title: What ape proximal femora tell us about femoroacetabular impingement: a comparison.
abstract: BACKGROUND
  Human hip morphology is variable, and some variations (or hip morphotypes) such as coxa profunda and coxa recta (cam-type hip) are associated with femoroacetabular impingement and the development of osteoarthrosis. Currently, however, this variability is unexplained. A broader perspective with background information on the morphology of the proximal femur of nonhuman apes is lacking. Specifically, no studies exist of nonhuman ape femora that quantify concavity and its variability.
  
  
  OBJECTIVE
  We hypothesized that, when compared with modern humans, the nonhuman apes would show (1) greater proximal femoral concavity; (2) less variability in concavity; and (3) less sexual dimorphism in proximal femoral morphology.
  
  
  METHODS
  Using identical methods, we compared 10 morphological parameters in 375 human femora that are part of the Hamann-Todd collection at the Cleveland Museum of Natural History with 210 nonhuman ape femora that are part of the collection of the Royal Museum for Central Africa, Tervuren, Belgium, and the Muséum National d'Histoire Naturelle, Paris, France.
  
  
  RESULTS
  The nonhuman apes have larger proximal femoral concavity than modern humans. This morphology is almost uniform without large variability or large differences neither between species nor between sexes.
  
  
  CONCLUSIONS
  Variability is seen in human but not in nonhuman ape proximal femoral morphology. An evolutionary explanation can be that proximal femoral concavity is more important for the nonhuman apes, for example for climbing, than for modern humans, where a lack of concavity may be related to high loading of the hip, for example in running.
authors: Department of Orthopaedic Surgery, Haga Hospital, Sportlaan 600, 2566 MJ, The Hague, The Netherlands.
authors: Joost T
authors: JT
authors: Fikkers
authors: Heinse W
authors: HW
authors: Bouma
authors: Stefan F
authors: SF
authors: de Boer
authors: Paul A
authors: PA
authors: Toogood
authors: Paulien M
authors: PM
authors: van Kampen
authors: Tom
authors: T
authors: Hogervorst
mesh_terms: D000717:Anatomy, Comparative; D000818:Animals; D057925:Femoracetabular Impingement / Q000473:pathology* / Q000601:surgery; D005269:Femur / Q000033:anatomy & histology* / Q000473:pathology; D005270:Femur Head / Q000033:anatomy & histology; D005272:Femur Neck / Q000033:anatomy & histology; D006621:Hip Joint / Q000000981:diagnostic imaging; D015186:Hominidae; D006801:Humans; D011859:Radiography