Is avascular necrosis of the femoral head the result of inhibition of angiogenesis?

A Molecular Troika of Angiogenesis, Coagulopathy and Endothelial Dysfunction in the Pathology of Avascular Necrosis of Femoral Head: A Comprehensive Review

Avascular necrosis of the femoral head (ANFH) is a painful disorder characterized by the cessation of blood supply to the femoral head, leading to its death and subsequent joint collapse. Influenced by several risk factors, including corticosteroid use, excessive alcohol intake, hypercholesterolemia, smoking and some inflammatory disorders, along with cancer, its clinical consequences are thrombus formation due to underlying inflammation and endothelial dysfunction, which collaborates with coagulopathy and impaired angiogenesis. Nonetheless, angiogenesis resolves the obstructed free flow of the blood by providing alternative routes. Clinical manifestations of early stage of ANFH mimic cysts or lesions in subchondral bone, vasculitis and transient osteoporosis of the hip, rendering it difficult to diagnose, complex to understand and complicated to cure. To date, the treatment methods for ANFH are controversial as no foolproof curative strategy is available, and these depend upon different severity levels of the ANFH. From an in-depth understanding of the pathological determinants of ANFH, it is clear that impaired angiogenesis, coagulopathy and endothelial dysfunction contribute significantly. The present review has set two aims, firstly to examine the role and relevance of this molecular triad (impaired angiogenesis, coagulopathy and endothelial dysfunction) in ANFH pathology and secondly to propose some putative therapeutic strategies, delineating the fact that, for the better management of ANFH, a combined strategy to curtail this molecular triangle must be composed rather than focusing on individual contributions.

Quantitative analysis of local microcirculation changes in early osteonecrosis of femoral head: DCE-MRI findings

Aim

This study aims to quantitatively analyze the changes in local microcirculation in early osteonecrosis of the femoral head (ONFH) by dynamic contrast-enhanced (DCE) MRI and to explore the pathophysiological mechanisms of early ONFH.

Patients and Methods

We selected 49 patients (98 hips) aged 21-59 years who were clinically diagnosed with early ONFH. A total of 77 femoral heads were diagnosed with different degrees of necrosis according to the Association Research Circulation Osseous (ARCO) staging system, and 21 femoral heads were judged to be completely healthy. All patients underwent DCE-MRI scanning. Pseudocolor images and time-signal intensity curves were generated by Tissue 4D processing software. The volume transfer constant (K ^trans), extracellular extravascular space, also known as vascular leakage (V _e), and transfer rate constant (K _ep) of healthy and different areas of necrotic femoral heads were measured on perfusion parameter maps. The differences and characteristics of these parameters in healthy and different areas of necrotic femoral heads were analyzed.

Results

The signal accumulation in healthy femoral heads is lower than that of necrotic femoral heads in pseudocolor images. The time-signal intensity curve of healthy femoral heads is along the horizontal direction, while they all have upward trends for different areas of necrotic femoral heads. The mean value of K ^trans of healthy femoral heads was lower than the integration of necrotic, boundary, and other areas (F = 3.133, P = .036). The K _ep value of healthy femoral heads was higher than the integration of lesion areas (F = 6.273, P = .001). The mean V _e value of healthy femoral heads was smaller than that of the lesion areas (F = 3.872, P = .016). The comparisons of parameters between different areas and comparisons among healthy areas and lesion areas showed different results.

Conclusion

ONFH is a complex ischemic lesion caused by changes in local microcirculation. It mainly manifests as increased permeability of the vascular wall, blood stasis in the posterior circulation, high intraosseous pressure in the femoral head, and decreased arterial blood flow. The application of DCE-MRI scanning to quantitatively analyze the visual manifestations of microcirculation after early ONFH is an ideal method to study the microcirculation changes of necrotic femoral heads.

Risk factors and pathogenesis of steroid-induced osteonecrosis of femoral head - A scoping review

Steroid induced osteonecrosis of the femoral head is commonly seen in clinical practice, but yet not fully understood. It is intriguing why only some cases develop and others escape from it. We did an extensive and up to date literature review on it, with the aim to identify its incidence, associated risk factor and pathogenesis. We found that the incidence ranged from 03 to 40%, and was more with associated risk factors. Several risk factors were identified, which included higher dose and prolonged duration of steroid consumption, and underlying disease for which the steroids were given. Pathogenesis of this disease is complex and not yet fully understood. Awareness about this condition and associated risk factors should help the clinicians in identifying the cases who are prone to develop osteonecrosis with the use of steroids.

Nilotinib induced avascular necrosis of femoral head in an adult chronic myeloid leukemia patient

We report a rare case of avascular necrosis of femoral head (AVNFH) in an adult chronic myeloid leukemia - chronic phase (CML-CP) patient during due course of therapy with second line Tyrosine Kinase Inhibitor (TKI), Nilotinib. A high index of clinical suspicion should be kept in any symptomatic CML patient on TKI's.

