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The aim of this article is to determine the safety and efficacy of core decompression (CD) combined with injection of autologous bone marrow concentrate (BMC), demineralized bone matrix (DBM), and platelet-rich fibrin (PRF) for treating femoral head osteonecrosis. Seventy-seven patients (53 males and 24 females) for a total of 87 hips were treated for hip osteonecrosis with CD combined with injection of autologous BMC, DBM, and PRF at Rizzoli Orthopedic Institute from September 2008 to December 2019. Patients were assessed at baseline, at 45 days, and at 3, 6, 12, 24, and 36 months postoperatively. The primary outcome was the survival rate of hips not converted to total hip arthroplasty (THA). The secondary outcomes were (I) radiographic positive evolution assessed by X-ray films and magnetic resonance imaging and (II) the clinical symptoms evaluated with the Harris Hip Score (HHS). Eighty-seven hips from 77 patients with femoral head osteonecrosis (FHON), 60 males and 27 females, with a median age of 34 years (range 15–55) were included. The cause of necrosis was steroid treatment in 30 patients (17 of these for hematological malignancies, 2 for lupus, 1 for Churg–Strauss syndrome, and the remaining for other causes), 1 was alcohol-related, 4 followed hip injury, while 15 patients had idiopathic causes. THA was carried out in 20 hips (40%). These patients had lesions classified as IIa on the Ficat stage in four cases, six were IIb, nine were III, and one was 4. No CD-related complications were found during THA surgery or at the last follow-up in these cohorts of patients. Radiographic progression of the FHON was found in 14 hips (28%), with a higher percentage on Ficat's stage IIb. There were procedure-related complications in two hips, including one femoral neck fracture and one deep infection. Nineteen hips with successful treatment had good to excellent functional results at a 3-year follow-up or more (HHS ≥ 80). The long-term outcomes of treatment with CD and injection with BMC combined with DBM and PRF are promising to prevent femoral head collapse in patients with FHON. Moreover, CD does not influence the outcome in cases of THA. [ABSTRACT FROM AUTHOR]

Osteonecrosis of femoral head (ONFH) can be a debilitating disease, for which numerous salvage surgeries have been popularized to halt its progression. The aim of this study was to assess the clinical and radiological outcomes of a single-incision core decompression (CD) technique using trochanteric autograft in ONFH and to determine the prognostic factors of treatment success. Sixty-six hips (41 patients) of Association Research Circulation (ARCO) 1 and 2 ONFH undergoing CD were included in the study with a mean follow-up of 58 months. Treatment failure was taken as radiographic collapse and/or conversion to total hip arthroplasty (THA). The following clinical and radiological factors impacting outcomes were evaluated—symptom duration, etiology, age, sex and body mass index, ARCO grade, Japanese Investigation Committee grade, modified Kerboul angle, and bone marrow edema (BME) on magnetic resonance imaging. Twenty-one of the 66 hips (31.8%) had a radiological collapse by the last follow-up, and 6 hips (9%) required THA. Overall, significant improvement in Harris hip scores (60.18 versus 80.81, P -value = .012) and visual analog scale scores (7.3 versus 1.2, P -value = .025) were noted postoperatively with no surgical complications. Late presentation (>3 months) (P -value = .001) and presence of BME (P  = 0.0002) were significantly correlated with poor outcomes. The 5-year collapse-free rate was 68.2%, and 91% hips were arthroplasty free. Our single-incision CD technique using a trochanteric autograft yielded favorable outcomes for precollapse stages of nontraumatic ONFH at 5-year follow-up. Delayed presentation and presence of BME are poor prognostic factors. Adequate patient selection is for achieving a good survivorship and improvement in patient-reported outcomes. [ABSTRACT FROM AUTHOR]

In this study, we investigated whether the ability of aucubin to mitigate the pathology of GONFH involves suppression of TLR4/NF‐κB signalling and promotion of macrophage polarization to an M2 phenotype. In necrotic bone tissues from GONFH patients, we compared levels of pro‐inflammatory M1 macrophages and anti‐inflammatory M2 macrophages as well as levels of TLR4/NF‐κB signalling. In a rat model of GONFH, we examined the effects of aucubin on these parameters. We further explored its mechanism of action in a cell culture model of M1 macrophages. Necrotic bone tissues from GONFH patients contained a significantly increased macrophage M1/M2 ratio, and higher levels of TLR4, MYD88 and NF‐κB p65 than bone tissues from patients with hip osteoarthritis. Treating GONFH rats with aucubin mitigated bone necrosis and demineralization as well as destruction of trabecular bone and marrow in a dose‐dependent manner, based on micro‐computed tomography. These therapeutic effects were associated with a decrease in the overall number of macrophages, decrease in the proportion of M1 macrophages, increase in the proportion of M2 macrophages, and downregulation of TLR4, MYD88 and NF‐κB p65. These effects in vivo were confirmed by treating cultures of M1 macrophage‐like cells with aucubin. Aucubin mitigates bone pathology in GONFH by suppressing TLR4/NF‐κB signalling to shift macrophages from a pro‐ to anti‐inflammatory phenotype. [ABSTRACT FROM AUTHOR]

Abstract Background Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD. Methods Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model. Results Compared to the original 3D model, the trials had a mean displacement of 1.440 ± 1.03 mm and a mean angle deviation of 1.093 ± 0.749º. Conclusions The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques.

