Current concepts on osteonecrosis of the femoral head

Location or size? A finite element analysis study of necrotic lesion impact on femoral head collapse

BACKGROUND

The location and size of necrotic lesions are important factors for collapse, The preserved angles (PAs) are divided into anterior preserved angle (APA) and lateral preserved angle (LPA), which could accurately measure the location of necrosis lesion. We used them to evaluate the effect of the location and size of necrotic lesions on collapse by finite element analysis, to offer a framework for evaluating the prognosis of osteonecrosis of the femoral head (ONFH) in clinical settings.

METHODS

3 left hip models were constructed based on CT data. Within each hip model, three necrosis lesion models were modeled, with necrotic tissue volumes of 30%, 50%, and 70% repectively. The ONFH models with LPA of 45.5°, 50.5°, 55.5°, 60.5°, 65.5°, 70.5°, and 75.5° when APA was 60.5°, and ONFH models with APAs of 45.5°, 50.5°, 55.5°, 60.5°, 65.5°, 70.5°, and 75.5° when LPA was 60.5° were Constructed. The maximum von Mises stess of the femoral head and necrotic lesion, as well as the femoral head displacement, were calculated to evaluate the biomechanical effects of these models.

RESULTS

(1) In models with the same necrotic volume, when APA was 60.5°, the indexes of the LPA < 60.5° models were significantly higher than those of the LPA ≥ 60.5° models (P < 0.05); the differences of the indexes among the LPA ≥ 60.5° models were not statistically significant (P > 0.05). (2) When LPA was 60.5°, the indexes of models with APA < 60.5 ° and APA ≥ 60.5 ° show the same trend as the former. (3) In the models with the same PAs, there was no statistically significant difference in the indexes (P > 0.05).

CONCLUSION

The location of the necrotic lesion exerts a greater impact on femoral head collapse compared with the size of the lesion. The location of the necrosis may deserve more consideration when assessing the risk of collapse in patients with early onset ONFH.

Avascular necrosis or rapid destruction of the hip following hip intra-articular corticosteroid injections: a systematic review

PURPOSE

This study aimed to systematically review the literature to identify the incidence of avascular necrosis (AVN) following hip intra-articular corticosteroid injections (IACSIs) as well as to elucidate risk factors that may predispose patients to AVN following IACSI.

METHODS

The MEDLINE, Embase, PubMed, and Web of Science databases were systematically searched through inception to July 21, 2024, in accordance with the PRISMA statement with data extracted for descriptive analysis. The inclusion criteria were hip IACSI and AVN of the femoral head. AVN identified solely prior to IACSI, animal studies, in vitro studies, and studies on paediatric populations were excluded.

RESULTS

A total of 3,652 studies were identified and screened resulting in a total of 14 studies that met the inclusion criteria. Seven were case reports, four were retrospective case-series, and three were retrospective cohort studies. The incidence of femoral head AVN following IACSI ranged from 0.6 to 20.4%. Kelly et al. reported that patient-related factors associated with increased rate of AVN included elevated BMI (p = 0.025), history of cancer therapy (p = 0.012), low serum Vitamin D (p = 0.030), and multiple injections (p = 0.004).

CONCLUSION

In the present literature, the incidence of AVN after hip IACSI ranges from 0.6 to 20.4% with mean follow-up times ranging from 5.4 to 25.3 months. Further randomized controlled trials are necessary to elucidate if there is a causative relationship between hip IACSI and AVN.

Risk of avascular necrosis in patients with inflammatory bowel disease: Insights from a nationwide cohort study and the impact of corticosteroid use

BACKGROUND AND AIM

Corticosteroid use is a risk factor for avascular necrosis (AVN) and inflammatory bowel disease (IBD) patients are often exposed to higher corticosteroid usage. We investigated the epidemiology and risk factors of AVN in a nationwide population-based cohort of IBD patients.

METHODS

Patients newly diagnosed with IBD were identified, and sex- and age-matched participants from the general population were selected in a 1:3 IBD:non-IBD ratio. We investigated newly diagnosed AVN and assessed the incidence rates and risk of AVN with multivariate Cox regression models.

