We studied the quantity and rate of formation of new bone during lengthening of 17 limb segments in 10 patients using dual-energy X-ray absorptiometry (DEXA), ultrasonography and radiography. Whereas new bone was detected by both DEXA and ultrasonography within 1 to 2 weeks of distraction, it was not visible on the radiographs until 4 to 8 weeks. Limb alignment and gap measurement were accurately assessed by DEXA without the need for standard radiographs or scanograms. With ultrasound the distraction gap appeared as an echolucent window which narrowed progressively producing a hyper-reflecting line after which further consolidation could not be assessed. As measured by DEXA the density of the new bone at this stage was approximately 45% of control values and did not represent normal cortication. Whereas ultrasound could be used to identify defects in mineralisation and to determine when to dynamise the fixator system, DEXA could measure the quantity and rate of formation of bone throughout lengthening.

We measured the extent and rate of new bone formation over an 18-month period before, during and after the lengthening of ten leg segments in six patients aged between 8 and 18 years, using dual-energy X-ray absorptiometry (DEXA). New bone formation could be identified within one week of the start of distraction. As lengthening proceeded, the bone density of the gap fell, reaching minimum values at the time of maximal distraction. Consolidation of the regenerating bone was started 1 to 2 weeks later in the tibia, and 2.5 to 3.0 weeks later in the femur. The rate of mineral accretion in new bone was significantly greater in the tibia than in the femur (16 +/- 1.86%/month, and 11 +/- 1.1%/month respectively; mean +/- SEM). There was significant osteoporosis distal to the osteotomy, more in the tibia than in the femur, particularly on the side of the fixator. The bone mineral density of the distal segment remained low at the time of fixator removal (44.2 +/- 5.58% and 61.0 +/- 4.2% of the control values at the tibia and femur respectively) and was only partially reversed by subsequent weight-bearing. We conclude that dual-energy X-ray absorptiometry provides an objective and quantitative assessment of new bone formation during leg lengthening. The technique also allows the measurement of the distraction gap and the assessment of leg alignment from the high-resolution images. Its use may decrease the requirements for conventional radiography.

We report the results of locked Seidel nailing for 30 fractures of the humerus. There were frequent technical difficulties at operation especially with the locking mechanisms. Protrusion of the nail above the greater tuberosity occurred in 12 cases, usually due to inadequate locking, and resulted in shoulder pain and poor function. Poor shoulder function was also seen in five patients with no nail protrusion, presumably because of local rotator cuff damage during insertion. Our results suggest that considerable modifications are required to the nail, and possibly to its site of insertion, before its use can be advocated.

We discuss the role of primary knee arthroplasty in supracondylar and intercondylar fractures of the femur in elderly patients with reference to 13 cases. This method of treatment is shown to be effective and to have good results. It is recommended for all type C and some type A supracondylar fractures in old people.

Five patients with Boyd type II congenital pseudarthrosis of the tibia underwent excision of the pseudarthrosis and double onlay bone grafting. Stability was maintained by extending intramedullary rods. Clinical union was achieved in all cases at a mean of 8.6 months (range six to 11). The rods extended by 15.7% (range 2% to 31.4%) as growth occurred. One rod was removed because of infection and a vascularised free fibular graft was subsequently performed. The extending rods provided stability while union occurred and did not require revision as the legs grew. The rods can be removed easily and have not jeopardized further surgical options.

We made a prospective study of 111 children with acute hip pain to assess whether ultrasound can replace traditional radiography. An effusion was diagnosed in 71% by ultrasound but in only 15% by radiography. This effusion persisted for a mean of nine days; symptoms lasted for five days. Two patients found to have Perthes' disease had longer-lasting effusion and symptoms. Patients without an effusion had no obvious cause for their pain, so the pressure of an effusion from a transient synovitis does not account for all patients with irritable hips. Patients with an effusion persisting for over 24 days (the mean + 2 s.d. of our series) had more symptoms, a significantly larger effusion and greater limitation of movement. They may be more at risk for avascular necrosis. We found that radiographic examination influenced the immediate management of only two patients, those with Perthes' disease. We therefore propose a protocol of management for irritable hip, using ultrasonography at the first presentation of certain categories of patients. This would reduce the number of early radiographs by 75%.

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.

We report nine cases of irreducible congenital dislocation of the knee which were treated by early operation with good results. All were resistant to conservative measures and operation was performed at an average age of nine months. The essential abnormality was a short quadriceps muscle together with subluxation of the hamstring muscles to lie anterior to the axis of knee flexion. The quadriceps tendon was lengthened by VY-plasty and in six cases additional length was gained by proximal mobilisation of the muscle. After operation all the patients were able to walk.

