Temporal Trends in Characteristics of Newly Diagnosed Nontraumatic Osteonecrosis of the Femoral Head From 1997 to 2011: A Hospital-Based Sentinel Monitoring System in Japan

Risk factors and prediction model for osteonecrosis of the femoral head in female systemic lupus erythematosus

Background

Osteonecrosis of the femoral head (ONFH) is a severe complication of systemic lupus erythematosus (SLE) and occurs more frequently in SLE patients than in other autoimmune diseases, which can influence patients' life quality. The objective of this research was to analyze risk factors for the occurrence of ONFH in female SLE patients, construct and validate a risk nomogram model.

Methods

Clinical records of SLE patients who fulfilled the 1997 American College of Rheumatology SLE classification criteria were retrospectively analyzed. The Least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression analysis were used to summarize the independent risk factors of ONFH in female SLE patients, which were used to develop a nomogram. The predictive performance of the nomogram was assessed using the receiver characteristic (ROC) curve, calibration curves and decision curve analysis (DCA).

Results

793 female SLE patients were ultimately included in this study, of which 87 patients (10.9%) developed ONFH. Ten independent risk factors including disease duration, respiratory involvement, menstrual abnormalities, Sjögren's syndrome, osteoporosis, anti-RNP, mycophenolate mofetil, cyclophosphamide, biologics, and the largest daily glucocorticoid (GC) were identified to construct the nomogram. The area under the ROC curve of the nomogram model was 0.826 (95% CI: 0.780-0.872) and its calibration for forecasting the occurrence of ONFH was good (χ2 = 5.589, P = 0.693). DCA showed that the use of nomogram prediction model had certain application in clinical practice when the threshold was 0.05 to 0.95. In subgroup analysis, we found that the risk of ONFH was significantly increased in age at SLE onset of ≤ 50 years old, largest daily GC dose of ≥50 mg and the therapy of GC combined with immunosuppressant patients with menstrual abnormalities.

Conclusion

Menstrual abnormalities were the first time reported for the risk factors of ONFH in female SLE patients, which remind that clinicians should pay more attention on female SLE patients with menstrual abnormalities and take early interventions to prevent or slow the progression of ONFH. Besides, the nomogram prediction model could provide an insightful and applicable tool for physicians to predict the risk of ONFH.

Corticosteroid-associated osteonecrosis of the femoral head in an 87-year-old patient following treatment for COVID-19-associated pneumonia: A case report

Coronavirus disease 2019 is known to cause severe acute respiratory syndrome, and serious cases need to be treated with corticosteroids. Herein, we report an 87-year-old woman who developed bilateral osteonecrosis of the femoral head after corticosteroid treatment for coronavirus disease 2019-related pneumonia. Sixteen months after treatment, she developed right hip pain without any evidence of trauma. A diagnosis of bilateral osteonecrosis of the femoral head was made based on sclerotic bands on plain radiographs and low-signal bands on T1-weighted magnetic resonance images. The patient underwent right total hip arthroplasty 4 months after symptom onset. Histological examination of the resected femoral head revealed pathological evidence of osteonecrosis. The postoperative course was good, and the patient can now walk unassisted. To the best of our knowledge, this is the first report of histologically proven osteonecrosis after corticosteroid therapy for coronavirus disease 2019-related disease.

Anti-sclerostin antibody therapy prevents post-ischemic osteonecrosis bone collapse via interleukin-6 association

Osteonecrosis of the femoral head (ONFH) is a debilitating condition characterized by subchondral bone necrosis, which frequently culminates in joint destruction. Although total hip arthroplasty is conventionally practiced to remediate ONFH, for patients under the age of 60, the outcomes can be suboptimal. Chronic inflammation, particularly that mediated by interleukin-6 (IL-6), has been conjectured to be a potential mechanism underlying the etiology of ONFH. This study aimed at exploring the interplay between IL-6, the canonical Wnt signaling pathway, and ONFH to provide insights for potential therapeutic interventions. Human ONFH specimens depicted an elevation in β-catenin expression in the transitional layer, while IL-6 levels were pronounced in the same region. Subsequently, mouse models of ischemic osteonecrosis were treated with an anti-sclerostin antibody to assess its effects on bone metabolism and cellular processes. Histological analysis revealed that the administration of anti-sclerostin antibodies effectuated early recovery from bone necrosis, reduced empty lacunae, and suppressed IL-6 expression. The treatment evidently initiated the activation of the Wnt/β-catenin signaling pathway, presenting a potential mechanism associated with IL-6-mediated inflammation. Furthermore, the antibody upregulated osteoblast formation, downregulated osteoclast formation, and increased bone volume. Micro-CT imaging demonstrated increased bone volume, prevented epiphyseal deformity, and improved compression strength. Therefore, this study yields significant findings, indicating the potency of anti-sclerostin antibodies in effectively modulating the Wnt/β-catenin pathway, associating with IL-6 expression, and preventing post-ONFH bone collapse. Additionally, this preclinical investigation in mouse models offers an avenue for prospective research on potential therapeutic interventions against human ONFH.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan

OBJECTIVES

This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity.

