Dynamic hyperextension of the big toe and supination of the forefoot may occur in the swing phase of walking in children with various neurological disorders. Symptoms arising from this have been successfully corrected in 13 feet of 11 children by transfer of extensor hallucis longus to the insertion of peroneus brevis.

There are differences of opinion about the pathogenesis of Perthes' disease. All are agreed that it is due to ischaemia, but the cause of this and the size and number of infarctions are in dispute. Through the generosity of the contributors six whole femoral heads and core biopsies of five other cases have been studied radiographically and histologically. The findings ranged from an ischaemic arrest of ossification in the capital articular cartilage without infarction to multiple complete infarctions of the epiphysial bone. The ensuing reparative process contributes to the pathology, which is of a range to warrant grading or grouping.

Thirteen patients with dyschondrosteosis from eight families are reviewed and their clinical and radiographic variation noted. Inheritance is likely to be autosomal dominant but with only 50 per cent penetrance. Stature was moderately reduced, due to shortening of the bones of the leg. Radio-ulnar shortening could either involve both bones equally or the radius predominantly, in which case a typical Madelung deformity was seen. Tibio-fibular disproportion was present in half the patients, two of them having severe deformity associated with tibia varum and a long fibula. The treatment of one of these patients is described. It is recommended that patients with dyschondrosteosis should be kept under surveillance during the growing period. Problems in the limbs, especially the legs, may require operations to equalise the length of the two bones.

Children with flail feet who have control of their hips and knees are able to walk but are unable to stand still and find it difficult to walk slowly. These problems have been overcome in fifty-three children with flail feet due to myelomeningocele by fitting them with below-knee orthoses which provide maximum stability and yet allow normal walking. The biomechanical principles and the development of the orthoses are discussed.

A technique of subtalar arthrodesis by means of metallic internal stabilisation and autogenous cancellous bone grafting is described. Of forty-eight feet with mobile pes planus treated by this method forty-five gained union after an average of seven and a half weeks in a below-knee weight-bearing plaster, and forty-three had satisfactory correction of the deformity.