[Purulent gonarthritis resulting from H1N1 viral pneumonia].

No articles on orthopedic complications of pneumonia due to influenza A H1N1 virus have yet been published. A 44-year-old male patient was hospitalized due to the suspicion of an infected knee. During arthroscopy beta-hemolytic Streptococcus group A and Acinetobacter were found and the histopathological diagnosis of an infectious bacterial synovialitis was made. Despite resistance-oriented antibiotic treatment the patient's general condition worsened. Influenza A H1N1 virus was detected in a nasal sample and was successfully treated with Tamiflu®. If fever and elevated infection markers persist a search for the focus has to be performed including unlikely diseases such as influenza A H1N1 virus.