Primary patellar osteomyelitis presenting as a pre-patellar bursitis in children: a potential diagnostic mistake

Abstract

A 14-year-old male presented with pain and swelling of left knee since 15 days with history of non-significant trauma and mild fever. On clinical examination there was raised superficial skin temperature and pre-patellar effusion with positive patellar tap. Haematological investigations show moderate leucocytosis and raised acute phase reactants, with an unremarkable radiography. Under the impression of infective pre-patellar bursitis, patient was posted for arthrotomy, debridement and wound wash. Post-operative broad spectrum antibiotics started. 2 weeks after surgery the swelling reappears, when an advanced imaging was offered which shows osteomyelitic changes in upper pole of patella. After 6 weeks of intravenous antibiotics and conservative management, the lesion was healed leaving no sequel.