RESULTS

During the median follow-up period of 7.22±3.85 years, 357 (0.62 %) were newly diagnosed with AVN. The risk of AVN was higher in IBD (aHR = 1.42, 95 % CI: 1.25-1.62). Ulcerative colitis (UC) patients showed a particularly elevated risk of developing AVN. IBD patients with higher cumulative corticosteroid intake and exposed to a mean prednisolone-equivalent daily dose>20 mg for >1 month were at higher risk of AVN. In Crohn's disease (CD), longer exposure time to >20 mg prednisolone-equivalent presented a trend in increased risk.

CONCLUSION

AVN risk was higher in IBD than in those without, particularly in UC and corticosteroid use in IBD could pose a crucial role. These underscore the importance of considering the AVN etiological factors, particularly corticosteroid use.

Research on Lipidomic Profiling and Biomarker Identification for Osteonecrosis of the Femoral Head

Objectives: Abnormal lipid metabolism is increasingly recognized as a contributing factor to the development of osteonecrosis of the femoral head (ONFH). This study aimed to explore the lipidomic profiles of ONFH patients, focusing on distinguishing between traumatic ONFH (TONFH) and non-traumatic ONFH (NONFH) subtypes and identifying potential biomarkers for diagnosis and understanding pathogenesis. Methods: Plasma samples were collected from 92 ONFH patients (divided into TONFH and NONFH subtypes) and 33 healthy normal control (NC) participants. Lipidomic profiling was performed using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Data analysis incorporated a machine learning-based feature selection method, least absolute shrinkage and selection operator (LASSO) regression, to identify significant lipid biomarkers. Results: Distinct lipidomic signatures were observed in both TONFH and NONFH groups compared to the NC group. LASSO regression identified 11 common lipid biomarkers that signify shared metabolic disruptions in both ONFH subtypes, several of which exhibited strong diagnostic performance with areas under the curve (AUCs) > 0.7. Additionally, subtype-specific lipid markers unique to TONFH and NONFH were identified, providing insights into the differential pathophysiological mechanisms underlying these subtypes. Conclusions: This study highlights the importance of lipidomic profiling in understanding ONFH-associated metabolic disorders and demonstrates the utility of machine learning approaches, such as LASSO regression, in high-dimensional data analysis. These findings not only improve disease characterization but also facilitate the discovery of diagnostic and mechanistic biomarkers, paving the way for more personalized therapeutic strategies in ONFH.

Human umbilical cord mesenchymal stem cells protect MC3T3-E1 osteoblasts from dexamethasone-induced apoptosis via induction of the Nrf2-ARE signaling pathway

Objective

To investigate the protective effect human umbilical cord mesenchymal stem cells (hUC-MSCs) have on Dexamethasone (Dex)-induced apoptosis in osteogenesis via the Nrf2-ARE signaling pathway.

Methods

Glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) was developed in rats through the administration of lipopolysaccharide and methylprednisolone. The incidence of femoral head necrosis, cavity notch, apoptosis of osteoblasts, and bone density were observed by HE staining, TUNEL staining, and Micro-CT. HUC-MSCs were co-cultured with mouse pre-osteoblast MC3T3-E1. The survival rate of osteoblasts was determined by CCK8, and apoptosis and ROS levels of osteoblasts were determined by flow cytometer. The viability of antioxidant enzymes SOD, GSH-Px, and CAT was analyzed by biochemistry. Nrf2 expression levels and those of its downstream proteins and apoptosis-related proteins were analyzed by Western blotting.

Results

In rats, hUC-MSCs can reduce the rates of empty bone lacuna and osteoblast apoptosis that are induced by glucocorticoids (GCs), while reducing the incidence of GC-ONFH. hUC-MSCs can significantly improve the survival rate and antioxidant SOD, GSH-Px, and CAT activity of MC3T3-E1 cells caused by Dex, and inhibit apoptosis and oxidative stress levels. In addition, hUC-MSCs can up-regulate the expression of osteoblast antioxidant protein Nrf2 and its downstream protein HO-1, NQO-1, GCLC, GCLM, and apoptosis-related protein bcl-2, while also down-regulating the expression of apoptosis-related protein bax, cleaved caspase-3, cleaved caspase-9, and cytochrome C in MC3T3-E1 cells. hUC-MSCs improve the ability of MC3T3-E1 cells to mineralize to osteogenesis. However, the promoting effects of hUC-MSCs were abolished following the blocking of the Nrf2-ARE signaling pathway for osteoblasts.