Background Steriod-induced osteonecrosis of femoral head (SIONFH) cystic degeneration have a "double-edged sword" effect. The method of activating blood and dredging collate is effective in the treatment of early SIONFH, but its regulatory effect on bone resorption/angiogenesis/osteogenic protein in cystic degeneration remains unclear. Objective To investigate the effect of activating blood and dredging collate method on serum bone resorption/angiogenesis/osteogenic protein in patients with cystic degeneration of SIONFH. Methods Sixty patients with SIONFH admitted to the Hip Joint Research Center of Guangzhou University of Traditional Chinese Medicine from January 2019 to January 2021 were included as the study subjects and divided into the control group and treatment group according to random number table method, with 30 cases in each group. Another 30 volunteers with normal physical examination in hospital at the same period and no history of hormone use were selected as the normal group. The treatment group was treated with Huoxuetongluo capsule (2 g/time, 3 times/day) and calcium carbonate (600 mg/time, 1 time/day), the control group was treated with the same amount of calcium carbonate, and the course of treatment of both groups was 12 months, simultaneously limiting weight-bearing on the affected limb. Fasting serum was collected, and the expression levels of nuclear factor κB receptor activating factor ligand (RANKL), platelet-derived growth factor-BB (PDGF-BB), vascular endothelial growth factor A (VEGFA), osteoprotegerin (OPG) and cadherin-associated protein (CTNNB1) in serum were detected by enzyme-linked immunosorbent assay. The patients were followed up twice at the 6th and 12th month after discharge, and the collapse of femoral head was defined as the end event. Hip pain visual analogue score (VAS), hip function (Harris) score and necrotic area score were used to evaluate the efficacy. Results Baseline RANKL, PDGF-BB, OPG and CTNNB1 levels were compared among the three groups, and the differences were statistically significant (P

• Steroids use is a common and effective strategy for the management of COVID-19. • The osteonecrosis risk in steroids-treated COVID-19 patients is currently unknown. • Osteonecrosis risk was not negligible (7.5 %) in steroids-treated COVID-19 patients. • Patients with osteonecrosis had severe disease and received higher steroids doses. • Early skeleton screening with MRI is rather reasonable at least in these patients. During the pandemic, steroids use at various dosages and durations for the treatment of COVID-19 patients, especially in hospitalized patients, was a common and effective strategy. However, steroid administration is associated with osteonecrosis as an adverse event. The aim of the study was to examine the prevalence of skeleton osteonecrosis in COVID-19 patients treated with or without steroids. Eighty randomly selected hospitalized COVID-19 patients were analyzed, of which 40 were managed with a published protocol including steroids and 40 did not receive steroids. Demographics and laboratory measurements including white blood cells count, C-reactive protein and ferritin were retrieved from the medical records. All patients underwent magnetic resonance imaging of the hips, shoulders, and knees. Subsequently, all patients were clinically examined and Oxford hip score (OHS) and EuroQol- 5 Dimension (EQ-5D-5 L) were documented. Three patients (3/40; 7.5 %) treated with steroids were diagnosed with femoral head osteonecrosis. None of the patients in the non-steroid-treated group developed osteonecrosis. There were no differences between the two groups regarding OHS and EQ-5D-5 L. Patients with osteonecrosis had higher ferritin levels, received higher doses of corticosteroids (median dose 2200 mg), and had longer hospitalization. COVID-19-related therapy with steroids resulted in lower prevalence of osteonecrosis than that previously recorded in patients with severe acute respiratory syndrome caused by coronavirus-type-1. However, this risk seems not negligible and therefore, high clinical suspicion for early diagnosis is warranted, given the fact that a great proportion of hospitalized patients received steroids during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Background: Femoral head avascular necrosis (AVN), or death of femoral head tissue due to a lack of blood supply, is a leading cause of total hip replacement for non-geriatric patients. Core decompression (CD) is an effective treatment to re-establish blood flow for patients with AVN. Techniques aimed at improving its efficacy are an area of active research. We propose the use of 3D printed drill guides to accurately guide therapeutic devices for CD. Methods: Using femur sawbones, image processing software, and 3D modeling software, we created a custom-built device with pre-determined drill trajectories and tested the feasibility of the 3D printed drill guides for CD. A fellowship trained orthopedic surgeon used the drill guide to position an 8 ga, 230 mm long decompression device in the three synthetic femurs. CT scans were taken of the sawbones with the drill guide and decompression device. CT scans were processed in the 3D modeling software. Descriptive statistics measuring the angular and needle-tip deviation were compared to the original virtually planned model. Results: Compared to the original 3D model, the trials had a mean displacement of 1.440 ± 1.03 mm and a mean angle deviation of 1.093 ± 0.749º. Conclusions: The drill guides were demonstrated to accurately guide the decompression device along its predetermined drill trajectory. Accuracy was assessed by comparing values to literature-reported values and considered AVN lesion size. This study demonstrates the potential use of 3D printing technology to improve the efficacy of CD techniques. [ABSTRACT FROM AUTHOR]

Background: The clinical potential of biologic augmentation in core decompression and bone grafting for femoral head necrosis is widely acknowledged, with platelet-rich plasma (PRP) being a frequently employed biologic adjunct. However, its clinical application is not standardized, and high-level evidence is lacking. This study aimed to evaluate the efficacy and safety of core decompression and bone grafting combined with PRP for femur head necrosis. Methods: Several databases were systematically retrieved for randomized controlled trials comparing core decompression and bone grafting combined with or without PRP. A systematic review and meta-analysis were conducted following the PRISMA 2020 and AMSTAR 2 guidelines. The study is registered with PROSPERO under the code CRD42022361007, and it is also listed in the research registry under the identification number reviewregistry1537. Results: Eleven studies with 642 participants (742 hips) were included. The pooled estimates revealed that when core decompression and bone grafting were combined with PRP, the Harris hip score (mean difference: 7.98; 95% CI: 5.77-10.20; P<0.001), visual analog scale (SMD: -0.68; 95% CI: -0.96 -- -0.40; P<0.001) and the pain component of Harris hip score (SMD: 8.4; 95% CI: 4.12-12.68; P<0.001), and reduction of radiographic progression [risk ratio (RR): 0.40; 95% CI: 0.27-0.59; P<0.001] were superior to core decompression and bone grafting alone. Fewer patients with treatment failure (RR: 0.27; 95% CI: 0.14-0.52; P<0.001) and higher good-to-excellent results (RR: 1.48; 95% CI: 1.17-1.86; P<0.001) were observed in treatment groups than control groups. Meanwhile, the pooled analysis substantiated the superior safety profile of PRP (RR: 0.29; 95% CI: 0.11-0.77; P=0.01). Conclusions: The combination of core decompression and bone grafting with PRP is superior to the approach without PRP, demonstrating enhanced effectiveness in terms of function, pain relief, and radiographic progression. Additionally, it results in lower rates of treatment failure and adverse events. However, further high-quality RCTs are needed to evaluate their effectiveness due to methodological and implementation limitations observed in the existing evidence. [ABSTRACT FROM AUTHOR]