Engineering in-vitro stem cell-based vascularized bone models for drug screening and predictive toxicology

The production of veritable in-vitro models of bone tissue is essential to understand the biology of bone and its surrounding environment, to analyze the pathogenesis of bone diseases (e.g., osteoporosis, osteoarthritis, osteomyelitis, etc.), to develop effective therapeutic drug screening, and to test potential therapeutic strategies. Dysregulated interactions between vasculature and bone cells are often related to the aforementioned pathologies, underscoring the need for a bone model that contains engineered vasculature. Due to ethical restraints and limited prediction power of animal models, human stem cell-based tissue engineering has gained increasing relevance as a candidate approach to overcome the limitations of animals and to serve as preclinical models for drug testing. Since bone is a highly vascularized tissue, the concomitant development of vasculature and mineralized matrix requires a synergistic interaction between osteogenic and endothelial precursors. A number of experimental approaches have been used to achieve this goal, such as the combination of angiogenic factors and three-dimensional scaffolds, prevascularization strategies, and coculture systems. In this review, we present an overview of the current models and approaches to generate in-vitro stem cell-based vascularized bone, with emphasis on the main challenges of vasculature engineering. These challenges are related to the choice of biomaterials, scaffold fabrication techniques, and cells, as well as the type of culturing conditions required, and specifically the application of dynamic culture systems using bioreactors.

Minimally invasive treatment for osteonecrosis of the femoral head with angioconductive bioceramic rod

PURPOSE

To describe the rationale, the surgical technique, and the short-term follow-up results of a new minimally invasive treatment of osteonecrosis of the femoral head (ONFH) with an angioconductive bioceramic rod (ABR) implant.

METHODS

Sixty-two patients (72 hips) with ARCO stage IIA-IIIC ONFH treated with the minimally invasive ABR from January 2012 to December 2016 were reviewed (17 females, 45 males, mean age 44.49). This technique used the angioconductive properties of the porous implant to repair the necrosis by driving vascularization from the trochanter to the necrotic area. Patients had a mean follow-up period of 26.74 months. The outcomes were evaluated by hip joint survival, radiograph, and the Harris Hip Score (HHS). The complications occurred during the treatment period were recorded.

RESULTS

No serious post-operative complications occurred during the treatment. The overall joint survival rate was 90.27%, with seven conversions to THA. Improvements were observed in 23 (31.95%) hips, 24 (33.33%) hips remained stable, and 25 (34.72%) hips had worse results according to the radiographic evaluation. The mean HHS at the end follow-up significantly improved compared to the pre-operative mean HHS (82.27 vs 58.14, p < 0.001). In both radiographic evaluation and HHS, the treatment was more effective on patients beneath 44 years old (p < 0.05); ARCO stage II compared to stage III (p < 0.05); and China-Japan Friendship Hospital (CJFH) type C compared to CJFH type L (p < 0.05).

CONCLUSIONS

The minimally invasive treatment of ONFH with ABR showed promising results in delaying or even terminating the progression of the necrosis and improving hip function, especially in younger patients and in the early stages of the disease.

Regulatory effect of microRNA-34a on osteogenesis and angiogenesis in glucocorticoid-induced osteonecrosis of the femoral head

Glucocorticoid-induced osteonecrosis of the femoral head (GIOFH) is a common and devastating orthopedic disease, and its underlying mechanism remains unclear. The aim of this study was to determine the role of microRNA-34a (mir-34a) in GIOFH. C57 mouse mesenchymal stem cells (mMSCs) and human umbilical vein endothelial cells (HUVECs) were cultured with dexamethasone (Dex). A total of 48 adult rats were treated with glucocorticoids, and after the onset of GIOFH, each femoral head was removed. Mir-34a mimics, an inhibitor and over-expressing lentivirus were used in vitro and in vivo, respectively. Real-time PCR, immunohistochemistry, ELISA, cell proliferation assays, osteoblastic differentiation, and endothelial activity assays were employed to evaluate the effect of mir-34a on mMSCs, osteoblasts, and vascular endothelial cells in glucocorticoid-treated mice. We found that Dex inhibited mMSC proliferation and osteoblastic differentiation, as well as the viability and activity of endothelial cells. Dex also caused osteonecrosis and decreased new vessel formation in vivo. Mir-34a alleviated the inhibitory effects of Dex on mMSCs and osteoblasts, while facilitating its inhibitory effects on endothelial cells. Mir-34a is an important regulator in osteogenesis and angiogenesis, and it might be useful as a therapeutic target for GIOFH. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:417-424, 2018.

Preclinical Study of Cell Therapy for Osteonecrosis of the Femoral Head with Allogenic Peripheral Blood-Derived Mesenchymal Stem Cells

PURPOSE

To explore the value of transplanting peripheral blood-derived mesenchymal stem cells from allogenic rabbits (rPBMSCs) to treat osteonecrosis of the femoral head (ONFH).

MATERIALS AND METHODS

rPBMSCs were separated/cultured from peripheral blood after granulocyte colony-stimulating factor mobilization. Afterwards, mobilized rPBMSCs from a second passage labeled with PKH26 were transplanted into rabbit ONFH models, which were established by liquid nitrogen freezing, to observe the effect of rPBMSCs on ONFH repair. Then, the mRNA expressions of BMP-2 and PPAR-γ in the femoral head were assessed by RT-PCR.

