Arthrographic findings in septic arthritis of the hip in infants.

Both standard radiography and arthrography are essential in the diagnosis of septic arthritis in infancy. Plain films demonstrate lateral subluxation, marked delay in appearance of the femoral ossification center, deformity of the femoral neck, and acetabular dysplasia. Arthrography shows cartilaginous deformity, subluxation, and contracture of capsular structures. These observations may distinguish the late sequelae of bacterial infection from other entities such as noninfectious avascular necrosis.