[Osteomyelitis of the ischium with ipsilateral hip dislocation in an infant].

Acute hematogenous osteomyelitis of the os ischii is a rare disease. Involvement of the acetabulum in a 4-month old girl with concomitant developmental dysplasia of the ipsilateral hip caused a dislocation of the hip joint due to synovitis. Arthroscopic joint lavage, antibiotic treatment and reduction of the hip in a pavlik-harness led to a satisfactory result.