The role of hypercoagulability in the development of osteonecrosis of the femoral head

Proteomic profiling of extracellular vesicles derived from human serum for the discovery of biomarkers in Avascular necrosis

BACKGROUND

Avascular necrosis (AVN) is a medical condition characterized by the destruction of bone tissue due to a diminished blood supply. When the rate of tissue destruction surpasses the rate of regeneration, effective treatment becomes challenging, leading to escalating pain, arthritis, and bone fragility as the disease advances. A timely diagnosis is imperative to prevent and initiate proactive treatment for osteonecrosis. We explored the potential of differentially expressed proteins in serum-derived extracellular vesicles (EVs) as biomarkers for AVN of the femoral head in humans. We analyzed the genetic material contained in serum-derived exosomes from patients for early diagnosis, treatment, and prognosis of avascular necrosis.

METHODS

EVs were isolated from the serum of both patients with AVN and a control group of healthy individuals. Proteomic analyses were conducted to compare the expression patterns of these proteins by proteomic analysis using LC-MS/MS.

RESULTS

Our results show that the levels of IGHV3-23, FN1, VWF, FGB, PRG4, FCGBP, and ZSWIM9 were upregulated in the EVs of patients with AVN compared with those of healthy controls. ELISA results showed that VWF and PRG4 were significantly upregulated in the patients with AVN.

CONCLUSIONS

These findings suggest that these EV proteins could serve as promising biomarkers for the early detection and diagnosis of AVN. Early diagnosis is paramount for effective treatment, and the identification of new osteonecrosis biomarkers is essential to facilitate swift diagnosis and proactive intervention. Our study provides novel insights into the identification of AVN-related biomarkers that can enhance clinical management and treatment outcomes.

Identification of hub genes and therapeutic drugs in osteonecrosis of the femoral head through integrated bioinformatics analysis and literature mining

Osteonecrosis of the femoral head (ONFH) is a multifactorial disease leading to severely limited function. By far, the etiology and pathogenesis of ONFH are not fully understood, and surgery is the only effective way to treat ONFH. This study aims to identify hub genes and therapeutic drugs in ONFH. Two gene expression profiles were downloaded from the gene expression omnibus database, and the hub genes and candidate drugs for ONFH were identified through integrated bioinformatics analysis and cross-validated by literature mining. A total of 159 DEGs were identified. PTGS2, LRRK2, ANXA5, IGF1R, MCL1, TIMP2, LYN, CD68, CBL, and RUNX2 were validated as 10 hub genes, which has considerable implications for future genetic research and related research fields of ONFH. Our findings indicate that 85 drugs interact with ONFH, with most drugs exhibiting a positive impact on ONFH by promoting osteogenesis and angiogenesis or inhibiting microcirculation embolism, rather than being anti-inflammatory. Our study provides novel insights into the pathogenesis, prevention, and treatment of ONFH.

What Are Drivers of Readmission for Readmission-Requiring Venous Thromboembolic Events After Primary Total Hip Arthroplasty? An Analysis of 544,443 Cases

BACKGROUND

Venous thromboembolism (VTE) is a potential postoperative complication after total hip arthroplasty (THA). These events present with a range of severity, and some require readmission. The present study aimed to identify unexplored risk factors for severe VTE that lead to hospital readmission.

METHODS

The Agency of Healthcare Research and Quality's National Readmissions Database was retrospectively queried for all patients who underwent primary THA (January 2016 to December 2018). Study population included patients who were readmitted for VTE within 90 days after an elective THA. Bivariate and multivariate regression analyses were performed using patient demographics, insurance status, elective nature of the surgery, healthcare institution characteristics, and baseline comorbidities.