RESULTS

After mobilization, the cultured rPBMSCs expressed mesenchymal markers of CD90, CD44, CD29, and CD105, but failed to express CD45, CD14, and CD34. The colony forming efficiency of mobilized rPBMSCs ranged from 2.8 to 10.8 per million peripheral mononuclear cells. After local transplantation, survival of the engrafted cells reached at least 8 weeks. Therein, BMP-2 was up-regulated, while PPAR-γ mRNA was down-regulated. Additionally, bone density and bone trabeculae tended to increase gradually.

CONCLUSION

We confirmed that local transplantation of rPBMSCs benefits ONFH treatment and that the beneficial effects are related to the up-regulation of BMP-2 expression and the down-regulation of PPAR-γ expression.

Poultry Femoral Head Separation and Necrosis: A Review

Femoral head separation (FHS) is a degenerative skeletal problem in fast-growing poultry wherein the growth plate of the proximal femur separates from its articular cartilage. At its early phase, FHS may remain asymptomatic but lead to epiphyseal breakage, infection, and femoral head necrosis (FHN). Healthy femoral head is viewed as a positive trait for genetic selection. However, the etiology of FHS is poorly understood for use in noninvasive diagnosis and genetic selection. Focal cell death and atrophic changes are likely associated with separation of tissues and necrotic changes. Fibrotic thickening of the articular surface can also impair free movement of the proximal epiphysis in the acetabulum, leading to FHS, under strain. The major limitation to understanding the pathophysiology of FHN is the lack of suitable experimental models and biomarkers to diagnose the problem. In this review, we discuss the possible etiologic factors, anatomic features of the chicken femoral head, biomarkers, and molecular mechanisms relevant to FHN.

Dasatinib Induced Avascular Necrosis of Femoral Head in Adult Patient with Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Philadelphia (Ph) chromosome resulting from the reciprocal translocation t(9;22)(q34;q11). The molecular consequence of this translocation is the generation of the BCR-ABL fusion gene, which encodes a constitutively active protein tyrosine kinase. The oncogenic protein tyrosine kinase, which is located in the cytoplasm, is responsible for the leukemia phenotype through the constitutive activation of multiple signaling pathways involved in the cell cycle and in adhesion and apoptosis. Avascular necrosis of the femoral head (AVNFH) is not a specific disease. It occurs as a complication or secondary to various causes. These conditions probably lead to impaired blood supply to the femoral head. The diagnosis of AVNFH is based on clinical findings and is supported by specific radiological manifestations. We reported a case of a 34-year-old Sudanese female with CML who developed AVNFH after receiving dasatinib as a second-line therapy. Though the mechanism by which dasatinib can cause avascular necrosis (AVN) is not clear, it can be postulated because of microcirculatory obstruction of the femoral head. To the best of our knowledge and after extensive literature search, this is the first reported case of AVNFH induced by dasatinib in a patient with CML.

Avascular necrosis in pediatric systemic lupus erythematosus: a brief report and review of the literature

Avascular necrosis (AVN) occurs in several chronic illnesses, including systemic lupus erythematosus (SLE), but can also occur in healthy children. There are multiple theories to explain why and how AVN occurs, but an exact mechanism has yet to be unraveled. AVN in the pediatric lupus population is understudied. The Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, provides an excellent venue to conduct an exploratory analysis to assess associations between AVN and demographics, SLE disease activity and vitamin D deficiency. Herein we present a brief report describing our findings, as well as reviewing the literature on AVN in SLE and other entities.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00065806.

Bone vascularization in normal and disease conditions

Bone vasculature is essential for many processes, such as skeletal development and growth, bone modeling and remodeling, and healing processes. Endothelium is an integral part of bone tissue, expressing a physiological paracrine function via growth factors and chemokines release, and interacting with several cellular lines. Alterations of the complex biochemical interactions between vasculature and bone cells may lead to various clinical manifestations. Two different types of pathologies result: a defect or an excess of bone vasculature or endothelium metabolism. Starting from the molecular basis of the interactions between endothelial and bone cells, the Authors present an overview of the recent acquisitions in the physiopathology of the most important clinical patterns, and the modern therapeutic strategies for their treatments.

Can local Erythropoietin administration enhance bone regeneration in osteonecrosis of femoral head?

Osteonecrosis of femoral head (ONFH) is a challenging disease. Regardless of underlying causes, the ultimate result in all cases is disruption of femoral head blood supply. Once the disease starts, it is progressive in 80% of cases. Since the majority of the affected individuals are young, every effort should be focused on preserving the patients own femoral head. These years, the role of angiogenic growth factors has been investigated with promising results in animal models of ONFH. Erythropoietin (EPO) is a well known hormone that has been used in treatment of chronic anemia for many years with few side effects. Considering the angiogenic properties of EPO, we hypothesize that local delivery of recombinant human EPO during core decompression will enhance bone regeneration in ONFH. In this way we also can avoid systemic side effects of EPO.

