Endothelin-1-induced femoral head epiphyseal artery constriction is enhanced by long-term corticosteroid treatment

Epidemiology and risk factors associated with avascular necrosis in patients with autoimmune diseases: a nationwide study

BACKGROUND/AIMS

Avascular necrosis (AVN) is a clinical condition characterized by the death of bone components due to interruption in the blood supply. This study aimed to investigate the epidemiology and determine the risk factors for AVN in patients with autoimmune diseases.

METHODS

We conducted a population-based retrospective cohort analysis using claims data from the Taiwan National Health Insurance Research Database. A total of 49,636 patients with autoimmune diseases between January 1, 2005 and December 31, 2013 were included. Cox regression analysis was used to identify associated risk factors for the development of AVN.

RESULTS

A total of 490/49,636 patients (1.0%) developed symptomatic AVN. The systemic lupus erythematosus patients had a higher risk of AVN compared to other autoimmune diseases. AVN was positively correlated with male sex (p < 0.001), alcoholism (p < 0.001), mean daily prednisolone dosage 7.51 to 30 mg (p < 0.001) and > 30 mg (p < 0.001), and total cumulative prednisolone dose 0 g to 5 g (p = 0.002). However, AVN was inversely correlated with cumulative duration of hydroxychloroquine exposure > 0.6 years (p < 0.001).

CONCLUSION

Male sex, systemic lupus erythematosus, alcoholism, mean daily corticosteroid > 7.5 mg and a total cumulative dose of corticosteroid 0 to 5 g were independently associated with the development of AVN in autoimmune patients. While hydroxychloroquine use > 0.6 years conferred significant protection against the development of AVN. Clinicians should regularly assess patients with risk factors to enable the early diagnosis of AVN.

The role of cell therapies and hip arthroscopy in the management of osteonecrosis: an update

The exact pathophysiology of osteonecrosis of the femoral head (ONFH) is still unknown. There is evidence to suggest that in ON there is decreased population and altered function of the mesenchymal stem cells (MSCs) of the femoral head. This could influence both the actual occurrence of ON itself and the repair process that follows. Hence, in such an environment it only is rational to consider the use of cell-based treatments to potentially regenerate lost or damaged bone. The aim of this review is to provide an up-to-date, evidence-based information in the use of cell therapies in the treatment of nontraumatic ONFH and the use of hip arthroscopy in the field.

The role of autophagy in steroid necrosis of the femoral head: a comprehensive research review

Steroid-induced osteonecrosis of the femoral head (ONFH) has the incidence of 9-40% in patients receiving long-term treatment and is mainly involved in the middle and young people. It is mostly bilateral, with a wide range of necrosis and high disability rate, which brings disaster for patients and families. The experimental study shows that autophagy participates in the pathological process of steroid ONFH and is closely related to apoptosis, and the interaction between autophagy and bone cells is related to the dose of hormones. Moreover, autophagy also affects the interaction between osteoblasts and osteoclasts in ONFH. In the present review, we have discussed the role of autophagy in the pathological process of the steroid-induced ONFH.

Combined Treatment with an Anticoagulant and a Vasodilator Prevents Steroid-Associated Osteonecrosis of Rabbit Femoral Heads by Improving Hypercoagulability

Steroid-associated osteonecrosis of the femoral head remains a challenging problem in orthopedics worldwide. One pathomechanism is ischemia of the femoral head, as a result of thrombus formation and vasoconstriction. The present study investigates the effects of combination prevention with enoxaparin and EGb 761 on steroid-associated ONFH in rabbits. Rabbits were randomly divided into 5 groups (control group, model group, enoxaparin group, ginkgo group, and combination group). With the exception of the control group, the groups of rabbits were modeled with lipopolysaccharide and methylprednisolone acetate. Starting with modeling, the enoxaparin group and ginkgo group were injected with 1 μg/kg/day enoxaparin subcutaneously and orally given 40 mg/kg/day EGb 761 for 4 weeks, respectively; the combination group received both treatments. After modeling for 6 weeks, the hematology data indicated prolonged PT and APTT in the three prevention groups. The micro-CT examination revealed higher bone density and better structure; histomorphometry revealed significant pathological changes. Immunohistochemistry revealed higher expression of BMP-2 and VEGF, thus revealing better osteogenesis and angiogenesis activities. Among the three prevention groups, the combination group had the most efficient results. In conclusion, the combined prevention with an anticoagulant and a vasodilator has the potential to decrease the incidence of steroid-associated ONFH in rabbits.

