title: In vivo observations of hydraulic stiffening in the canine femoral head.
abstract: The role that intertrabecular contents and their boundary conditions have on the dynamic mechanical response of canine femoral heads was investigated in vivo. Femoral heads from paired intact hind limbs of canine specimens were subjected to a sinusoidal strain excitation at physiologic frequencies, in the cranio-caudal direction. The fluid boundary conditions for the contralateral limbs were changed by predrilling through the lateral femoral cortex and into the femoral neck. The drilling procedure did not invade the head itself. This femoral head fluid boundary alteration reduced the stiffness by 19 percent for testing at 1 Hz. The results of this study demonstrate that fluid stiffening occurs in vivo as previously observed ex vivo.
authors.affiliation: Johnson & Johnson Professional, Raynham, MA 02767, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Ochoa
authors.forename: A P
authors.initials: AP
authors.lastname: Sanders
authors.forename: T W
authors.initials: TW
authors.lastname: Kiesler
authors.forename: D A
authors.initials: DA
authors.lastname: Heck
authors.forename: J P
authors.initials: JP
authors.lastname: Toombs
authors.forename: K D
authors.initials: KD
authors.lastname: Brandt
authors.forename: B M
authors.initials: BM
authors.lastname: Hillberry
mesh_terms: D000818:Animals; D004285:Dogs; D004548:Elasticity; D005270:Femur Head / Q000502:physiology*; D018495:Fluid Shifts / Q000502:physiology*; D008297:Male; D011312:Pressure; D013314:Stress, Mechanical; D016474:Weight-Bearing