Abstract Objective Testing an experimental model for ischemic necrosis of the femoral head in Legg-Calvé-Perthes disease by evaluating gait, imaging and morphohistology. Methods The operation was done in 11 piglets. Necrosis by cerclage in the right femoral neck was induced. Piglets were divided into group A, with 8 animals, euthanizing two in the 2nd, 4th, 6th, and 8th weeks, respectively; and group B, with 2 animals (sham), submitted to the surgical procedure without cerclage of the right femoral neck. The gait classification used was that of Etterlin. The frozen femurs were submitted to digital radiography and computed tomography. The height and width of the epiphysis and epiphysary coefficient were measured at study times. Light microscopy and immunohistochemistry with TGF-β1 were performed. Results One animal died of sepsis in Group A. In this group, claudication was observed in all animals. On digital radiography and computed tomography, bone sclerosis, enlargement of the right femoral neck, flattening, collapse, and fragmentation of the right femoral head were observed. All epiphysis height and epiphysary coefficient values of the right femoral head were lower than the contralateral ones, in which were observed chondrocytes disordered and separated by gaps. A reduction in TGF-β1 expression was observed at 2 and 6 weeks in the right femoral head and at eight in the left. In group B, there were no signs of necrosis and gait was normal. Conclusions The model presented reproduced macroscopic necrosis on digital radiography, computed tomography, and microscopy. Gait evaluation showed a good correlation with other ischemia findings. Level of EvidenceV. Diagnostic studies.

Exposure to tobacco smoke (TS) has been considered a risk factor for osteonecrosis of the femoral head (ONFH). Soluble epoxide hydrolase inhibitors (sEHIs) have been found to reduce inflammation and oxidative stress in a variety of pathologies. This study was designed to assess the effect of sEHI on the development of ONFH phenotypes induced by TS exposure in spontaneously hypertensive (SH) rats. SH and normotensive Wistar Kyoto (WKY) rats were exposed to filtered air (FA) or TS (80 mg/m3 particulate concentration) 6 h/day, 3 days/week for 8 weeks. During this period, sEHI was delivered through drinking water at a concentration of 6 mg/L. Histology, immunohistochemistry, and micro-CT morphometry were performed for phenotypic evaluation. As results, TS exposure induced significant increases in adipocyte area, bone specific surface (BS/BV), and trabecular separation (Tb.SP), as well as significant decreases in bone mineral density (BMD), percent trabecular area (Tb.Ar), HIF-1a expression, bone volume fraction (BV/TV), trabecular numbers (Tb.N), and trabecular thickness (Tb.Th) in both SH and WKY rats. However, the protective effects of sEHI were mainly observed in TS-exposed SH rats, specifically in the density of osteocytes, BMD, Tb.Ar, HIF-1a expression, BV/TV, BS/BV, Tb.N, and Tb.SP. Our study confirms that TS exposure can induce ONFH especially in SH rats, and suggests that sEHI therapy may protect against TS exposure-induced osteonecrotic changes in the femoral head.

Background Steroid-induced osteonecrosis of the femoral head (SONFH) is common and disabling. The efficacy of Huoxue Tongluo Capsule has been consistently demonstrated in the prevention and treatment of osteonecrosis of the femoral head, but there is no research on whether the treatment can be carried out by regulating the intestinal flora. Objective To establish SONFH rat model intervened by Huoxue Tongluo Capsule, analyze and compare the diversity of intestinal flora in each group of rats, screen out SONFH-specific altered bacterial genera and observe the effect of Huoxue Tongluo Capsule on intestinal flora. Methods 24 male SD rats were selected from April to October 2022 and divided into the blank group (n=8), model group (n=8) and Huoxue Tongluo group (n=8) by random number table method. The SONFH model was prepared. The Huoxue Tongluo group was given 0.63 g·kg-1·d-1 Huoxue Tongluo Capsule by gavage on the 3rd to 28th day of modeling. The blank group and model group were given an equal volume of 0.9% sodium chloride solution by gavage. After drug intervention, rat femurs were collected for HE staining and Micro-CT analysis. Rat feces were collected for 16S rDNA sequencing. α diversity analysis was used to evaluate species diversity, β diversity analysis was used to explore the similarity or dissimilarity of sample community composition, and linear discriminant analysis (LEfSe) was used to compare the differences of intestinal flora among the three groups. COG function was used to predict the intestinal flora function of the rats in the three groups. Results There were significant differences in the rate of empty bone lacunae among the three groups, and the rate of empty bone lacunae in the model group was higher than that in the blank group, while the rate of empty bone lacunae in the Huoxue Tongluo group was lower than that in the model group (P

Objective The number of primary hip arthroplasty (PHA) has increased sharply in recent years. Whether the epidemiological characteristics and trends of PHA have changed are unknown. This study aims to analyze the epidemiological characteristics and trends of those patients are urgent for public health institutions. Methods The data of patients who underwent PHA in five tertiary hospitals from January 2011 to December 2020 were retrospectively reviewed. A total of 21,898 patients were included, most of whom were aged 60–69 years (25.1% males and 31.5% females). According to the hospitalization date, the patients were divided into two groups (Group A and Group B). The patients admitted between January 2011 and December 2015 were designated as Group A (7862), and those admitted between January 2016 and December 2020 were designated as Group B (14036). The patient data of the two groups, including sex, age, disease causes, body mass index (BMI), comorbidities, surgical procedures, hospital stay duration, and hospitalization costs, were analyzed by Pearson chi‐Square test, Student t test or Mann–Whitney U test. Results More women were included in Group B than in Group A (58.5% vs 52.5%, P

Abstract Objectives Although osteonecrosis of the femoral head is a prevalent condition, its effects on gait parameters have not been thoroughly studied and are not well-established in the current literature. The primary aim of the present study is to describe gait in patients with a diagnosis of osteonecrosis. Methods This is a cross-sectional study. Nine patients diagnosed with osteonecrosis of the femoral head who were regularly followed-up at an outpatient clinic were selected for the present study and underwent gait analysis using Vicon Motion Capture Systems. Spatiotemporal data was obtained, and joint angles were calculated using an Euler angle coordinate system. Distal coordinate systems were used to calculate joint momentsand forceplatestoobtaingroundreactionforces. Results Patients with osteonecrosis presented with slower velocity (0.54 m/s ± 0.19) and smaller cadence (83.01 steps/min ± 13.23) than healthy patients. The pelvic obliquity range of motion was of 10.12° ± 3.03 and rotation was of 18.23° ± 9.17. The mean hip flexion was of 9.48° ± 3.40. Ground reaction forces showed reduced braking and propelling forces. Joint moments were reduced for flexion and adduction (0.42 Nm/kg ± 0.2 and 0.30 Nm/kg ± 0.11, respectively) but the abduction moment was increased (0.42 Nm/kg ± 0.18). Conclusions The present study showed that osteonecrosis of the femoral head presents compensatory gait mechanisms, with increased pelvic motion and decreased knee flexion to protect the hip joint. Decreased moments for hip flexion and adduction were also identified and muscle weakness for those groups may be correlated to the disease.

