A method of treatment of pyogenic arthritis of the adult knee employing wide open arthrotomy and early active motion, as well as synovectomy in some knees, was used in thirty-four patients with pyogenic arthritis of the knee. Of these patients, sixteen had a good result, twelve had a fair result, and six had a poor result. This method of treatment was used as a salvage procedure in most of the patients, but may have more general application in the treatment of pyogenic arthritis of the knee.