RESULTS

Higher risk of readmission for VTE was evident among elderly (71-80 years vs <40 years: odds ratio [OR] 1.7, 95% confidence interval [CI] 1.3-2.2, P = .0002), male patients (OR 1.2, 95% CI 1.2-1.3). Nonelective THAs were associated with markedly higher odds of readmission for VTE (OR 20.5, 95% CI 18.9-22.2), peripheral vascular disease (OR 1.2, 95% CI 1.1-1.4), lymphoma (OR 1.5, 95% CI 1.1-2.1), metastatic cancer (OR 1.8, 95% CI 1.4-2.2), obesity (OR 1.5, 95% CI 1.4-1.6), and fluid-electrolyte imbalance (OR 1.1, 95% CI 1.0-1.2). Home health care (OR 0.8, 95% CI 0.7-0.8) and discharge to skilled nursing facility (OR 0.7, 95% CI 0.7-0.8) had lower odds of readmission for VTE vs unsupervised home discharge, while insurance type was not a significant driver(P > .05).

CONCLUSION

One in 135 THA patients is likely to experience a VTE requiring readmission after THA. Male patients, age >70 years, and specific baseline comorbidities increase such risk. Furthermore, discharge to a supervised setting mitigated the risk of VTE requiring readmission compared to unsupervised discharge. As VTE prophylaxis protocols continue to evolve, these patients may require optimized perioperative care pathways to mitigate VTE complications.

Osteonecrosis of the Jaws in Patients with Hereditary Thrombophilia/Hypofibrinolysis-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the jaws (ONJ) usually has a clear etiology. Local infection or trauma, radiotherapy and drugs that disrupt the vascular supply or bone turnover in the jaws are its major contributors. The thrombotic occlusion of the bone’s venous outflow that occurs in individuals with hereditary thrombophilia and/or hypofibrinolysis has a less known impact on jaw health and healing capability. Our research provides the most comprehensive, up-to-date and systematized information on the prevalence and significance of hereditary thrombophilia and/or hypofibrinolysis states in ONJ. We found that hereditary prothrombotic abnormalities are common in patients with ONJ refractory to conventional medical and dental treatments. Thrombophilia traits usually coexist with hypofibrinolysis traits. We also found that frequently acquired prothrombotic abnormalities coexist with hereditary ones and enhance their negative effect on the bone. Therefore, we recommend a personalized therapeutic approach that addresses, in particular, the modifiable risk factors of ONJ. Patients will have clear benefits, as they will be relieved of persistent pain and repeated dental procedures.

Risk factors for multi-joint disease in patients with glucocorticoid-induced osteonecrosis

This study investigated risk factors for osteonecrosis involving multiple joints (MJON) among glucocorticoid-treated patients. The best predictor of MJON was cumulative oral glucocorticoid dose. Risk of MJON was 12-fold higher in patients who had a second risk factor for osteonecrosis. Further research is needed into strategies for prevention of MJON.

INTRODUCTION

Osteonecrosis (ON) is a debilitating musculoskeletal condition in which bone cell death can lead to mechanical failure. When multiple joints are affected, pain and disability are compounded. Glucocorticoid treatment is one of the most common predisposing factors for ON. This study investigated risk factors for ON involving multiple joints (MJON) among glucocorticoid-treated patients.

METHODS

Fifty-five adults with glucocorticoid-induced ON were prospectively enrolled. MJON was defined as ON in ≥ three joints. Route, dose, duration, and timing of glucocorticoid treatment were assessed.

RESULTS

Mean age of enrolled subjects was 44 years, 58% were women. Half had underlying conditions associated with increased ON risk: systemic lupus erythematosus (29%), acute lymphoblastic leukemia (11%), HIV (9%), and alcohol use (4%). Mean daily oral dose of glucocorticoids was 29 mg. Average cumulative oral dose was 30 g over 5 years. The best predictor of MJON was cumulative oral glucocorticoid dose. For each increase of 1,000 mg, risk of MJON increased by 3.2% (95% CI 1.03, 1.67). Glucocorticoid exposure in the first 6 months of therapy, peak dose (oral or IV), and mean daily dose did not independently increase risk of MJON. The risk of MJON was 12-fold in patients who had a second risk factor (95% CI 3.2, 44.4).

CONCLUSIONS

Among patients with glucocorticoid-induced ON, cumulative oral dose was the best predictor of multi-joint disease; initial doses of IV and oral glucocorticoids did not independently increase risk. Further research is needed to better define optimal strategies for prevention and treatment of MJON.