Background: Developmental dysplasia of the hip (DDH) is a common pediatric orthopedic condition. Closed reduction (CR) is the conservative treatment approach with high success rates for DDH. However, avascular necrosis (AVN) is a severe potential complication after this procedure. This study retrospectively assessed the potential risk factors for AVN occurrence after CR and Spica cast immobilization. Materials and Methods: In a retrospective observational study, 71 patients (89 hips) with DDH aged 6-24 months old undergoing CR were enrolled. All patients were followed up for 3 years, and their demographic data, initial Tönnis grade, pre-reduction procedures, abduction angle in the Spica cast, and the AVN presence (based on Bucholz and Ogden classification [3rd-4th class]) were documented. Results: Of 71 patients (89 hips) with a mean age of 12.5 ± 3.9 months, 13 patients (18 hips) developed AVN. The mean age of patients in the AVN and non-AVN groups was 14.3 ± 4.9 and 12.2 ± 3 months (P = 0.07); also, the mean abduction angle in patients with and without AVN was 51.86 ± 3.66 and 58.46 ± 3.91 (P < 0.001) in univariate analysis. The distribution of initial Tönnis grade, and previous conservative procedures, adductor tenotomies during the CR were comparable between the two groups (P > 0.05). We found age 12 months and 54° in abduction angle as the best cutoff values for differentiating AVN patients from non-AVN and the risk of experiencing AVN for patients older than 12 months was odds ratio (OR) =4.22 (P = 0.06) and patients with abduction angle greater than 54 was OR = 34.88 (P < 0.001). Conclusion: In this study, older age at the time of intervention and larger abduction angle in the hip Spica cast were two predictors of experiencing AVN in DDH patients after undergoing CR treatment approach. Performing CR at a younger age and keeping the abduction angle lower than 54° in the hip Spica cast could help to have the best possible prognosis. Level of Evidence: IV, retrospective, observational, cross-sectional study. [ABSTRACT FROM AUTHOR]

Introduction: Femur head necrosis (FHN) is a challenging clinical disease with unclear underlying mechanism, which pathologically is associated with disordered metabolism. However, the disordered metabolism in cancellous bone of FHN was never analyzed by gas chromatography-mass spectrometry (GC-MS). Objectives: To elucidate altered metabolism pathways in FHN and identify putative biomarkers for the detection of FHN. Methods: We recruited 26 patients with femur head necrosis and 22 patients with femur neck fracture in this study. Cancellous bone tissues from the femoral heads were collected after the surgery and were analyzed by GC-MS based untargeted metabolomics approach. The resulting data were analyzed via uni- and multivariate statistical approaches. The changed metabolites were used for the pathway analysis and potential biomarker identification. Results: Thirty-seven metabolites distinctly changed in FHN group were identified. Among them, 32 metabolites were upregulated and 5 were downregulated in FHN. The pathway analysis showed that linoleic acid metabolism were the most relevant to FHN pathology. On the basis of metabolites network, L-lysine, L-glutamine and L-serine were deemed as the junctions of the whole metabolites. Finally, 9,12-octadecadienoic acid, inosine, L-proline and octadecanoic acid were considered as the potential biomarkers of FHN. Conclusion: This study provides a new insight into the pathogenesis of FHN and confirms linoleic acid metabolism as the core. [ABSTRACT FROM AUTHOR]

Osteonecrosis of the femoral head (ONFH), a condition characterized by the presence of a necrotic bone lesion in the femoral head, is caused by a disruption in the blood supply. Its occurrence is more common in young and middle-aged adults and it is the main reason for performance of total hip arthroplasty in this age group. Its incidence is increasing along with increased use of glucocorticoids for management of adjuvant therapy for treatment of leukemia as well as organ transplantation and other myelogenous diseases. Current information on etiology and pathogenesis, as well as natural history, stage system, and treatments is provided in this review. A description of the Association Research Circulation Osseous (ARCO) criteria for classification of glucocorticoids- and alcohol-associated ONFH, 2019 ARCO staging system, and 2021 ARCO classification using computed tomography for the early stages of ONFH is also provided. [ABSTRACT FROM AUTHOR]

Objective: The number of primary hip arthroplasty (PHA) has increased sharply in recent years. Whether the epidemiological characteristics and trends of PHA have changed are unknown. This study aims to analyze the epidemiological characteristics and trends of those patients are urgent for public health institutions. Methods: The data of patients who underwent PHA in five tertiary hospitals from January 2011 to December 2020 were retrospectively reviewed. A total of 21,898 patients were included, most of whom were aged 60–69 years (25.1% males and 31.5% females). According to the hospitalization date, the patients were divided into two groups (Group A and Group B). The patients admitted between January 2011 and December 2015 were designated as Group A (7862), and those admitted between January 2016 and December 2020 were designated as Group B (14036). The patient data of the two groups, including sex, age, disease causes, body mass index (BMI), comorbidities, surgical procedures, hospital stay duration, and hospitalization costs, were analyzed by Pearson chi‐Square test, Student t test or Mann–Whitney U test. Results: More women were included in Group B than in Group A (58.5% vs 52.5%, P < 0.001). The mean age of Group B was less than that of Group A (62.27 ± 14.77 vs 60.69 ± 14.44 years, P < 0.001). Femoral head necrosis was the primary pathogenic factor in both groups, with a higher proportion in Group B than in Group A (55.5% vs 45.5%, P < 0.001). Significant differences were found between the two groups in BMI, comorbidities, surgical procedures, hospital stay duration, and hospitalization costs. Total hip arthroplasty (THA) was the most common surgical procedure in both groups, with a higher proportion in Group B than in Group A (89.8% vs 79.3%, P < 0.001). The proportion of patients with one or more comorbidities was significantly higher in Group B than in Group A (69.2% vs 59.9%, P < 0.001). In addition, Group B had a shorter hospital stay duration and higher hospitalization costs than Group A. Conclusion: Femoral head necrosis was the primary etiology for PHA in this study, followed by femoral neck fracture and hip osteoarthritis. Patients who underwent PHA exhibited a higher percentage of femoral head necrosis; underwent THA more often; and had larger BMIs, more comorbidities, higher medical costs, and younger age in the past decade. [ABSTRACT FROM AUTHOR]

