Biomechanical Investigation of the Effect of Bone Disorders on Pediatric Femur Fracture Potential

As submitted by the proposer: Child abuse is the leading cause of trauma-related fatalities in children less than four years of age. Clinicians, child protective services, and law enforcement personnel are often faced with determining whether a child’s injuries are the result of accidental causes or whether abuse should be suspected. These assessments are particularly challenging in cases where children have bone fragility disorders. Children with bone disorders may present with fractures that are misdiagnosed as abuse. Conversely, speculative bone disorders may be provided as false explanations for fractures by in criminal cases of child abuse. Objective information regarding fracture potential in children with bone disorders may aid in delineation of abusive and accidental injuries. Bone disorders such as osteogenesis imperfecta (OI) and rickets are associated with noticeable changes in both bone morphology (shape) and material properties (e.g. stiffness and density). Our research goal is to determine how material and morphologic bone differences in children with OI and rickets affect bone strength and fracture potential. Knowledge of differing fracture potential in children with these bone disorders may improve assessment of fracture and history compatibility leading to increased accuracy in clinical diagnoses and forensic investigations of child abuse. This study will identify differences in femur properties between healthy children aged 0-3 years and those with rickets or OI by reviewing radiographic data obtained from clinical collaborators at Kosair Children’s Hospital in Louisville, KY and Ann & Robert H. Lurie Children’s Hospital of Chicago. Additionally, computed tomography scans of pediatric femurs will be obtained from the University of New Mexico Center for Forensic Imaging and used to generate three-dimensional parametric finite element models. These models will enable further investigation of the influence morphologic and material parameters on femur fracture potential. Parametric models are useful for describing variability of a population based upon a small sample of subjects. In this study, parametric models will be used to develop virtual femurs for healthy children and those with bone disorders that will enable age-matched comparisons of fracture potential. Outcomes from this project include parametric femur models for healthy children of various ages and those with OI and rickets in which comparative assessments of fracture potential under different loading scenarios will be conducted. This study will also provide objective information regarding the influence of specific material and morphologic parameters (e.g. density and bone diameter) on fracture potential. This project contains a research and/or development component, as defined in applicable law. ca/ncf