Skeletal scintigraphy manifestations of hematologic disorders

Skeletal manifestations are common in hematologic disorders. Benign entities such as Sickle cell disease develop microvascular embolization causing skeletal crisis. Leukemia, acute myeloblastic or lymphoblastic may develop bone marrow infarcts. Compromised immunity makes them susceptible to secondary infection leading to osteomyelitis or septic arthritis. Exposure to steroids may lead to osteonecrosis in these cases. Presented here is an atlas of various scintigraphic skeletal manifestations encountered over the past 10 years, in hematologic disorders.

Treatment of early avascular necrosis of femoral head by small intestinal submucosal matrix with peripheral blood stem cells

BACKGROUND

Avascular necrosis of the femoral head (ANFH) is a highly mutilating disease. There are no effective ways to treat early femoral head ischemia. Peripheral blood stem cell (PBSC) transplantation may be superior to conventional bone marrow transplantation. Small intestinal submucosae matrix (SIS) is composed of highly conserved collagens, glycoproteins, proteoglycans, and glycoaminoglycans in their natural configuration and concentrations. When implanted in a number of microenvironments in vivo, SIS has been used to induce proliferation, remodeling, and regeneration of host tissues. This study was designed to verify the curative effects of PBSC and SIS transplantation-induced vascular regeneration to improve ischemic femoral head necrosis in rabbits.

METHODS

32 New Zealand white rabbits underwent ischemic femoral head necrosis modeling in both hindlimbs by liquid-nitrogen refrigeration. All rabbits were intraperitoneally injected with grannlocytectomy-stimulating factor (250 μg/kg/d), except for normal control subjects injected with equivalent saline solution. After separation of peripheral blood stem cells (PBSCs), 64 femoral heads in 32 rabbits were randomly divided into 4 groups: group A, cancellous bone and peripheral blood stem cells cultured with small intestinal submucosa; group B, cancellous bone and PBSCs; group C, cancellous bone autografts; and group D, no treatment. The specimens were harvested at 4 and 8 weeks after surgery. All specimens were examined to observe angiogenesis and osteogenesis repairing the avascular necrosis of the femoral head by using gross observation, x-ray, histology, and immunohistochemical staining.

RESULTS

In 4 weeks after peripheral stem cell transplantation, the standing ability and activity of the transplanted hindlimbs were improved remarkably, but there were no obvious changes in the control limbs. X-rays showed a greater density of grafts than the host bone in groups A,B, and group C was unchanged at 4 weeks. Histology revealed many osteoprogenitor cells and osteoblasts and no inflammatory cell infiltration at 4 weeks with much new bone formed at 8 weeks in group A and at 4 weeks in group B. The cancellous bone autograft was absorbed completely at 8 weeks in group C. There was little osteoid tissue formed in group D at 8 weeks. The zone of new bone formation in group A was greater than that in group B (P < .05), but there was no significant difference between groups A and C (P > .05). Immunohistochemical staining with CD31 mouse antibody showed greater amounts and zones of new blood vessels in groups A and B at 4 and 8 weeks and little evidence in group D. There was no significant difference between groups A and B (P > .05) and significant differences between groups A and B versus C and D (P < .05).

CONCLUSION

Transplantation of PBSCs cultured with SIS effectively improved ischemic femoral head necrosis.

Osteonecrosis in children after therapy for malignancy

OBJECTIVE

Osteonecrosis in the growing population of childhood cancer survivors results from disease and treatment. Imagers must be knowledgeable about patient groups at risk for its development, patterns of involvement and potential implications. This review will focus on implications of this potentially life-altering toxicity.

CONCLUSION

Childhood cancer survivors are at increased risk for developing osteonecrosis. Because osteonecrosis is often asymptomatic until late in the process, imaging is critical for its detection and characterization when interventions may be most effective to ameliorate its progression.

Avascular necrosis of the femoral head in patients with Hodgkin's disease

Avascular necrosis of the femoral head (ANFH) is a rare complication that may occur in patients diagnosed with Hodgkin's Disease (HD), as a result of treatment. A review was made of 315 cases of HD treated with systemic chemotherapy associated with high doses of steroids and radiation therapy and 18 patients (5.71%) were found to have developed ANFH during treatment. The mean follow-up time for chemotherapy was 40 months (range 20-110 months) with an average dose of prednisone of 8.45 g (range 3.20 - 18.50). The patients were treated by simple forage, simple forage plus IES and total hip arthroplasty (THA). In 8 cases (44.44%) forage associated with IES was performed as the initial treatment option and 6 of these cases were found to be in Ficat stage II (75%), 1 was found to be in stage III (12.55%) and another in stage IV (12.5%). In 2 cases, the central decompression technique was used (Simple Forage); both were in Ficat stage II. In the other 8 cases, a total hip arthroplasty (THA) was chosen as the initial treatment option, with 3 of these patients in Ficat stage III and 5 in Ficat stage IV. The clinical outcomes (time to postoperative pain, time to radiological failure, and time to arthroplasty from the forage) following surgical management using the forage-biopsy technique with and without internal electrostimulation (IES) were recorded. We observed that treatment with Forage + IES was better than simple Forage in stages below III in patients with Hodgkin's Disease. We considered that in Ficat stage III and IV arthroplasty (THA) was the better option. Steroids do not appear to be the only factor that worsens the outcomes of the parameters tested, and, in our opinion, other associated factors exist.

