Septic arthritis caused by chronic osteomyelitis.

We have treated four cases of previously quiescent osteomyelitis which presented as septic arthritis in an adjacent joint. The osteomyelitic focus was in the bone proximal to the involved joints (zero to ten centimeters above the joint line). Based on the presenting history, physical findings, laboratory tests and cultures of joint fluids, the joint sepsis was low grade in all patients which led to delays in diagnosis and treatment. Aggressive surgical debridement of both bone and joint, followed by a prolonged course of antibiotics led to resolution in all patients. A high index of suspicion combined with adequate radiographs of the surrounding bones should lead to the appropriate diagnosis and treatment.