Reinforcement of Articular Cartilage with a Tissue-interpenetrating Polymer Network Reduces Friction and Modulates Interstitial Fluid Load Support

Summary Objective Osteoarthritis is associated with increased articular cartilage hydraulic permeability and decreased maintenance of high interstitial fluid load support during articulation, resulting in increased friction on the cartilage solid matrix. This study assesses frictional response following in situ synthesis of an interpenetrating polymer network designed to mimic glycosaminoglycans depleted during osteoarthritis. Methods Cylindrical osteochondral explants containing various interpenetrating polymer concentrations were subjected to a torsional friction test under unconfined creep compression. Time-varying coefficient of friction, compressive engineering strain, and interstitial fluid load support proportion were calculated and analyzed. Results The polymer network reduced friction coefficient over the duration of the friction test, both under moderate fluid load support as well as under 0% fluid load support. A positive trend was observed relating polymer network concentration with magnitude of friction reduction compared to non-treated tissue. The calculated hydraulic permeability of polymer-treated tissue was 27% decreased compared to non-treated tissue. Conclusion The cartilage-interpenetrating polymer treatment improves lubrication by augmenting the biphasic tissue’s interstitial fluid phase, and additionally improves the friction dissipation of the tissue’s solid matrix. This technique demonstrates potential as a therapy to restore optimal tribological function of degenerated cartilage.