Osteonecrosis of the Femoral Head in Patients with Hypercoagulability-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the femoral head (ONFH) is a debilitating disease with major social and economic impacts. It frequently affects relatively young adults and has a predilection for rapid progression to femoral head collapse and end-stage hip arthritis. If not diagnosed and treated properly in the early stages, ONFH has devastating consequences and leads to mandatory total hip arthroplasty. The pathophysiology of non-traumatic ONFH is very complex and not fully understood. While multiple risk factors have been associated with secondary ONFH, there are still many cases in which a clear etiology cannot be established. Recognition of the prothrombotic state as part of the etiopathogeny of primary ONFH provides an opportunity for early medical intervention, with implications for both prophylaxis and therapy aimed at slowing or stopping the progression of the disease. Hereditary thrombophilia and hypofibrinolysis are associated with thrombotic occlusion of bone vessels. Anticoagulant treatment can change the natural course of the disease and improve patients' quality of life. The present work focused on highlighting the association between hereditary thrombophilia/hypofibrinolysis states and ONFH, emphasizing the importance of identifying this condition. We have also provided strong arguments to support the efficiency and safety of anticoagulant treatment in the early stages of the disease, encouraging etiological diagnosis and prompt therapeutic intervention. In the era of direct oral anticoagulants, new therapeutic options have become available, enabling better long-term compliance.

Reciprocal effect of microRNA-224 on osteogenesis and adipogenesis in steroid-induced osteonecrosis of the femoral head

The adverse effects of glucocorticoids (GCs) on bone marrow stromal stem cells (BMSCs) play an important role in steroid-induced osteonecrosis of the femoral head (ONFH). Our previous miRNA microarray analysis indicated that microRNA-224-5p (miR-224-5p) could be a potential regulator; however, the underlying mechanism remains unclear. In the present study, we demonstrated that miR-224-5p was upregulated in GC-treated BMSCs, and functional experiments revealed that miR-224-5p could suppress osteogenic but promote adipogenic differentiation of BMSCs. Smad4 was identified as a direct target gene of miR-224-5p, and the Smad4-Taz axis was confirmed as the regulatory pathway for adipo-osteogenic differentiation of BMSCs. Our in vivo experiments further confirmed that the miR-224-5p antagomir could alleviate the inhibitory effects of GCs and facilitate bone formation in steroid-induced ONFH models. Therefore, these findings provide insight into the function of miR-224-5p as a reciprocal regulator of the adipo-osteogenic differentiation of BMSCs, and it could serve as a novel therapeutic target for steroid-induced ONFH.

Multiple Joint Osteonecrosis in a Patient on Long-term Intranasal Corticosteroids

We present the first report of bilateral knee and left ankle osteonecrosis in a 58-year-old female patient on long-term intranasal corticosteroids. Initially, our patient presented with progressive disabling knee pain with normal radiographs. The patient was presumed to have mild degenerative joint disease; therefore, she was treated conservatively. Then, the patient developed severe left ankle pain, and she was thought to have L5/S1 radiculopathy; therefore, she underwent epidural steroid injection that did not provide any benefit. However, extensive bilateral osteonecrosis of the medial tibial plateau in addition to osteonecrosis of the talus bone of left ankle were later diagnosed by MRI. The patient underwent staged bilateral total knee arthroplasty. In conclusion, the diagnosis of osteonecrosis might be challenging because of overlapping clinical presentation with other disorders particularly in the early stage of the disease with normal radiographs. Therefore, a high index of suspicion and thorough history with supplemental MRI imaging are essential for the assessment of patients presented with atypical refractory joint pain particularly in the presence of risk factors.

Zoledronic acid for the treatment of pregnancy-associated femoral head necrosis: A case report

Introduction

The management of pregnancy-associated femoral necrosis is controversial. Conservative management may eventually lead to hip replacement.

Case

A 40-year-old woman developed necrosis of the left hip during her first pregnancy. Treatment with zoledronic acid three months after delivery resulted in rapid reduction of the necrotic area. The patient's second pregnancy shortly afterwards had no complications. A magnetic resonance scan three years later documented complete resolution.

Conclusion

Femoral head necrosis should be suspected in the differential diagnosis of pain in pregnancy. Zoledronic acid given in the early stages prevented progression to hip arthritis in this case.