After having had a standard decompression for anterior compartment syndrome, five patients presented with persistent symptoms and pressure values above normal. A repeat procedure combined with fasciectomy relieved their pain; postoperative pressure values were normal.

We present three cases of a previously undescribed condition characterised by unilateral tibia vara associated with an area of focal fibrocartilaginous dysplasia in the medial aspect of the proximal tibia. The three children affected were aged 9, 15 and 27 months respectively. Two required tibial osteotomy, but in one the deformity resolved without treatment. The pathogenesis of the focal lesion remains conjectural; the most likely explanation is that the mesenchymal anlage of the tibial metaphysis has, for unknown reasons, developed abnormally at the insertion of the pes anserinus.

A cortical bone graft on a muscle pedicle was taken from the ulna and transferred to bridge a complete defect of the radius in 16 dogs. In 14 control dogs a free graft was used, that is, one without a muscle pedicle. Union in the group with pedicle grafts was far superior to that in the group with free grafts, mainly because in those with pedicle grafts there was good subperiosteal new bone formation from active viable periosteum. In six of the pedicle grafts the viability of some osteocytes was retained over a 12-week period and in five the graft was almost completely replaced by new bone.

Seven pectoralis major transfers in children suffering from bilateral paralysis of elbow flexion due to arthrogryposis or to trauma are reported. A technique is described in which the muscle is mobilised from the clavicle to allow the tendon of insertion to be attached to the biceps tendon at the elbow. The biceps tendon was found to be present and could be mobilised forwards in all the arthrogrypotic elbows. Subjectively, the results were considered by patients or parents to be very good in six cases and fair in one. Elbow flexion power against gravity and against some resistance was achieved in all patients except one. The overall function was very good in one elbow, good in two, fair in three and poor in only one. The merits of the various procedures described for the restoration of elbow flexion in arthrogryposis are discussed. It is concluded that total pectoralis major transfer by the method described here has given the best results.

Excellent results can be achieved by plating fractures of the shaft of the humerus in patients with multiple injuries. This helps in nursing care and in the management of other injuries. In 38 patients admitted to a regional trauma centre, 39 humeral shaft fractures were plated. There were 27 men and 11 women, with an average age of 31.5 years. Fourteen of the humeral fractures were compound and 20 had significant comminution; 23 were fixed by a plate on the day of admission and all 39 by the twentieth day. Follow-up of 34 fractures showed that all had united, 33 primarily. All patients but one had a fully functional shoulder and no patient with a fractured humerus alone had lost any elbow movement. Complications were rare--one case each of non-union, fixation failure and infection. No permanent nerve injuries were produced at operation. The plating of fractures of the humerus in these circumstances has been shown to produce excellent results and has a place in the management of the patient with multiple injuries.

We report the ulnar impingement syndrome, which is caused by a shortened ulna impinging on the distal radius and causing a painful, disabling pseudarthrosis. Of the 11 cases reported, 10 were due to excision of the distal ulna after injury to the wrist; the other was a result of a growth arrest after a fracture of the distal ulna in a child. The symptoms are a painful, clicking wrist and a weak grip; clinical examination reveals a narrow wrist with pain on compression of the radius and ulna and on forced supination. Radiographs in the majority of cases show scalloping of the distal radius corresponding to the site of impingement. The mechanism by which ulnar impingement occurs after radio-ulnar convergence is illustrated. The plan of management for the young patient with traumatic dysfunction of the distal radio-ulnar joint is discussed; excision of the lower end of the ulna is not advised in such patients.

Ruptures of the calcaneal tendon which present late may be repaired using carbon fibre to induce a neotendon. The operative technique is described and the results of five cases reviewed. The average muscle power obtained was 88% of normal, and the thickness of the neotendon was 148% of that of the normal side. It would appear that this tendon formation in man is comparable to that previously described in sheep.

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.

1. Twenty-one cases of congenital dislocation of the hip were found on examination of 1,881 consecutive neonates on the first day of life, giving an incidence of eleven per 1,000 live births.

2. Insignificant high-pitched "clicks" were noted in 10 per cent of newborn children.

3. Conversion of half of the patients with hip dislocation to normal occurred during the first post-natal week.

4. Joint laxity was not a feature of the newborn with congenital dislocation of the hip.

5. Oestradiol, oestrone and oestriol were estimated in twenty-fourhour urine samples collected from sixteen patients with congenital dislocation of the hip and nineteen matched controls during the first six days of life. No significant differences in oestrogen output between the two groups were found.

6. The hypothesis that congenital dislocation of the hip is a result of an inborn error of oestrogen metabolism in the newborn is not supported.