A total of 45 tibial shaft fractures, all conservatively treated and with union delayed for more than 16 but less than 32 weeks were entered in a double-blind multi-centre trial. The fractures were selected for their liability to delayed union by the presence of moderate or severe displacement, angulation or comminution or a compound lesion with moderate or severe injury to skin and soft tissues. Treatment was by plaster immobilisation in all, with active electromagnetic stimulation units in 20 patients and dummy control units in 25 patients for 12 weeks. Radiographs were assessed blindly and independently by a radiologist and an orthopaedic surgeon. Statistical analysis showed the treatment groups to be comparable except in their age distribution, but age was not found to affect the outcome and the effect of treatment was consistent for each age group. The radiologist's assessment of the active group showed radiological union in five fractures, progress to union in five but no progress to union in 10. In the control group there was union in one fracture and progress towards union in one but no progress in 23. Using Fisher's exact test, the results were very significantly in favour of the active group (p = 0.002). The orthopaedic surgeon's assessment showed union in nine fractures and absence of union in 11 fractures in the active group. There was union in three fractures and absence of union in 22 fractures in the control group. These results were also significantly in favour of the active group (p = 0.02). It was concluded that pulsed electromagnetic fields significantly influence healing in tibial fractures with delayed union.

1. The distribution of the permanent paresis and paralysis in the muscles of 203 lower limbs affected by poliomyelitis is analysed and related to the destruction of motor nerve cells in the grey matter of the lumbo-sacral cord. 2. The tibialis anterior and tibialis posterior and the long muscles of the toes are more often paralysed than paretic; these muscles are innervated by short motor cell columns. Muscles such as the hip flexors and hip adductors that are more often paretic than paralysed are innervated by long cell columns. 3. Muscles innervated by the upper lumbar spinal segments are more frequently affected than those innervated by the sarcal segments. This agrees with the segmental incidence of motor cell destruction found in poliomyelitic spinal cords. 4. Each muscle or muscle group is associated in paralysis with other specific muscles. For instance, the long toe extensors with the peronei and the calf muscles (triceps surae) with the biceps femoris. Associated muscles are innervated by adjacent motor cell columns. The probability of recovery in a paralysed muscle can be determined by reference to the degree of involvement in its associated muscles. 5. The distribution of the paralysis in an individual lower limb is determined by the site and size of foci of motor cell destruction. The cell loss in certain common patterns of paralysis is described. 6. The practical application of these findings is discussed.

The clinical and radiological state of the hips of a group of children with cerebral palsy treated without operation is compared with that in a group treated by operation to correct adduction and flexion deformity and to obtain balanced action in the hip muscles. In the first group, 11 per cent of hips were dislocated, 28 per cent subluxated, 46 per cent dysplastic and 15 per cent normal. In the second group no hip was dislocated, 13 per cent were subluxated, 35 per cent dysplastic and 52 per cent normal. Surgical intervention is indicated clinically for a range of abduction diminishing to less than 45 degrees and–on radiological criteria–for early dysplastic changes, especially a break in Shenton's line, irrespective of the patient's age, severity of involvement or neurological maturity. Prevention of subluxation or dislocation improves function and diminishes the liability to develop a painful hip in adolescence or early adult life.

1. Deformities of the foot in children with myelomeningocele are described and classified. The results of a policy of operative correction of deformity in 148 patients all of whom had had at least one operation on the foot between 1947 and 1965 are described. 2. In 241 feet in which there were deformities 433 operations were performed, including tenotomies, soft-tissue divisions, tendon transfers and bony procedures. At the time of review successful correction of deformity had been obtained in 81 per cent with a plantigrade foot that could bear weight safely, and with a distribution of muscle activity that required minimal external support and presented the least liability to recurrent deformity. 3. The management of individual deformities is described and the causes of failure are analysed and discussed.

wrong type of case or for the wrong indications. An account of the paralysis and its relation to the condition of the hip in meningomyelocele is therefore warranted before the operation and its results are described.

1. Five cases of postero-lateral dislocation of the knee with capsular interposition are described. 2. The mechanism of the injury is considered in the light of the case histories and the findings at operation. 3. The constant clinical findings associated with this injury are described. 4. Open reduction is recommended: with early operation the prognosis for function and stability is good.

1. The management of severe kyphosis of the lumbar spine in association with myelomeningocele is discussed. 2. Neonatal spinal osteotomy-resection has been performed in six patients with partial correction of the deformity and a greatly improved ease of closure and healing of the skin defect. The severity of lower limb paralysis has been diminished compared with the complete paraplegia that almost always results from conservative management of closure of the defect without osteotomy. 3. In an older child who has not had the benefit of neonatal osteotomy and who has complete lower limb paralysis, transverse spinal osteotomy or excision of the prominent laminae and pedicles on each side of the midline makes possible the fitting of apparatus for walking and diminishes the liability to recurrent ulceration of the skin.

We report the results of using 83 expanding intramedullary rods in 24 children with osteogenesis imperfecta after a mean follow-up of five years three months. In all, 62% of the rods have expanded after one primary operation. Thirty-four additional operations were necessary; 11 for the correction of rotation or angulation deformities and 23 for revision of the rod or T-piece. All these revisions were successful. Complications were more frequent in children who required very small rods. Problems with Bailey-Dubow rods led to the development of the Sheffield rod system; 17 bones treated with these rods are included in the series. Before surgery only eight of the 24 children were able to walk but at review 20 children were walking, 15 without walking aids. Elongating intramedullary rods should be available to all children with osteogenesis imperfecta as they improve walking capability, reduce the number of fractures, prevent deformity and allow integration of the child into society.