•

Osteonecrosis of the femoral head must always be taken into account in the differential diagnosis of hip pain in pregnancy.

•

Conservative treatment of pregnancy-associated osteonecrosis may lead to hip replacement.

•

A prompt treatment may be essential to prevent arthroplasty.

•

We report for the first time a case of femoral osteonecrosis treated with zoledronate in a primigravid woman.

•

Zoledronic acid proved safe and effective and the outcome persisted throughout the duration of a second pregnancy.

The relationship between apolipoprotein genes polymorphisms and susceptibility to osteonecrosis of the femoral head: a meta-analysis

Background

The objective of this study was to evaluate whether apolipoprotein gene polymorphisms confer susceptibility to osteonecrosis of the femoral head (ONFH).

Methods

The relevant literature was screened from databases of Pubmed, Embase, Wanfang, Weipu and China National Knowledge Internet (CNKI) until May, 2017. In addition, odds ratio (OR) and its corresponding 95% confidence interval (CI) were used as a measure of effect size for calculating effect size.

Results

Totally, six case-control studies were included in this meta-analysis. It revealed that ApoB-C7623T polymorphism frequency was increased in ONFH group than in control group under three genetic models, including allele model (T vs. C, OR = 4.5149, 95% CI: 1.6968–12.0134); additive model (TC vs. CC, OR = 6.2515, 95% CI: 2.0939–18.6640); and dominant model (TT + TC vs. CC, OR = 5.4998, 95% CI: 1.9246–15.7163). In addition, the increased risk of ONFH were related to ApoA1-rs1799837 polymorphism under additive model (AA vs. GG, OR = 1.4175, 95% CI: 1.0522–1.9096) and recessive model (AA vs. GG + AG, OR = 1.7727, 95% CI: 1.3399–2.3452). However, four ApoB rs1042031, rs693, 3’-VNTR and G12619A polymorphisms under the all genetic models were not associated with susceptibility to ONFH.

Conclusion

The T allele and TC genotype of ApoB-C7623T and AA genotype of ApoA1-rs1799837 may contribute to increase the risk of ONFH.

National use of total hip arthroplasty among patients with a history of breast, lung, prostate, colon or bladder cancer-an analysis of the Medicare population

Background

Total hip arthroplasty (THA) is a common and growing procedure in the United States. Concomitantly, there has been a rise in patients diagnosed with certain types of malignancies including solid organ ones. Unfortunately there is limited data available in the literature that describes the use of THA in patients who concomitantly have one of these forms of cancer. Because of the limited data available in the literature regarding this topic, the purpose of this study was to analyze the trends in use of THA among patients with the five most common malignancies in the United States, which include breast, lung, prostate, colon and bladder cancer according to the National Cancer Institute (NCI).

Methods

We conducted a retrospective review of the entire Medicare patient population to analyze the use of THA in patients with a diagnosis of solid organ malignancy including breast, lung, prostate, colon and bladder cancer.

Results

Our analysis of over 14 million patients, demonstrate that THA is not as commonly performed procedure in patients with such diagnoses with a 0.26% prevalence. The mean incidence of THA was 0.29%, 0.17%, 0.31%, 0.33% and 0.36% for patients with breast, lung, prostate, colon and bladder cancer respectively.

Conclusions

THA in cancer patients are not frequently performed but the use of this technique has increased significantly in patients with lung, prostate and bladder cancer.

