We have compared the survival of two hydroxyapatite (HA)-coated cups, 1208 Atoll hemispheric and 2641 Tropic threaded, with cemented Charnley all-polyethylene cups (16 021) using the Cox regression model. The Tropic cup used in combination with an alumina ceramic femoral head, had good results, similar to those of the Charnley cup. When used in combination with a stainless-steel head, however, the risk of revision beyond four years was increased 3.4 times for the Tropic cup compared with the Charnley cup (p < 0.001). Over the same period, the Atoll cup had an increased risk of revision of 3.8 times when used with the alumina heads (p < 0.001) and an increased risk of 6.1 times when used with stainless-steel heads (p < 0.001). Revision because of wear and osteolysis was more common with both types of HA-coated cup than with the Charnley cup. The rate of revision of the Atoll cup because of aseptic loosening was also increased. We found that HA-coated cups did not perform better than the Charnley cup

1. The duration of Legg-Perthes' disease seems somewhat shortened by abduction weightbearing plaster treatnlent. The average age of onset of our sixty patients at the start of this treatment was seven years nine months. The patients were treated in abduction plasters for an average of nineteen months. 2. The contour of the femoral head in relation to the acetabulum is better preserved than after our previous methods of treatment. We have evaluated our cases by the method of Mose, by the epiphysial index of Eyre-Brook and the epiphysial quotient of Sjovall, and by the centre/edge angle of Wiberg. 3. There was no undue influence on the growing epiphysis and no evidence of ligamentous strain. 4. With this type of protected weight-bearing, the patients were kept active when both hips were affected. 5. No patient with unilateral disease showed Legg-Perthes' changes on the opposite side while under treatment or at follow-up. 6. The children were able to be at home and to attend school

1. Various types of fracture of the femoral neck represent different stages of one and the same displacing movement. 2. The displacement first produces an "abduction fracture" and terminates in an "adduction fracture," passing through the stage of an " intermediary fracture" which is less well recognised. 3. These three types of fracture occur in response to the same injury and they differ only in the degree of displacement. 4. It is a mistake to believe that in " adduction fractures" the femoral head lies medially to the collum : it lies posteriorly. 5. "Impaction" is no more than the first stage of displacement of fractures in which there is limited displacement, with contact still maintained between the fragments. 6. An "impacted fracture" is not necessarily stable—if there is additional strain it may progress to the next stage of a displaced and unstable fracture. 7. These principles apply not only to fractures of the femoral neck but to all other fractures at the ends of long bones

We compared the results of the surgical treatment of trochanteric hip fractures before and after surgeons had been introduced to the tip-apex distance (TAD) as a method of evaluating screw position. There were 198 fractures evaluated retrospectively and 118 after instruction. The TAD is the sum of the distance from the tip of the screw to the apex of the femoral head on antero-posterior and lateral views. This decreased from a mean of 25 mm in the control group to 20 mm in the study group (p = 0.0001). The number of mechanical failures by cut-out of the screw from the head decreased from 16 (8%) in the control group at a mean of 13 months to none in the study group at a mean of eight months (p = 0.0015). There were significantly fewer poor reductions in the study group. Our study confirms the importance of good surgical technique in the treatment of trochanteric fractures and supports the concept of the TAD as a clinically useful way of describing the position of the screw

Much of the current confusion and contradiction on the treatment of avascular necrosis of the femoral head is caused by the lack of an agreed efficient, quantitative system for evaluation and staging. We have used a new system to evaluate over 1000 hips with avascular necrosis during a period of 12 years; it has proved to be very valuable. The system is based on the sequence of pathological events known to take place. It allows accurate quantification in both early and later stages, does not use older, invasive diagnostic procedures, and incorporates the newer techniques of bone scanning and MRI. Clinical records of pain and reduced function are not a specific part of the system, although they help to determine treatment and outcome. Hips are first placed into one of seven stages from 0 to VI, based upon the type of radiological change. The extent of involvement is then measured. This allows more accurate evaluation of progression or resolution and better comparison of different methods of management. The system also helps to provide a prognosis and to decide on the best available method of treatment

Aims

This study sought to establish the prevalence of the cross over sign (COS) and posterior wall sign (PWS) in relation to the anterior pelvic plane (APP) in an asymptomatic population through reliable and accurate 3D-CT based assessment.

