Pseudoseptic reaction to an intra-articular platelet-rich plasma injection into the knee: a case report.

A variety of intra-articular injections are used for the management of osteoarthritis. A rare complication of intra-articular injections is acute pseudoseptic arthritis, which mimics true septic arthritis. To the authors knowledge, pseudosepsis has not been reported as a complication after platelet-rich plasma (PRP) injections. We present a case report of pseudoseptic arthritis resulting in acute postinjection pain and a joint effusion after an intra-articular PRP injection into the knee. Clinically, pseudosepsis can occur after PRP treatment with significantly elevated white blood cell counts in the synovial fluid, and should be a consideration in cases of post-PRP injection flares.