K. Culliton (Ottawa, CA)
The Ottawa Hospital Research Institute Division of Orthopaedic SurgeryPresenter Of 1 Presentation
10.4.10 - The role of biaxial sliding and cyclic uniaxial compression on solute transport in articular cartilage
Abstract
Purpose
Articular cartilage relies on diffusion pathways to obtain essential nutrients and molecules for cellular activity. Understanding these transport pathways is essential to maintaining and improving the health of articular cartilage and ultimately synovial joints. Several studies have shown that joint articulation is associated with fluid and solute uptake although it remains unclear what role biaxial sliding and cyclic uniaxial compression independently play.
Methods and Materials
Cartilage-bone plugs (10mm) were obtained from porcine knee joints and sealed along the radial edge into purpose made diffusion chambers. The bone side of the chamber was filled with PBS to maintain tissue hydration while the cartilage side was filled with 0.01mg/ml fluorescein sodium salt (FNa) prepared using PBS. Samples were either subject to biaxial sliding (1.4 MPa at 5 mm/s) or cyclic uniaxial compression (0-1.4 MPa at 0.4MPa/s) using a 25 mm diameter spherical indenter for 0.5 or 1 hour. Both loading configurations were compared to unloaded control samples. After diffusion tests, samples were sectioned and imaged using an epifluorescent microscope with a filter for FNa. Intensity profiles were mapped and normalized from the articular surface to the subchondral bone. Fluorescent intensity represents solute uptake into the cartilage and is scaled from 0 – 100% of the dynamic range.
Results
Samples that had been subjected to sliding demonstrated accelerated penetration and solute accumulation compared to compression samples (figure 1). Both loading configurations exceeded solute penetration and accumulation compared to unloaded controls
Conclusion
Biaxial sliding and cyclic uniaxial compression play an important role in the uptake of solutes into the cartilage matrix. Maintaining joint motion both post injury and in the arthritic process is a critical component of cartilage nutrition. Samples that had been subject to biaxial sliding demonstrated accelerated solute penetration and accumulation in the cartilage matrix, exceeding concentrations achieved cyclic uniaxial compression and passive diffusion.