Mechanics means relating to or caused by movement or physical forces. I shall contend that OA is almost always caused by increased physical forces leading to damage to a joint. While examples of joint injury such as meniscal tears causing osteoarthritis are numerous, I shall contend that most or almost all osteoarthritis is caused in part by mechanically induced injury to joint tissues. Major traumatic injury induces OA in young joints with healthy tissues, but minor minimally traumatic injury is implicated as the cause of OA in older vulnerable joints. Further, once joint pathology has developed, like in clinical osteoarthritis, pathomechanics overwhelms all other factors in causing disease progression. Treatments which correct the pathomechanics have long lasting favorable effects on pain and joint function compared with treatments that suppress inflammation which have only temporary effects. Lastly, there is lots of evidence of inflammation in osteoarthritic joints, but I shall lastly contend that this inflammation is secondary— it is induced by mechanically induced joint injury and further that the role of this inflammation in worsening structural damage in the osteoarthritic joint has not yet been proven.

Disclosure of Interest None Declared