DESIGN

Retrospective observational study of a nationwide database.

SETTING

The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint.

PARTICIPANTS

This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018.

MAIN OUTCOME MEASURE

The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis.

RESULTS

The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years.

CONCLUSION

ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact.

TRIAL REGISTRATION NUMBER

Chiba University ID1049.

Treatment of non-traumatic avascular necrosis of the femoral head (Review)

Non-traumatic osteonecrosis of the femoral head is the main cause of disability in young individuals and incurs major health care expenditure. The lifestyle changes in recent years, especially increased use of hormones and alcohol consumption, has greatly increased the incidence of femoral head necrosis. The underlying causes and risk factors of osteonecrosis of the femoral head are increasingly being elucidated, which has led to the development of novel surgical and non-surgical treatment options. Although the main goal of any treatment method is prevention and delaying the progression of disease, there is no common consensus on the most suitable method of treatment. The present review discussed the latest developments in the etiology and treatment methods for femoral head necrosis.

Geographic distribution of the incidence of osteonecrosis of the femoral head in Japan and its relation to smoking prevalence

OBJECTIVES

Alcohol intake and smoking are modifiable lifestyle-related risk factors for osteonecrosis of the femoral head (ONFH). We investigated geographic differences in ONFH incidence in Japan and the correlation with alcohol intake and smoking to develop prevention strategies for ONFH in Japan.

METHODS

This ecological study was conducted in Japan primarily using the following data sources: nationwide epidemiological survey and national survey. We estimated the annual ONFH incidence and the prevalence of alcohol drinking and smoking in each prefecture. Prefectural incidence and prevalence were calculated by sex and age-standardization.

RESULTS

The mean annual ONFH incidence per 100,000 population was 3.08 in men and 1.63 in women, respectively. There was no significant correlation between ONFH incidence and the prevalence of any levels of alcohol intake, while smoking ≥20 cigarettes/day showed a significant and moderate correlation in men (r = 0.47, p = .01). This correlation remained significant after adjustment for the prevalence of any levels of alcohol intake (standardized partial regression coefficient = 0.47-0.49, p = .009-.01).

CONCLUSION

ONFH incidence is geographically variable in Japan, and this may be partly explained by the distribution of smoking prevalence. Smoking cessation may contribute to an effective decline in the overall ONFH incidence in Japan.

Geographical distribution of the associated factors of osteonecrosis of the femoral head, using the designated intractable disease database in Japan

OBJECTIVES

Osteonecrosis of the femoral head (ONFH) is a designated intractable disease (DID) in Japan. The Ministry of Health, Labour, and Welfare launched an online registry system for DIDs. We aimed to investigate the epidemiological characteristics of patients with ONFH using the DID database.

METHODS

Data of patients with ONFH registered in the DID database between January 2004 and December 2013 were extracted. The incidence of new cases and distributions of sex, age, and associated risk factors were investigated. The prevalence of the two categories, 'steroid-associated' and 'alcohol-associated' risk factors, was estimated for each prefecture.

RESULTS

New 15,049 cases of ONFH were investigated. The mean registration rate-corrected annual ONFH incidence per 100,000 individuals was 1.77. The male-to-female ratio was 1.33. Age distribution peaked in the 40s and 50s for male and 60s for female. The prevalence of steroid-associated ONFH was lower in males (28.6%) than in females (49.8%), while that of alcohol-associated ONFH was higher in males (47.2%) than in females (9.3%). No clear region was identified for the steroids. The incidence of alcohol-associated ONFH was significantly higher in Tokyo and Okinawa, regardless of sex.

CONCLUSIONS

Alcohol-associated ONFH incidence varies geographically across Japan, suggesting that it has regional characteristics.

Epidemiological study of osteonecrosis of the femoral head using the national registry of designated intractable diseases in Japan

OBJECTIVES

We aimed to investigate the epidemiological characteristics of osteonecrosis of the femoral head (ONFH) using the designated intractable diseases (DID) database in Japan.

METHODS

Data on patients who had received public subsidies for medical costs due to ONFH from 2012 to 2013 were extracted from the DID database. The incidence and prevalence of ONFH, distribution of gender, age, and the prevalence of associated risk factors were assessed. These epidemiological characteristics were compared with those of another nationwide ONFH survey conducted during a similar period.

