Knee loading dynamically alters intramedullary pressure in mouse femora

Bone. 2007 Feb;40(2):538-43. doi: 10.1016/j.bone.2006.09.018. Epub 2006 Oct 27.


Dynamic mechanical loads have been known to stimulate bone formation. Many biophysical factors such as number of daily loading cycles, bone strain, strain-induced interstitial fluid flow, molecular transport, and modulation of intramedullary pressure have been considered as potential mediators in mechanotransduction of bone. Using a knee loading modality that enhances anabolic responses in mouse hindlimb, we addressed a question: Do oscillatory loads applied to the knee induce dynamic alteration of intramedullary pressure in the femoral medullary cavity? To answer this question, mechanical loads were applied to the knee with a custom-made piezoelectric loader and intramedullary pressure in the femoral medullary cavity was measured with a fiber optic pressure sensor. We observed that in response to sinusoidal forces of 0.5 Hz and 10 Hz, pressure amplitude increased up to 4-N loads and reached a plateau at 130 Pa. This amplitude significantly decreased with a loading frequency above 20 Hz. To confirm alteration of intramedullary pressure, real-time motion of microparticles in a glass tube inserted to the femoral medullary cavity ex vivo was visualized. Taken together, these data reveal that knee loading dynamically alters intramedullary pressure as a function of loading intensities and frequencies.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Female
  • Femur / physiology*
  • Hindlimb / physiology*
  • Joints / physiology
  • Mice
  • Mice, Inbred C57BL
  • Microspheres
  • Stress, Mechanical
  • Weight-Bearing