biological marker; hyaluronic acid; adult; aged; analysis of variance; aspiration; blood sampling; body mass; clinical article; clinical outcome; comparative effectiveness; compression instrument; conference abstract; controlled study; coronavirus disease 2019; diagnostic test accuracy study; female; health survey; human; intraarticular drug administration; Italy; knee osteoarthritis; male; needle; outcome assessment; pain assessment; prospective study; questionnaire; radiologist; real time ultrasound scanner; rheumatologist; synovial fluid; visual analog scale; walking distance; Western Ontario and McMaster Universities Osteoarthritis Index; X ray film