Scientists from the Department of Chemical Engineering and the Department of Materials at UC Santa Barabara are looking at new ways to characterize and detect the early onset and progression of arthritis. The team members are studying the patterns of friction between cartilage pads using a Surface Force Apparatus (detailed description here).
Using the Surface Force Apparatus, the researchers were able to identify a signature frictional pattern for the cartilage. Contrary to the current theory that a high friction force is responsible for the wear and tear seen in arthritic joints, the team identified stick-slip friction as a dominant frictional pattern between cartilage. One of the implications of this is that future research should focus on minimizing stick-slip friction in the joint.
Stick-slip friction leads to more jerky movements between the joints and as a result exhibits a jagged frictional profile. The researchers believe in the future that this profile will be observable with sensitive acoustic sensors and detection algorithms which could replace current invasive tests for arthritis.
Study abstract in PNAS PLUS: Stick-slip friction and wear of articular joints