Conclusion

The results reveal that hUC-MSCs can reduce Dex-induced apoptosis in osteoblasts via the Nrf2-ARE signaling pathway.

Comparison of epoprostenol and viscum album efficiencies in the treatment of avascular necrosis of the femoral head: An experimental animal study

BACKGROUND

The aim of our study is to compare the efficacy of epoprostenol and viscum album in the treatment of femoral head avascular necrosis with an experimental study. Our hypothesis is that viscum album, which has similar properties to epoprostenol on the vascular system, is as effective as epoprostenol in the treatment of avascular necrosis.

METHODS

Avascular necrosis was created on the femoral heads of 45 New Zealand type rabbits by surgical vascular deprivation method. The rabbits were divided into 3 groups. Group 1 was designed as a control group, in group 2 Ilomedin (epoprostenol analogue) was administrated to subjects and in group 3, Helixor (viscum album extract) was administrated. At the end of the study, there were nine subjects in each group. Osteocyte necrosis, bone marrow necrosis, new bone formation and cartilage degeneration were evaluated microscopically. The extent of bone necrosis and repair and involvement of epiphysis, the bone marrow cellularity ratio and trabecular bone volume were investigated.

RESULTS

Subchondral necrosis was seen in more animals in the control group (p=0.03). Osteoblastic and osteoclastic activity were more prominent in the Ilomedin group (p=0.25 and 0.07, respectively). It was seen that the cartilages of the subjects in the Helixor and Ilomedin groups were less damaged. In the Ilomedin group, more animals were seen in the chronic phase of the repair process than in the other groups (p=0.07). Bone marrow cellularity was higher in treatment groups (22% and 20,6% for Ilomedin and Helixor, respectively, p=0,04). Trabecular volume was found to be increased in damaged femoral heads in the treatment groups, the highest increased observed in the Helixor group (p=0.01).

CONCLUSION

Viscum album seems to be effective in decreasing the extention of necrosis and protecting the articular cartilage, and epoprostenol in increasing repair and regeneration.

Mechanism of action of Salvia miltiorrhiza on avascular necrosis of the femoral head determined by integrated network pharmacology and molecular dynamics simulation

Avascular necrosis of the femoral head (ANFH) is a progressive, multifactorial, and challenging clinical condition that often leads to hip dysfunction and deterioration. The pathogenesis of ANFH is complex, and there is no foolproof treatment strategy. Although some pharmacologic and surgical treatments have been shown to improve ANFH, the associated side effects and poor prognosis are of concern. Therefore, there is an urgent need to explore therapeutic interventions with superior efficacy and safety to improve the quality of life of patients with ANFH. Salvia miltiorrhiza (SM), a traditional Chinese medicine with a long history, is widely used for the treatment of cardiovascular and musculoskeletal diseases due to its multiple pharmacological activities. However, the molecular mechanism of SM for the treatment of ANFH is still unclear. Therefore, this study aimed to explore the potential targets and mechanisms of SM for the treatment of ANFH using network pharmacology and molecular modeling techniques. By searching multiple databases, we screened 52 compounds and 42 common targets involved in ANFH therapy and identified dan-shexinkum d, cryptotanshinone, tanshinone iia, and dihydrotanshinlactone as key compounds. Based on the protein-protein interaction (PPI) network, TP53, AKT1, EGFR, STAT3, BCL2, IL6, and TNF were identified as core targets. Subsequent enrichment analysis revealed that these targets were mainly enriched in the AGE-RAGE, IL-17, and TNF pathways, which were mainly associated with inflammatory responses, apoptosis, and oxidative stress. In addition, molecular docking and 100 nanoseconds molecular dynamics (MD) simulations showed that the bioactive compounds of SM had excellent affinity and binding strength to the core targets. Among them, dan-shexinkum d possessed the lowest binding free energy (-215.874 kcal/mol and - 140.277 kcal/mol, respectively) for AKT1 and EGFR. These results demonstrated the multi-component, multi-target, and multi-pathway intervention mechanism of SM in the treatment of ANFH, which provided theoretical basis and clues for further experimental validation and development of anti-ANFH drugs.

