Clinical, laboratory and radiological data of 35 patients (> 60 years) with septic arthritis were retrospectively analyzed in 2 groups submitted to different treatment protocols based on the radiological stage of destruction. Group I: intraarticular gentamicin-PMMA beads (8 cases), group II: resection-arthroplasty with gentamicincement spacer (27 cases). The average diagnostic delay was 4.8 months. Diagnostic errors were: osteoarthrosis in 9 cases, periarthritis of the shoulder in 5, femoral head necrosis in 4 cases, sciatic pain in 3, osteoporosis in 1, and thrombosis in 1 case. The re-operation rate in group I was 1.4 (range 1-2 operations) and in group II 1.2 (range 0-3 operations). Fifteen patients were left with a resection-arthroplasty. The restriction of motion remained moderate in 6 and severe in 9 cases. Three patients had sepsis and died. The final results were poor after both treatment protocols. Early diagnosis seems to be the most determining factor concerning the final outcome of septic arthritis.