The development of antibiotics and arthroscopic treatment have been two major turning points in the management of septic arthritis of the knee joint. We report a retrospective review of 78 patients managed in three surgery units and one rheumatology unit. Management practices varied between the units. Joint aspiration was proposed for all patients seen by rheumatologists. Certain surgeons proposed arthroscopy systematically at admission while others preferred a more selective approach. Arthroscopic wash-out was proposed as the first-line procedure for only 33 patients. All were given systemic antibiotics using a variety of protocols. The course under antibiotic treatment confirmed the potential gravity of septic arthritis of the knee joint since two patients died and 34 required surgery, half of which had more than one operation. The functional outcome at mean 19 months was rather poor. Only 65 knees were free of any implant and only 40 (62%) were pain free. Mean flexion was 116 degrees and 11 patients (17%) had significant flexion contracture. Factors of poor prognosis were initially high sedimentation rate, advanced stage according to Gächter, presence of specific germs (meti-R S. aureus, Gram-negative bacilli), and failure of first-line treatment. A management algorithm was proposed: initial aspiration for evacuation, medical treatment alone if there is no synovitis, and reduction synovectomy otherwise. The key to success is early well adapted treatment.