A number of experimental models of bacterial arthritis demonstrated that immune factors, especially directed cytokines, play an important role in cartilage destruction. The most important studies in bacterial arthritis were a review of the clinical manifestations of gonococcal arthritis and two reports of the use of polymerase chain reaction to detect Neisseria gonorrhoeae DNA in synovial fluid. Polymerase chain reaction may be an important diagnostic test in culture-negative cases and may be very helpful in understanding the pathophysiology of gonococcal arthritis.