Primary haematogenous osteomyelitis of the patella: a rare cause for anterior knee pain in an adult.

Acute osteomyelitis of the patella is a very rare condition, which commonly affects children between the ages of 5-15 years. Primary haematogenous osteomyelitis in an adult usually occurs in patients with associated risk factors like intravenous drug abuse, HIV infection, and trauma. This report discusses a similar condition in a 46 year old women with no associated predisposing risk factors. The rarity of this condition and its atypical presentation should be borne in mind while treating an adult patient with anterior knee pain. Point tenderness over the patella should alert a physician to the possibility of osteomyelitis of the patella. The value of bone scan and computed tomography in the early stages to help diagnose this condition has been stressed. The literature has been reviewed and discussed briefly.