The practice of regular radiological follow-up of infants with a positive family history of developmental dysplasia of the hip is based on the widespread belief that primary acetabular dysplasia is a genetic disorder which can occur in the absence of frank subluxation or dislocation. We reviewed all infants who were involved in our screening programme for developmental dysplasia of the hip, between November 2002 and January 2004, and who had a normal clinical and ultrasound examination of the hip at six to eight weeks of age, but who, because of a family history of developmental dysplasia of the hip, had undergone further radiography after an interval of 6 to 12 months. The radiographs of 89 infants were analysed for signs of late dysplasia of the hip and assessed independently by three observers to allow for variability of measurement. There were 11 infants (11%) lost to follow-up.

All the patients had normal radiographs at the final follow-up and none required any intervention. We therefore question the need for routine radiological follow-up of infants with a positive family history of developmental dysplasia of the hip, but who are normal on clinical examination and assessment by ultrasound screening when six to eight weeks old.

Two protocols for the operative technique and care of the pin-site with external fixation were compared prospectively. There was a total of 120 patients with 46 in group A and 74 in group B. Infection was defined as an episode of pain or inflammation at a pin site, accompanied by a discharge which was either positive on bacterial culture or responded to a course of antibiotics.

Patients in group B had a lower proportion of infected pin sites (p = 0.003) and the time to the first episode of infection was longer (p < 0.001). The risk of pin-site infection is lower if attention is paid to avoiding thermal injury and local formation of haematoma during surgery and if after-care includes the use of an alcoholic antiseptic and occlusive pressure dressings.

Tricho-rhino-phalangeal syndrome is probably not so much uncommon as unrecognised. Its significance to orthopaedic surgeons, apart from the functionally unimportant minor finger deformities, lies in its mimicking both Perthes' disease and diaphyseal aclasis. The 14 cases analysed in this paper illustrate the wide range of clinical variation.

An attempt has been made to estimate the number of living people with skeletal dysplasias (osteochondrodysplasias) in Scotland, England and Wales, ascertained through five orthopaedic centres in different parts of Britain. Index patients and their affected relatives were sought and reassessed. Over the 30-year period between 1950 and 1979 inclusive a minimum prevalence was calculated (excluding stillbirths, perinatal deaths, and patients with chromosome anomalies, metabolic bone disease and short stature per se). The results indicate that there were in the community upwards of 10 000 individuals, at various ages over this period, with these largely genetic disorders. A more accurate estimate is of some 6000 of them requiring substantial orthopaedic care, and who were physically handicapped throughout life, about half of them severely so.

Blood flow in intact tendons in dogs was measured using 57Co-labelled microspheres and compared with the simultaneous clearance of a diffusible radionuclide, 85Sr, by the same tendons. Clearance was significantly greater than flow in all tendons, indicating that diffusion from surrounding tissues may be important in the nutrition of normal tendons.

A kindred of 15 affected individuals in five generations is described with autosomal dominant inheritance of bilateral five-fingered hand. Some of them had additional pre-axial polydactyly of the fingers or toes and some had partial or complete absence of the tibia. The range of expression of the gene is variable and genetic advice to these families must take account of the whole spectrum of defects. The function of both upper and lower limbs was improved by surgery. A distinction is drawn between the five-fingered hand shown in this family and the different deformity of a four-fingered hand with a triphalangeal thumb.

Ten cases of a complication of Garden screw fixation of subcapital fracture, namely subtrochanteric fracture through the lower screw hole, are presented. Their possible aetiology, prevention and difficulties in management are discussed. It is recommended that, during the insertion of Garden screws, care should be taken to avoid multiple attempts at passing the guide wire. If subtrochanteric fracture occurs internal fixation with a nail plate or screw plate is advised. Ideally the nail or screw should be inserted along the track of one of the existing screws.

Seventeen patients with congenital spondylo-epiphysial dysplasia from six centres in Britain have been investigated and two variants delineated. There is wide clinical and radiological variability in each group with overlap between them, but 12 of the patients had very short stature and grossly disorganised hips with severe coxa vara, and the five remaining patients were less seriously affected with height only a little below the third percentile and only mild coxa vara. Both groups can be diagnosed at birth but the two cannot be differentiated on clinical and radiological grounds until after the age of three to four years when the developing severe coxa vara and difference in stature become apparent. All cases were sporadic with the exception of a concordant twin-pair.