TGF‑β1 expression in adults with non‑traumatic osteonecrosis of the femoral head

Non-traumatic osteonecrosis of the femoral head (NONFH) is a common clinical osteoarthropathy. The present study aimed to investigate the association between transforming growth factor β1 (TGF‑β1) and NONFH. Femoral head specimens were collected from patients with NONFH. Patients with traumatic osteonecrosis served as the control. Hematoxylin and eosin (H&E) staining was used to visualize the bone tissue architecture. Immunohistochemistry and densitometry were performed to quantify TGF‑β1 expression in tissues. Flow cytometry was used to detect cluster of differentiation (CD)3+, CD4+ and CD8+ cells, and the ratio of CD4+ to CD8+ T cells in the peripheral blood. H&E staining revealed osteonecrosis, disintegration of osteocytes with karyopyknosis and karyorrhexis, loss of osteocyte lacunae, aberrantly arranged circumferential lamellae, as well as dissolution of the lamellae and subtle osteogenesis in the experimental group, as opposed to the control group. Immunohistochemistry revealed that the expression of TGF‑β1 was significantly reduced in the experimental group (P<0.01). Further, the NONFH group had a decrease in the CD3+ and CD4+ cell populations (P<0.05 and P<0.01, respectively), an increase in the CD8+ cell population (P<0.05), as well as a reduction in the ratio of CD4+ to CD8+ cells (P<0.01). The present study indicated that TGF‑β1 expression was reduced in NONFH. This was associated with impaired repairing capacity of the femoral head and dysregulated subsets of T‑lymphocytes and possible immune functions.

Avascular Necrosis of Femoral Head: A Metabolomic, Biophysical, Biochemical, Electron Microscopic and Histopathological Characterization

Avascular necrosis of the femur head (AVNFH) is a debilitating disease caused due to the use of alcohol, steroids, following trauma or unclear (idiopathic) etiology, affecting mostly the middle aged population. Clinically AVNFH is associated with impaired blood supply to the femoral head resulting in bone necrosis and collapse. Although Homocysteine (HC) has been implicated in AVNFH, levels of homocysteine and its associated pathway metabolites have not been characterized. We demonstrate elevated levels of homocysteine and concomitantly reduced levels of vitamins B6 and B12, in plasma of AVNFH patients. AVNFH patients also had elevated blood levels of sodium and creatinine, and reduced levels of random glucose and haemoglobin. Biophysical and ultrastructural analysis of AVNFH bone revealed increased remodelling and reduced bone mineral density portrayed by increased carbonate to phosphate ratio and decreased Phosphate to amide ratio together with disrupted trabeculae, loss of osteocytes, presence of calcified marrow, and elevated expression of osteocalcin in the osteoblasts localized in necrotic regions. Taken together, our studies for the first time characterize the metabolomic, pathophysiological and morphometric changes associated with AVNFH providing insights for development of new markers and therapeutic strategies for this debilitating disorder.

Effect of rivaroxaban on preventing deep vein thrombosis in aged diabetics with femoral neck fractures after hip replacement

The present study estimates the effect of rivaroxaban on preventing deep vein thrombosis (DVT) in aged diabetics with femoral neck fractures after hip replacement. Our study consisted of 236 aged diabetics with femoral neck fractures, which were divided into the rivaroxaban and control groups. Reaction time (R time), clot formation time (K time), α angle (α), maximum amplitude (MA), clot elasticity (G) and coagulation index (CI), prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. DVT was diagnosed by color duplex Doppler ultrasound (CDDU). The risk factors of DVT were analysed by logistic regression analysis. Compared with the control group, in the rivaroxaban group, R time and K time were extended and α, MA and G decreased 1 day before operation. One day after operation, the rivaroxaban group had less PT and APPT and lower incidence of DVT than the control group. In the two groups, preoperative and postoperative PT and APPT significantly differed. Body mass index (BMI) ≥25, abnormal coagulation indicators, use of cemented femoral hip prosthesis, high haemoglobin content and non-ankle pump exercise after operation were the risk factors for DVT. Rivaroxaban could prevent DVT in aged diabetics with femoral neck fractures after hip replacement.

Aseptic necrosis of the femoral head after pregnancy: a case report

A documented case of beginning aseptic necrosis of the femoral head associated with pregnancy together with a review of the literature about this rare complication of pregnancy is presented. The known risk factors of osteonecrosis are; steroid use, alcoholism, organ transplantation, especially after kidney transplant or bone marrow transplantation bone, systemic lupus erythematosus, dyslipidemia especially hypertriglyceridemia, dysbaric decompression sickness, drepanocytosis and Gaucher's disease. Among the less established factors, we mention procoagulations abnormalities, HIV infection, chemotherapy. We report a case of osteonecrosis of femoral head after pregnancy.

