At yearly intervals we compared the radiological wear characteristics of 81 alumina ceramic femoral heads with a well-matched group of 43 cobalt-chrome femoral heads. Using a computer-assisted measurement system we assessed two-dimensional penetration of the head into the polyethylene liner. We used linear regression analysis of temporal data of the penetration of the head to calculate the true rates of polyethylene wear for both groups. At a mean of seven years the true rate of wear of the ceramic group was slightly greater (0.09 mm/year, SD 0.07) than that of the cobalt-chrome group (0.07 mm/year, SD 0.04). Despite the numerous theoretical advantages of ceramic over cobalt-chrome femoral heads, the wear performance in vivo of these components was similar

We studied 50 patients with fractures of the femoral neck, 33 intracapsular and 17 extracapsular. Intraosseous pressure was measured by a transducer within the bone to quantify blood flow, and intracapsular pressure by a needle introduced into the joint space. The mean intracapsular pressure was lower in the extracapsular fractures. In these, the mean intraosseous pressure in the femoral head was unchanged by aspiration of the joint. However in the intracapsular fractures aspiration produced a significant decrease in intra-osseous pressure and an increase in pulse pressure within the femoral head. The results suggest that aspiration of intracapsular haematoma produced an increase in femoral head blood flow by relieving tamponade

We reviewed 18 hips in 17 patients at a mean of five years after performing Sugioka's transtrochanteric anterior rotational osteotomy for avascular necrosis. The results were satisfactory in only three hips (17%). Twelve hips had been revised by hip replacement, revision was pending in one and two others were unsatisfactory. Hip replacement was not compromised by the previous Sugioka osteotomy. Fifteen hips (83%) had shown further collapse of the femoral head, and we conclude from this and from isotope scans that the osteotomy may have impaired the residual blood supply of the femoral head. It seems that ethnic origin may be a factor in the outcome of this procedure; we have abandoned its use

The systemic use of steroids and habitual alcohol intake are two major causative factors in the development of idiopathic osteonecrosis of the femoral head (ONFH). To examine any interaction between oral corticosteroid use and alcohol intake on the risk of ONFH, we conducted a hospital-based case-control study of 71 cases with ONFH (mean age 45 years (20 to 79)) and 227 matched controls (mean age 47 years (18 to 79)). Alcohol intake was positively associated with ONFH among all subjects: the adjusted odds ratio (OR) of subjects with ≥ 3032 drink-years was 3.93 (95% confidence interval (CI) 1.18 to 13.1) compared with never-drinkers. When stratified by steroid use, the OR of such drinkers was 11.1 (95% CI 1.30 to 95.5) among those who had never used steroids, but 1.10 (95% CI 0.21 to 4.79) among those who had. When we assessed any interaction based on a two-by-two table of alcohol and steroid use, the OR of those non-drinkers who did use steroids was markedly elevated (OR 31.5) compared with users of neither. However, no further increase in OR was noted for the effect of using both (OR 31.6). We detected neither a multiplicative nor an additive interaction (p for multiplicative interaction 0.19; synergy index 0.95), suggesting that the added effect of alcohol may be trivial compared with the overwhelming effect of steroids in the development of ONFH. Cite this article: Bone Joint J 2013;95-B:320–5

1. The routes by which adult human articular cartilage can receive its nutrition is still a subject of controversy. 2. Microscopic examination of normal adult human femoral heads has revealed vascular channels which penetrate the subchondral plate and calcified cartilage. These channels bring the medullary soft tissue into contact with the articular cartilage. 3. A fluorescent dye migration technique was used to show that the observed vascular channels are pathways for dye from the medullary cavity to the articular cartilage. It is suggested that these pathways could also be routes by which articular cartilage receives part of its nutrition. 4. The nutritional mechanism in the mature rabbit and adult human femoral heads cannot be compared because histological studies revealed differences in their subchondral structures

We studied factors contributing to the initiation of fracture and failure of a zirconia ceramic femoral head. The materials retrieved during a revision total hip replacement were submitted to either visual, stereomicroscopic and scanning electron microscopy (SEM) or SEM and energy-dispersive x-ray analysis. X-ray diffraction was performed in order to investigate the extent of tetragonal to monoclinic phase transition. Histological examination was performed on the periprosthetic tissues. The results showed that failure was due to the propagation during clinical use of defects which may have been introduced into the material during the processing of the ceramic, rather than those intrinsic to zirconia. The literature relating to previous failures of zirconia components is reviewed

Osteonecrosis of the femoral head usually affects young individuals and is responsible for up to 12% of total hip arthroplasties. The underlying pathophysiology of the death of the bone cells remains uncertain. We have investigated nitric oxide mediated apoptosis as a potential mechanism and found that steroid- and alcohol-induced osteonecrosis is accompanied by widespread apoptosis of osteoblasts and osteocytes. Certain drugs or their metabolites may have a direct cytotoxic effect on cancellous bone of the femoral head leading to apoptosis rather than purely necrosis