The bone impaction grafting through femoral head–neck fenestration was a favorable hip preservation procedure but without prognosis estimation. This study retrospectively reviewed 79 patients' clinical data (114 hips) with osteonecrosis of the femoral head (ONFH) who underwent this procedure from June 2009 to June 2019. By the end of June 2022, the median survival time of the hip was (74.13 ± 44.88) months, and the success rate of hip preservation was 68.42%. Lateral reserved angle (LPA) and combined reserved angle (CPA) had statistically significant differences (P  < 0.001) both in univariate analysis and a multivariate logistic regression model. The multivariate logistic regression model of area under curve (AUC) area of the receiver operating characteristic (ROC) curve was 0.931(sensitivity = 95.00%, specificity = 88.40%, log-rank test: P  < 0.01), and the calibration curve indicated good prediction accuracy. The ROC analysis and Cox proportional hazards regression model revealed that the cutoff point of LPA was 50.95° (sensitivity = 95.00%, specificity = 72.09%, log-rank test: P  < 0.05) and the cutoff point of CPA was 90.51° (sensitivity = 90.00%, specificity = 90.70%, log-rank test: P  < 0.05). A nomogram plot to predict the risk of failure (C-index = 0.873, 95% CI: 0.785 to 0.961) and nomograms for predicting the survival probability at 1, 2 or 3 years whose calibration curves showed excellent prediction accuracy were available for the clinician. Preserved angles (PAs) are valuable in the prediction of prognosis in surgical treatment. The bone impaction grafting through femoral head–neck fenestration can achieve better clinical efficacy, especially for patients with LPA >50.95° and CPA >90.51°. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the clinical results of the modified Codivilla–Hey Groves–Colonna capsular arthroplasty in the treatment of young patients with developmental dislocation of the hip. We retrospectively evaluated 90 patients (92 hips) who underwent the modified capsular arthroplasty from June 2012 to June 2021. Hips were evaluated using the modified hip Harris score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the 12-item International Hip Outcome Tool (iHOT-12). The Tönnis osteoarthritis grade and the Severin classification system were used to assess the radiographic outcomes. The average age was 15.7 years (range: 8–26 years). The mean pre-operative mHHS, the WOMAC score and the iHOT-12 score were 83.03, 14.05 and 52.79, respectively. The patients were followed for a mean of 41.1 months (range: 12.1–120.9 months). The patients had a mean mHHS of 83.61 (range: 31.2–97), a WOMAC score of 16.41 (range: 0–51) and an iHOT-12 score of 64.81 (range: 12.9–98.2) at the final follow-up. Capsular thickness had a positive predication on the final functional outcomes. The excellent/good rate of radiological reduction was 79.3%. More than 60% of patients had no/slight osteoarthritis. A total of 54 hips (58.7%) had superior radiographic outcomes. The risk factors for inferior radiographic outcomes were capsular quality (odds ratio [OR]: 0.358, 95% confidence interval [CI]: 0.113–0.931) and capsular thickness (OR: 0.265, 95% CI: 0.134–0.525). Joint stiffness was the most common complication (14.1%). We confirmed the efficacy of this procedure in the treatment of developmental hip dislocation. Patients with poor capsular quality are not suitable for this procedure. With suitable selection according to indications, this procedure can restore the hip rotation center with a low incidence of femoral head necrosis or severe osteoarthritis. [ABSTRACT FROM AUTHOR]

Developmental hip dysplasia(DDH)is one of the most common extremity deformities in children.Early screening and timely diagnosis are essential in the treatment of DDH.Delayed or improper interventions lead to serious consequences.Avascular necrosis(AVN)of the femoral head is the most serious and common complication after closed reduction of DDH.Practical difficulty of preventing and avoiding the occurrence of AVN has always perplexed pediatric orthopedic surgeons.The existence of ossification nucleus before closed reduction seems to be helpful to reduce the incidence of AVN.Waiting for the appearance of ossification nucleus means postponing treatment.Balancing the occurrence of AVN and the concept of early diagnosis and treatment of DDH are particularly important.This review summarized the relevant literature to further explore whether the existence of ossification nucleus before closed reduction affects the occurrence of AVN and discussed the influence of ossification nucleus on the timing of clinical treatment. [ABSTRACT FROM AUTHOR]

Abstract Objective The present study analyzed the incidence of epiphyseal avascular necrosis in patients with slipped capital femoral epiphysis (SCFE) treated using a modified Dunn technique. In addition, this study determined the correlation of other variables with this incidence and described treatment complications. Methods This is a retrospective study with 20 patients treated by the same surgical team from 2009 to 2019 and followed up for 2 to 12 years. The analysis included general features, time from presentation to surgical procedure, classification, and intraoperative blood perfusion of the epiphysis, as well as complications and their treatment. Results All cases were severe; 65% were acute on chronic, and 55% of the SCFEs were unstable. Our complication rate was 45%, with 5 cases of avascular necrosis, 2 cases of deep infection, 1 case of material failure, and 1 case of joint instability. The statistical analysis revealed that the risk of necrosis was higher when the surgery occurred after a long hospitalization time and there was no intraoperative epiphyseal perfusion. Four necrosis cases happened within the first 5 years, and 1 case in the last 5 years of the study. Conclusion Our study showed that necrosis was the most common complication. It also revealed that surgery delay and lack of intraoperative epiphysis perfusion potentially predispose to avascular necrosis. Although with no statistical significance, coxofemoral instability occurred in chronic SCFE, and surgical fixation with threaded wires was less effective than fixation with a cannulated screw. The modified Dunn procedure should be reserved for severe cases in which other techniques are not feasible and performed by an experienced, trained, and qualified team.

