Defining the Properties of Osseointegrated and Ingrowth Bone Around Orthopedic Medical Devices and Their Effect on Fracture Risk in Elderly Populations: A Forensic Anthropological Perspective

As elder abuse is becoming more recognized in the medicolegal death investigation of elderly individuals, it is important to understand the factors that impact fracture risk. That risk is not well defined for elderly individuals with joint replacement. Understanding of bone morphology is based on bone functional adaptation, which theorizes that the strain bone undergoes in life dictates its strength and mass. While this phenomenon has been well explored in an ideal model, it lacks consideration of unique loading instances such as that of a joint replacement, which is the objective of this research. The goal of this research is to understand the long-term effects of joint replacement on the human skeleton and fracture risk. The research design will consist of examining bone properties and fracture rates. Bone properties will be assessed through micro computed tomography (micro-CT) analysis, 3D modeling, and gross observation. Properties will be compared between groups of individuals who do and do not have knee and/or hip replacements. Comparing those without joint replacements who are matched by age, sex, and BMI to those with a joint replacement will allow the differences in skeletal properties to be clearly shown while mitigating other external influences. This project will use micro-CT to image the internal and external structures of femora and tibiae. Research questions will assess differences in trabecular bone qualities (volume, thickness, and orientation of the bone struts) and cortical cross-sectional bone qualities (bone area, porosity, shape, and strength). Analyzing these properties will show if the implants remain well integrated into the bone throughout life and positively impacted bone strength. As bone strength should inversely correlate with fracture risk, bone properties paired with macroscopic observations of fracture rates will inform on the skeletal fragility in individuals with implants. Bone changes will be assessed systemically and locally at multiple skeletal sites. 
Research on the long-term effects of hip and knee replacement on the human skeleton and the influence of joint replacement on fracture risk in elderly individuals will be disseminated in scientific journals. Additionally, information from this research will be incorporated into workshops presented to death investigators and law enforcement professionals. This research will contribute to the understanding of the influence of joint replacements on bone biology and fracture patterns in the elderly. The determination of fracture etiology is essential to determining the manner of death and the presence of elder abuse for the pursuit of criminal justice. CA/NCF