Angiogenesis of Avascular Necrosis of the Femoral Head: A Classic Treatment Strategy

Avascular necrosis of the femoral head (ANFH) is a type of osteonecrosis due to the cessation of blood supply, characterized by persistent local pain and collapse of the joint. The etiology of ANFH is multifaceted, and while its precise pathogenesis remains elusive, it is currently widely believed that the femoral head is highly dependent on the vascular system. A large number of studies have shown that vascular injury is the initial factor in the onset of ANFH. In this review, we briefly introduced the process of angiogenesis and the blood supply to the femoral head, with a focus on summarizing the existing research on promoting angiogenesis for the treatment of ANFH. We conclude that providing alternative pathways through angiogenesis to resolve the problem of the obstructed free flow of the blood is an important means of treating ANFH. Moreover, we also looked forward to the mechanism of endothelial metabolism, which has not yet been studied in femoral head necrosis models, providing potential strategies for more effective use of angiogenesis for the treatment of femoral head necrosis.

Avascular necrosis of the femoral head: which MRI parameters or findings are more decisive for determining the prognosis?

BACKGROUND

Predicting the development of collapse in patients with avascular necrosis of the femoral head (ANFH) is critical in determining prognosis and management.

OBJECTIVE

We aimed to evaluate whether MRI findings and parameters based on the Association Research Circulation Osseous (ARCO), Japanese Investigation Committee (JIC), modified Kerboul, and Mitchell classifications can predict prognosis in patients with early-stage ANFH at initial diagnosis.

METHODS

This study comprises a retrospective analysis of early-stage ANFH patients without femoral head collapse. Hips with ANFH were divided into two groups based on whether they developed collapse during at least 1 year of follow-up or not. MRI findings were assessed by two radiologists and compared between the groups. Interobserver reliability was also evaluated.

RESULTS

Patients who developed collapse had higher measurements in the percentage of midcoronal area, midsagittal area, maximum coronal area, and total necrotic area (p = 0.001, p = 0.001, p < 0.001, p = 0.003, respectively). Although all AUC values were close to each other, the percentage of maximum coronal area showed the highest AUC value (0.857; 95% CI 0.714-1.000; sensitivity 85.7%, specificity 80%) in ROC curve analysis. Interobserver reliability was best for the JIC and worst for the modified Kerboul classification (Kappa values: 0.890 and 0.492, respectively). No statistically significant difference was found among etiological factors, bone marrow edema, cyst-like changes, synovial effusion, and collapse development (p > 0.05). The double-line sign was statistically significantly more frequent in hips without collapse (p = 0.025).

CONCLUSION

The risk of collapse development is higher with a greater volume of necrosis in the femoral head and when the osteonecrosis is located more laterally.

Osteonecrosis: A disabling disease not to be ignored in asthma and atopic conditions

Osteonecrosis, also referred to as avascular necrosis, is a disease characterized by necrosis or death of a bone secondary to impairment in blood supply. The condition affects the epiphyseal ends of the bones such as the femur and the humerus, but it can also involve the metacarpal and metatarsal bones, the patella, the knee, the vertebrae, and the jaw. A plethora of inflammatory, autoimmune, hematological, thrombotic, and vascular diseases can lead to osteonecrosis. Corticosteroids are intimately linked to the development of osteonecrosis. The frequent use of systemic corticosteroids in patients with asthma, eczema, nasal polyposis, sinusitis, urticaria and angioedema, or anaphylaxis makes this disease of great relevance to the practicing allergist and pulmonologist. Untreated, bone necrosis leads to frustrated bone remodeling and angiogenesis, leading to subchondral fractures and collapse of the articular heads of the bones, and culminating in debilitating osteoarthritis, often requiring arthroplasty. Recent studies have shed light on the molecular mechanisms underlying osteonecrosis and on the role of glucocorticoids. The gold standard test in patients suspected of having the disease is magnetic resonance imaging scanning, with plain radiographs having a lower sensitivity and specificity. Early diagnosis and intervention are essential. The allergist should avoid the frequent use of glucocorticoids and consider early introduction of steroid-sparing alternatives for asthma or sinusitis. Smoking and alcohol ingestion need to be addressed, and the management of glucocorticoid-induced osteoporosis may be helpful. It is essential for allergists to familiarize themselves with the disease and its diagnosis and to consider early referral to an orthopedic surgeon for surgical intervention.