The use of joint-specific and whole-body MRI in osteonecrosis: a study in patients with juvenile systemic lupus erythematosus

OBJECTIVE

This study aimed to estimate the prevalence of osteonecrosis (ON) in juvenile systemic lupus erythematosus (SLE) patients using joint-specific and whole-body MRI; to explore risk factors that are associated with the development of ON; and to evaluate prospectively patients 1 year after initial imaging.

METHOD

Within a 2 year period, we studied 40 juvenile SLE patients (aged 8-18 years) with a history of steroid use of more than 3 months duration. Risk factors including disease activity, corticosteroid use, vasculitis, Raynaud's phenomenon and lipid profile were evaluated. All patients underwent MRI of the hips, knees and ankles using joint-specific MRI. Whole-body STIR (short tau inversion recovery) MRI was performed in all patients with ON lesions.

RESULTS

Osteonecrosis was identified in 7 patients (17.5 %) upon joint-specific MRI. Whole-body STIR MRI detected ON in 6 of these 7 patients. There was no significant difference between the ON and non-ON groups in the risk factors studied. One patient had pre-existing symptomatic ON. At 1 year follow-up, the ON lesions had resolved in one patient, remained stable in four and decreased in size in two. No asymptomatic patients with ON developed clinical manifestations.

CONCLUSION

Whole-body STIR MRI may be useful in detecting ON lesions in juvenile SLE patients but larger studies are needed to define its role.

Peripheral blood stem cell transplantation for ischemic femoral head necrosis

BACKGROUND

Avascular necrosis of the femoral head (ANFH) is a highly mutilating disease. There is no effective way to treat femoral head ischemia. This study was designed to show the curative effects of peripheral blood stem cell transplantation to induce vascular regeneration and improve ischemic femoral head necrosis in rabbits.

METHODS

Twenty New Zealand white rabbits underwent ischemic femoral head necrosis in both hindlimbs using liquid-nitrogen refrigeration. One cohort of rats was intraperitoneally injected with granulocyte-specific colony-stimulating factor (250 microg/kg/d), and control animals received equivalent saline solution. The right side was used as the transplantation group and the left as the control. After separation of peripheral blood, a stem cell suspension was poured into the right femoral artery and saline solution into the left femoral artery.

RESULTS

At 4 weeks after peripheral stem cell transplantation, standing ability and activity of the the transplanted right hindlimb were remarkably improved, but there were no obvious changes in the control limbs. The experimental rabbits underwent arteriography of bilateral femoral heads, which indicated increased and thickened blood supply to the transplanted right hindlimb compared with the left control.

CONCLUSION

Peripheral blood stem cell transplantation improved ischemic femoral head necrosis.

Doping and musculoskeletal system: short-term and long-lasting effects of doping agents

Doping is a problem that has plagued the world of competition and sports for ages. Even before the dawn of Olympic history in ancient Greece, competitors have looked for artificial means to improve athletic performance. Since ancient times, athletes have attempted to gain an unfair competitive advantage through the use of doping substances. A Prohibited List of doping substances and methods banned in sports is published yearly by the World Anti-Doping Agency. Among the substances included are steroidal and peptide hormones and their modulators, stimulants, glucocorticosteroids, β₂-agonists, diuretics and masking agents, narcotics, and cannabinoids. Blood doping, tampering, infusions, and gene doping are examples of prohibited methods indicated on the List. Apart from the unethical aspect of doping, as it abrogates fair-play's principle, it is extremely important to consider the hazards it presents to the health and well-being of athletes. The referred negative effects for the athlete's health have to do, on the one hand, by the high doses of the performance-enhancing agents and on the other hand, by the relentless, superhuman strict training that the elite or amateur athletes put their muscles, bones, and joints. The purpose of this article is to highlight the early and the long-lasting consequences of the doping abuse on bone and muscle metabolism.

Avascular necrosis of the femoral head as the first manifestation of acute lymphoblastic leukemia

Avascular necrosis of bone is a well-described complication of cancer chemotherapy containing corticosteroids and has been observed in lymphomas and acute lymphoblastic leukemia (ALL). This study reports the case of a young male patient in whom avascular necrosis of right femur head was the presenting feature of acute lymphoblastic leukemia. The temporal association in this instance implicates a pathophysiologic relationship between the development of ALL and necrosis.

Bisphosphonate-related osteonecrosis of the jaws: a single-center study of 101 patients

PURPOSE

Osteonecrosis of the jaw (ONJ) is a devastating side effect of long-term bisphosphonate (BP) use. We present the largest case series from a single department.

MATERIALS AND METHODS

This case series included 101 ONJ patients. Data on demographics, medical background, type and duration of BP use, possible triggering events, mode of therapy, and outcome were recorded.

