Tuberculosis of the patella imitating chronic knee synovitis

Tuberculosis of patella is a rare occurrence with incidence of less than 0.15% in the literature. Owing to its rarity the diagnosis is usually missed. Here we present a case of tuberculosis of the patella, being treated as chronic synovitis elsewhere. An 11-year-old boy presented to us with chronic knee swelling and a draining sinus of 5 months duration. He was being treated with broad spectrum antibiotics and incision and drainage. Standard X-rays revealed a lytic area with surrounding coke such as sequestrum in patella. MRI was suggestive of osteomyelitis of the patella with soft tissue oedema. Diagnosis was confirmed on biopsy. The patient was managed by curettage and excision of the sinus tract along with antitubercular treatment. The patient responded well to antitubercular therapy and gained excellent functional range of movement. In today's era of potent antituberculous drugs and decreasing tuberculosis incidence the rare and unusual locations of tuberculosis such as patella should be borne in mind while dealing with chronic lesions of the knee especially in tubercular endemic areas. A timely diagnosis helps in regaining good range of motion and a satisfactory outcome.