Home › Blog › Knee Arthritis Stiction: Friction isn’t Killing Your Joints, “Stiction” Is…

The words Knee Arthritis Stiction would up until now, be assumed to be a misspelling, however, a new study has changed the game.  The concept for the last half century or so has been that as arthritis advances, the friction inside the joint increases. This additional friction in the joint leads to more wear and tear and a “degenerative spiral”. This seemed to make sense, until now. Researchers at the University of California, Santa Barbara have developed a new concept of arthritis wear and tear they call “stiction” or “stick-slip” friction.” Believe it or not, this is an actual established materials engineering term (I had to look it up). Both friction and stiction are characterized by surfaces that initially stick together, and then accelerate away quickly once the static friction force is overcome. With stick-slip friction, the surfaces eventually pull slightly apart and slide across each other, stick again, and pull apart, causing jerky movements. This concept of joint wear opens up a host of possibilities about how certain therapies may work. For example. hyaluronic acid is often injected into joints as an artificial lubricant (brand names SynVisc, Orthovisc, Euflexa, Hyalgan, and Orthovisc). While this lubricant might help reduce friction, it would also be particularly good at preventing stiction. In addition, certain material properties of synovial fluid (the natural lubricant in the knee) might be better at preventing knee arthritis stiction. Finally, it’s also possible that one mechanism of how stem cells work in a severely degenerated joint without resurfacing new cartilage would be by improving the health of the synovial fluid in the knee so that stiction is reduced. This fits with recent animal models showing that stem cell injections delayed the progression of arthritis. The upshot? The next time your joints feel “creaky” it just may be stiction, not friction…

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile