The pathogenesis of multifocal osteonecrosis

Canonical pathways for validating steroid-associated osteonecrosis in mice

The present study aimed to establish and evaluate a preclinical model of steroid-associated osteonecrosis (SAON) in mice. Sixteen 24-week-old male C57BL/6 mice were used to establish SAON by two intraperitoneal injections of lipopolysaccharide (LPS), followed by three subcutaneous injections of methylprednisolone (MPS). Each injection was conducted on working day, with an interval of 24 h. Six cycles of injections were conducted. Additional twelve mice (age- and gender-matched) were used as normal controls. At 2 and 6 weeks after completing induction, bilateral femora and bilateral tibiae were collected for histological examination, micro-CT scanning, and bulk RNA sequencing. All mice were alive until sacrificed at the indicated time points. The typical SAON lesion was identified by histological evaluation at week 2 and week 6 with increased lacunae and TUNEL+ osteocytes. Micro-CT showed significant bone degeneration at week 6 in SAON model. Histology and histomorphometry showed significantly lower Runx2+ area, mineralizing surface (MS/BS), mineral apposition rate (MAR), bone formation rate (BFR/BS), type H vessels, Ki67+ (proliferating) cells, and higher marrow fat fraction, osteoclast number and TNFα+ areas in SAON group. Bulk RNA-seq revealed changed canonical signaling pathways regulating cell cycle, angiogenesis, osteogenesis, and osteoclastogenesis in the SAON group. The present study successfully established SAON in mice with a combination treatment of LPS and MPS, which could be considered a reliable and reproducible animal model to study the pathophysiology and molecular mechanism of early-stage SAON and to develop potential therapeutic approaches for the prevention and treatment of SAON.

Quantitative dynamic contrast-enhanced MRI of bone marrow perfusion at the proximal femur: influence of femoral head osteonecrosis risk factor and overt osteonecrosis

OBJECTIVE

To evaluate the MRI perfusion changes in patients with risk factors for osteonecrosis and normally appearing femoral heads prior to overt femoral head osteonecrosis.

METHODS

Fifty-eight patients (105 hips) were prospectively included in this ethics committee-approved study. There were 46 hips with no image anomalies and no risk factors for osteonecrosis of the femoral head (ONFH) risk factors, 38 with ONFH risk factors and no image abnormalities, and 21 with overt ONFH. All patients underwent DCE-MRI. Semi-quantitative (peak enhancement [PE], area under the curve [AUC], time to maximum enhancement [TME]) and quantitative perfusion parameters (volume plasma, KTRANS, and KEP) were calculated. Excessive alcohol consumption, corticosteroid use, and trauma were considered major risk factors for osteonecrosis of the femoral head.

RESULTS

Measured at the femoral neck and compared to the healthy hips without OFNH risk factors, PE was significantly lower in the hips of patients with OFNH risk factors. Moreover, the difference was greater in females with risk factors, who presented significantly lower PE values (p = 0.0096). A PE threshold of 1.4% yielded a 92% sensitivity and 54% specificity for the presence of associated ONFH risk factors. The hips with overt OFNH compared to those with normally appearing showed an increase of PE of 45% in the neck (p < 0.014). Various epiphyseal femoral head perfusion parameters (PE, TME, AUC, and K_trans) presented statistically significant differences in hips with ONFH and those without (p < 0.0001).

CONCLUSION

DCE-MRI can identify perfusion marrow changes related to the presence of ONFH risk factors and adjacent to osteonecrosis areas.

KEY POINTS

• Bone marrow perfusion changes may occur prior to overt ONFH and extend beyond the osteonecrosis area to the entire femoral head and neck. • Peak enhancement values were significantly reduced in patients with ONFH risk factors, compared to those without. • The presence of ONFH led to a significant increase in marrow perfusion adjacent to the osteonecrosis area.

Familial Thrombophilia Is Associated With Primary Multifocal Osteonecrosis: A Case-Control Study of 40 Patients

To characterize pathoetiologic associations of heritable thrombophilia-hypofibrinolysis with idiopathic (primary) multifocal osteonecrosis (ON) (≥3 ON anatomic sites), we prospectively studied 28 women and 12 men with primary multifocal ON compared with 27 women and 24 men with primary nonmultifocal ON (<3 sites) and 110 healthy controls without ON. The 40 cases with primary multifocal ON differed from controls for 3 familial thrombophilias: Factor V Leiden heterozygosity (6 of 40 [15%] vs 2 of 109 [2%], P=.002), G20210A prothrombin gene heterozygosity (6 of 40 [15%] vs 3 of 110 [3%], P=.011), and high (>150%) Factor VIII (8 of 40 [20%] vs 7 of 103 [7%], P=.031). These case-control familial coagulation differences paralleled those in 51 concurrently evaluated cases with primary nonmulti-focal ON, 7 of 51 (14%) of whom had Factor V Leiden heterozygosity vs 2% of controls (P=.005) and 14 of 44 (32%) of whom had high Factor VIII vs 7 of 103 (7%) of controls (P=.0002). Recognition of familial thrombophilia as a common pathoetiology of primary multifocal ON provides an opportunity for early anticoagulation (before joint collapse), allowing both prophylaxis and therapy aimed at relieving pain and slowing or stopping progression of the disease to joint collapse. [Orthopedics. 202X;XX(X):xx-xx.].

Avascular necrosis of the epiphyses of bones in patients who have had SARS-CoV-2 infection: Clinical observations and a narrative review of literature data

The SARS-CoV-2 coronavirus pandemic is a leading medical problem that is in the focus of attention of representatives of all medical specialties. In addition to fighting the COVID-19 infection itself, the task of preventing and treating a wide range of complications arising after the disease is becoming increasingly urgent. One of these complications is avascular necrosis (AN) of bone tissue – a severe pathology that leads to serious suffering, a decrease in the quality of life and disability of patients. For the period from 2020 to 2022 there are 9 reviews in the world literature devoted to the pathogenesis, clinical features and treatment possibilities of this complication. During the same period, 5 articles were published describing clinical observations of AN after suffering COVID-19.The purpose of this work is to demonstrate our own clinical observations, as well as to review the available literature data on the problem of AN after COVID-19 infection. Based on the analysis, it can be concluded that AN after SARS-CoV-2 infection most often develops in the femoral head (>50% of cases), occurs regardless of the severity of the disease and the cumulative dose of glucocorticoids used in the acute period of the disease. It seems advisable to perform an MRI of the hip joints at least once every 3 months for all patients who have had COVID-19 in severe and moderate form during the first year after convalescence.

Rheumatological picture of a patient having multifocal osteonecrosis associated with sickle cell anemia: a case study

Avascular necrosis (AVN) is a critical health condition associated with local death of the bone tissue resulting in multifocal osteonecrosis (MFON). After a prior patient's consent, we present a case of sickle cell anemia associated with severe MFON that affected both long bones and short bones. She had a positive history of DVT. Initially, she presented with generalized severe bone pain with fever for seven days that got worse on the day of admission, a picture suggestive of sickle cell anemia-induced vaso-occlusive crisis. She was treated with adequate hydration, morphine, enoxaparin (a low molecular weight heparin), paracetamol and ceftriaxone. She got improved on treatment. On 5^th day after admission, she developed sudden severe local tenderness at the distal tibia above the medial malleoli in both legs and she was unable to put a weight on her feet and could not stand up or walk. Plain X-ray films were not diagnostic. Complete liver function tests and kidney function tests were normal. The patient had leukocytosis, high serum urate and high serum LDH (may reflect cellular damage in bone cells). MRI scans revealed an evidence of bilateral multiple avascular necrosis in both femoral heads, left shoulder, left knee, and pelvic bones were evident. The patient's condition was evaluated and the diagnosis of MFON associated with sickle cell crisis was established. This patient responded well to same treatments and her condition got improved. In conclusion, MFON should be considered after vaso-occlusive crisis of sickle cell anemia. Plain X-ray is non-conclusive in diagnosing bony lesions induced by AVN while MRI is diagnostic.

Treatment options for secondary osteonecrosis of the knee

Knee osteonecrosis is a debilitating progressive degenerative disease characterized by subchondral bone ischemia. It can lead to localized necrosis, tissue death, and progressive joint destruction. For this reason, it is essential to diagnose and treat this disease early to avoid subchondral collapse, chondral damage, and end-stage osteoarthritis, where the only solution is total knee arthroplasty. Three types of knee osteonecrosis have been documented in the literature: spontaneous or primitive, secondary, and post arthroscopy. Spontaneous osteonecrosis is the most common type studied in the literature. Secondary osteonecrosis of the knee is a rare disease and, unlike the spontaneous one, involves patients younger than 50 years. It presents a particular set of pathological, clinical, imaging, and progression features. The management of secondary osteonecrosis is determined by the stage of the disorder, the clinical manifestation, the size and location of the lesions, whether the involvement is unilateral or bilateral, the patient's age, level of activity, general health, and life expectancy. This review aims to present the recent evidence on treatment options for secondary osteonecrosis of the knee, including conservative treatment, joint preserving surgery, and knee replacement.

A case of completed course multifocal osteonecrosis (MFON) during pregnancy due to primary antiphospholipid syndrome

Osteonecrosis of both shoulders and hips is a rare presentation of primary antiphospholipid syndrome. A female patient aged 23 years old with no systemic diseases has her only complaint which was pain and limitations in both hips followed by both shoulders. Careful detailed history and clinical examination is essential for reaching optimum diagnosis thus good management. MRI for hip and shoulder joints is essential for the diagnosis of osteonecrosis. Exclusion of all causes of secondary osteonecrosis by history, clinical examination, and laboratory studies should be done before diagnosing the rare causes of osteonecrosis or the primary type. Pregnancy is an exacerbation factor for primary osteonecrosis. We recommend that the female patient with primary osteonecrosis should receive prophylactic antithrombotic during pregnancy. In conclusion, exclusion of all secondary causes of osteonecrosis is mandatory to reach an accurate diagnosis.

Evaluation of whole-body modalities for diagnosis of multifocal osteonecrosis-a pilot study

Background

This study aimed to investigate the ability of whole-body bone scintigraphy (WB-BS) in the detection of multifocal osteonecrosis (ON) compared to whole-body magnetic resonance imaging (WB-MRI) and to clarify the characteristics of patients with multifocal ON among those with ON of the femoral head (ONFH) using WB-MRI.

Methods

Forty-six patients who had symptomatic ONFH and underwent surgery in our hospital from April 2019 to October 2020 were included in the study. Data on patient demographics, including age, sex, body mass index (BMI), history of corticosteroid intake, alcohol abuse, smoking, and symptomatic joints, were collected from their medical records. All patients underwent WB-MRI and WB-BS before surgery.

Results

The agreement in the detection of ON by WB-MRI vs the uptake lesions by WB-BS in the hip joints was moderate (κ = 0.584), while that in other joints was low (κ < 0.40). Among the 152 joints with ON detected by WB-MRI, 92 joints (60.5%) were symptomatic, and 60 joints (39.5%) were asymptomatic. Twelve out of the 46 (26.0%) patients had multifocal (three or more distinct anatomical sites) ON. Nonetheless, while WB-BS detected symptomatic ON detected by WB-MRI as uptake lesions in 82.6% (76/92) of the joints, asymptomatic ON detected by WB-MRI was detected as uptake lesions in 21.7% (13/60) of the joints. All patients with multifocal ON had a history of steroid therapy, which was significantly higher than that in patients with oligofocal ON (P = 0.035). The patients with a hematologic disease had multifocal ON at a higher rate (P = 0.015).

Conclusions

It might be difficult for WB-BS to detect the asymptomatic ON detected by WB-MRI compared to symptomatic ON. Considering the cost, examination time, and radiation exposure, WB-MRI might be useful for evaluating multifocal ON. Larger longitudinal studies evaluating the benefits of WB-MRI for detecting the risk factors for multifocal ON are required.

Inflammation, Bone Healing and Osteonecrosis: From Bedside to Bench

Osteonecrosis of the epiphyseal and metaphyseal regions of major weight-bearing bones of the extremities is a condition that is associated with local death of bone cells and marrow in the afflicted compartment. Chronic inflammation is a prominent feature of osteonecrosis. If the persistent inflammation is not resolved, this process will result in progressive collapse and subsequent degenerative arthritis. In the pre-collapse stage of osteonecrosis, attempt at joint preservation rather than joint replacement in this younger population with osteonecrosis is a major clinical objective. In this regard, core decompression, with/without local injection of bone marrow aspirate concentrate (BMAC), is an accepted and evidence-based method to help arrest the progression and improve the outcome of early-stage osteonecrosis. However, some patients do not respond favorably to this treatment. Thus, it is prudent to consider strategies to mitigate chronic inflammation concurrent with addressing the deficiencies in osteogenesis and vasculogenesis in order to save the affected joint. Interestingly, the processes of inflammation, osteonecrosis, and bone healing are highly inter-related. Therefore, modulating the biological processes and crosstalk among cells of the innate immune system, the mesenchymal stem cell-osteoblast lineage and others are important to providing the local microenvironment for resolution of inflammation and subsequent repair. This review summarizes the clinical and biologic principles associated with osteonecrosis and provides potential cutting-end strategies for modulating chronic inflammation and facilitating osteogenesis and vasculogenesis using local interventions. Although these studies are still in the preclinical stages, it is hoped that safe, efficacious, and cost-effective interventions will be developed to save the host’s natural joint.

