The treatment of bone cysts by topical injection of methylprednisolone acetate was initiated at the end of 1973, and the late results are reported in this paper. In seventy-two cases followed up for one to three years favourable results have been obtained in about 90 per cent. The technique of local injection and the surgical equipment employed, in the case of focal recurrences, are considered. With this method, surgical treatment of bone cysts in youth is seldom necessary.

A few points in this report deserve to be stressed.

Indications–It is important that the orthopaedic surgeon should decide at a very early stage which of the two methods, closed or open, he must use. These do not exclude each other but are on the other hand complementary. Nowadays the dislocated hip can be reduced by open operation with a very good chance of lasting success. This should be carried out if a hip cannot easily be reduced otherwise, or if there is any doubt that closed reduction has been successful–and as early as possible, preferably before the age of three years.

Technique–Ample exposure of the joint and removal of all obstacles to reduction are important. Reduction must be complete and stable but without stress, and there must be no interference with the articular bone and cartilage.

After-care–Reduction, however perfect, is only the first step towards recovery. The hip must be observed carefully and the most suitable moments for mobilisation and for walking must be chosen; this calls for nice judgment. When it is clear that the roof of the acetabulum is not developing or that persistent valgus and anteversion may encourage subluxation, a secondary operation should be undertaken at once. Radiography is necessary about every three months for the first two years.

Assessment of results–With a strict system of assessment, like McFarland's, we have observed 68·3 per cent favourable results in 171 hips treated by open reduction.

It is obvious that the problem of congenital dislocation of the hip has not yet been completely solved. But if we review the progress of recent years we come to the encouraging conclusion that much has already been achieved, and that the efforts of the many orthopaedic surgeons who have dedicated themselves to the treatment of congenital dislocation of the hip have not gone unrewarded.