title: The effect of age on the structural properties of human ribs.
abstract: Traumatic injury from motor vehicle crashes is a major cause of morbidity and mortality in the United States. The thorax is particularly at risk in motor vehicle crashes and is studied extensively by the injury biomechanics community. Unfortunately, most samples used in such research generally do not include children or the very elderly, despite the common occurrence of thorax injuries at both ends of the age spectrum. Rib fractures in particular, are one of the most common injuries, especially in the elderly, and can greatly affect morbidity, mortality, and quality of life. As the proportion of older adults in the population increases, such age-related fragility fractures will continually grow as a worldwide problem. Additionally, the risk of rib fracture significantly increases with age with confounding deleterious effects. Studies on elderly ribs are not uncommon, however very few studies exist which explore the mechanical properties and behavior of immature human bone, especially of ribs. Previous research identifying rib properties has provided useful information for numerous applications. However, no study has included a comprehensive sample of all ages (pediatric through elderly) in which ribs are tested in the same repeatable set-up. The goal of this study is to characterize differences in rib structural response across the age spectrum. One-hundred forty excised ribs from 70 individuals were experimentally tested in a custom-built pendulum fixture simulating a dynamic frontal impact. The sample includes individuals of ages ranging from six to 99 years old and includes 58 males and 12 females. Reported data include fracture location, displacement in the X and Y directions at fracture (δX, δY), force at fracture (FX), and linear structural stiffness (K). δX and K exhibit a statistically significant linear decrease with age (p<0.0001). FX reveals a trend in which a peak is reached in the young adult years (25-40). Detailed mechanical property data, as provided here, will prove useful for application in computational modeling efforts, which are vital to help prevent injury and to understand injury mechanisms from childhood through old age.
authors.affiliation: The Ohio State University, Injury Biomechanics Research Center, 2063 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210, United States. Electronic address: Amanda.Agnew@osumc.edu.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Agnew
authors.affiliation: The Ohio State University, Injury Biomechanics Research Center, 2063 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210, United States. Electronic address: Schafman.1@osu.edu.
authors.forename: Michelle
authors.initials: M
authors.lastname: Schafman
authors.affiliation: National Highway Traffic Safety Administration (NHTSA), Vehicle Research & Test Center (VRTC), P.O. Box B37, 10820 SR 347, East Liberty, OH 43319-0337, United States. Electronic address: Kevin.Moorhouse@dot.gov.
authors.forename: Kevin
authors.initials: K
authors.lastname: Moorhouse
authors.affiliation: The Ohio State University, Division of Health Information Management and Systems, 543 Atwell Hall, 453 10th Avenue, Columbus, OH 43210, United States. Electronic address: Susan.White@osumc.edu.
authors.forename: Susan E
authors.initials: SE
authors.lastname: White
authors.affiliation: The Ohio State University, Injury Biomechanics Research Center, 2063 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210, United States. Electronic address: YunSeok.Kang@osumc.edu.
authors.forename: Yun-Seok
authors.initials: YS
authors.lastname: Kang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D055595:Mechanical Phenomena; D008875:Middle Aged; D012253:Rib Fractures / Q000503:physiopathology; D012272:Ribs / Q000293:injuries / Q000502:physiology*; D016474:Weight-Bearing; D055815:Young Adult
keywords: Displacement; Force; Fracture; Stiffness; Thorax injury