In a clinical, radiological and biochemical study of forty-two patients from Oxford with osteogenesis imperfecta, it was found that patients could be divided simply into mild, moderate and severe groups according to deformity of long bones. In the severe group (seventeen patients) a family history of affected members was uncommon and fractures began earlier and were more frequent than in the mild group (twenty-two patients); sixteen patients in the severe group had scoliosis and eleven had white sclerae; no patients in the mild group had white sclerae or scoliosis. Radiological examination of the femur showed only minor modelling defects in patients in the mild group, whereas in the severe group five distinct appearances of bone (thin, thick, cystic and buttressed bones, and those with hyperplastic callus) were seen. The polymeric (structural) collagen from skin was unstable to depolymerisation in patients in the severe group, but normal in amount, whereas the reverse was found in the mild group. This division according to long bone deformity may provide a basis for future research more useful than previous classifications.

The efficacy of modern drugs in the treatment of tuberculosis of the spine has been evaluated by a personal follow-up for three to ten years. Operation on the vertebral lesion was done only for those patients with or without neural complications who failed to respond favourably to drug therapy and rest. Thus absolute indications for operation were present in only 6 per cent of cases without neural involvement and in 60 per cent of patients with neural deficit. Of the patients who responded to drug therapy alone, only 19 per cent revealed increase of kyphosis by more than 10 degrees. The diseased area showed radiological evidence of osseous replacement in 29.6 per cent of cases, of fibro-osseous union in 50 per cent and of fibrous replacement in 202 per cent. The overall results of this regime compare favourably with those of radical operation. It is suggested that freatment should in the first place be by modern antitubercular drugs.

The cause of pseudarthrosis of the clavicle is obscure. Right-sidedness is an almost constant feature. We have proposed that the lesion is sometimes due to pressure upon the developing clavicle by the subclavian artery which is normally at a higher level on the right side. This may be accentuated in the presence of cervical ribs or unduly elevated first ribs, both of which we have observed in association with pseudarthrosis. We have also noted pseudarthrosis on the left side in association with dextrocardia (when the relative positions of the subclavian arteries are reversed) and in the presence of a large left cervical rib.

We have speculated upon the nature of the clavicular defect in cranio-cleido dysostosis, in which disorder the first ribs are habitually elevated. A similar mechanism may be involved.

One thousand and forty-two McKee-Farrar prostheses of the present design inserted in Norwich from January 1965 to December 1972 have been reviewed retrospectively to determine the incidence of complications needing revision. Of prostheses implanted for more than two years, 6.6 per cent needed revision for loosening (cup 35 per cent; stem 2.2 per cent; both components 0.9 per cent). Of the total number, 2.3 per cent became infected and 1.9 per cent dislocated. Most dislocations needed only a single closed reduction but 08 per cent were revised. The outcome of revision operations was also assessed. Of revisions for loosening, 40 per cent needed no further operation but 23 per cent required excision; pelvic fracture or bone destruction around the components made success unlikely. Revisions for dislocation were disappointing. Of all revisions 17 per cent became infected. Excision arthroplasty is better than a series of failed revisions in an elderly patient.

Using bone decalcilied with 0.6 N hydrochloric acid as an inducing agent, the inductive capacity of different soft tissue sites was investigated. Muscle and fascia regularly permitted the induction of bone, while spleen, liver and kidney suppressed bone induction. Bone formation could be induced in these organs if living autologous fascia was implanted together with the inducing agent; while bone formation was inhibited when living autologous spleen tissue was implanted with the inducing agent to normally favourable sites. The administration of systemic heparin and the diphosphonate ethane-1-hydroxyl, 1-diphosphonic acid (EHDP) suppressed bone induction.

It is suggested that for bone induction to occur in soft tissues, three conditions must be present: 1) an inducing agent; 2) an osteogenic precursor cell; and 3) an environment which is permissive to osteogenesis. The presence of osteogenic inhibitors in spleen, liver and kidney is postulated.

This investigation examined the validity of the hypothesis that the acetabulum in congenital dislocation of the hip will develop satisfactorily provided accurate congruous and concentric reduction is obtained as early as possible, and is maintained throughout growth.

Seventy-two patients with eighty-five hips were studied. The children were more than one year old on admission and over ten years at the time of review. Acetabular development was assessed radiologically by measurement of the acetabular angle. Angles of less than 21 degrees were regarded as normal, and more than 21 degrees as indicating some failure of development. Satisfactory acetabular development occurred in 80 per cent (angles 24 degrees or below), and was unsatisfactory in 20 per cent (angles above 24 degrees).

If three errors in management, namely failure to obtain congruity, failure to maintain congruity and ischaemic necrosis secondary to manipulative reductions, are excluded from the analysis, it is found that 95 per cent of acetabula develop satisfactorily. The outcome is largely independent of the age on admission up to four years old, and of bilateral involvement. It is concluded that acetabuloplasty should not be necessary if the patient is admitted under the age of four or congruity is obtained in the functional position under four and a half years.