RESULTS

ONJ was associated with intravenous BPs in 85 patients and with oral BPs in 16 patients. It was diagnosed after 48, 27, and 67 months of pamidronate, zoledronic acid, and alendronate use, respectively. Long-term antibiotics and minimal surgical procedures resulted in complete or partial healing in 18% and 52% of the patients, respectively; 30% had no response. There was no association between ONJ and diabetes, steroid and antiangiogenic treatment, or underlying periodontal disease. Diagnostic biopsies aggravated lesions without being informative about pathogenesis. A conservative regimen is our treatment of choice.

CONCLUSION

Solutions for decreasing morbidity and poor outcome of ONJ remain elusive.

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.

Chemotherapy-associated osteonecrosis in cancer patients with solid tumours: a systematic review

Non-traumatic osteonecrosis of bone is recognized as a potential complication in solid-tumour cancer patients receiving treatment with cytotoxic chemotherapy. This review summarizes recent reports of osteonecrosis associated with chemotherapy in cancer patients, and describes the possible underlying pathophysiology and options available for its diagnosis, prevention and treatment. Fifty-four reported cases of non-traumatic osteonecrosis in adult patients with solid tumours receiving chemotherapy were identified by searching for reports in the medical literature. Osteonecrosis was observed most commonly in men receiving chemotherapy for testicular cancer. Osteonecrosis was also seen in patients receiving chemotherapy for breast, ovarian, small-cell lung cancer and osteosarcoma. Most patients had received corticosteroids, had femoral head involvement and had delayed onset of osteonecrosis. It appears that patients at higher risk for osteonecrosis with chemotherapy are identifiable. As the long-term survival of patients with solid tumours receiving chemotherapy increases, the prevalence of treatment-related osteonecrosis may also increase. Patients should be informed that osteonecrosis is a potential complication of cancer treatment. Measures to reduce risk should be taken, and patients should be monitored for early symptoms. Routine screening for chemotherapy-associated osteonecrosis is not recommended; however, a high index of clinical suspicion in patients at risk may allow for early intervention and preservation of the joints.

Zoledronate, smoking, and obesity are strong risk factors for osteonecrosis of the jaw: a case-control study

PURPOSE

Bisphosphonates (BPs) effectively treat metastatic bone disease, hypercalcemia, and osteoporosis. BP exposure, however, may be associated with osteonecrosis of the jaw (ONJ). The aim of the present study was to estimate the magnitude of the association between intravenous (IV) BP exposure and ONJ, and to identify potential confounders.

MATERIALS AND METHODS

Using a case-control study design, the investigators identified and adjudicated a sample of cases with ONJ and matched them randomly with 5 controls per case. The controls were matched to cases on age, gender, cancer type, and date of cancer diagnosis. The medical records were abstracted and data on BP exposure, cancer therapy, and comorbidities were recorded. Statistical analyses were carried out using conditional logistic regression in Stata 9.0 (Stata Corp, College Station, TX).

RESULTS

Thirty cases of ONJ were identified at Massachusetts General Hospital from February 2003 through February 2007. Zoledronate was found to confer significant risk toward development of ONJ (adjusted odds ratio = 31.8, P < .05). Although a trend toward increased risk was noted for pamidronate, this association was not significant after controlling for zoledronate. Obesity and smoking were associated significantly with ONJ development, whereas oral BPs had no effect.

CONCLUSION

In this study, cancer patients who had received zoledronate exhibited a significant 30-fold increase in their risk to develop ONJ. More studies are needed to elucidate the exact role of obesity and smoking in the development of ONJ, and the complex interactions of IV BPs with other chemotherapies during cancer treatment.

Avascular necrosis of the femoral head: vascular hypotheses

Vascular hypotheses provide compelling pathogenic mechanisms for the etiology of avascular necrosis of the femoral head (ANFH). A decrease in local blood flow of the femoral head has been postulated to be the cause of the disease. Several studies in human and animal models of ANFH have shown microvascular thrombosis. Endothelial cell damage could be followed by abnormal blood coagulation and thrombus formation with any resulting degeneration distal to the site of vascular occlusion. Other studies suggest that thrombophilia, particularly impaired fibrinolysis, plays a potential role in thrombus formation in ANFH. Reduction in shear stress due to decreased blood flow could lead to apoptosis of endothelial cells, which can ultimately contribute to plaque erosion and thrombus formation. Dysregulation of endothelial cell activating factors and stimulators of angiogenesis or repair processes could also affect the progression and outcome of ANFH. Likewise, regional endothelium dysfunction (RED), referred to as a potential defect in endothelial cells located in the feeding vessels of the femoral head itself, may also have a crucial role in the pathogenesis of ANFH. Molecular gene analysis of regional endothelial cells could also help to determine potential pathways important in the pathogenesis of ANFH.

Avascular necroses inducing limb-girdle syndrome

Disuse myopathy can be caused by many disorders. However, disuse myopathy with symmetrical weakness of the proximal muscles in the four limbs is rare. Here we report a 45-year-old man who presented with the appearance of myopathy similar to the clinical picture of limb-girdle syndrome with symmetrical weakness of proximal muscles in four limbs. A battery of intensive investigations confirmed that the patient had symmetric disuse myopathy induced by multiple avascular necroses of hip and shoulder joints. After the patient had received bilateral total hip replacement operations he had remarkable improvement in his muscle power in both lower limbs. This report highlights that some myopathies can be reversed if their underlying causes are correctable.