Identification and validation of endoplasmic reticulum stress-related genes in patients with steroid-induced osteonecrosis of the femoral head

Steroid-induced osteonecrosis of the femoral head (SONFH) is a debilitating condition caused by long-term corticosteroid use, leading to impaired blood flow and bone cell death. The disruption of cellular processes and promotion of apoptosis by endoplasmic reticulum stress (ERS) is implicated in the pathogenesis of SONFH. We identified ERS-associated genes in SONFH and investigated their potential as therapeutic targets. We analysed the GSE123568 GEO dataset to identify differentially expressed genes (DEGs) related to ERS in SONFH. We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, identified hub genes by protein-protein interaction (PPI) analyses, and evaluated their functions by gene set enrichment analysis (GSEA). We constructed mRNA-miRNA networks, identified potential therapeutics, and assessed immune cell infiltration. We performed cross-validation using the GEO dataset GSE74089, qRT-PCR on clinical samples from patients with SONFH and controls, and a receiver operating characteristic (ROC) curve analysis to assess the diagnostic performance of the hub genes. We identified 195 ERS-related genes in SONFH, which were primarily involved in oxidative stress, immune responses, and metabolic pathways. The PPI network suggested CXCL8, STAT3, IL1B, TLR4, PTGS2, TLR2, CASP1, CYBB, CAT, and HOMX1 to be key hub genes, which were shown by GSEA to be involved in biological pathways related to metabolism, immune modulation, and cellular integrity. We also identified 261 microRNAs (miRNAs) as well as drugs such as dibenziodolium and N-acetyl-L-cysteine that modulated inflammatory responses in SONFH. Twenty-two immune cell subtypes showed significant correlations, such as a positive correlation between activated mast cells and Tregs, and patients with SONFH had fewer dendritic cells than controls. The hub genes CYBB and TLR4 showed significant correlations with M1 macrophages and CD8 T cells, respectively. Cross-validation and qRT-PCR confirmed the upregulation of STAT3, IL1B, TLR2, and CASP1 in patients with SONFH, validating the bioinformatics findings. An ROC curve analysis confirmed the diagnostic potential of the hub genes. The top 10 hub genes show promise as ERS-related diagnostic biomarkers for SONFH. We discovered that 261 miRNAs, including hsa-miR-23, influence these genes and identified potential therapeutics such as dibenziodolium and simvastatin. Immune profiling indicated altered immune functions in SONFH, with significant correlations among immune cell types. Validation confirmed the upregulation of STAT3, IL1B, TLR2 and CASP1, which had diagnostic potential. The findings suggest potential diagnostic markers and therapeutic targets for SONFH.

The Multiplicative Effects of Individual Risk Factors in the Development of Osteonecrosis of the Femoral Head

BACKGROUND

While individual risk factors, including chronic corticosteroid use, alcohol abuse, and smoking, are implicated in osteonecrosis of the femoral head (ONFH), the degree to which multiple risk factors increase risk is unknown. This study aimed to: (1) identify the demographic characteristics of patients who have ONFH; (2) quantify the effects of individual risk factors on ONFH development; (3) quantify the effects of combined risk factors on ONFH development; and (4) determine the prognostic implications of combined risk factors on ONFH development.

METHODS

This was a retrospective cohort study. A national insurance database was used to study a population of 2,612,383 adult patients who had a 10-year follow-up period. There were 10,233 patients identified who had a diagnosis of ONFH. We identified patients who had chronic corticosteroid use, tobacco use, and/or alcohol abuse and assessed the risk of developing ONFH over a 10-year period. Patients who had individual and multiple risk factors were grouped for comparison, and Chi-square analyses were performed.

RESULTS

Higher proportions of patients who had each individual risk factor developed ONFH compared to proportions of patients who did not have risk factors. Patients who had combined risk factors were at greater risk of developing ONFH compared to patients who had no risk factors and those who had single risk factors. Combined risk factors demonstrated multiplicative effects on the development of ONFH: tobacco-alcohol risk ratio (RR) 5.25, corticosteroid-alcohol RR 10.20, tobacco-corticosteroid RR 8.69, and corticosteroid-tobacco-alcohol RR 12.54. Patients who had combined risk factors developed ONFH at younger ages than those who had single risk factors. Kaplan-Meier curve analyses demonstrated worse 10-year hip survival in the setting of combined risk factors.

CONCLUSIONS

Combined risk factors have a multiplicative effect on the risk of developing of atraumatic ONFH. Orthopaedic surgeons may care for at-risk individuals through modulation of risk factors.

LEVEL OF EVIDENCE

Retrospective Cohort Study, Level III.