RESULTS

Data on 3264 newly diagnosed patients (incident cases) and 20,042 patients registered until 2013 (prevalent cases) were evaluated. The corrected annual incidence and prevalence of ONFH per 100,000 were 3.0 and 18.2-19.2, respectively. The ratio of males to females was 1.4 in 2012 and 1.2 in 2013, respectively. Peak distribution was observed at ages 40s and 60s in males and females, respectively. The prevalence of the risk factors were steroid-associated: 39%, alcohol-associated: 30%, both: 4%, and none: 27%.

CONCLUSIONS

The DID database data showed a similar distribution of gender and age to that in other nationwide surveys but lower incidence and prevalence of ONFH. Sampling bias may affect the epidemiological characteristics of ONFH.

The efficacy of core decompression for steroid-associated osteonecrosis of the femoral head in rabbits

Although core decompression (CD) is often performed in the early stage of osteonecrosis of the femoral head (ONFH), the procedure does not always prevent subsequent deterioration and the effects of CD are not fully clarified. The aim of this study is to evaluate the efficacy of CD for steroid-associated ONFH in rabbits. Twelve male and 12 female New Zealand rabbits were injected intramuscularly 20 mg/kg of methylprednisolone once and were divided into the disease control and CD groups. In the disease control group, rabbits had no treatment and were euthanized at 12 weeks postinjection. In the CD group, rabbits underwent left femoral CD at 4 weeks postinjection and were euthanized 8 weeks postoperatively. The left femurs were collected to perform morphological, biomechanical, and histological analysis. Bone mineral density and bone volume fraction in the femoral head in the CD group were significantly higher than in the disease control group. However, no difference in the mechanical strength was observed between the two groups. Histological analysis showed that alkaline phosphatase and CD31 positive cells significantly increased in the males after CD treatment. The number of empty lacunae in the surrounding trabecular bone was significantly higher in the CD group. The current study indicated that CD improved the morphological properties, but did not improve the mechanical strength in the femoral head at early-stage ONFH. These data suggest the need for additional biological, mechanical strategies, and therapeutic windows to improve the outcome of early-stage steroid-associated ONFH.

Non-modifiable Risk Factors Associated with Avascular Necrosis in the US Military

INTRODUCTION

Often referred to as aseptic or osteonecrosis, avascular necrosis (AVN) typically affects people between 30 and 50 years of age. Given the substantial morbidity associated with AVN as well as overlapping age groups of both the military and average age at diagnosis for AVN, the military represents an ideal cohort for a large database study to elicit the incidence and epidemiology of AVN. The purpose of this study was to identify demographic risk factors in the United States military.

MATERIALS AND METHODS

First-time occurrences for ICD-9-CM codes for all types of AVN (head of humerus, head and neck of femur, medial femoral condyle, talus, and other bone) between 2004 and 2014 were queried in the Defense Medical Epidemiology Database. Multivariate data analysis was performed to obtain adjusted rate (adjusted for age, sex, race, rank, and branch of service).

RESULTS

Between 2005 and 2014, 2,671 cases of AVN occurred among an at-risk population of 13,820,906 servicemembers for an unadjusted IR of 0.19 per 1,000 person-years. The most common location was located at the proximal femur, responsible for 41.7% of all cases. With an adjusted rate ratio of 18.7, the over 40 age-group accounted for 53.3% of cases. Servicemembers of black race, Senior rank, and the Army branch of service were more at risk for AVN.

CONCLUSIONS

The overall incidence of AVN was 0.19 per 1,000 person-years. Whilte increasing age had the greatest influence on the development of symptomatic AVN, other statistically significant risk factors were found to be increasing age, black race, senior enlisted rank, and Army branch of service.

Transitional changes in the incidence of hip osteonecrosis among renal transplant recipients

BACKGROUND

Immunosuppressive therapy for renal allograft recipients has changed substantially since the introduction of the anti-CD25 monoclonal antibody, basiliximab. We hypothesized that recent improvements in immunosuppressive treatment may reduce the incidence of osteonecrosis of the femoral head (ONFH). This study aimed to investigate transitional changes in the incidence of OFNH among renal transplant recipients by MRI.

METHODS

Participants comprised 110 patients who had undergone renal transplantation from 2003 to 2012, during which time basiliximab was in regular use at our institute (Recent group), and 232 patients who had undergone RT between 1986 and 2003 (Past group). We compared ONFH incidence between the two groups and evaluated risk factors for ONFH, including immunosuppressants (calcineurin inhibitors, basiliximab, and/or steroids) and postoperative renal function.

RESULTS

Incidence of ONFH was lower in the Recent group (0%) than in the Past group (3.4%; p = 0.043). In the Recent group, age was greater, ABO/human leukocyte antigen incompatibility was worse, while steroid dose was decreased and post-transplant renal function was improved. Cumulative methylprednisolone dose at postoperative week 2 and delayed graft function were identified as risk factors for ONFH.

CONCLUSION

Risk of ONFH after renal transplantation has fallen with the advent of regular use of basiliximab, although this agent does not appear to be a factor directly associated with the incidence of ONFH.

STUDY DESIGN

Clinical prognostic study (Level III case control study).

Surgery trends for osteonecrosis of the femoral head: a fifteen-year multi-centre study in Japan

PURPOSE

The most appropriate procedure and at what type and stage of osteonecrosis of the femoral head (ONFH) these procedures had been argued. We attempted to clarify the trend in surgical operations with respect to the age of patients, type classification, and stage of ONFH over a period of 15 years by using the multi-center sentinel monitoring system in Japan.

METHODS

We evaluated the hips of 3844 patients using this system in three phases of every five  years from 2003 to 2017. We classified the surgical procedures as osteotomy (OT), hemiarthroplasty (Hemi), and total hip arthroplasty (THA). We assessed the trend in age, type classification, and stage of ONFH over three time periods; "early," and the "late." We calculated the proportion of surgeries for ONFH in each period. We used the Cochran-Armitage test to evaluate trends in proportion of two levels of characteristics across three time periods.

RESULTS

The proportion of younger patients significantly decreased. The proportion of OT and Hemi decreased over time, while the proportion of THA increased. The proportion of patients with types C1 and C2 who underwent OT and Hemi decreased over time. In contrast, that of THA increased. The proportion of patients who underwent OT and Hemi significantly decreased; the proportion of patients who underwent THA significantly increased over time at all stages.

CONCLUSIONS

In Japan, the younger patients underwent surgery for ONFH decreased. The patients who underwent OT and Hemi for ONFH decreased, while that of THA increased over time.

The proton pump inhibitor, lansoprazole, prevents the development of non-traumatic osteonecrosis of the femoral head: an experimental and prospective clinical trial

Background

An effective prevention strategy for osteonecrosis of the femoral head (ONFH) has yet to be established. We previously reported that the innate immune system via the toll-like receptor (TLR) response induced by corticosteroids leads to the development of ONFH and that repression of IRF7 activity by an inhibitor could interfere with the development of ONFH while maintaining the therapeutic effect of the corticosteroids.

Objective

In the present study, we hypothesize that lansoprazole has the potential to suppress IRF7 activity and prevent corticosteroid-induced ONFH in rats. Furthermore, we conducted a preliminary clinical trial to prevent corticosteroid-induced ONFH in autoimmune disease patients.

Methods

Male Wistar rats were randomly divided into four groups. On Day 1, each rat was injected with TLR4 ligand (LPS) or TLR7 ligand (imiquimod), followed by methylprednisolone with or without lansoprazole on Day 2. They were killed at 1 or 14 days after the last injection.We prospectively recruited 30 patients requiring primary high-dose corticosteroid treatment for immune diseases. All patients were administered lansoprazole, starting the night before corticosteroid treatment began. MRI was performed before corticosteroid treatment, and at 4, 12 and 24 weeks afterward.

Results

In rats, co-treatment of lansoprazole with corticosteroids significantly repressed both IRF7 activity and the development of ONFH. Moreover, in the human patients, the incidence of ONFH was significantly decreased from 53.4 to 13.3%.

Conclusions

Although the present study is preliminary, the results show that co-treatment of lansoprazole with corticosteroids prevents ONFH development. Lansoprazole may be both safe and effective in preventing osteonecrosis of the femoral head in patients needing corticosteroid treatment.

LncRNA AWPPH participates in the development of non-traumatic osteonecrosis of femoral head by upregulating Runx2

AWPPH is a newly discovered long noncoding (lnc)RNA that plays an oncogenic role in development of several types of malignancies, whiles its involvement in non-traumatic osteonecrosis of femoral head (ONFH) is unknown. Therefore, the present study aimed to investigate the functionality of AWPPH in non-traumatic ONFH. Blood and mesenchymal stem cells (MSCs) were obtained from both non-traumatic ONFH patients and healthy controls, and expression of AWPPH in those tissues was detected by RT-qPCR. Receiver operating characteristic curve analysis was performed to investigate the diagnostic value of lncRNA AWPPH expression for non-traumatic ONFH. Bone morphogenic protein (BMP-2) was used to treat MSCs to induce osteogenic differentiation and the effects on lncRNA AWPPH expression was detected by RT-qPCR. LncRNA AWPPH overexpression and short hairpin (sh)RNA silencing cell lines were established and the effects on runt-related transcription factor 2 (Runx2) expression were detected by western blotting. It was demonstrated that AWPPH was significantly downregulated in non-traumatic ONFH patients compared with in healthy controls in both MSCs and serum. Expression of AWPPH in MSCs and serum is a sensitive diagnostic marker for non-traumatic ONFH. Expression of AWPPH exhibited no significant correlation with patients' age, gender and living habits, but was significantly correlated with course of disease. BMP-2 treatment significantly increased the expression level of AWPPH in human MSCs from bone marrow (hMSC-BM). AWPPH overexpression promoted, while AWPPH short hairpin RNA silencing inhibited the expression of Runx2 expression in hMSC-BM cells. Therefore, it was concluded that lncRNA AWPPH may participate in the development of ONFH by upregulating Runx2.

