After acute knee trauma, the concentrations of IL-1ra generally increase in the synovial fluid within the first two weeks after injury, but then IL-1ra becomes undetectable, while, in contrast, IL-1β remains significantly elevated up to 1.5 months after knee trauma and rises again once clinical PTOA of the knee is diagnosed [3], suggesting that IL-1ra supplementation may be beneficial in preventing knee PTOA. Here, IL1B is linked to injury.