Core Decompression with Bone Marrow Aspirate Concentrate Implantation in Osteonecrosis of the Femoral Head with a Minimum of 2-year Follow-up - A Pilot Study

Introduction

Osteonecrosis of the femoral head (ONFH), resulting from impaired blood supply to the head of the femur, presents a significant challenge to clinicians due to its debilitating nature. Conservative treatment often offers insufficient pain relief and debilitating functional outcomes which necessitate alternative therapies. Bone marrow aspirate concentrate (BMAC), a potent orthobiologics and rich in mesenchymal stromal cells and growth factors, holds good promise as the minimally invasive procedure for ONFH. With the preceding research suggesting clinical and functional efficacy, we assessed the therapeutic effectiveness of BMAC in ONFH management in joint preservation.

Materials and Methods

A prospective cohort study was conducted with 20 patients suffering from ONFH who failed to respond to 6 months of conservative treatment. A uniform surgical procedure was performed by a single surgeon, involving bone marrow extraction from the anterior iliac crest and subsequent processing into an 8-10 mL of BMAC concentrate. The BMAC was then injected into the implanted into the decompressed femoral head. The post-operative protocol comprised weight-bearing mobilization, physiotherapy, and a 4-week NSAID-free regimen. Outcome measures included pain scores, hip function, knee symptoms, sports activities, patient satisfaction, and recommendation of the procedure.

Results

Of the 20 patients suffering from ONFH, primarily the left side, most of whom were at stage 2b, significant pain reduction and functional improvement were observed over 24 months. The mean pain score decreased from 9.00 to 3.55, while the hip function score increased from 46.12 to 88.60. However, some patients encountered complications such as symptom recurrence (5%), disease progression (10%), and persistent pain (5%).

Conclusion

Core decompression with BMAC implantation emerges as a promising, effective, and safe treatment for ONFH with better costeffectiveness and minimal side effects, making it a feasible treatment alternative.

Efficacy of Autologous Adult Live-Cultured Osteoblast (AALCO) Implantation in Avascular Necrosis of the Femoral Head: A Mid-Term Outcome Analysis

Introduction

Avascular Necrosis (AVN) of the femoral head, a condition characterized by the interruption of blood supply leading to bone tissue death, presents significant therapeutic challenges. Recent advancements in orthobiologics, including the use of Autologous Adult Live-Cultured Osteoblasts (AALCO), combined with core decompression, offer a novel approach for managing AVN. This study assesses the efficacy of this treatment modality in improving functional outcomes and hindering disease progression.

Materials and methods

This retrospective observational study encompassed 30 patients treated between 2020 and 2023 for idiopathic AVN of the femoral head, grades I to III, who had not responded to conservative treatment. Patients were excluded based on specific criteria including age, secondary AVN causes, and certain health conditions. The treatment involved a two-stage surgical procedure under spinal anesthesia with OSSGROW® for AALCO generation. Post-operative care emphasized early mobilization, DVT prevention, and avoidance of NSAIDs. Outcome measures were evaluated using the Visual Analog Scale (VAS) for pain, modified Harris Hip Score, and annual MRI imaging for up to 36 months.

Results

Among 26 patients (41 hips) completing the study, statistically significant improvements in pain and hip functionality were documented, alongside positive radiological signs of osteogenesis in the majority of cases. However, four instances required advancement to total hip replacement due to disease progression.

Conclusion

The combination of core decompression and AALCO implantation shows promise as an effective treatment for AVN of the femoral head, with notable improvements in functional and radiological outcomes. This study supports the potential of orthobiologic approaches in AVN treatment, warranting further investigation through comprehensive randomized controlled trials.

Graphical Abstract

Exploring the genetic association between immune cells and susceptibility to osteonecrosis using large-scale population data

Objectives

Research shows a close association between aberrant immune reactions in osteonecrotic tissues and immune cell infiltration. However, due to limitations in sample size and dataset comprehensiveness, the causal relationship between them is not fully established. This study aims to determine whether there is a causal relationship using a larger and more diverse dataset.