Of 24 intertrochanteric osteotomies for avascular necrosis of the femoral head, 22 were followed up for an average of 63 months. Sixteen of the 22 cases had good or excellent results, including 5 of the 6 cases with Stage II disease and 11 of the 16 with Stage III changes. Success seemed to be inversely related to the size of the lesion. There were six major orthopaedic complications, but despite these we feel that the operation has a definite role in the treatment of the young active patient

In ten patients with sickle-cell disease, we used a new technique of cement injection for the treatment of 16 painful hips with a radiographic crescent line or flattening of the articular surface due to avascular necrosis. The necrotic bone and overlying cartilage are elevated by the injection to restore the sphericity of the femoral head. Five days after the operation, full weight-bearing was allowed with the help of crutches for three weeks. The time in hospital averaged eight days; the average blood loss was 100 ml. There was early pain relief and postoperative radiographs showed improvement in the shape of the femoral head. At a mean follow-up of 5 years (3 to 7), 14 of the 16 hips were still improved although some gave slight pain. Only two hips had required revision to total hip arthroplasty, at one year and two years respectively. The increasing longevity of patients with sickle-cell disease means that avascular necrosis will be an increasing problem. Total hip replacement has a poor prognosis because of the risks of infection, high blood loss, and early loosening. Cement injection does not have these problems and allows for earlier, more conservative surgery

We followed, prospectively, 77 patients (90 hips) with early-stage, non-traumatic osteonecrosis of the femoral head for a mean period of nine years. At the time of final review, 56 (62%) were symptomatic. Using the Cox model, the initial radiological stage, the progression of staging, the reduction in size of the lesions and the percentage of necrotic volume on MRI were identified as risk factors. Using the Harris score of < 70 or surgery as the endpoint, the cumulative rates of survival were 60.0% at one year, 43.3% at two years, 38.9% at five years and 37.2% at ten years. Survival curves demonstrated that clinical deterioration could occur 90 months after the initial diagnosis, suggesting that asymptomatic patients should be followed carefully for several years. Radiological time-dependent reduction in size without progressive collapse may represent repair even when the collapse is minimal

We performed single-photon-emission CT (SPECT) and planar bone scans to assess femoral head vascularity in ten patients with displaced intracapsular hip fracture. The heads were labelled with tetracycline and after excision at hemiarthroplasty were assessed for tetracycline uptake distribution by fluorescence under UV light. The four which had the greatest tetracycline uptake were normal on SPECT and planar imaging. In two cases the planar bone scans were normal although SPECT suggested avascularity thus giving false-negative results. Surgeons should be aware of this; SPECT may prove to be a more accurate method of assessing vascularity of the femoral head in fractures of the femoral neck

1 . The arterial pattern and the histological features in the femoral head and neck were studied at necropsy in twenty-five specimens with intracapsular fractures. An improved visual-arteriographic method employing barium sulphate dyed with Prussian blue was used. Twenty-three of the fractures were from a few days to twenty-four weeks old and two were seven and ten years old. Nineteen had been nailed or nail-plated. 2. The results were divided into four groups according to the state of the femoral head. In the first group, four heads were histologically viable and had a normal vascular pattern; in the second group, four showed partial avascular necrosis with part of the head retaining a normal blood supply; in the third group, ten had avascular necrosis in all or most of the head and showed little or no revasculanisation; and in the fourth group, seven showed extensive revascularisation of grossly necrotic heads. Total or subtotal capital necrosis had occurred in 64 per cent and total or partial necrosis in 84 per cent of the specimens. The results indicated that interruption of the retinacular vessels was the cause of gross necrosis; and that in most cases an intact blood supply through the ligamentum teres cannot keep more than a part of the head alive when the other vessels are cut off. Occasionally the ligamentum teres is torn by the nail, or though intact, its blood supply is interrupted. This accounts for completion of avascular necrosis in most cases with total capital necrosis. Viability of the subfoveal area from an intact supply through the ligamentum teres was the main source of revascularisation after capital necrosis. Other sources–from across a uniting fracture line, from growth of soft tissue round the head and neck and from other small viable foci in the head and neck–were much less important and the degree of revascularisation was generally limited. Revascularisation was accompanied by fibrocellular invasion of the marrow, differentiation of cells and the formation of oil cysts whereby the necrotic fat is removed; but bony reconstitution was limited. 3. Six fractures were uniting and another had united by bone making an overall union frequency of 50 per cent considering only the nailed fractures older than two weeks. Four of them (57 per cent) showed total or subtotal capital necrosis. In fractures older than two weeks the frequency of union among the eleven nailed fractures with avascular necrosis was 36 per cent, and it was 100 per cent among the three nailed ones with viable or substantially viable heads. Necrosis of the neck side of the fracture was unrelated to non-union because it soon becomes invaded by fibrovascular tissue and new bone. 4. Fibrosis was the basis of union when the head was dead but examination of older fractures at necropsy is needed to assess the long-term results of revascularisation and union. The clinical desirability or otherwise of capital revascularisation after necrosis also needs to be studied