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months

We examined 50 patients with diastrophic dysplasia both clinically and radiologically. Two legally aborted fetuses were dissected. The mean age of the patients was 16.2 years (newborn to 38) and the mean follow-up was 11.4 years (3 months to 34 years). The fetal hips and MRI of newborn infants showed congruity and no significant joint deformity. Flexion contracture of the hip became evident later in 93% and was progressive. The radiological appearance of the proximal femoral ossific nuclei was delayed and in 17% of males and 28% of females the ossific nuclei had not appeared by the age of 12 years. Radiological measurements differed considerably from reference values and were related to the rapid and progressive restriction of rotational movement and the increase in flexion contracture. The typical findings were flattening and inferomedial bulking of the femoral head and a double-hump deformation. The changes in the hip led to secondary osteoarthritis before early middle age. We describe the clinical and radiological measurements which define the early degeneration of the joint

A technique of examining the infant hip joint with real-time ultrasound is described. Since the cartilaginous femoral head is clearly imaged by ultrasound, anatomical structures and their relationships can be accurately determined. Dislocated hips are easily detected and subluxations also can be visualized. We report our experience with 131 examinations in 104 patients, comprising 259 single hip studies. Of 83 patients who were previously untreated, there were 178 hip studies with three false-negative and four false-positive ultrasound results. No dislocations were missed. Twenty-seven patients who were already being treated were examined to assess hip location, comprising a total of 81 hip studies. In some cases the patients were examined while in an abduction device, cast, or Pavlik harness. In one case a dislocation was not detected. The method of examination using real-time ultrasound is considered to be reliable, accurate, and a useful adjunct to radiography. The advantages are that it is non-invasive, portable, and involves no exposure to radiation

The records of 107 patients with displaced subcaptial hip fractures treated by Thompson's femoral head replacements have been reviewed to determine the mortality and certain aspects of systemic morbidity. Comparison was made with a group, matched exactly for age and sex, in which intertrochanteric fractures were treated by nail-plate fixation. The patients treated by Thompson's arthroplasty were further subdivided into two groups: one in which methylacrylic cement was used, and one in which it was not used. We found no difference in the mortality of the patients undergoing replacement arthroplasty and nail-plate fixation. Similarly there was no difference in the incidence of cerebrovascular incidents and myocardial infarction after operation. There was a higher incidence of transient cardiac failure following Thompson's arthroplasty. Hypotension during the operation occurred irrespective of whether cement was used; nor was the use of cement associated with increased mortality. However, it seems that methylacrylic cement does contribute to the cardiac failure that may occur after Thompson's arthroplasty

Coxa valga may sometimes occur as a complication of varus osteotomy for congenital dislocation of the hip. Six such cases are described with a minimum follow-up of nine years. In three cases the varus osteotomy had been performed on only one side; in one case it was done on both sides and coxa valga developed bilaterally; and in two further bilateral cases coxa valga developed on one side only. In each case the coxa valga was sub-capital. Detailed radiographic analysis included measurements of neck-shaft angle, acetabular angle and C.E. angle. The epiphysis-shaft angle is described; it is an index of the constant tendency of the capital epiphysis to assume a horizontal position. The cause remains unknown, but damage to the trochanteric growth plate or to the lateral part of the capital growth plate could not be identified as aetiological factors. Poor acetabular cover was considered a possible factor. All the patients in this series had functionally excellent hips, but the long-term prognosis of the hips with partly uncovered femoral heads is doubtful

We have considered the reasons for securing containment of the femoral head in Perthes' disease and have reviewed briefly the methods used. The present investigation describes the outcome in a controlled series of forty-eight hips treated by containment by femoral varus-rotation osteotomy in selected patients. In assessing the results we have emphasised that controls are essential, and for this purpose we have used two comparable groups, one untreated and the other treated by methods other than containment. The same factors were considered in assessment--namely age, duration, group, and the presence or absence of "at risk" signs. The results were graded similarly as good, fair and poor in all groups. We have concluded that containment by femoral osteotomy is the treatment of choice in patients with "at risk" signs provided that severe deformity has not already occurred. There is no evidence that treatment of any kind favourably influences the course of the disorder in the remainder. Although this is predominantly a radiological study some clinical features are discussed

1. Experimental work with piglets supports the theory that diminished blood supply to the femoral head not only causes necrosis of the epiphysis but also a decrease in cartilage cell production in the germinal layer of the epiphysial plate, thus causing decreased longitudinal bone growth. Appositional growth continues in the metaphysis because its blood supply remains intact or, at least, is less impaired. The resulting disturbance of the normal remodelling must lead to a short wide neck such as occurs in Legg-Perthes' disease. 2. Measurements were made of the length and width of the femoral neck on radiographs of forty patients with Legg-Perthes' disease. The results showed that the degree of shortening and widening is related to the extent of structural change in the head. 3. Repeated measurements in the early stages of the active disease may permit an early prognosis which may be of great assistance in selecting the treatment suitable to each patient. The financial assistance of the Ontario Society for Crippled Children is gratefully acknowledged

1 . A preliminary report is presented of a clinical trial to compare the results of early and late weight bearing in randomly selected patients of comparable age groups whose displaced femoral neck fractures were treated by internal fixation with a sliding nail-plate. 2. When 124 patients were assessed at three months and 107 at six months after operation there was no significant difference between those who started unguarded weight bearing two weeks after operation and those who avoided weight bearing for three months. 3. Early weight bearing appears to have no harmful effect on the early post-operative stability of this fracture when a sliding nail-plate is used for fixation. 4. Further information is necessary before any conclusion can be reached about the effect of early weight bearing on the ultimate fate of the fracture and of the femoral head. For this reason, and also to increase the numbers of patients in the series, the trial is continuing and the patients are being followed up for a three-year period

