[Secondary infection of joint implants: diagnostic criteria, treatment and prevention].

Peroperative contamination is the most frequent cause of infection after arthroplasty. For other cases of infection subsequent to bacteremia or a neighboring focus, it would be more appropriate to use the term "secondary" infections rather than hematogeneous infections. Arguments favoring secondary infection include long symptom-free interval between prosthesis implantation and the infectious episode, a causal germ not generally responsible for peroperative infection, presence of a distant infectious focus, positive blood culture, and a positive bacteriological sample from the prosthesis level showing the same strain as grown from the distant focus or blood samples. Both acute and chronic infections are observed, leading to prosthesis dysfunction. History taking generally identifies a neglected acute but transient episode. Search for a bacteriological diagnosis must be completed before initiating an antibiotic regimen. If detected very early, washing with open synovectomy and resection of suspicious tissue should be attempted in order to maintain the implant if possible. Local antibiotics have proven efficacy. Beyond a certain delay, treatment for chronic infection usually requires removing the prosthesis, cleaning the bone interface, and new arthroplasty delayed or not. Search for the portal must be undertaken early in order to initiate appropriate local treatment. The causal event may be any invasive procedure, with or without material implantation. The risk-benefit ratio for antibiotic prophylaxis remains to be determined.