Serum Biomarkers Related to Glucocorticoid-Induced Osteonecrosis of the Femoral Head: A Prospective Nested Case-Control Study

Early diagnosis and prevention of glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) continues to be a challenging problem for clinicians and researchers. However, the role of circulating biomarkers for GC-induced ONFH, which may reveal individual susceptibility and facilitate earlier diagnosis, remains to be determined. The aim of this study was to identify potential biomarkers that may predict early GC-induced ONFH. A total of 123 patients scheduled for initial systemic GC therapy were enrolled in this prospective nested case-control study. The serum concentrations of 13 potential biomarkers were measured in seven patients with GC-induced ONFH, diagnosed instantly after short-term use of GCs and in 20 controls who did not develop osteonecrosis despite similar GC therapy. Biomarkers were measured both before and after taking GCs to identify any differences in marker levels and the changes during GC therapy between two groups. Type I collagen cross-linked C-telopeptide (β-CTX; p = 0.000) was significantly lower, high-density lipoprotein cholesterol (p = 0.092) and apolipoprotein (apo)-B/apo-A1 (p = 0.085) tended to be lower and higher, respectively, before GC treatment in osteonecrosis group. After GC therapy, β-CTX (p = 0.014) was significantly lower and amino terminal telopeptide of procollagen type I (PINP; p = 0.068) tended to be lower in the osteonecrosis group. As secondary outcomes, we observed remarkable changes in nine potential biomarkers following short-term GC therapy in both groups. In conclusion, we found that β-CTX, could potentially be used to predict GC-induced ONFH before GC therapy. Lower β-CTX and PINP are promising biomarkers for the early diagnosis of GC-induced ONFH. These findings need to be confirmed in large-scale prospective studies. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2348-2357, 2019.

Ten-year results of concentrated autologous bone marrow aspirate transplantation for osteonecrosis of the femoral head: a retrospective study

BACKGROUND

Idiopathic osteonecrosis of the femoral head (ONFH) occurs at a relatively younger age. It is therefore important to prevent the resultant femoral head collapse and requirement of total hip arthroplasty in these patients. In 2003, we initiated concentrated autologous bone marrow aspirate transplantation (CABMAT), a joint-preserving treatment for ONFH, at our institution. Here, we report the long-term results of CABMAT treatment.

METHODS

We retrospectively collated and analyzed the demographic and treatment data of 69 patients (109 hips) with idiopathic ONFH treated with CABMAT between April 2003 and April 2008.

RESULTS

Totally, 44 patients (21 men, 23 women, 80 hips) completed the 10-year follow-up. The follow-up rate was 73.4%, and the mean follow-up period was 12.0 (range, 10.0-15.4) years. The mean age of the patients was 42.2 (range, 16.3-70.5) years. Using the Association Research Circulation Osseous (ARCO) classification system for preoperative analysis, 12, 31, 32, and 5 hips were classified as stages 1, 2, 3, and 4, respectively. The overall rate of conversion to total hip arthroplasty (THA) was 34% (27/80 hips). In a multivariate regression analysis, the preoperative stage of ONFH and the body mass index were found to correlate significantly with conversion to THA. Totally, 43 hips (of 80) were classified as belonging to the pre-collapse stage (i.e., stages 1 or 2). The overall collapse rate and the THA-conversion rate of these hips were estimated to be 49% (21/43) and 14% (6/43), respectively.

CONCLUSIONS

On the basis of our long-term findings, the minimally invasive and feasible CABMAT therapy can be utilized as one of a joint-preserving treatment for ONFH.

Incidence of osteonecrosis and insufficiency fracture of the hip and knee joints based on MRI in 300 renal transplant patients

INTRODUCTION

The purpose of this study was to investigate the incidence of necrosis and insufficiency fracture of the hip and knee using magnetic resonance imaging (MRI) in renal transplant patients.

METHODS

We examined 300 consecutive renal transplant patients using MRI of the hips and knees (T1-weighted coronal MRI) preoperatively and at 3 and 6 months postoperatively. Oblique axial-plane T1-weighted MRI and short-tau inversion-recovery T2-weighted MRI were performed parallel to the femoral neck when distinguishing the osteonecrosis of the femoral head (ONFH) from subchondral insufficiency fracture (SIF) of the femoral head was difficult.

RESULTS

ONFH was observed in 3 hips (3 cases, 1.0%). Osteonecrosis of the knee was observed in 2 knees (1 case, 0.3%). SIF of the femoral head was observed in 5 hips (3 cases, 1.0%). Bilateral simultaneous onset of SIF of the femoral head was observed in 2 cases (0.7%). Insufficiency fracture of the knee was observed in 2 knees (1 case, 0.3%).

