TNF and hemarthrosis: Similar to the aforementioned study [21], Swärd et al. showed that injured patients with hemarthrosis, which is bleeding into the joint cavity, exhibited an increase in IL-1β, TNF-α, IL-6 and IL-8 in the SF 24 h after injury, followed by a time-dependent decrease thereafter, with IL-8 remaining significantly higher than age- and gender-matched healthy controls up to 15 days and IL-1β, TNF-α and IL-6 up to 23 days after injury [23].