10">Significant increased interleukin-1 receptor antagonist (IL-1ra) and interleukin-1 beta (IL-1β) concentrations in osteoarthritis (OA) joints compared to normal joints.

15">No significant difference of synovial fluid (SF) IL-1ra and IL-1β concentrations between metacarpophalangeal/metatarsophalangeal, radiocarpal, and talocrural joints.

Arthrocentesis did not increase SF IL-1ra and IL-1β levels within 1 hour after joint puncture.

Positive correlation of SF white blood cell (WBC) count and protein concentration.

No significant difference of SF WBC count and protein concentration between normal an OA joints.

Positive correlation of SF IL-1β and IL-1ra concentration.