CONCLUSIONS

When it was difficult to distinguish ONFH from SIF of the femoral head, oblique axial-plane T1-weighted MRI and the short-tau inversion-recovery T2-weighted MRI parallel to the femoral neck were useful to establish the correct diagnosis.

Which Classification System Is Most Useful for Classifying Osteonecrosis of the Femoral Head?

BACKGROUND

Many studies have confirmed that the size and location of necrotic lesions are major factors that affect the prevalence of collapse and prognosis in patients with osteonecrosis of the femoral head (ONFH). Although several classification systems categorize and quantify ONFH, there is no agreement on which one is most useful for the purpose.

QUESTIONS/PURPOSES

We compared the Steinberg, modified Kerboul, and Japanese Investigation Committee (JIC) classifications of ONFH in terms of (1) the correlation among the three different classification systems. We further examined (2) the inter- and intraobserver reliability of the three classification systems and (3) the association of higher grades within each classification and the risk of subsequent collapse.

METHODS

Between January 2000 and December 2014, we treated 101 hips in 74 patients for precollapse ONFH, diagnosed either on plain radiographs or MRI. Of those, one patient (1%) died, six patients (8%) were lost to followup, and two patients (3%) underwent osteotomy before 2 years, leaving 86 hips in 65 patients (88%) for analysis here. Three-dimensional spoiled gradient-echo sequence (3D-SPGR) MRI was performed for all hips, and the presence of ONFH was determined by finding the area surrounded by the outer margin of the low-signal-intensity band on 3D-SPGR MRI. Patients with ONFH were categorized using the Steinberg, modified Kerboul, and JIC classification systems, and correlations among these three classification systems were investigated. Inter- and intraobserver reliability was assessed by 10 orthopaedic surgeons using 40 sets of 3D-SPGR MR images. The reliability of each system was evaluated using the kappa coefficient. The cumulative survival rate with collapse and undergoing hip arthroplasty as the endpoints was evaluated for each of the three classification systems (mean followup, 9 years; range, 2-16 years), and the association of higher grades within each classification and the risk of subsequent collapse were also evaluated.

RESULTS

We found strong correlations between the Steinberg and modified Kerboul classifications (ρ = 0.83, p < 0.001), the Steinberg and JIC classifications (ρ = 0.77, p < 0.001), and the modified Kerboul and JIC classifications (ρ = 0.80, p < 0.001). Interobserver reliability in the JIC classification (0.72; range, 0.30-0.90) was higher than that in the Steinberg classification (0.56; range, 0.24-0.84; p < 0.001) and the modified Kerboul classification (0.57; range, 0.35-0.80; p < 0.001). The cumulative survival rate with collapse as the endpoint after a minimum of 2 years of followup in the Steinberg classification differed between Grades A (82%; 95% confidence interval [CI], 66%-97%) and B (43%; 95% CI, 21.9%-64.8%; p = 0.007), Grades A and C (20%; 95% CI, 4.3%-35.7%; p < 0.001), and Grades B and C (p = 0.029). Survival was lower for modified Kerboul Grade 4 hips (12%; 95% CI, 0%-27.1%) than for Steinberg Grade C hips (20%; 95% CI, 4.3%-35.7%) and JIC Type C2 hips (18%; 95% CI, 2.8%-34.0%). The JIC classification was best able to identify hips at low risk of collapse because no JIC Type A hips collapsed.

CONCLUSIONS

The JIC classification was more reliable and effective, at least for early-stage ONFH, than the Steinberg or modified Kerboul classifications. Further investigation might be useful to identify whether each classification system emphasizes specific risk factors for collapse.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Nationwide multicenter follow-up cohort study of hip arthroplasties performed for osteonecrosis of the femoral head

PURPOSE

To identify modifiable factors related to post-operative dislocation and reoperation in patients with osteonecrosis of the femoral head (ONFH) in a large cohort.

METHODS

We studied 4995 hip arthroplasties: total hip arthroplasty (THA) was performed in 79% of patients; bipolar hemiarthroplasty (BP), 17%; total resurfacing arthroplasty (tRS), 3%; and hemi-resurfacing arthroplasty (hRS), 1%. A new type of BP (accounting for 49% of BPs) comprised a femoral component with a polished or smooth, small-diameter (approximately 10 mm) neck with a round or oval axial cut surface and no sharp corners.