Methods

We conducted a comprehensive Mendelian Randomization (MR) analysis to investigate the causal relationship between immune cell characteristics and osteonecrosis. Utilizing publicly available genetic data, we explored the causal relationships between 731 immune cell features and 604 cases from the FinnGen Finnish database, as well as 257 cases from the UK Biobank database with osteonecrosis data. The inverse-variance weighted (IVW) method was used for the primary analysis, and we employed sensitivity analyses to assess the robustness of the main results. In addition, considering data from the two databases used in this study, a meta-analysis was conducted on the significant immune cells associated with osteonecrosis (FDR <0.05).

Results

our findings suggested that specific immune cell signatures, such as CD20- % lymphocytes, CD62L-monocytes, and CD33br HLA DR+ CD14-cells were associated with increased odds of osteonecrosis. In contrast, EM CD4+ activated cells and DP (CD4+ CD8+) T cells were associated with decreased odds. Notably, osteonecrosis was associated with a potential decrease in CD45 on immature MDSC cell content.

Conclusion

From a genetic perspective, we demonstrated a close association between immune cells and osteonecrosis. These findings significantly enhance our understanding of the interplay between immune cell infiltration and the risk of osteonecrosis, contributing to the potential design of therapeutic strategies from an immunological standpoint.

Identification of steroid-induced osteonecrosis of the femoral head biomarkers based on immunization and animal experiments

BACKGROUND

Steroid-induced osteonecrosis of femoral head (SONFH) is a severe health risk, and this study aims to identify immune-related biomarkers and pathways associated with the disease through bioinformatics analysis and animal experiments.

METHOD

Using SONFH-related datasets obtained from the GEO database, we performed differential expression analysis and weighted gene co-expression network analysis (WGCNA) to extract SONFH-related genes. A protein-protein interaction (PPI) network was then constructed, and core sub-network genes were identified. Immune cell infiltration and clustering analysis of SONFH samples were performed to assess differences in immune cell populations. WGCNA analysis was used to identify module genes associated with immune cells, and hub genes were identified using machine learning. Internal and external validation along with animal experiments were conducted to confirm the differential expression of hub genes and infiltration of immune cells in SONFH.

RESULTS

Differential expression analysis revealed 502 DEGs. WGCNA analysis identified a blue module closely related to SONFH, containing 1928 module genes. Intersection analysis between DEGs and blue module genes resulted in 453 intersecting genes. The PPI network and MCODE module identified 15 key targets enriched in various signaling pathways. Analysis of immune cell infiltration showed statistically significant differences in CD8 + t cells, monocytes, macrophages M2 and neutrophils between SONFH and control samples. Unsupervised clustering classified SONFH samples into two clusters (C1 and C2), which also exhibited significant differences in immune cell infiltration. The hub genes (ICAM1, NR3C1, and IKBKB) were further identified using WGCNA and machine learning analysis. Based on these hub genes, a clinical prediction model was constructed and validated internally and externally. Animal experiments confirmed the upregulation of hub genes in SONFH, with an associated increase in immune cell infiltration.

CONCLUSION

This study identified ICAM1, NR3C1, and IKBKB as potential immune-related biomarkers involved in immune cell infiltration of CD8 + t cells, monocytes, macrophages M2, neutrophils and other immune cells in the pathogenesis of SONFH. These biomarkers act through modulation of the chemokine signaling pathway, Toll-like receptor signaling pathway, and other pathways. These findings provide valuable insights into the disease mechanism of SONFH and may aid in future drug development efforts.

Deep learning approach to femoral AVN detection in digital radiography: differentiating patients and pre-collapse stages

OBJECTIVE

This study aimed to evaluate a new deep-learning model for diagnosing avascular necrosis of the femoral head (AVNFH) by analyzing pelvic anteroposterior digital radiography.

METHODS

The study sample included 1167 hips. The radiographs were independently classified into 6 stages by a radiologist using their simultaneous MRIs. After that, the radiographs were given to train and test the deep learning models of the project including SVM and ANFIS layer using the Python programming language and TensorFlow library. In the last step, the test set of hip radiographs was provided to two independent radiologists with different work experiences to compare their diagnosis performance to the deep learning models' performance using the F1 score and Mcnemar test analysis.

RESULTS

The performance of SVM for AVNFH detection (AUC = 82.88%) was slightly higher than less experienced radiologists (79.68%) and slightly lower than experienced radiologists (88.4%) without reaching significance (p-value > 0.05). Evaluation of the performance of SVM for pre-collapse AVNFH detection with an AUC of 73.58% showed significantly higher performance than less experienced radiologists (AUC = 60.70%, p-value < 0.001). On the other hand, no significant difference is noted between experienced radiologists and SVM for pre-collapse detection. ANFIS algorithm for AVNFH detection with an AUC of 86.60% showed significantly higher performance than less experienced radiologists (AUC = 79.68%, p-value = 0.04). Although reaching less performance compared to experienced radiologists statistically not significant (AUC = 88.40%, p-value = 0.20).

