[The painful hip joint in the child: differential diagnosis and therapy of coxitis fugax, Perthes disease and septic coxitis].

The differential diagnosis of a painful hip joint in children is important. Transient synovitis is frequently seen in children from 3 to 7 years of age with a short history of limping. The joint effusion is visualized by ultrasound. Radiograms and laboratory data are negative. Therapy consists of short term bed rest supported by an oral antiphlogistic drug. Children with Legg-Calve-Perthes disease complain about knee or hip pain in an early stage. X-ray documentation in the a.p and axial view are mandatory as well as ultrasound visualization of the accompanying effusion. Healing of the capital femural epiphysis is aided by weight relief and improved head containment. This may need from one to three years according to the age of the child and the amount of head involvement. More than half of the children's hips with Perthes disease surgical help to achieve a satisfactory result. Hip pain is overwhelming in cases of septic arthritis of the hip joint. This is the most important help to differentiate septic coxitis from transient synovitis or Perthes disease. Rapidly rising values of red cell sedimentation and c-reactive protein are important for early diagnosis. Septic effusions are visualized by ultrasound. X-ray changes are absent in the beginning and are seen only in delayed cases. Early arthrotomy with scrupulous rinsing of the joint, followed by parenteral antibiotic treatment, is the treatment of choice.