Recurrent Pyarthrosis of the Knee Causing Aortic Valve Endocarditis

We present a rare case of a 75-year-old man with recurrent Streptococcus pneumoniae endocarditis caused by septic knee arthritis and complicated by a severe second infection after implantation of a total knee endoprosthesis. During the first episode of pneumococcal arthritis, the oligosymptomatic patient was discharged under antibiotic therapy. He returned to hospital with cardiac decompensation 1 week later. The initial finding was a perforation of the left aortic valve cusp without vegetation or abscess, which led to conventional aortic valve replacement with a biological prosthesis 12 days after diagnosis. Ceftriaxone was administered for a cumulative duration of 6 weeks after the operation day. There were no further complaints concerning the knee and the patient could be mobilised for cardiac rehabilitation. Twelve months later, the patient received an endoprosthesis of the affected knee. After another 6 months he developed a severe second infection with involvement of the aortic valve prosthesis and a huge periannular abscess. As the main infective focus, the knee endoprosthesis had to be explanted before aortic root treatment. Correct treatment by means of modified Duke criteria, interaction of interdisciplinary approach and the definition of appropriate procedure timing represent the main challenge in this exceptional case, and are worth discussing.