The Effects of Increasing Positively Charged Metal Ions Within Synovial Fluid
Osteoarthritis is a degenerative joint disease that affects 10% of men and 13% of women over age of 60. It is the degradation of the cartilage between two bones; obesity, age, overuse, or injury are major contributors to the development of this disease. The joint is incapsulated by the synovial sac filled with a viscous solution that aids in lubrication referred to as synovial fluid. If the synovial sac is ruptured due to injury, positive ions (K+, Na+, Ca2+, and Fe3+) may affect viscoelastic properties within the sac. The purpose of this study was to understand how positive metal ions affect the synovial matrix and its rheological and tribological properties across two different age groups to better the understand the development of osteoarthritis. The hypothesis was that positively charged metal ions from blood or ruptured cells weaken the repulsive forces in the meshwork causing destructive changes in the rheological and tribological properties of the synovial fluid. The results for NaCl and KCl supported the hypothesis by disrupting the rheological properties of old synovial fluid, but other data suggested a significant increase in the viscoelastic behavior of young synovial fluid when NaCl and KCl are introduced. The data also suggested that FeCl3 and CaCl2 significantly increase the elastic potential in old synovial fluid.