Late congenital dislocation of the hip.

Congenital dislocation of the hip in a child over the age of 4 may be discovered as a late untreated displacement, presenting with subluxation or dislocation, or as a late treated displacement presenting as a subluxating or subluxated hip. Conservative treatment is inadequate in untreated dislocations. Surgical reduction is the only possible procedure, associated with shortening femoral. The procedure may be used up to the age of 7 in bilateral cases, and up to the age of 12 in unilateral cases. Subluxating hips are recognised on the anteroposterior radiograph by a break in Shenton's line. A delayed Trendelenburg sign may also been seen. In such cases, innominate osteotomy or femoral derotation osteotomy should be performed, according to the anatomical defects present. Femoral shortening may be indicated in cases of increased length of the lower limb, associated with residual coxa valga or over growth following a previous rotation osteotomy to avoid the mechanical effects on the opposite hip. In cases of subluxated hip, varus upper femoral osteotomy may be indicated, or a Chiari osteotomy in painful hips. It is concluded that routine follow-up radiography is necessary, surgery being indicated as soon as a loss of acetabularcover of the femoral head is detected.