[Acute gonarthritis--application of current diagnostic study methods exemplified by a case report].

The evaluation of acute inflammatory knee arthritis deserves special emphasis, because immediate benefit may result from identification and treatment of the underlying disease. The diagnostic approach to and the differential diagnosis of an acute knee arthritis are presented. By means of a case report, the use of the needle arthroscopy and the polymerase chain reaction (PCR) method for analysis of synovial fluid and synovial tissue in the diagnosis and evaluation of treatment of Lyme disease is described. The significance of this approach in diagnostic and therapeutic procedures has yet to be defined.