Diagnosis of Tuberculosis in the Left Knee: X-ray Reveals Phemister Triad

Tuberculosis (TB)is endemic in various parts of the world and health-care practitioners should have high-end suspicion of TB knee in various cases of monoarthritis of the knee with atypical findings. We present a case of monoarthritis knee with an initial diagnosis being septic arthritis, with TB- cartridge-based nucleic acid amplification test negative for aspirated synovial fluid; followed by radiographic findings and synovial biopsy positive for chronic nonspecific inflammation with giant cells suggestive of TB, hence diagnosed as TB.