Avascular Necrosis of Femoral and/or Humeral Heads in Multiple Myeloma: Results of a Prospective Study of Patients Treated With Dexamethasone-Based Regimens and High-Dose Chemotherapy

Purpose

To assess the prevalence, time of onset, risk factors, and outcome of avascular necrosis (AVN) of bone in patients with multiple myeloma undergoing antineoplastic therapy.

Patients and Methods

A total of 553 consecutive assessable patients were enrolled onto a treatment protocol consisting of dexamethasone-containing induction chemotherapy, autologous stem-cell transplantation, consolidation chemotherapy, and maintenance with interferon alfa. Patients were randomly assigned to receive thalidomide (269 patients) or no thalidomide (284 patients) throughout the study period.

Results

With a median follow-up of 33 months (range, 5 to 114 months), AVN of the femoral head(s) developed in 49 patients (9%). Median time to onset of AVN was 12 months (range, 2 to 41 months). Three risk factors for AVN were identified by multivariate analysis: cumulative dexamethasone dose (odds ratio [OR], 1.028; 95% CI, 1.012 to 1.044; P = .0006 [per 40 mg dexamethasone]), male sex (OR, 0.390; 95% CI, 0.192 to 0.790; P = .009), and younger age (OR, 0.961; 95% CI, 0.934 to 0.991 per year; P = .0122). Thalidomide-treated patients had a prevalence of AVN similar to that of the control group (8% v 10%, respectively; P = .58). AVN-related pain and limited range of motion of the affected joint were present in only nine and four patients, respectively, and four patients underwent hip replacement because of AVN. Fluorine-18 fluorodeoxyglucose positron emission tomography failed to detect abnormal uptake in the AVN-affected bones.

Conclusion

AVN is a rare and usually asymptomatic complication during myeloma therapy. Cumulative dexamethasone dose, male sex, and younger age, but not thalidomide, increase the risk of AVN.

Avascular necrosis and bone marrow edema syndrome

MR imaging is the most accurate modality for the diagnosis of AVN, bone marrow edema syndrome, and femoral head insufficiency fractures. When the particular demographics of the patient are considered, the specificity of this examination is high. The reported success rates of joint-sparing operative intervention are variable. When compared with conservative management, the outcome of joint-sparing operative intervention in patients who have early (stage I, II) AVN lesions is improved. This is impetus for screening programs for patients who are known to be at high risk for AVN, such as patients who have undergone renal transplants and others who are on long-term, high-dose corticosteroid treatment. There is strong evidence that bone marrow edema syndrome (TO) is a distinct entity with demonstrable unique histopathology and well-defined demographics. Increased spatial resolution revealed typical subchondral findings of AVN in lesions that were once believed to represent irreversible TO. SIF of the femoral head is a new concept with a seemingly distinct population and with clinical presentation and imaging characteristics that should permit its differentiation from AVN.

Avascular necrosis of common bones seen in the ED

Missed diagnosis of avascular necrosis (AVN) may result in substantial morbidity. Early diagnosis is crucial for appropriate intervention and, ultimately, improved outcome. Emerging physicians need to recognize AVN to avoid unsatisfactory clinical results for their patients. Avascular necrosis (AVN) of the bone can occur when the blood supply to the bone is disrupted and is usually found in areas with terminal circulation. Commonly involved bones include the femoral head, talus, and scaphoid.

Pathogenesis and natural history of osteonecrosis

BACKGROUND AND OBJECTIVES

Osteonecrosis (avascular necrosis) is a relatively common disorder seen by both rheumatologists and orthopedic surgeons. The vast majority of cases are secondary to trauma. However, for non-traumatic cases, there often remains a diagnostic challenge in defining the cause of bone death. The goal of this article is to review data extensively in the medical literature with respect to the pathogenesis of osteonecrosis, its natural history, and treatment.

METHODS

A review of 524 studies on osteonecrosis was performed, of which 213 were selected and cited.

RESULTS

Non-traumatic osteonecrosis has been associated with corticosteroid usage, alcoholism, infections, hyperbaric events, storage disorders, marrow infiltrating diseases, coagulation defects, and some autoimmune diseases. However, a large number of idiopathic cases of osteonecrosis have been described without an obvious etiologic factor. Although corticosteroids can produce osteonecrosis, careful history is always warranted to identify other risk factors. The pathogenesis of non-traumatic osteonecrosis appears to involve vascular compromise, bone and cell death, or defective bone repair as the primary event. Our understanding of the pathogenesis of osteonecrosis is now much better defined and skeletal scintigraphy and magnetic resonance imaging have enhanced diagnosis greatly. Early detection is important because the prognosis depends on the stage and location of the lesion, although the treatment of femoral head osteonecrosis remains primarily a surgical one.

CONCLUSIONS

Osteonecrosis has been associated with a wide range of conditions. Many theories have been proposed to decipher the mechanism behind the development of osteonecrosis but none have been proven. Because osteonecrosis may affect patients with a variety of risk factors, it is important that caregivers have a heightened index of suspicion. Early detection may affect prognosis because prognosis is dependent on the stage and location of the disease. In particular, the disease should be suspected in patients with a history of steroid usage, especially in conjunction with other illnesses that predispose the patient to osteonecrosis.