From November 1994 to March 1997, we harvested 137 grafts of the femoral head from 125 patients for donation during total hip arthroplasty according to the guidelines of the American Associations of Tissue Banks (AATB) and the European Association of Musculo-Skeletal transplantation (EAMST). In addition to the standards recommended by these authorities, we performed histopathological examination of a core biopsy of the retrieved bone allograft and of the synovium. Of the 137 allografts, 48 (35.0%) fulfilled all criteria and were free for donation; 31 (22.6%) were not regarded as suitable for transplantation because the serological retests at six months were not yet complete and 58 (42.3%) were discarded because of incomplete data. Of those discarded, five showed abnormal histopathological findings; three were highly suspicious of low-grade B-cell lymphoma, one of monoclonal plasmacytosis and the other of non-specific inflammation of bone marrow. However, according to the standards of the AATB or EAMST they all met the criteria and were eligible for transplantation. Our findings indicate that the incidence of abnormal histopathology in these retrieved allografts was 3.6%. Since it is essential to confirm the quality of donor bones in bone banking, we advise that histopathological screening of donor bone should be performed to exclude abnormal allografts

We describe a case of traumatic anterior dislocation of the hip in a 14-year-old boy with associated intrapelvic displacement of the femoral head and ipsilateral fractures of the shaft of the femur and greater trochanter. There was a delay in presentation of eight days. At operation the femoral head was reduced into the acetabulum after enlarging the obturator foramen by performing an osteotomy of the superior pubic ramus

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head

We studied the prognostic value of MRI in 32 radiographically normal, asymptomatic hips in 25 patients at risk of osteonecrosis from glucocorticoids or alcoholism. The early findings were band-like hypointense zones on spin-echo images. No operations were performed. Life-table survival curves showed that femoral heads in which the hypointense zone traversed the middle portion of the head were most at risk of subsequent segmental collapse

We have reviewed the results of 30 operations performed on 23 patients with Ficat stage-III or stage-IV osteonecrosis of the femoral head in which autogenous cortical and cancellous bone grafting had been performed through a so-called trapdoor made in the femoral head. At a mean of 56 months (30 to 60) after operation 20 of 24 stage-III hips (83%) had a good or excellent result as determined by the Harris hip-scoring system. Two of six stage-IV hips (33%) had good or excellent results. Eighteen of 21 hips (86%) with a combined necrotic angle of 200° had good or excellent clinical results compared with only four of nine hips (44%) with a combined necrotic angle of more than 200°. Six of the eight hips which had fair or poor results were in patients who had received corticosteroids; five of these six hips had lesions with a combined necrotic angle of greater than 200° or were in a late stage (stage IV). There were no perioperative complications. Our results suggest that the trapdoor procedure with autogenous cancellous and cortical bone grafting can be successful in Ficat and Arlet stage-III osteonecrosis of the hip in patients with small- to medium-sized lesions

It has been suggested that transient osteoporosis or the bone marrow oedema syndrome (BMOS) may be the initial phase of osteonecrosis of the femoral head (ONFH) and that there may be a common pathophysiology. In this study, we have assessed the MR images of 200 consecutive patients with ONFH in respect of the BMO pattern in order to test this hypothesis. This pattern was not observed in the early stage of ONFH. The initial abnormal finding detected on the MR images was an abnormal band of intensity at the junction between the necrotic area and the normal bone. Structural damage of the head seems to result in the appearance of the BMO pattern and the development of pain in ONFH. There was no finding to support the existence of a continuum between BMOS and ONFH

1. The femoral head has been examined in specimens taken from cadavers, patients suffering subcapital fracture of the femoral neck and patients undergoing total replacement arthroplasty for osteoarthrosis and rheumatoid arthritis. 2. Lesions have been seen, some of which appear to be uniting fatigue fractures of individual trabeculae. 3. It is suggested that excessive cyclical loading, sometimes leading to fatigue fractures, may represent a fundamental pathological process of general importance in the evolution of certain skeletal and articular diseases

Human articular cartilage taken from 92 femoral heads at autopsy was examined macroscopically and microscopically. Fifty-two showed no changes except for occasional slight degeneration in the non-pressure areas; these changes were visible only microscopically. In the remaining 40 heads, different degrees of osteoarthrosis were seen; half the heads also showed focal lacunar resorptive lesions in the cartilage. The origin of this focal cartilage resorption is discussed and its possible association with necrosis, pannus formation and enzymatic synovial activities. We conclude that there is no evidence of a direct relationship between focal cartilage resorption and osteoarthrosis