Pyarthrosis of the knee was treated in 11 patients by arthroscopic lavage and debridement. There were 4 men and 7 women patients whose ages raged from 8 months to 80 years. Staphylococcus aureus was cultured in 5 knees. Four patients were caused by the injection of steroids. There were no recurrences. Arthroscopy can aid in establishing the diagnosis and implementing the appropriate treatment when a septic knee is suspected.