Tetramethylpyrazine enhances vascularization and prevents osteonecrosis in steroid-treated rats

Steroid-induced osteonecrosis of the femoral head (steroid-induced ONFH) is an avascular necrosis disease of bone. Tetramethylpyrazine (TMP), with significant vascular protective properties, has been widely used for the treatments of ischemic neural disorders and cardiovascular diseases. However, its role in the treatment of steroid-induced ONFH has not been evaluated. In this study, our results showed that TMP significantly decreased the ratio of empty lacuna, adipose tissue area, and adipocyte perimeter in steroid-induced ONFH rats histopathologically. TMP also reduced the levels of serum lipid dramatically by haematological examination. According to the micro-CT quantification, TMP could improve the microstructure of the trabecular bone and increases bone mineral density in steroid-induced ONFH rats. Moreover, TMP significantly increased the vessel volume, vessel surface, percentage of vessel volume, and vessel thickness of the femoral heads by micro-CT. Interestingly, the downregulation of VEGF and FLK1 proteins in the sera and necrotic femoral heads could be reversed by TMP treatment, and this was true for their mRNA expressions in femoral heads. In conclusion, these findings suggest for the first time that TMP may prevent steroid-induced ONFH and also enhance femoral head vascularization by inhibiting the effect of steroid on VEGF/FLK1 signal pathway.

Operative treatment and avascular necrosis of the hip development disorder

PURPOSE

The purpose of this research was (1) to evaluate the consequences of an operative treatment of hip developmental disorder in children, (2) to evaluate the significance of hip vascular supply in children through indirect radiological signs, such as morphological changes on femoral head, and to classify them with standard classification methods, and (3) to analyse the research results and make a recommendation for the following treatment dilemma: when is the optimal time for an operative treatment of a hip development disorder?

METHODS

The research is a retrospective and observational analysis based on the classification of indirect radiological signs of local vascular disorder by the Bucholz-Ogden's scale. Materials used for this research are medical records of treated patients at the Clinic for Orthopaedics and Traumatology of the Sarajevo University Clinical Centre. Using a random selection, two groups of 30 patients with hip development disorder were formed. The first group was comprised of patients aged six to 18 months and the second group of patients aged 18-60 months. The medical records used for this research included all necessary anamnestic details and postoperative state treatments with clinical findings and regular radiological check-up findings that include the presence or absence of the ossification nucleus as well as its position. All patients underwent surgery with the same operative technique. Data analysis points include the state at the beginning of the treatment, the postoperative state, the state at discharge as well as control findings that followed the development of the proximal femoral part up to 72 months on average. The analysis covered data such as age, sex, family anamnestic data, clinical findings and radiological findings regarding the femoral head morphology (appearance, size, shape, position and indirect signs showing lack of vascular supply). In addition, data analysis included the types of any previous conservative or operative treatments, the duration of previous conservative treatments and repeated hospitalization.

RESULTS

In group 1, 86.6 % were female patients and 80 % in group 2. Family history was positive in 15.6 % in group 1 and 13.3 % in group 2. A total of 51.6 % of all patients started walking on time, while the rest had problems with verticalization. Of all patients, 47 % did not undergo any kind of prior treatment. Only 62.2 % of group 1 patients had ossification nucleus present, while the entire group 2 had it present. Results showed that 24.32 % of group 1 patients had none or minimal signs of avascular necrosis (AVN) while 39.47 % of group 2 had none or minimal signs of AVN; 60.52 % of group 2 patients had signs of AVN.

CONCLUSION

The results of this study show that the performance of a surgical treatment during the age between 12 and 20 months is burdened by the highest percentage of avascular necrosis. Even though AVN can be noticed in other age groups, according to the results of our research, it seems that vascular supply of the hip is the most vulnerable in the period between 12 and 20 months.

