- Major patients hospitalized in Rheumatology, Infectiology, Orthopedy Department (hospital of Nantes, of La Roche sur Yon and of Saint-Nazaire) with a septic arthritis of shoulder, or elbow, or wrist , or hip, or knee, or ankle on native joint, with positive microbiologic culture joint fluid or positive hemoculture; the diagnosis was based on positive histology or imagery with an inflammatory joint fluid if the microbiologic cultures (hemoculture or joint effusion) were negative.