1. The capsular changes in osteoarthritis of the hip and their pathogenesis are described, and it is concluded that symptoms are due mainly to this abnormality. 2. The clinical significance and pathogenesis of subchondral sclerosis, cysts, osteophytes, secondary subluxation and new bone formation on the lower border of the femoral neck are discussed. 3. These bony features which can be seen in the radiograph may, under certain circumstances, be correlated with the symptoms. 4. The influence of joint debris and capsular fibrosis upon the symptoms arising in other osteoarthritic joints is considered. 5. The mechanism by which osteoarthritis develops in hip joints with an anatomical abnormality is discussed in relation to the normal functional anatomy of the hip. 6. The evolution of osteoarthritis in dysplasia of the hip is considered with special reference to its diagnosis, prognosis and early treatment. 7. The supposition that osteoarthritis is commonly due to progressive ischaemia in the femoral head has been investigated and is rejected. 8. The cause of idiopathic osteoarthritis remains obscure but the evidence suggests that constitutional rather than local conditions in the joint account for many of these cases

Aims

The aim of this study was to report the initial results of the Exeter V40 stem, which became available in 2000.

We retrospectively reviewed 56 patients (71 hips) treated by total replacement for severe disability after pelvic irradiation. Symptoms were associated with various radiological lesions due to irradiation, including atraumatic femoral-neck fracture, osteonecrosis of the femoral head or of the acetabulum, and radiation osteitis of the whole pelvis. From 1970 to 1982 we used standard cemented components in 49 hips and had a high rate of acetabular loosening (52%) at a mean follow-up of 69 months. This was probably due to the mechanical insufficiency of irradiated periacetabular bone. From 1983 to 1990 we routinely used acetabular reinforcement rings. The rate of aseptic acetabular loosening in 22 hips at a mean follow-up of 40 months was 19%, but there were two septic loosenings emphasising the risk of infection in these patients. When total replacement is required for an irradiated hip, we recommend reinforcement of the acetabulum using a metallic ring, but there is still an increased risk of infection and in difficult cases such as severe acetabular destruction or soft-tissue or vascular injuries, a Girdlestone procedure may be indicated

From 1970 to 1980 cemented metal-on-plastic total hip replacement was performed on 799 hips with primary osteoarthritis using one surgical technique. At the 10- to 20-year follow-up there had been 97 revisions for mechanical loosening. Univariate survivorship analysis showed that an increased risk of revision was associated with male gender, young age at primary THR, the Brunswik and Lubinus snap-fit prostheses with large femoral heads (as compared with the Charnley prosthesis), and varying experience of the surgeon. Multivariate statistical analysis showed a three-fold increased risk of revision for men (p < 0.0001), an increase in relative risk of 1.8 per 10 years younger at surgery (p < 0.0001), a fivefold increase in risk for the Brunswik prosthesis (p < 0.0001) and a twofold increase for the Lubinus prosthesis (p = 0.0067). Inexperience of the surgeon, however, was not validated as a risk factor. The study shows that the true risk factors for revision can be identified accurately by combining univariate survivorship and multivariate statistical analyses

We implanted 51 Metal-Cancellous Cementless Lübeck (MCCL) prostheses into 45 patients with dysplastic hips and followed 49 hips (96.1%) for five to nine years. One had needed revision for stem fracture and one for infection; the clinical outcome of the other 47 hips was assessed using the Merle d’Aubigné and Postel hip score. All hips were either excellent (63%) or good (37%). Three patients (6%) had mild thigh pain at six months, but this had settled within two years. Serial radiographs showed stable fixation with bone ingrowth in all hips, with increased density of the cancellous bone in contact with the implant and some trabecular ingrowth. There was early varus shift of the stem in one hip, but this stabilised in three months. Osteolysis of the femoral cortex was seen in one hip at seven years after surgery, and mild bone resorption due to stress shielding in 31 (63%). Acetabular bone grafting with autogenous bone from the femoral head gave successful support to the socket in 13 hips. The MCCL prosthesis gave satisfactory mid-term results in patients with osteoarthritis secondary to hip dysplasia

We have reviewed the serial radiographs of 63 hips in 53 children treated by closed reduction for congenital dislocation with a view to finding a radiological measurement which can predict subsequent acetabular development. All had been followed for more than seven years, and at latest review, 34 hips were dysplastic. Failure to obtain concentric reduction or its loss by migration of the femoral head within one year of reduction were the best predictors of persisting acetabular dysplasia and were best quantitated by the h/b ratio (Smith et al. 1968). The acetabular index at reduction or its decrease in the first year were not reliable predictors. Late treatment was less likely to lead to normal acetabular development, but avascular necrosis did not appear to have a significant influence. The average age at which the acetabulum stopped developing was five years, but ranged from 17 months to eight years. The failure of a dysplastic acetabulum to improve in each annual radiograph after closed reduction should lead to consideration of operation on the acetabulum