. Mandible fracture treatment may involve surgically fitting small titanium miniplates across the fracture to stabilise the bony segments while they heal to restore function. However, post-operative complications are common and there remains limited knowledge around best practices for fracture fixation for the most common fracture sites, such as the mandibular angle. Angle fractures are typically treated via the minimally invasive Champy method or the more invasive mono-planar and bi-planar methods. We hypothesised that physiological loading of Champy’s fixation results in tension across the inferior border of the fracture line and limits healing. We tested the biomechanical efficacy of all three fixation techniques during unilateral chewing using finite element analysis. Results show that post-fixation, jaw biomechanics were strongly affected by the side that the subject chews on during rehabilitation. We suggest that two-plate fixation, such as the mono-planar and bi- planar methods, is biomechanically the most stable, though more in vivo research is required to assess its impacts on bone healing. Our findings can be used alongside future research to inform best practice for mandible fracture repair procedures.
Dr Hyab Mehari Abraha is a recent graduate of the Faculty of Medicine, Nursing and Health Sciences at Monash University. Her PhD project focused on determining the effects of mandibular repair techniques on bone biomechanics during chewing.