The etiology and mechanism of steroid-induced osteonecrosis of femoral head (SONFH) have not been fully elucidated, and effective treatments have not yet emerged. With the application of stem cell therapy technology in various disciplines, the nature and function of stem cells have been extensively studied and applied in the treatment of SONFH. However, stem cell transplantation alone is not effective, and its efficacy can be enhanced by pretransplantation modification. This paper reviews the research progress of bone marrow mesenchymal stem cells in the treatment of SONFH. [ABSTRACT FROM AUTHOR]

Femur head necrosis (FHN), also known as bacterial chondronecrosis with osteomyelitis (BCO), has remained an animal welfare and production concern for modern broilers regardless of efforts to select against it in primary breeder flocks. Characterized by the bacterial infection of weak bone, FHN has been found in birds without clinical lameness and remains only detectable via necropsy. This presents an opportunity to utilize untargeted metabolomics to elucidate potential non-invasive biomarkers and key causative pathways involved in FHN pathology. The current study used ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC–HRMS) and identified a total of 152 metabolites. Mean intensity differences at p < 0.05 were found in 44 metabolites, with 3 significantly down-regulated and 41 up-regulated in FHN-affected bone. Multivariate analysis and a partial least squares discriminant analysis (PLS-DA) scores plot showed the distinct clustering of metabolite profiles from FHN-affected vs. normal bone. Biologically related molecular networks were predicted using an ingenuity pathway analysis (IPA) knowledge base. Using a fold-change cut off of −1.5 and 1.5, top canonical pathways, networks, diseases, molecular functions, and upstream regulators were generated using the 44 differentially abundant metabolites. The results showed the metabolites NAD+, NADP+, and NADH to be downregulated, while 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) and histamine were significantly increased in FHN. Ascorbate recycling and purine nucleotides degradation were the top canonical pathways, indicating the potential dysregulation of redox homeostasis and osteogenesis. Lipid metabolism and cellular growth and proliferation were some of the top molecular functions predicted based on the metabolite profile in FHN-affected bone. Network analysis showed significant overlap across metabolites and predicted upstream and downstream complexes, including AMP-activated protein kinase (AMPK), insulin, collagen type IV, mitochondrial complex, c-Jun N-terminal kinase (Jnk), extracellular signal-regulated kinase (ERK), and 3β-hydroxysteroid dehydrogenase (3β HSD). The qPCR analysis of relevant factors showed a significant decrease in AMPKα2 mRNA expression in FHN-affected bone, supporting the predicted downregulation found in the IPA network analysis. Taken as a whole, these results demonstrate a shift in energy production, bone homeostasis, and bone cell differentiation that is distinct in FHN-affected bone, with implications for how metabolites drive the pathology of FHN. [ABSTRACT FROM AUTHOR]

Introduction While the COVID-19 pandemic may still be ongoing, we have simultaneously entered into the post-acute phase of COVID-19, which comes with its own challenges. This case series reports 11 patients of COVID-19 treated with corticosteroids who subsequently developed osteonecrosis of the femoral head (ONFH). Methods All consecutive patients diagnosed on MRI with ONFH from August 2020 to May 2021 and were retrospectively COVID-19 positive were included. The treatment administered for COVID-19 was retrieved and evaluated. The patients were managed for femoral head necrosis, and results were reported. Results Overall, 11 patients developed ONFH in a total of 16 hips. The severity of femoral head necrosis depended on the dose of corticosteroid administered during COVID-19. A high dose for a longer duration resulted in a higher ONFH stage (FICAT & Arlet ). Hips in the lower grade were treated conservatively, and in the higher grade were treated surgically. The follow-up scores of patients demonstrated steady improvement. Conclusions High suspicion of femoral head necrosis has to be considered in patients treated with corticosteroids for COVID-19 as it can aid in early detection and early intervention to preserve the native femoral head.

Objective: To assess the frequency of collapse-related bone changes at multi-detector CT (MDCT) in osteonecrotic femoral heads (ONFH) and to compare clinical parameters and MRI findings in Association Research Circulation Osseous (ARCO) 1–2 ONFH with or without collapse-related bone changes (CRBC) at MDCT. Materials and methods: This is a secondary analysis of radiographic, MRI, and MDCT examinations of ONFH of patients eligible for a prospective clinical trial. Radiographs and MRI were analyzed to perform ARCO staging. Frequency of CRBC at MDCT including cortical interruption, trabecular interruption, impaction, and resorption was determined by two readers (R1, R2) blinded to radiographic, MRI, and clinical data. Baseline clinical and imaging data of ARCO 1–2 ONFH were compared between hips with or without CRBC at MDCT. Results: One hundred thirty-two hips of 77 participants were analyzed. There were 78 non-collapsed and 54 collapsed ONFH. For R1 and R2, 31/78 (40%) and 20/78 (26%) ARCO 1–2 ONFH and 54/54 (100%) and 53/54 (98%) ARCO 3–4 ONFH showed at least one CRBC at MDCT. For both readers, there was no significant difference in pain, functional impairment, size of lesion, and the presence of BME on MRI between ARCO 1–2 hips with or without CRBC at MDCT. Conclusion: Twenty-six to forty percent of ARCO 1–2 ONFH demonstrate at least one collapse-related bone change at CT. Their clinical and MRI findings do not differ from those without collapse-related bone changes. Key Points: • Ninety-eight to one hundred percent of collapsed and 26–40% of non-collapsed osteonecrotic femoral heads presented at least one collapse-related bone change at CT (cortical or trabecular bone interruption, trabecular bone impaction, or resorption). • There was no significant difference in age, sex, pain, functional impairment, size of lesion, or frequency of marrow edema on MRI between non-collapsed hips with or without collapse-related bone changes at CT. • The significance of collapse-related bone changes at CT should be further assessed. [ABSTRACT FROM AUTHOR]