Relationship between preservation of the lateral pillar and collapse of the femoral head in patients with osteonecrosis

It is difficult to predict if and when the femoral head will collapse and whether the collapse can be minimized. This study examined the final outcome of early-stage osteonecrosis of the femoral head (ONFH) using magnetic resonance imaging to verify the relationship between preservation of the lateral pillar and collapse of the femoral head. A midcoronal section of the femoral head was divided into 3 pillars (medial, central, and lateral) on a T1-weighted image. According to the site of necrosis on the lateral pillar, the necrosis was divided into 3 types: I, the necrosis occupies the central and medial pillars, and the lateral pillar is preserved; II, the necrosis partially occupies the lateral pillar; and III, the necrosis totally occupies the lateral pillar. One group of 87 patients (127 hips) with Association for Research on Osseous Circulation (ARCO) stage I ONFH underwent nonoperative treatment and were followed for 3 to 8 years (average, 6.2 years). Another group of 42 patients (72 hips) with ARCO stage I ONFH underwent debridement and impacted bone graft and were followed for 5 to 9 years (average, 7.1 years). In both groups, the more preserved the lateral pillar, the less collapse occurred. The authors concluded that whether ONFH progressed to collapse is determined by preservation of the lateral pillar. The lateral pillar is the keystone for maintaining the sphere of the femoral head and its preservation.

Primary epiphyseal arteriopathy in a mouse model of steroid-induced osteonecrosis

Patients undergoing glucocorticoid therapy for a variety of disorders, including autoimmune diseases and hematological malignancies, are at risk of developing osteonecrosis. Despite extensive research in both patients and animal models, the underlying pathogenesis remains unclear. Proposed inciting mechanisms include intravascular thrombotic occlusion, marrow fat hypertrophy, osteocyte and/or endothelial cell apoptosis, hypercoagulability, and vasoconstriction of specific arteries and arterioles supplying bone. Our laboratory has developed a model of steroid-induced osteonecrosis in BALBcJ mice which reflects clinically relevant exposures to glucocorticoids in which treated mice develop osteonecrosis of the distal femoral epiphysis when administered 4 to 8 mg/L dexamethasone in drinking water for 6 weeks. We identified lesions in arterioles supplying this area, with the mildest occurring in knees without any evidence of osteonecrosis. However, arteriopathy was more common among mice that did versus did not develop osteonecrosis (P < 0.0001); in mice with osteonecrosis, the associated vessels showed transmural necrosis and thickening of the vessel wall progressing to the point of luminal obstruction. In the most severe cases of osteonecrosis, end-stage lesions consisted of fully occluded vessels with marrow and bone necrosis involving the entire epiphysis. We propose that a primary arteriopathy is the initiating event in the genesis of steroid-induced osteonecrosis and provides a basis for future investigation of this disease process.

Thirty-year follow-up after Wagner resurfacing hip arthroplasty: Case report

Wagner hip arthroplasty has been used as a resurfacing and thereby bone-preserving method for the treatment of disabling osteoarthritis particularly in younger individuals. The underlying rationale was to replace exclusively diseased tissue, to restore anatomy and function and to optimize range of motion and stress transfer to the proximal femur. Wagner's approach was designed to reduce the risk of infection and to make later revisions easier. The technique was however associated with a high revision rate due to early aseptic wear induced component loosening and neck fractures. Nevertheless, we report a case of a 30 years follow-up of a Wagner resurfacing hip arthroplasty.

Incidence of genetic polymorphisms involved in lipid metabolism among Chinese patients with osteonecrosis of the femoral head

BACKGROUND AND PURPOSE Corticosteroid treatment is associated with osteonecrosis of the femoral head (ON) in certain patients. The degree of drug sensitivity in general is governed by genetic variation between individuals. We investigated the relationship between ON and the presence of different alleles of the cytochrome P450 gene (CYP3A4), the product of which metabolizes corticosteroids, and of the P-glycoprotein (P-gp) gene (ABCBI), the product of which modulates cellular uptake of corticosteroids, to determine whether patients with certain alleles may be at higher risk of ON after corticosteroid treatment.

METHODS

We studied 31 patients from Guangdong, China who were both treated with corticosteroid therapy and developed ON, and 17 corticosteroid-therapy patients without ON. Patient DNA was screened for known polymorphisms in the CYP3A4 gene (CYP3A4*4, CYP3A4*5, CYP3A4*6) and the P-gp gene ABCB1 (mutations C3435T, G2677T/A).