Avascular necrosis in systemic sclerosis patients: a case-based review of demographics, presentation, and management

Avascular necrosis (AVN) is a pathologic process involving death of bony tissue resulting from loss of blood supply from various causes. Various traumatic and nontraumatic causes of AVN are known, including systemic autoimmune diseases. AVN has been well described in patients with autoimmune diseases such as systemic lupus erythematosus, but in systemic sclerosis (SSc) patients, there have been limited case reports and case series. There have only been three case reports of AVN in multiple anatomic sites (multifocal AVN) reported in SSc patients in the literature. We present a case of multifocal AVN in an SSc patient and a review of literature on the previously reported cases of SSc-related AVN in terms of demographics, clinical presentation, and management. To our knowledge, this is the only literature review of reported AVN cases in SSc patients.

Clinical characteristics and role of whole-body bone scan in multifocal osteonecrosis

Background

Multifocal osteonecrosis (ON) is defined as ON involving three or more distinct anatomical sites. We investigated the clinical characteristics and utility of whole-body bone scans (WBBS) in patients with multifocal ON.

Methods

A total of 254 patients with ON confirmed by magnetic resonance imaging (MRI) or X-rays of the hips or other anatomic regions were evaluated using WBBS and divided into those with multifocal disease and those with oligofocal disease; their clinical characteristics were then compared. All data were analyzed retrospectively both visually and quantitatively (via uptake grading and defect scoring). Associations between the MRI Association Research Circulation Osseous (ARCO) classification and bone scan photon defects and uptake grade were assessed. Factors associated with multifocal ON were identified using logistic regression.

Results

Of the 254 ON patients, 26 (10.2%) had multifocal ON. Their mean age (42.8 ± 14.3 years) was less than that of patients with oligofocal ON (50.9 ± 15.4 years; p = 0.011). Comorbidities, corticosteroid use, and treatment with immunosuppressive agents were more frequent in patients with multifocal ON. Age (odds ratio [OR] = 0.964, p = 0.013), the presence of a comorbidity (OR = 3.387, p = 0.006), present corticosteroid use (OR = 5.696, p < 0.001), and treatment with immunosuppressive agents (OR = 3.447, p = 0.004) were significantly associated with multifocal ON. The MRI ARCO classification was not associated with photon defects in the bone scans of those with femoral ON. However, the ARCO classification was significantly associated with uptake grade.

Conclusions

WBBS may be an additional tool for evaluating ON patients with risk factors for multiple ON, such as younger age, corticosteroid use, and comorbidities.

Multifocal avascular necrosis in a patient with refractory immune thrombocytopenia and antiphospholipid antibodies; case report and review of literature

Avascular necrosis (AVN) is a devastating condition that is rarely reported in patients with immune thrombocytopenia (ITP). Treatment with steroids remains a major risk factor for developing AVN. However, the incidence of AVN in patients with ITP requiring corticosteroid therapy is much less than that observed with other clinical conditions requiring corticosteroids. ITP is a bleeding disorder but can be also be a pro-thrombotic state via different mechanisms and thus could result in AVN. Among the possible causes of this pro-thrombotic state is the presence of antiphospholipid antibodies (aPLs). In this case, we report a patient with refractory ITP who developed multifocal AVN around the time she acquired new aPLs. We also discuss different mechanisms by which risk of thrombosis is increased in ITP and the relationship between ITP, aPLs and antiphospholipid syndrome.

Use of autologous bone marrow stem cell implantation for osteonecrosis of the knee in sickle cell disease: a preliminary report

Background

The purpose of our study was to evaluate safety, feasibility and clinical results of bone marrow mononuclear cell (BMC) implantation for early-stage osteonecrosis of the knee (OK) secondary to sickle cell disease.

Methods

Thirty-three SCD patients (45 knees) with OK treated with BMC implantation in the osteonecrotic lesion were clinically and functionally evaluated through the American Knee Society Clinical Score (KSS), Knee Functional Score (KFS) and Numeric Rating Scale (NRS) pain score. MRI and radiographic examinations of the knee were assessed during a period of five years after intervention.

Results

No complications or serious adverse event were associated with BMC implantation. From preoperative assessment to the latest follow-up, there was a significant (p < 0.001) improvement of clinical KSS (64.3 ± 9.7, range: 45–80 and 2.2 ± 4.1, range: 84–100, respectively), KFS (44.5 ± 8.0, range: 30–55 and 91.6 ± 5.8, range: 80–100, respectively) and reduction of NRS pain score (6.7 ± 1.2, range: 4–9 and 3.4 ± 1.0, range: 2–5, respectively). In total, 87% of patients (29/33) consistently experienced improvements in joint function and activity level as compared to preoperative score. No patient had additional surgery following BMC implantation. Radiographic assessment showed joint preservation and no progression to subchondral collapse at most recent follow-up.