Effects of Modified Qing'e Pill () on expression of adiponectin, bone morphogenetic protein 2 and coagulation-related factors in patients with nontraumatic osteonecrosis of femoral head

OBJECTIVES

To observe the regulation of Chinese herbal medicine, Modifified Qing'e Pill (, MQEP), on the expression of adiponectin, bone morphogenetic protein 2 (BMP2), osteoprotegerin (OPG) and other potentially relevant risk factors in patients with nontraumatic osteonecrosis of the femoral head (ONFH).

METHODS

A total of 96 patients with nontraumatic ONFH were unequal randomly divided into treatment group (60 cases) and control group (36 cases). The treatment group were treated with MQEP while the control group were treated with simulated pills. Both groups were given caltrate D. Six months were taken as a treatment course. Patients were followed up every 2 months. The levels of plasma adiponectin, BMP2, OPG, von Willebrand factor (vWF), von Willebrand factor cleaving protease (vWF-cp), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA), C-reactive protein (CRP), blood rheology, bone mineral density (BMD) of the femoral head and Harris Hip Score were measured before and after treatment.

RESULTS

After 6 months of treatment, compared with the control group, patients in the treatment group had signifificantly higher adiponectin and BMP2 levels (P<0.01 and P=0.013, respectively), lower vWF, PAI-1 and CRP levels (P=0.019, P<0.01 and P<0.01, respectively), and lower blood rheology parameters. BMD of the femoral neck, triangle area and Harris Hip Score in the treatment group were signifificantly higher than those in the control group. Moreover, plasma adiponectin showed a positive association with BMP2 (r=0.231, P=0.003) and a negative association with PAI-1 (r=-0.159, P<0.05).

CONCLUSION

MQEP may play a protective role against nontraumatic ONFH by increasing the expression of adiponectin, regulating bone metabolism and improving the hypercoagulation state, which may provide an experimental base for its clinical effects.

Testosterone Therapy Can Interact With Thrombophilia, Leading to Osteonecrosis

Although this effect is not widely recognized, testosterone therapy can interact with thrombophilia, causing osteonecrosis. In 12 men and 4 women who had idiopathic osteonecrosis a median of 6 months after the onset of testosterone therapy, the authors examined the interaction between testosterone therapy and previously undiagnosed thrombophilia. The authors hypothesized that patients who had osteonecrosis after starting testosterone therapy were more likely than 110 normal control subjects or 48 patients who had osteonecrosis and were not receiving testosterone therapy to have thrombophilia. Measures of thrombophilia included Factor V Leiden, prothrombin, PAI-1 gene mutations, Factor VIII, Factor XI, anticardiolipin antibody immunoglobulin G or immunoglobulin M, and homocysteine values. In 10 cases, osteonecrosis occurred 6 months or less after the onset of testosterone therapy, and in all 16 cases, it occurred after a median of 6 months of testosterone therapy. Of the 16 cases, 5 (31%) were Factor V Leiden heterozygotes vs 2 of 109 (2%) healthy control subjects (P=.0003) and 4 of 48 patients who had osteonecrosis and were not receiving testosterone therapy (P=.04). Of the 16 cases, 4 (25%) had high (>150%) Factor VIII levels vs 7 of 103 (7%) healthy control subjects (P=.04), and 3 (19%) had high (>150%) Factor XI levels vs 3 of 101 (3%) healthy control subjects (P=.03). Of the 16 patients with osteonecrosis, 14 (88%) had at least 1 abnormal procoagulant value (of the 8 measured) vs 47 of 110 (43%) healthy control subjects (P=.0009). Of the 5 men whose serum estradiol level was measured while they were receiving testosterone therapy, this level was high (≥42.6 pg/mL) in 4. When testosterone therapy is given to patients with thrombophilia, they are at increased risk for osteonecrosis.

Easily-handled method to isolate mesenchymal stem cells from coagulated human bone marrow samples

AIM: To establish an easily-handled method to isolate mesenchymal stem cells (MSCs) from coagulated human bone marrow samples.

METHODS: Thrombin was added to aliquots of seven heparinized human bone marrow samples to mimic marrow coagulation. The clots were untreated, treated with urokinase or mechanically cut into pieces before culture for MSCs. The un-coagulated samples and the clots were also stored at 4 °C for 8 or 16 h before the treatment. The numbers of colony-forming unit-fibroblast (CFU-F) in the different samples were determined. The adherent cells from different groups were passaged and their surface profile was analyzed with flow cytometry. Their capacities of in vitro osteogenesis and adipogenesis were observed after the cells were exposed to specific inductive agents.