RESULTS

The majority (20/31) of the corticosteroid-treated patients who developed ON were heterozygous for ABCB1, whereas only 3/17 without ON were heterozygous. Statistical significance was observed between the ON and the control groups for the ABCB1 G2677T/A polymorphism. Analysis of haplotypic frequencies indicated significant linkage disequilibrium between the two ABCB1 polymorphisms, C3435T and G2677T/A (D' = 0.034). No CYP3A4 polymorphisms were detected in any of the patients.

INTERPRETATION

Patients carrying an ABCB1 polymorphism had a higher risk of having corticosteroid-associated ON than those with wild-type genotypes. This statistically significant association conflicts with previous studies, possibly due to different sampling methods. Knowing which genetic backgrounds are most strongly associated with corticosteroid-associated ON provides a method of screening for patients who are most at risk of developing ON.

Glucocorticoids in osteonecrosis of the femoral head: a new understanding of the mechanisms of action

Glucocorticoid (GC) usage is the most common non-traumatic cause of osteonecrosis of the femoral head (ON). Despite the strong association of GC with ON, the underlying mechanisms have been unclear. Investigators have proposed both direct and indirect effects of GC on cells. Indirect and direct mechanisms remain intimately related and often result in positive feedback loops to potentiate the disease processes. However, the direct effects, in particular apoptosis, have recently been shown to be increasingly important. Suppression of osteoblast and osteoclast precursor production, increased apoptosis of osteoblasts and osteocytes, prolongation of the lifespan of osteoclasts and apoptosis of endothelial cells (EC) are all direct effects of GC usage. Elevated blood pressure through several pathways may raise the risk of clot formation. High-dose GC also decreases tissue plasminogen activator activity (t-PA) and increases plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels increasing the procoagulant potential of GC. Inhibited angiogenesis, altered bone repair and nitric oxide metabolism can also result. Also, GC treatment modulates other vasoactive mediators such as endothelin-1, noradrenalin and bradykinin. Thus, GCs act as a regulator of local blood flow by modulating vascular responsiveness to vasoactive substances. Vasoconstriction induced in intraosseous femoral head arteries causes femoral head ischemia. GCs also cause ischemia through increased intraosseous pressure, which subsequently decreases the blood flow to the femoral head by apoptosis of ECs as well as elevating the level of adipogenesis and fat hypertrophy in the bone marrow. It is difficult to predict which patients receiving a specific dose of GC will develop ON, indicating individual differences in steroid sensitivity and the potential of additional mechanisms. The textbook model of ON is a multiple hit theory in which, with a greater number of risk factors, the risk of ON increases. While more effort is needed to better comprehend the role of GC in ON, newer data on GC action upon the endothelial cell and the regional endothelial bed dysfunction theory sheds new light on particular GC mechanisms. Better understanding of GC pathomechanisms can lead to better treatment options.

Steroid-induced osteonecrosis: the number of lesions is related to the dosage

Severe acute respiratory syndrome (SARS) is a newly described infectious disease caused by the SARS coronavirus which attacks the immune system and pulmonary epithelium. It is treated with regular high doses of corticosteroids. Our aim was to determine the relationship between the dosage of steroids and the number and distribution of osteonecrotic lesions in patients treated with steroids during the SARS epidemic in Beijing, China in 2003. We identified 114 patients for inclusion in the study. Of these, 43 with osteonecrosis received a significantly higher cumulative and peak methylprednisolone-equivalent dose than 71 patients with no osteonecrosis identified by MRI. We confirmed that the number of osteonecrotic lesions was directly related to the dosage of steroids and that a very high dose, a peak dose of more than 200 mg or a cumulative methylprednisolone-equivalent dose of more than 4000 mg, is a significant risk factor for multifocal osteonecrosis with both epiphyseal and diaphyseal lesions. Patients with diaphyseal osteonecrosis received a significantly higher cumulative methylprednisolone-equivalent dose than those with epiphyseal osteonecrosis. Multifocal osteonecrosis should be suspected if a patient is diagnosed with osteonecrosis in the shaft of a long bone.