RELEVANCE

A better understanding of the pathophysiology, diagnosis and treatment of osteonecrosis will help the physician determine which patients are at risk for osteonecrosis, facilitating early diagnosis and better treatment options.

Avascular necrosis not Charcot's

BACKGROUND

A case of avascular necrosis (AN) of the navicular bone, in a 24-year-old woman with Type 1 diabetes with peripheral neuropathy, in the absence of any history of direct trauma is presented. The clinical and radiological features at presentation suggested an evolving Charcot arthropathy (CA), but subsequent serial X-rays clearly confirmed AN.

CONCLUSIONS

Swelling and foot deformity in association with long-standing diabetic peripheral neuropathy is suggestive of CA, although AN, a less common condition, may show the same clinical features. It is therefore important to undertake further confirmatory radiological investigations if there is any doubt about the diagnosis.

Serum uric acid and patterns of radiographic osteoarthritis--the Ulm Osteoarthritis Study

OBJECTIVE

To assess the association between uric acid and patterns of osteoarthritis (OA).

METHODS

OA patterns were studied in 809 patients with arthroplasty due to hip or knee OA. Patients with OA were categorized as having bilateral or generalized OA according to the presence of radiographic OA in the contralateral or different finger joints. Odds ratios (OR) and 95% confidence intervals (CI) for thirds of serum uric acid and OA patterns were estimated with multivariable logistic regression.

RESULTS

Eighty-five percent of the participants had bilateral OA and 26% generalized OA. A positive association between serum uric acid and generalized OA was observed in patients with hip OA (highest versus lowest tertile OR=3.5; 95% CI: 1.3-9.1), but not among patients with knee OA (corresponding OR = 1.1). Serum uric acid was not associated with bilateral OA.

CONCLUSION

Our results suggest a possible role of elevated serum uric acid in the multifactorial etiology of generalized OA.

Avascular necrosis of the femoral head in chronic myeloid leukemia patients treated with interferon-alpha: a synergistic correlation?

BACKGROUND

The objectives of this study were to describe cases of avascular necrosis of the femoral head (ANFH) observed in chronic myeloid leukemia (CML) patients who were treated with interferon-alpha and to review the literature.

METHODS

The authors undertook a case review of the M. D. Anderson experience with ANFH occurring in CML patients who were managed with interferon-alpha-based therapy. MEDLINE (from 1966 to November 1999) and CancerLit (from 1983 to November 1999) searches were conducted to identify cases of avascular necrosis (AVN) associated with either CML or interferon-alpha.

RESULTS

Three patients with ANFH were identified from the authors' experience. No common features related to the disease or therapy were seen among them, except for the presence of thrombocytosis and loss of response. A literature review revealed seven cases of ANFH associated with CML with or without interferon-alpha-based therapy. ANFH was not reported in association with interferon-alpha use for indications other than the treatment of patients with CML.

CONCLUSIONS

ANFH may be the result of an interaction between CML and interferon-alpha therapy. ANFH that occurs in patients with CML who are treated with interferon-alpha should be recognized for treatment implications. Thrombocytosis with consequent microvascular thrombi and avascular necrosis manifesting in susceptible vascular or weight-bearing areas (e.g., the femoral head) may be an associated finding along with loss of response to interferon-alpha therapy.

Transforming growth factor-beta1 modulates the expression of vascular endothelial growth factor by osteoblasts

Angiogenesis is essential to both normal and pathological bone physiology. Vascular endothelial growth factor (VEGF) has been implicated in angiogenesis, whereas transforming growth factor-beta1 (TGF-beta1) modulates bone differentiation, matrix formation, and cytokine expression. The purpose of this study was to investigate the relationship between TGF-beta1 and VEGF expression in osteoblasts and osteoblast-like cells. Northern blot analysis revealed an early peak of VEGF mRNA (6-fold at 3 h) in fetal rat calvarial cells and MC3T3-E1 osteoblast-like cells after stimulation with TGF-beta1 (2.5 ng/ml). The stability of VEGF mRNA in MC3T3-E1 cells was not increased after TGF-beta1 treatment. Actinomycin D inhibited the TGF-beta1-induced peak in VEGF mRNA, whereas cycloheximide did not. Blockade of TGF-beta1 signal transduction via a dominant-negative receptor II adenovirus significantly decreased TGF-beta1 induction of VEGF mRNA. Additionally, TGF-beta1 induced a dose-dependent increase in VEGF protein expression by MC3T3-E1 cells (P < 0.01). Dexamethasone similarly inhibited VEGF protein expression. Both TGF-beta1 mRNA and VEGF mRNA were concurrently present in rat membranous bone, and both followed similar patterns of expression during rat mandibular fracture healing (mRNA and protein). In summary, TGF-beta1-induced VEGF expression by osteoblasts and osteoblast-like cells is a dose-dependent event that may be intimately related to bone development and fracture healing.