A Study on the Changes of the Femoral Head following Treatment of Congenital Dislocation of the Hip

Although the incidence of avascular necrosis of the pmximal end of the femur has declined by early diagnosis and gentle dynamic reduction, it is still one of the major complication in treatment of congenital dislocation of the hip. From 65 cases, followed up at least one year after reduction at the Department of Orthopaedic Surgery, Busan National University Hospital from January, 1980 to June, 1984, the authom studied the factom causing avascular necrosis of the femoral head and its radiographic classification. The following results were obtained. 1. Based on Salter's criteria, avascular necrosis of the femoral head was considered in 16 of the 65 hips, a rate of 24.6%. 2. Based on the classification of Bucholz and Ogden, radiographic patterns of avascular necrosis were: type 1, 6(37.5%); type 2,3(18.8%); type 3, 5(31.3%); type 4, 2(12.5%). 3. Generally, the older the child when treatment was initiated, the more likely was avascular necrosis to develop, and the more severe was its damage. 4. The incidences of avascular necrosis in various treatments were: Pavlik harness, 10%; manipulative reduction, 17%; medial approach open reduction 40%; Salters innominate osteotomy only, 36%; femoral osteotomy with pelvic osteotomy, 20%. The high incidence in medial approach open reduction and Salters innominate osteotomy may be due to failure of previous manipulative reduction. 5. The preliminary traction of 14 days or more substantially reduced the incidence of avascular necrosis. 6. There was particularly high incidence of avascular necrosis in cast immobilization of Lorenz position. 7. The correlation between adductor tenotomy and avascular necrosis was not noticed. There was no avascular necrosis in the normal contralateral hip after cast immobilization.