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.

Forty-eight patients with achondroplasia and 24 with hypochondroplasia have been reviewed in order to clarify the differences between the two disorders and establish the height, body proportions and other clinical and radiological variations within each group. Some of the "classical" findings in achondroplasia are not always present, and hypochondroplasia at its most severe is indistinguishable from achondroplasia at its least severe. The frequency of spinal stenosis and neurological complications was established in an unselected group of 27 achondroplastic and 12 hypochondroplastic patients aged 10 years and over. Only three of the former were free of symptoms but only three developed serious complications (11 per cent). Measurement of radiographs of the lumbar canal did not in general correlate well with the severity of spinal stenosis symptoms, but it was found that the ratio of interpedicular distances at the first and fourth lumbar vertebrae had some value. Neurological complications were rare in patients with simple narrowing of the spinal canal or with persistence of a thoracolumbar kyphos but when these occurred together there was a high risk of serious neurological involvement.

Arthrogryposis multiplex congenita is believed to be a specific clinical entity which is aetiologically unrelated to the "arthrogryposis-like" deformities of known neurological diseases such as myelomeningocele and myelodysplasia. The observation that the condition appeared to be three times as common in Melbourne, Australia, as in four centres in the United Kingdom (Wynne-Davies and Lloyd-Roberts 1976), prompted this survey of 132 patients: 73 from the United Kingdom, 34 from Australia and 25 from Wilmington, Delaware, USA. The survey aimed to established the same criteria for diagnosis in the three countries and to search for prenatal and genetic aetiological factors. It was shown that all centers treated more newborn children with this disorder during the 1960s than either before or after that period. All cases were sporadic and there was no family association with talipes equinovarus, congenital dislocation of the hip or hereditary neuromuscular disease. "Environmental" findings from all three centers were similar and it was concluded that arthrogryposis multiplex cogenita is a non-genetic disease of early pregnancy, associated with a variety of unfavourable intra-uterine factors. In addition, an unknown but possibly viral environmental agent may have been present to a significant extent only during recent decades and is now declining.

A radiographic suvey has been carried out of 147 first-degree relatives of forty-seven patients treated in Edinburgh for spondylolisthesis of the fifth lumbar vertebra; twelve patients had the dysplastic (congenital) type and thirty-five an isthmic defect. The survey identified 19 per cent of relatives with spondylolysis, and index patients with each type of spondylolisthesis had relatives with the opposite type. Index patients with the dysplastic form had a higher proportion of affected relatives (33 per cent) than had those with the isthmic type (15 per cent), but both figures were significantly in excess of the estimated frequency for the general population of under 1 per cent and 5 per cent respectively. Spina bifida occulta at the fifth lumbar or first sacral level or both, and lumbosacral segmental defects were commoner amongst all individuals with spondylolysis than amongst unaffected relatives (dysplastic form 94 per cent, isthmic type 32 per cent, unaffected relatives 7 per cent). However, there was no single instance of a neural tube defect (anencephaly, spina bifida with or without meningocele, other generalised vertebral anomalies or spinal dysraphism) amongst 826 first-, second- or third-degree relatives. It is concluded that the developmental defects of the vertebrae associated with spondylolysis are not aetiologically related to the neural tube defects. The one in three risk of spondylolysis to near relatives of patients with the dysplastic form of spondylolisthesis is emphasised in order that the deformity in their sibs and children can be recognised at any early age.

The residue and extraction of technetium-labelled methylene diphosphonate (99mTc-MDP), a substance used in bone scanning, was examined in the canine tibia and found to be low. Examination of washout curves suggested that there were four compartments in cortical bone, a vascular, a perivascular, a bone fluid and a bone compartment. After an osteotomy in the canine tibia the residue of 99mTc-MDP increased. This was believed to be due to an increase in the blood supply to the bone and to an associated increase in new bone available for exchange. Bone scanning in a fracture is therefore a reflection of the vascular status of the bone being examined and of the uptake by bone. This is dependent on there being an adequate blood supply to the bone and an increased number of mineral-binding sites.