RESULTS

The infection rate was relatively low (0.56%) even though 58% of cases of ONFH were associated with systemic steroid use, a known risk factor for infection. Post-operative dislocation occurred in 4.3% of cases, with re-operation needed in 3.9%. The dislocation rate was related to surgery type: 5.2% in THA, 0.9% in BP, and 0% in tRS and hRS. Among total arthroplasties with six month or longer follow-up (3670 THAs and 159 tRSs), the risk factors for post-operative dislocation were younger (≤ 40 years) or older (≥ 62 years) age, higher body weight, posterolateral approach, and smaller prosthetic head diameter. Regarding the need for re-operation, higher body weight and surgery type were identified as risk factors.

CONCLUSIONS

The relatively high dislocation rate of 5.2% in THA is a cause for concern. The identified risk factors for dislocation should be considered when selecting THA for treatment. Prosthesis survivorship in hRSs was inferior to that in BPs or THAs. Body weight also affected the survivorship of hip arthroplasties.

Do femoral head collapse and the contralateral condition affect patient-reported quality of life and referral pain in patients with osteonecrosis of the femoral head?

PURPOSES

The objectives of this study were to investigate patient-reported outcomes and referral pain at the first visit in patients with osteonecrosis of the femoral head (ONFH) and to clarify the influence of collapse of the femoral head and the contralateral condition.

METHODS

The study included 105 patients (130 hips) with ONFH at the first visit, who were divided into two groups based on the presence of bilateral walking hip pain (bilateral group 25 patients, 50 hips) and unilateral hip pain (unilateral group 80 patients, 80 hips). We compared the Short Form-36 (SF-36), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and visual analog scale (VAS) responses for hip, knee, and low back pain between the groups to investigate the influence of the contralateral condition. Regarding the influence of femoral head collapse, we investigated these subjects based on the stage classification in the unilateral group.

RESULTS

The physical component summary (PCS) of the SF-36 and all domains of the JHEQ were poorer in the bilateral group than in the unilateral group. In addition, the VAS score for low back pain was significantly poorer in the bilateral group than in the unilateral group. Regarding the collapse of the femoral head, the SF-36 for the PCS and JHEQ for pain had a significant relationship in the ONFH stage. The VAS scores for hip and knee pain had a significant relationship in the ONFH stage.

CONCLUSION

Collapse of the femoral head and the contralateral condition of ONFH strongly affect patients' activities of daily life.

Association of common comorbidities with osteonecrosis: a nationwide population-based case-control study in Denmark

OBJECTIVE

To examine recent time trends in the incidence of osteonecrosis (ON) in Denmark and to investigate different common comorbidities association with ON in a population-based setting.

METHODS

Using Danish medical databases, we included all patients with a first-time hospital diagnosis of ON during 1995-2012. Each ON case was matched with 10 randomly selected population control subjects from general population. For all participants, we obtained a complete hospital history of comorbidities included in the CharlsonComorbidity Index 5 years preceding the inclusion date.

RESULTS

4107 ON cases and 41 063 controls were included. The incidence of ON increased from 3.9 in 1995 to 5.5 in 2012 per 100 000 inhabitants. Solid cancer was the most common comorbidity, associated with an adjusted OR (aOR) for ON of 2.0 (95% CI 1.7 to 2.2). For advanced metastatic cancer, leukaemia and lymphoma, aORs of ON were 3.4 (95% CI 2.5 to 4.5), 4.3 (95% CI 2.7 to 7.0) and 5.8 (95% CI 4.3 to 7.8), respectively. Among other chronic conditions, aORs were 3.5 (95% CI 3.0 to 4.1) for connective tissue diseases and 2.3 (95% CI 2.0 to 2.7) for chronic pulmonary diseases. aORs were also increased at 2.8 (95% CI 1.9 to 4.1) and 4.5 (95% CI 2.5 to 8.2) for mild and moderate-to-severe liver disease, respectively, and 4.2 (95% CI 3.4 to 5.2) for renal disease.

CONCLUSION

This large population-based study provides evidence for an increasing ON incidence in the general population and documents an association between several common comorbid conditions and risk of ON.

Differential proteomic screening and identification for non-traumatic necrotic femoral osseous tissue

Currently, there is a lack of effective early screening and detection methods for femoral head necrosis. Current research on most orthopedic diseases focuses on proteomics in the preliminary stage. The recent fluorescence differential in gel electrophoresis (DIGE) has advantages such as a high reproducibility, high sensitivity, high throughput, and high dynamic range. It is currently one of the most widely used quantitative proteomic research means. We conducted this study to investigate the pathogenesis of non-traumatic femoral head necrosis using the fluorescence DIGE to screen non-traumatic femoral head necrosis based on proteomics and provide a theoretical basis for screening possible biomarkers and molecular targeted treatment. The DIGE technique was used to separate the protein. An electrophoretogram was established on the basis of scanning and analysis. Identification and a bioinformatics analysis were conducted for the differential protein. The protein with differential expression of over 2-fold was excavated and ionized by means of substrate assisted laser desorption. The flight time was identified with a mass spectrometer (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF/TOF). The formation on sequences, structures and functions of these proteins were obtained through database retrieval. Western blot analysis was used to verify the differential protein expression and the reliability of the DIGE result was verified. DIGE was used to successfully separate 1,500±40 protein spots. There were 252 significant differential protein spots. The Ettan™ Spot Picker automatic work station was used to excavate 49 significant differential protein spots with expression difference over 2-fold. The MALDI-TOF/TOF mass spectrometer was used to identify these differential protein spots. Six proteins were identified in total, which include apolipoprotein A1 (APOA1), fibrous protein original chain, fibrous protein original chain, serum albumin, sulfur-oxygen protein peroxiredoxin 2 (PRDX2) and actin. APOA1 and PRDX2 were subject to western blot analysis detection; results were consistent with the DIGE result. Based on an analysis of the biological information, these proteins may be associated with the incidence and progression of femoral head necrosis.