Seventy-two posterior psoas transfer operations performed in forty-four children with lumbar myelomeningocele were reviewed one to eight years after operation in an attempt to assess its value. Muscle charting, an objective recording of the child's walking ability, and radiographic examination of the hips were done. Hip stability was improved: 49 per cent were stable at the time of psoas transfer and 94 per cent at review. Functional results depended mainly on the level of neurological activity present: 57 per cent of the children had an acceptable functional result. Usually, posterior psoas transfer should be done as soon after the age of nine months as the child's condition will allow. Over the age of two years it should be restricted to children with activity in the third and fourth segments of the lumbar cord.

Eighty-three Waildius arthroplasties, performed by one surgeon as a salvage operation on the knee joint between 1966 and 1972, were independently reviewed. The fifty-seven living patients with sixty-seven arthroplasties were interviewed and examined and the clinical records of the deceased patients were inspected. Sixty-seven arthroplasties (81 per cent) were successful and sixteen failed (19 per cent). Acrylic cement was used to secure the prosthesis on eight occasions only. There were two primary infections (24 per cent) and two delayed (24 per cent). Major loosening occurred in three arthroplasties (36 per cent). Minor loosening was compatible with a good result. Arthrodesis was successful on the two occasions on which it became necessary to remove the implant. There were no disasters. On the basis of these results it is considered that the Walidius arthroplasty can justifiably be offered as an alternative to primary arthrodesis of the knee.

Fourteen cases of pseudarthrosis of the tibia in childhood presented at a hospital in Burma over a period of eight years. The ages of the patients ranged from one month to seventeen years. Nine were treated by a pointed graft driven into the medullary cavity of the distal tibia, and usually across the ankle joint into the body of the talus, before fixation to the proximal tibia. In six of the nine union was secured, but one case required a second grafting. Transarticular segments of graft showed a marked tendency to undergo absorption. No significant deformity was observed to follow central penetration of the growth plate and epiphysis of the lower tibia.

The natural history of 120 popliteal cysts in children has been reviewed. Of seventy untreated cysts fifty-one disappeared spontaneously during a mean period of one year and eight months. Of fifty cysts submitted to operation, twenty-one recurred in a mean period of seven months. Three children with recurrences had more than one further operation. Most popliteal cysts in children disappear spontaneously, and operation without very good reason is unjustified.

Link arthroplasty is a system of joint replacement in which the joint is left almost intact with no great removal of bone. It is based on a two-piece self-locking hinge slotted into the metacarpal head and phalangeal shaft. The operation is simple and no special instruments are needed. The preliminary follow-up of fifty-four metacarpo-phalangeal joint replacements showed thirty-five good and sixteen fair results.

A benign chondroblastoma of bone is reported. It was unusual because it occurred in an old lady, in a toe, and it was not painful and radiologically resembled a chondroma. The coarsely lobulated tumour showed a varied microscopic appearance, but it consisted chiefly of closely packed sheets of small, round polygonal or fusiform cells. There was some calcification present. The literature is reviewed.

Of four hangman's fractures of the axis, three occurred in road accidents and were stable, undisplaced and free of neurological signs, with full recovery after six to twelve weeks in a cervical collar. The fourth fracture occurred in a fall with profound tefraparesis from haemorrhage into the spinal cord, and the patient died a week later. There are two types of hangman's fracture: that of the axis pedicle, which results from more common than usually supposed because of the extension and compression of the cervical column, is slight symptoms it causes.

Injuries involving the midtarsal joint, which are frequently misdiagnosed, have been studied to clarify the mechanism, classification and treatment. The necessity for routine antero-posterior, lateral and oblique radiographs is emphasised. Seventy-one injuries have been classified according to the direction of the deforming force : medial, longitudinal compression, lateral, plantar and crush types are described. Included in the medial and lateral types is a hitherto undescribed tarsal rotation or " swivel" injury. The mechanism whereby longitudinal compression causes fractures of the body of the navicular is described, and two varieties having different prognoses are defined : one due to purely longitudinal compression and the other due to longitudinal compression with a medial component.

The results of treatment have been assessed clinically and radiologically. Reduction, open if necessary, with internal fixation, is recommended for displaced fractures : primary arthrodesis is not indicated. For severe persistent symptoms from medial and longitudinal force injuries triple arthrodesis is recommended, and from lateral force injuries, calcaneo-cuboid arthrodesis.

The forces under the foot while walking have been measured using a high sensitivity force-plate of the strip-suspended type combined with simultaneous filming of the sole of the foot. The recording of data and the calculation and plotting of results were much simplified by computer aid. Normal and abnormal feet, both barefoot and shod, were investigated in sixteen subjects. It was found that in normal barefoot walking the forefoot carried a total load of the order of three times that of the heel. When footwear was worn the function of the forefoot was progressively reduced as the rigidity of the sole of the shoe increased. Painful conditions of the forefoot also produced a large reduction in the proportion of the total load transferred.

Joint deformity secondary to extensive haemangiomatous involvement of the soft tissues has been well described and is easy to diagnose. If the haemangioma is small, localised and within the belly of a muscle the diagnosis is more difficult. In equinus deformity of obscure aetiology localised calf tenderness may be the only diagnostic sign. Three children with equinus deformity caused by a small haemangioma in the calf muscles were treated by simple excision with satisfactory results.