Osteomyelitis is a progressive infection of the bone and bone marrow resulting in inflammatory destruction of the bone, necrosis, and new bone formation. It can occur following hematogenous or contiguous spread of infection.
Classic hematogenous spread is from S. aureus in pediatrics or salmonella in patients with sickle cell anemia. It most commonly affects the metaphysis of the tibia (50%), femur (30%), or fibula (12%).
Contiguous infections tend to be polymicrobial and most commonly occurs after trauma, with ulcers, and in patients with diabetes and vascular insufficiency.