The aims of this survey were to establish the familial incidence of Perthes' disease, to note any associated developmental anomalies and to collect information on preceding trauma or synovitis, on the pregnancy and birth, and on various sociological factors. Height and weight measurements were obtained for 217 patients, and comparisons made with those of their parents, unaffected sibs and (local) controls. Results showed an extremely low frequency of Perthes' disease among relatives, with no obvious pattern of inheritance. As genetic factors were not apparent, environmental and sociological causes were sought. The disease occurred particularly in children who were third-born or later in the family, and had older than average parents. Many came from low-income families and one in ten had been a breech birth, shown other malposition or had had a version late in pregnancy. Many children were already undersized at the time of developing Perthes' disease and remained short than average throughout life. Neither their parents nor sibs were shorter than normal, indicating that the patients' short stature was not familial. The child who is going to develop Perthes' disease is already constitutionally and socially at a disadvantage, and during the perinatal period and the first few years of life is perhaps more susceptible to trauma than is a normal child.

An attempt has been made to determine the aetiological factors in infantile idiopathic scoliosis from a clinical, genetic and epidemiological survey of 134 infants, ninety-seven of whom developed a curve in the first six months of life. Plagiocephaly was present in all cases; mental retardation occurred in 13 per cent of males with progressive scoliosis; congenital dislocation of the hip occurred in 3.5 per cent of cases and congenital heart disease in 2.5 per cent; and inguinal hernia was found in 7.4 per cent of males. Approximately 3 per cent of parents and 3 per cent of sibs had the same deformity, thirty times the general population frequency for the Edinburgh area. Other positive findings included an excess of breech presentations and of premature, low birthweight males, and a preponderance of curves developing in the winter months. Infants with progressive scoliosis tended to have older mothers and to come from poorer families. Only three children, all with resolving scoliosis, habitually lay prone in early infancy, in marked contrast to North American infants where this posture is usual. The almost complete absence of infantile idiopathic scoliosis in North America is noted and it is thought that the two facts may be related. The aetiology is likely to be multifactorial, with a genetic tendency to the deformity which is either "triggered off" or prevented by external factors.

1. Skeletal and other clinical features in twenty-three patients with homocystinuria have been compared with those in sixteen patients with Marfan's syndrome.

2. The two diseases are clinically similar but florid arachnodactyly and scoliosis are commoner in Marfan's syndrome, whereas widening of epiphyses and metaphyses of long bones is a distinctive feature of homocystinuria.

3. Patients with homocystinuria frequently have osteoporosis at a young age with a high incidence of vertebral involvement including biconcavity and flattening. Patients with Marfan's syndrome do not have osteoporosis and may have excessively tall vertebrae.

4. Mental retardation and thrombosis are common in homocystinuria and uncommon in Marfan's syndrome.

5. Homocystinuria is most probably inherited as an autosomal recessive and Marfan's syndrome as an autosomal dominant.

6. The two diseases should be differentiated because of the thrombotic risk in homocystinuria, and also because in this disease there is a possibility of treating the biochemical defect.

7. Although patients with homocystinuria may present to the orthopaedic surgeon with osteoporosis, severe genu valgum or scoliosis, the disease is an uncommon cause of these defects.

1. A survey of genetic and other etiological factors has been carried out in 589 index patients with congenital dislocation of the hip and their families, with special investigation of acetabular dysplasia, familial joint laxity and a comparison of neonatal and late-diagnosis cases.

2. It is believed that there are two etiological groups with congenital dislocation of the hip, i) a group with acetabular dysplasia which is inherited as a multiple gene system and is responsible for a high proportion of cases diagnosed late, and ii) a group with joint laxity which is responsible for a high proportion of neonatal cases.

3. Evidence is presented to show that acetabular dysplasia is a separate heritable system in some families.

4. Other findings relating to the genetic aspects of the survey are summarised.

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.