Susceptibility of Males, but Not Females to Developing Femoral Head Osteonecrosis in Response to Alcohol Consumption

Background

We previously reported that ethanol-containing liquid diet feeding induces osteonecrosis of the femoral head in male rats. Also, it was reported that a large amount of consumed ethanol and a long-term history of drinking were risk factors for osteonecrosis of the femoral head, and that the frequency of alcohol-induced osteonecrosis of the femoral head in males was much greater than in females. The higher incidence of alcohol-induced osteonecrosis of the femoral head could be due to either higher prevalence of alcohol drinking in males or due to their potential higher sensitivity to alcohol. The aim of the study is to investigate the influence of alcohol consumption and drinking period on the development of osteonecrosis of the femoral head in rats of both sex.

Methods

All the experimental male rats were allocated to the male one-month ethanol drinking group (M1). Female rats were randomly divided into the female one- to five-months ethanol drinking groups (F1-5). All rats were fed a Lieber-DeCarli liquid diet containing 5% ethanol for one to five months.

Results

One-month feeding with the ethanol-containing liquid diet resulted in the development of osteonecrosis of the femoral head in seven of twenty in the M1 group, but none in the F1 group, although the mean intake of ethanol per body weight in the M1 group was significantly lower than that in the F1 group. Furthermore, long drinking periods with a large amount of ethanol intake in the F2-5 groups did not induce osteonecrosis of the femoral head.

Conclusion

The present study shows that lower alcohol consumption over short periods of time that were sufficient to induce osteonecrosis of the femoral head in males had no effect on females. Even with greater alcohol consumption and longer duration, females did not develop osteonecrosis of the femoral head. Therefore, unknown factors related to sex must be responsible for the development of this condition.

Knee loading protects against osteonecrosis of the femoral head by enhancing vessel remodeling and bone healing

Osteonecrosis of the femoral head is a serious orthopedic problem. Moderate loads with knee loading promote bone formation, but their effects on osteonecrosis have not been investigated. Using a rat model, we examined a hypothesis that knee loading enhances vessel remodeling and bone healing through the modulation of the fate of bone marrow-derived cells. In this study, osteonecrosis was induced by transecting the ligamentum teres followed by a tight ligature around the femoral neck. For knee loading, 5 N loads were laterally applied to the knee at 15 Hz for 5 min/day for 5 weeks. Changes in bone mineral density (BMD) and bone mineral content (BMC) of the femur were measured by pDEXA, and ink infusion was performed to evaluate vessel remodeling. Femoral heads were harvested for histomorphometry, and bone marrow-derived cells were isolated to examine osteoclast development and osteoblast differentiation. The results showed that osteonecrosis significantly induced bone loss, and knee loading stimulated both vessel remodeling and bone healing. The osteonecrosis group exhibited the lowest trabecular BV/TV (p b 0.001) in the femoral head, and lowest femoral BMD and BMC (both p b 0.01). However, knee loading increased trabecular BV/TV (p b 0.05) as well as BMD (pb 0.05) and BMC (p b 0.01). Osteonecrosis decreased the vessel volume (pb 0.001), vessel number (pb 0.001) and VEGF expression (p b 0.01), and knee loading increased them (pb 0.001, pb 0.001 and p b 0.01). Osteonecrosis activated osteoclast development, and knee loading reduced its formation, migration, adhesion and the level of “pit” formation (pb 0.001, pb 0.01, pb 0.001 and pb 0.001). Furthermore, knee loading significantly increased osteoblast differentiation and CFU-F (both p b 0.001). A significantly positive correlation was observed between vessel remodeling and bone healing (both p b 0.01). These results indicate that knee loading could be effective in repair osteonecrosis of the femoral head in a rat model. This effect might be attributed to promoting vessel remodeling, suppressing osteoclast development, and increasing osteoblast and fibroblast differentiation. In summary, the current study suggests that knee loading might potentially be employed as a non-invasive therapy for osteonecrosis of the femoral head.