1. The results are presented of upper tibial osteotomy carried out in ten patients for osteoarthritis of the knee associated with lateral deformity.

2. The operation is indicated when there is severe pain, valgus or varus deformity, and a range of flexion of at least 90 degrees.

3. In every case pain has been relieved, and recovery of movement after operation has been easy.

1. Serial radiographs of fifty-two normal children's feet, taken at six-monthly intervals between two and five years, have been reviewed.

2. Twenty-one naviculars have been injected post-mortem and the vascularisation of the growing bone investigated.

3. The records of sixty-two children with a diagnosis of Köhler's disease have been studied.

4. It is submitted that abnormal ossification results from compression of the bony nucleus at a critical phase during growth of a navicular bone whose appearance is delayed.

5. Symptoms in Köhler's disease are related to further compression which produces vascular changes in the bony nucleus. Consequent ischaemia is followed by hyperaemia which produces local pain, tenderness and swelling.

6. Two radiographic types of Köhler's disease are described and attributed to variations in the basic vascular pattern of the affected bone.

7. The usual complete recovery of the navicular is ascribed in part to the basic arrangement of numerous radially penetrating vessels.

1. Forty-four patients with tuberculous tenosynovitis have been reviewed.

2. The lesions (fifty-two in all) are classified and described according to their anatomical sites.

3. Particular reference is made to the natural history of the condition and the results of treatment.

4. Early and extensive excision of the affected tendon sheaths combined with the use of anti-tuberculous drugs is recommended.

1. Radiographic changes in bone structure which follow the insertion of an unplasticised acrylic prosthesis of the Judet type are described.

2. Technical details of the operation and their relation to these changes are discussed.

3. Although the period of observation is short it is suggested that after initial loosening the prosthesis becomes stabilised owing to local bone reaction.

1 . Complications of the Judet arthroplasty are few.

2. The antero-lateral approach provides good access to the joint for insertion of the prosthesis.

3. Details of treatment before and after operation are described and their importance in limiting complications is emphasised.

4. The complications that have been encountered—including dislocation and fracture of the stem—are described and factors in their causation are discussed.

5. Study of the mechanical state of the new joint and the diagnosis of complications are aided by radio-opaque markers in the prosthesis.