RESULTS: The average CFU-F number of urokinase-treated samples (16.85 ± 11.77/10⁶) was comparable to that of un-coagulated control samples (20.22 ± 10.65/10⁶, P = 0.293), which was significantly higher than those of mechanically-cut clots (6.5 ± 5.32/10⁶, P < 0.01) and untreated clots (1.95 ± 1.86/10⁶, P < 0.01). The CFU-F numbers decreased after samples were stored, but those of control and urokinase-treated clots remained higher than the other two groups. Consistently, the numbers of the attached cells at passage 0 were higher in control and urokinase-treated clots than those of mechanically-cut clots and untreated clots. The attached cells were fibroblast-like in morphology and homogenously positive for CD44, CD73 and CD90, and negative for CD31 and CD45. Also, they could be induced to differentiate into osteoblasts and adipocytes in vitro.

CONCLUSION: Urokinase pretreatment is an optimal strategy to isolate MSCs from human bone marrow samples that are poorly aspirated and clotted.

Genetic association between methylenetetrahydrofolate reductase gene polymorphism and risk of osteonecrosis of the femoral head

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) SNP rs1801133 has been frequently investigated in recent years. Relevant candidate gene association studies with this SNP and osteonecrosis of the femoral head (ONFH) reported conflicting results. Meta-analysis provides a method to combine these data and to determine the association in a larger sample size.

METHOD

We conducted a systematic search to identify possible studies. Four pooled ORs (odds ratios, T versus C, TT versus CC, TT/CT versus CC, and TT versus CT/CC), along with 95% confidence interval (CI), were calculated to evaluate the association between SNP rs1801133 and ONFH susceptibility. Both fixed effects model and random effects model were used.

FINDINGS

We eventually included twelve studies in this analysis, with results showing no overall association between ONFH susceptibility and SNP rs1801133 (T versus C: OR=1.15, 95% CI=0.97-1.38; TT versus CC: OR=1.15, 95% CI=0.91-1.46; TT/CT versus CC: OR=1.09, 95% CI=0.95-1.25; and TT versus

CT/CC

OR=1.16, 95% CI=0.93-1.45). When stratified based on ethnicity, the results were still not significant.

CONCLUSION

Our findings are generally supportive of no association between MTHFR SNP rs1801133 and the etiology of ONFH.

Enoxaparin prevents steroid-related avascular necrosis of the femoral head

Nontraumatic osteonecrosis of the femoral head is still a challenging problem in orthopedic surgery. It is responsible for 10% of the 500,000 hip replacement surgeries in the USA and affects relatively young, active patients in particular. Main reasons for nontraumatic osteonecrosis are glucocorticoid use, alcoholism, thrombophilia, and hypofibrinolysis (Glueck et al., 1997; Orth and Anagnostakos, 2013). One pathomechanism of steroid-induced osteonecrosis is thought to be impaired blood flow to the femoral head caused by increased thrombus formation and vasoconstriction. To investigate the preventive effect of enoxaparin on steroid-related osteonecrosis, we used male New Zealand white rabbits. Osteonecrosis was induced by methylprednisolone-injection (1 × 20 mg/kg body weight). Control animals were treated with phosphate-buffered saline. Treatment consisted of an injection of 11.7 mg/kg body weight of enoxaparin per day (Clexane) in addition to methylprednisolone. Four weeks after methylprednisolone-injection the animals were sacrificed. Histology (hematoxylin-eosin and Ladewig staining) was performed, and empty lacunae and histological signs of osteonecrosis were quantified. Histomorphometry revealed a significant increase in empty lacunae and necrotic changed osteocytes in glucocorticoid-treated animals as compared with the glucocorticoid- and Clexane-treated animals and with the control group. No significant difference was detected between the glucocorticoid and Clexane group and the control group. This finding suggests that cotreatment with enoxaparin has the potential to prevent steroid-associated osteonecrosis.