Objective To explore the clinical value of serum progranulin (PGRN) in non-traumatic osteonecrosis of femoral head (NONFH). Methods A total of 75 patients with NONFH were selected as the NONFH group, and 67 healthy individuals matched for sex and age were selected as the healthy group. Serum PGRN concentration was detected by enzymelinked immunosorbent assay. The visual analogue scale (VAS) and Harris score were used to evaluate the hip joint pain and function. The general data and imaging results were compared between the two groups. The serum PGRN levels of NONFH patients with different clinical characteristics were compared. The correlation between PGRN and clinical indicators was analyzed. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of serum PGRN level in NONFH. Results The level of serum PGRN was significantly higher in the NONFH group than that in the healthy group (P＜0.05). There was no significant difference in PGRN levels between NONFH patients with different etiologies. The level of PGRN was significantly higher in NONFH patients with bilateral necrosis than that in patients with unilateral necrosis, and the level of PGRN was significantly higher in NONFH patients with femoral head collapse than that in patients without collapse (P＜0.05). The level of serum PGRN was positively correlated with ARCO stage (rs=0.645) and VAS score of pain (r=0.694), but negatively correlated with Harris score (r=-0.732, P＜0.01). ROC curve results showed that the area under the curve of PGRN for the diagnosis of NONFH was 0.786 (95%CI: 0.710-0.862, P＜0.01), the optimal cut-off value was 14.55 µg/L, the sensitivity was 0.640 and the specificity was 0.910. Conclusion Serum PGRN level can reflect the severity of NONFH and has certain value in the diagnosis of NONFH. [ABSTRACT FROM AUTHOR]

Introduction. Osteonecrosis (ON) of the femoral head (FH) – (ONFH) is an intractable disease that causes progressive femoral head collapse, severe pain, and gait disturbance. We report a case of avascular necrosis of the femoral head following an occult femoral neck (FN) stress fracture. Case report. A 55-year-old woman presented to our department with a chief complaint of low back pain that radiated into the left anterolateral thigh over the period of two months. Her left anterolateral thigh became progressively more painful over the past two weeks. No abnormal findings indicative of ONFH or an occult fracture of the FN were detected by X-ray or computed tomography, but an occult insufficiency fracture of the left FN was identified on magnetic resonance imaging (MRI). The diagnosis of FN stress fracture was delayed, resulting in femoral head necrosis. The fracture was treated with total hip arthroplasty, and the resected FH was subjected to histopathology (HP). Based on the HP findings, the final diagnosis of this case was ONFH with an occult fracture of the left FN. Clinical symptoms were relieved postoperatively. Conclusion. An early MRI examination is recommended in patients presenting with a suspected stress fracture of the FN to avoid FH necrosis due to a delayed diagnosis.

BackgroundNontraumatic osteonecrosis of the femoral head (ONFH) can be corticosteroid-induced, alcohol-induced, and idiopathic ONFH (IONFH). Although corticosteroid- and alcohol-induced ONFH has been investigated extensively regarding its relationship with blood lipids and coagulation factor levels. However, the effect of blood lipid metabolism and coagulation function on IONFH has rarely been studied. Therefore, this study aimed to analyse the relationship of IONFH with blood lipid and coagulation indicators.MethodsTotal 680 patients diagnosed with IONFH in our institution during January 2011–June 2019 who met the inclusion criteria composed the case group; 613 healthy persons who underwent physical examination at our institution during the same period composed the control group. Propensity scores were used for baseline feature matching, and two matching groups each with 450 patients were established. After the matching, blood lipid and coagulation factor levels of both groups were comparatively analysed.ResultsThe case group showed significantly higher total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) levels, low-density/high-density lipoprotein (LDL/HDL) ratio, and apolipoprotein B (Apo-B) levels than the control group (p 0.05). Furthermore, fibrinogen (FIB) levels and thrombin time (TT) in the case group were higher than those in the control group. There were significant differences between the two groups only in terms of FIB levels (p 0.05).ConclusionsIONFH has strong associations with blood lipid metabolism and coagulation function, which provide an avenue for exploring the mechanism of IONFH.

Objective: Unusual or unexpected effect of treatment Background: Arthrogryposis is a congenital condition of multiple contractures of joints associated with hip dislocation. The outcome of open reduction of hip dislocation in arthrogryposis patients is debatable. Open reduction of arthrogryposis is challenging for shallow acetabulum and extensive adhesions and fibrosis. For this reason, a careful extensive release must be carried out to achieve the open reduction of the hip in arthrogryposis patients. The literature lacks surgical recommendations for open reduction of the hip in arthrogryposis patients and how to deal with cases of the extruded bone segment during open reduction. Case Report: The patient presented in the first few weeks of life with bilateral clubfoot and left hip dislocation. Clinical diagnosis of arthrogryposis was made after referral to a genetics specialist. The hip was clinically irreducible. The patient underwent open reduction and femoral shortening using the Smith Peterson approach at the age of 15 months, with accidental extrusion of the proximal femur, which was retained immediately. The clinical outcome showed a painless, good range of motion. Radiographically, features of avascular necrosis and healed osteotomy site were evident. Conclusions: A difficult hip reduction was expected in this arthrogryposis patient, which required careful dissection of surrounding fibrosis and appropriate femoral shortening. Careful dissection should be carried out during open reduction to avoid jeopardization of femoral head vascularity or even complete devitalization of the proximal femur. [ABSTRACT FROM AUTHOR]

Osteonecrosis of the femoral head is a recalcitrant and paralyzing disease often discovered in the end stage at the time of diagnosis, which is often performed by physical examination and diagnostic imaging. Osteonecrosis of the femoral head is typically caused by trauma or long-term steroid use. There are over 30 million patients in the US taking steroids, and roughly 40% will develop osteonecrosis of the femoral head. However, the exact pathophysiological process is not well understood. This study aims to examine the alteration in serum glycosylation of osteonecrosis of the femoral head using the state-of-the-art analytical tools to provide more chemical data for pathophysiology research and possibly biomarker discovery. A training set containing 27 serum samples from steroid-induced osteonecrosis of the femoral head patients and 25 from gender- and age-matched controls was collected and analyzed. Glycosylation of whole serum and site-specific glycosylation of immunoglobulins are characterized using electrospray ionization-Q-time of flight and electrospray ionization-Triple-Quadruple via multiple reaction monitoring, respectively. The whole serum glycosylation analysis yielded 14 N-glycan compositions and multiple reaction monitoring yielded eight glycopeptides that were altered between cases and controls with statistical significance. The increase of nonsialylated, nonfucosylated N-glycans and decrease of fucosylated N-glycans are associated with the development of osteonecrosis of the femoral head. Glycosylation is a posttranslational protein modification and is apparently affected by osteonecrosis of the femoral head. Future studies with a larger cohort and patients from earlier stage will be performed to assess these potential markers' value in disease onset.

