1. Fifteen patients who had had osteomyelitis of the lower femur or upper tibia during infancy have been studied. The cases of four patients showing particular features of the disease are presented in detail and the remainder are summarised.

2. It is suggested that damage to the epiphysis may be due to an abscess, or to ischaemia following occlusion of the blood supply. In the latter instance the prognosis may be better.

3. In the early stages the radiographic appearances may be deceptive, suggesting that damage to the epiphysis is irreparable.

4. Significant recovery of the epiphysis may occur in some patients after a delay of several years. This, together with the often good function which is preserved at the joint, should deter the surgeon from early destructive operation on the limb.

5. Deformity, which was present to some extent in all cases, appeared early and was not well controlled by conservative treatment. Operations were performed in twelve patients.

6. Shortening of the limb occurred in all patients and in some it was severe.

1. Six cases of development of heterotopic bone around joints in association with paralysis from intracranial lesions are presented. It is suggested that such bone may occur more commonly than is realised.

2. The features of these cases are very similar to those seen in association with paraplegia.

3. Extensive new bone is usually associated with fixed contractures.

4. Operation is hazardous in paraplegia but should not necessarily be so in other paralytic conditions.

5. In the presence of returning motor function excision of the bone, allowing correction of the deformity together with some movement, is a worthwhile procedure. In the hip, osteotomy alone usually requires plaster fixation with the attendant risks of venous thrombosis. Previous excision of the bone allows internal fixation of the osteotomy with early mobilisation.