At the end of the procedure, we told the patients that their knee might be swollen due to retained saline, and to expect this additional swelling to resolve over 24-48 hours, during which time they were to minimize activity. The person who did the procedure (the principal investigator) then left the room. The study nurse, who was not present for the procedure and was blinded to the procedure's identity, asked the patients which treatment they thought they received (tidal lavage or sham lavage). We scheduled patient followups with this study nurse for 3, 6, and 12 months, and patients completed questionnaires at each visit. Questionnaires were both arthritis-specific (WOMAC) and global (Quality of Well-Being).