The purpose of the study is to evaluate the feasibility of blood oxygenation level-dependent MRI (BOLD-MRI) to early detect the femoral head osteonecrosis (FHON). One hundred twelve patients were recruited who had received steroid treatment. The normal control group included 10 volunteers with 20 hips. MRI examinations were performed in all patients following up at 1, 4 to 5, 7 to 8, and 12 to 13 months after steroid therapy. With the section cross as the biggest lesion in coronal images, we set 6 regions of interest (ROIs) per section to analyze the morphological performance of routine MRI sequences and the differences of R2* values and their dynamic changes of BOLD-MRI between the control and the FHON group. A total of 15 hip joints were diagnosed with FHON. Seven right hips and 8 left hips were affected. In the first and second MRI examinations, the area of the lesion for both conventional MRI and BOLD-MRI R2* mapping was difficult to distinguish the lesion border. However, at the third and the fourth MRI examinations, some of the affected regions for R2* mapping were larger than those in conventional sequences for the same patient. BOLD-MRI has some significant advantages in early detecting FHON over conventional MRI techniques and it can be feasible noninvasive tool for detecting and evaluating FHON after steroid therapy.

BACKGROUND: Femoral head fractures are uncommon injuries. Small series constitute the majority of the available literature. Surgical approach and fracture management is variable. The purpose of this study was to evaluate the incidence, method of treatment, and outcomes of consecutive femoral head fractures at a regional academic Level I trauma center. MATERIALS AND METHODS: A retrospective review of a prospective database was performed over a 13-year period. All AO/OTA 31C femoral head fractures were identified. A surgical approach and fixation method was recorded. Clinical and radiographic evaluation was performed for patients with 6 months or greater follow-up. Radiographs were evaluated for fixation failure, heterotopic ossification (HO), avascular necrosis (AVN) and post-traumatic arthritis. RESULTS: We identified 164 fractures in 163 patients; 147 fractures were available for review. Treatment was operative reduction and internal fixation (ORIF) in 78 (53.1%), fragment excision in 37 (25.1%) and non-operative in 28 (19%). An anterior approach and mini-fragment screws were used in the majority of patients treated with fixation. Sixty-nine fractures had follow-up greater than 6 months. Sixty-two fractures (89.9%) proceeded to uneventful union. All Pipkin III fractures failed operative fixation. Six patients developed AVN, seven patients had a known conversion to hip arthroplasty; HO developed in 28 (40.6%) patients and rarely required excision. CONCLUSIONS: Fractures of the femoral head are rare. An anterior approach can be used for fragment excision or fixation using mini-fragment screws. Pipkin III fractures represent catastrophic injuries. Non-bridging, asymptomatic HO is common. AVN and posttraumatic degenerative disease of the hip occur but are uncommon. LEVEL OF EVIDENCE: IV-prognostic.

BackgroundFemoral head fractures are uncommon injuries. Small series constitute the majority of the available literature. Surgical approach and fracture management is variable. The purpose of this study was to evaluate the incidence, method of treatment, and outcomes of consecutive femoral head fractures at a regional academic Level I trauma center.Materials and methodsA retrospective review of a prospective database was performed over a 13-year period. All AO/OTA 31C femoral head fractures were identified. A surgical approach and fixation method was recorded. Clinical and radiographic evaluation was performed for patients with 6 months or greater follow-up. Radiographs were evaluated for fixation failure, heterotopic ossification (HO), avascular necrosis (AVN) and post-traumatic arthritis.ResultsWe identified 164 fractures in 163 patients; 147 fractures were available for review. Treatment was operative reduction and internal fixation (ORIF) in 78 (53.1%), fragment excision in 37 (25.1%) and non-operative in 28 (19%). An anterior approach and mini-fragment screws were used in the majority of patients treated with fixation. Sixty-nine fractures had follow-up greater than 6 months. Sixty-two fractures (89.9%) proceeded to uneventful union. All Pipkin III fractures failed operative fixation. Six patients developed AVN, seven patients had a known conversion to hip arthroplasty; HO developed in 28 (40.6%) patients and rarely required excision.ConclusionsFractures of the femoral head are rare. An anterior approach can be used for fragment excision or fixation using mini-fragment screws. Pipkin III fractures represent catastrophic injuries. Non-bridging, asymptomatic HO is common. AVN and posttraumatic degenerative disease of the hip occur but are uncommon.Level of evidenceIV-prognostic.

Introduction: The risk of adverse events, specifically avascular necrosis (AVN), associated with corticosteroid use is not well reported. The aim of this study was to evaluate the prevalence of AVN among patients with prior oral corticosteroid administration. Methods: An institutional database query recognized 113,734 adult patients with oral corticosteroid administration between January 2006 and May 2017. A temporal query performed on this cohort determined that 789 had a diagnosis of AVN following oral corticosteroids. A retrospective review was performed on this cohort. Data collected included demographics, comorbidities, date of initial oral corticosteroid exposure, and time to diagnosis of AVN. Records without radiographic confirmation of AVN were excluded from analysis. Patients with cumulative lifetime dosages greater than 10,000 mg prednisone were excluded from analysis. Results: A total of 789 patients with oral corticosteroid use prior to diagnosis of AVN were identified. Five hundred and seventy‐two patients were excluded due to insufficient documentation of oral corticosteroid dosage, no radiographic evidence supporting the diagnosis of AVN, insufficient data confirming the temporal relationship between oral corticosteroids and AVN, and/or a cumulative dosing of >10,000 mg prednisone. This left 217 patients included in the analysis. The mean duration of use prior to diagnosis of AVN was 219 (± 374) days, and mean cumulative dose was 3314 (± 2908) mg prednisone equivalents. Mean time between diagnosis of AVN and onset of pathologic fracture was 379 (± 1046) days. Conclusion: For patients receiving low cumulative doses of oral corticosteroids, corticosteroids pose a small risk of development of AVN. More studies are required to better characterize risk. [ABSTRACT FROM AUTHOR]