Conclusions

The technique of BMC implantation is a promising, relatively simple and safe procedure for OK in SCD patients. Larger and long-term controlled trials are needed to support its clinical effectiveness.

Trial registration

ClinicalTrials.gov NCT02448121. Retrospectively registered 19 May 2015.

Steroid-associated osteonecrosis animal model in rats

OBJECTIVE

Established preclinical disease models are essential for not only studying aetiology and/or pathophysiology of the relevant diseases but more importantly also for testing prevention and/or treatment concept(s). The present study proposed and established a detailed induction and assessment protocol for a unique and cost-effective preclinical steroid-associated osteonecrosis (SAON) in rats with pulsed injections of lipopolysaccharide (LPS) and methylprednisolone (MPS).

METHODS

Sixteen 24-week-old male Sprague-Dawley rats were used to induce SAON by one intravenous injection of LPS (0.2 mg/kg) and three intraperitoneal injections of MPS (100 mg/kg) with a time interval of 24 hour, and then, MPS (40 mg/kg) was intraperitoneally injected three times a week from week 2 until sacrifice. Additional 12 rats were used as normal controls. Two and six weeks after induction, animals were scanned by metabolic dual energy X-ray absorptiometry for evaluation of tissue composition; serum was collected for bone turnover markers, Microfil perfusion was performed for angiography, the liver was collected for histopathology and bilateral femora and bilateral tibiae were collected for histological examination.

RESULTS

Three rats died after LPS injection, i.e., with 15.8% (3/19) mortality. Histological evaluation showed 100% incidence of SAON at week 2. Dual energy X-ray absorptiometry showed significantly higher fat percent and lower lean mass in SAON group at week 6. Micro-computed tomography (Micro-CT) showed significant bone degradation at proximal tibia 6 weeks after SAON induction. Angiography illustrated significantly less blood vessels in the proximal tibia and significantly more leakage particles in the distal tibia 2 weeks after SAON induction. Serum amino-terminal propeptide of type I collagen and osteocalcin were significantly lower at both 2 and 6 weeks after SAON induction, and serum carboxy-terminal telopeptide was significantly lower at 6 weeks after SAON induction. Histomorphometry revealed significantly lower osteoblast surface and higher marrow fat fraction and oedema area in SAON group. Hepatic oedema appeared 2 weeks after SAON induction, and lipid accumulation appeared in the liver of SAON rats 6 weeks after SAON induction.

CONCLUSION

The present study successfully induced SAON in rats with pulsed injection of LPS and MPS, which was well simulating the clinical feature and pathology. Apart from available large animal models, such as bipedal emus or quadrupedal rabbits, our current SAON small model in rats could be a cost-effective preclinical experimental model to study body metabolism, molecular mechanism of SAON and potential drugs developed for prevention or treatment of SAON.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

The present study successfully induced SAON in a small animal model in rats with pulsed injection of LPS and MPS. The evaluation protocols with typical histopathologic ON features and advanced evaluation approaches to identify the metabolic disorders of SAON could be used in future rat SAON studies. The SAON rat model is a suitable and cost-effective animal model to study molecular mechanism of SAON and potential drugs developed for prevention and treatment of SAON.

Osteonecrosis in sickle cell disease patients from Bahia, Brazil: a cross-sectional study

PURPOSE

The aim of this study was to describe the clinical features of osteonecrosis (ON) in sickle cell disease (SCD) patients in Bahia, a Northeast state with the highest prevalence of the disease in Brazil.

METHODS

Between 2006 and 2017, 283 cases of osteonecrosis in SCD patients were enrolled to analyse the age at diagnosis, genotype, gender, pain, distribution of the lesions and disease staging. MRI and radiograph were obtained at the participation.

RESULTS

Of the 283 SCD cases, 120 (42.4%) were haemoglobin SS genotype while 163 (57.6%) were SC genotype. Two hundred and forty-six cases were bilateral and 37 were unilateral, with an average age at diagnosis of 33.7 (range 10-67) years. The most frequent identified ON site not only was the hip (74.6%), but also affected shoulder, knee and ankle. Most cases presented at early stage I (172, 60.8%) disease. No significant differences on the features of osteonecrosis were identified between haemoglobin SS and haemoglobin SC cases.

CONCLUSIONS

Given the relatively high prevalence of bilateral osteonecrosis at early stages, painful symptoms and rather late age at diagnosis, SCD patients should have radiological examination of their joints more often in order to prevent severe functional disability and increase patient's life quality.