CONCLUSIONS

Our study has shed light on the remarkable capabilities of SVM and ANFIS as diagnostic tools for AVNFH detection in radiography. Their ability to achieve high accuracy with remarkable efficiency makes them promising candidates for early detection and intervention, ultimately contributing to improved patient outcomes.

Conservative Treatment in Avascular Necrosis of the Femoral Head: A Systematic Review

INTRODUCTION

Avascular necrosis (AVN) of the femoral head is a pressing orthopedic issue, leading to bone tissue death due to disrupted blood supply and affecting the quality of life of individuals significantly. This review focuses on conservative treatments, evaluating their efficacy as mainstay therapies. Enhanced understanding of AVN's pathophysiology and advancements in diagnostic tools have rekindled interest in non-surgical interventions, emphasizing personalized, multidisciplinary approaches for improved outcomes.

MATERIAL AND METHOD

A systematic search was conducted on PubMed, SCOPUS, and Google Scholar databases from January 2020 to August 2023, with the objective of focusing on conservative treatments for AVN of the femoral head. Eligible studies, including original research, case reports, and observational studies, were examined for relevant, well-documented patient outcomes post-conservative treatments, excluding non-English and surgically focused articles without comparative conservative data.

RESULTS

A systematic search yielded 376 records on AVN of the femoral head across multiple databases. After de-duplication and rigorous screening for relevance and quality, 11 full-text articles were ultimately included for a comprehensive qualitative synthesis, focusing on conservatively managing the condition.

CONCLUSIONS

This review evaluates the effectiveness of conservative treatments such as pharmacological interventions and physical modalities in managing AVN of the femoral head. Despite promising results in symptom alleviation and disease progression delay, variability in outcomes and methodological limitations in studies necessitate further rigorous, randomized controlled trials for a robust, patient-centric approach to optimize therapeutic outcomes in AVN management.

Three-dimensional distribution of subchondral fracture lines in osteonecrosis of the femoral head

Objective

To investigate the characteristics of three-dimensional distribution of subchondral fracture lines on the surface of the osteonecrosis femoral head, and to discuss the underlying mechanisms that contribute to its collapse.

Methods

We retrospectively analyzed computed tomography (CT) images from 75 patients (comprising a total of 77 femoral heads) diagnosed with Association Research Circulation Osseous (ARCO) stage IIIA or IIIB femoral head necrosis. The three-dimensional structures of both the femoral head and the subchondral fracture line were reconstructed and subsequently fitted into normal femoral head model. A heat map of fracture line was generated to visualize its spatial distribution across the femoral heads surface.to observe its distribution. In addition to that, the femoral head was partitioned into four zones, and the frequency of each fracture line traversing different zones was calculated and analysed.

Results

Highest and lowest density of subchondral fracture lines was demonstrated in anterolateral and posterolateral zone respectively. and most sparse in posterolateral. Furthermore, the three-dimensional heat map of fracture lines highlighted their most frequent occurrence in the anterolateral area, particularly near the junction of the femoral head and neck. One fracture line may pass through multiple areas, passage frequencies for fracture lines was observed in zones I, II, III and IV for 66 times (85.7 %), 52 times (67.5 %), 25 times (32.5 %) and 46 times (59.7 %), respectively, with a significant difference between zone I and other zones (P < 0.001).

Conclusion

Subchondral fracture line of femoral head occurs most frequently in anterolateral femoral head, suggesting that the anterolateral part may be the initial location of collapse.

Translational potential of this article

We found that the subchondral fracture line was most frequently located anterolateral to the femoral head, suggesting that this may be the site of initiation of collapse. Furthermore, we propose an innovative method for analyzing and visualizing subchondral fracture distribution in femoral head necrosis in the form of fracture line heat maps. By doing so, we provide a valuable reference for physicians, enabling them to enhance their management strategies for femoral head necrosis. Ultimately, this approach holds the promise of significantly improving the prognosis and outcomes for patients afflicted with this condition.