Infections of prosthetic joints are a common cause of failure of joint replacements. The correct assignment of the antibiotic to the causative agent of the infection is crucial for successful treatment. For revision procedures, clindamycin or ciprofloxacin 400 mg is administered intravenously 2 hours before surgery. Clindamycin is preferred for its good permeability into bone – 80 to 150% of the serum level penetrates into bone tissue[1][4]. The treatment includes a two-phase operation: in the first phase extraction of the prosthesis, disinfection of the bone bed and introduction of a spacer with antibiotics, in the second phase reimplantation after 6 months[1]. In septic arthritis of an artificial joint, the prosthesis is removed and replaced with a temporary device made of antibiotic cement, a new prosthesis is implanted several months later[2]. Antibiotics are given first intravenously and then orally for several weeks to months[2].