Perthes’ disease is associated with impaired blood flow (avascularity) to the upper end of the femur at the hip joint in children. It affects boys more than girls, with a peak incidence about the age of 4 years. The cause of the avascularity is unknown but local stress factors are thought to be involved. Symptoms of the disease include pain and limping. X-ray examination of the femoral head (Fig 1) reveals supero-lateral flattening of the bony femoral head (epiphysis), thickened cartilage infero-medially (‘tear-drop distance’), and radiological translucencies in the femoral head and neck. In a normal hip joint the femoral head is almost spherical, but in Perthes’ disease the femoral head gradually becomes deformed. In some older children, the deformed femoral head becomes indented by the outer margin of the hip joint socket (‘hingeing’). B.S. Choo, A.D.C. Hogg, R.G. Burwell, A. Moulton and B.S. Worthington
In developed countries, joint disorders of various forms constitute a significant part of the burden on health services, including general practitioners, hospital in-and out-patient facilities, and community care services. About 30 years ago, before total joint replacement was generally practised, many sufferers from arthiritis of the hip or knee had effectively to choose between a surgical fusion and severely restricted mobility, perhaps in a wheelchair. The development of total joint replacement has introduced a third possibility, which is the treatment of choice for many patients. As is well known when it is good, it is very very good; the patient feels as if the joint is the same as before the onset of arthritis. Such a result is obviously immeasurably better for the patient and the patient’s family; it is also cheaper for the community than providing aids for disabled people, earlier pensions, etc. Professor S.A.V. Swanson
Corrosion of reinforcement in concrete has in recent years become more widespread and of greater concern than in the past. There are numerous causes, many avoidable, for the increase in corrosion, not least among these being the large volume of rapid construction in the 1960s and '70s. A.S. Safier
Standard production steel reinforcement protected with a fusion-bonded epoxy coating has been subjected to accelerated testing on a natural exposure site over a 5-year period alongside plain steel and galvanised steel in purpose-designed concrete specimens. The epoxy coating provided considerable protection to the steel for the length of the trial when exposed in concrete with a high concentration of added chloride leading to significant practical advantage. However, the use of these coatings in practice does not provide complete protection since corrosion was observed to be spreading from points of defect in the coatings when the steel was embedded in concretes containing high levels of chloride. K.W.J. Treadaway and H. Davies
Use of expanding foam in roofs Eric Skilton, of John Pryke & Partners, writes expressing concern over the apparent growing use of expanding foam for the insulation and stabilisation of old roof coverings: While this process would appear to fulfil its intended function of upgrading the insulation to the loft space and providing additional fixity to the roof covering, it strikes me that we are sowing the seeds of future problems with this refurbishment technique. Verulam