Allison R Moats1, Raghav Badrinath2, Linda B Spurlock3, Daniel Cooperman2. 1. Department of Human Evolutionary Biology, Harvard University, Peabody Museum 53C, 11 Divinity Avenue, Cambridge, MA 02138. 2. Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, Yale Physicians Building, 800 Howard Avenue, 1st Floor, New Haven, CT 06519. E-mail address for R. Badrinath: raghav.badrinath@yale.edu. 3. Department of Anthropology, School of Biomedical Sciences, Kent State University, 750 Hilltop Drive, 226 Lowry Hall, Kent, OH 44242.
Abstract
BACKGROUND: The precise etiology of cam impingement continues to be incompletely understood. The prevailing hypothesis posits that the deformity arises as a developmental injury prior to skeletal maturation. There is a possible evolutionary role, with an aspherical femoral head affording upright humans better stability. We set out to identify the antiquity of the cam deformity to better understand the comparative roles of modern behavior and evolution in its development. METHODS: We used 249 physical specimens of femora from the Libben osteological collection, a set of bones from an ancient population who lived between the eighth and the eleventh century. These femora were photographed in four different orientations, and six specific proximal femoral angles were measured. The values were also compared with those from modern human femora using the Student t test, with a two-tailed p value of 0.05 denoting significance. RESULTS: In total, 249 femora from 175 individuals were included in the final analysis. The ages of the individuals ranged between seventeen and fifty-five years. Interobserver and intraobserver correlation was good or excellent for all variables measured. Compared with modern populations, ancient human hips were significantly more anteverted (19.96° versus 12.85°; p < 0.001) and varus (true neck-shaft angle, 121.96° versus 129.23°; p < 0.001). The alpha angle was significantly lower in ancient humans (35.33° versus 45.61°; p < 0.001), and none of the ancient femora met the modern criteria for a cam deformity (an alpha angle of >50°). CONCLUSIONS AND CLINICAL RELEVANCE: It appears that the cam deformity was nonexistent among ancient humans and is perhaps predominantly a product of modern-day stresses. Further clinical investigation into behavioral modifications in adolescence is warranted to potentially prevent the development of deformity and impingement.
BACKGROUND: The precise etiology of cam impingement continues to be incompletely understood. The prevailing hypothesis posits that the deformity arises as a developmental injury prior to skeletal maturation. There is a possible evolutionary role, with an aspherical femoral head affording upright humans better stability. We set out to identify the antiquity of the camdeformity to better understand the comparative roles of modern behavior and evolution in its development. METHODS: We used 249 physical specimens of femora from the Libben osteological collection, a set of bones from an ancient population who lived between the eighth and the eleventh century. These femora were photographed in four different orientations, and six specific proximal femoral angles were measured. The values were also compared with those from modern human femora using the Student t test, with a two-tailed p value of 0.05 denoting significance. RESULTS: In total, 249 femora from 175 individuals were included in the final analysis. The ages of the individuals ranged between seventeen and fifty-five years. Interobserver and intraobserver correlation was good or excellent for all variables measured. Compared with modern populations, ancient human hips were significantly more anteverted (19.96° versus 12.85°; p < 0.001) and varus (true neck-shaft angle, 121.96° versus 129.23°; p < 0.001). The alpha angle was significantly lower in ancient humans (35.33° versus 45.61°; p < 0.001), and none of the ancient femora met the modern criteria for a camdeformity (an alpha angle of >50°). CONCLUSIONS AND CLINICAL RELEVANCE: It appears that the camdeformity was nonexistent among ancient humans and is perhaps predominantly a product of modern-day stresses. Further clinical investigation into behavioral modifications in adolescence is warranted to potentially prevent the development of deformity and impingement.
Authors: Bartosz Jan Musielak; Anna Maria Kubicka; Łukasz Woźniak; Marek Jóźwiak; Raymond W Liu Journal: Clin Orthop Relat Res Date: 2021-08-01 Impact factor: 4.755