Recurrent arthritis as presenting symptom of osteomyelitis.

We present a patient who had one episode of prepatellar bursitis and subsequently several episodes of arthritis of his right knee. Cultures of several punctures of his knee remained sterile, but the patient had been taking oral antibiotics on each of these occasions against our medical advice. Ultimately a diagnostic puncture revealed growth of Staphylococcus aureus. An X-ray demonstrated an osteolytic lesion of the patella, but no defect in the articular surface of the patella could be visualised. MRI demonstrated a communication between the osteomyelitic focus through the medial retinaculum to the bursa suprapatellaris and the knee joint. Osteomyelitis of the patella is mainly a disease of childhood. This case is, to our knowledge, the first report on the association between bursitis, osteomyelitis of the patella and recurrent septic arthritis of the knee in an adult. The literature is reviewed and discussed briefly.