Osteomyelitis of the pelvis and proximal femur: diagnostic difficulties.

Osteomyelitis of the pelvis or proximal femur may still be diagnosed late because the infection is deeply placed and investigations may concentrate solely upon the possibility of septic arthritis. Periacetabular infection was diagnosed in 16 children between 1994 and 1998. A high index of suspicion and the use of appropriate imaging will ensure that the condition is not allowed to progress, although in this series one child underwent an unnecessary appendectomy, and a subsequent sepsis of the hip joint was drained in another case. Radiographs of the pelvis were rarely abnormal within 7 days of the onset of symptoms and an ultrasound scan focused on the hip joint may miss the periarticular changes.