Pronounced risk of nontraumatic osteonecrosis of the femoral head among cigarette smokers who have never used oral corticosteroids: a multicenter case-control study in Japan

The Hawkins Sign of the Talus: The Impact of Patient Factors on Prediction Accuracy

BACKGROUND

Osteonecrosis is a complication of talar neck fractures associated with chronic pain and poor functional outcomes. The Hawkins sign, the radiographic presence of subchondral lucency seen in the talar dome 6 to 8 weeks after trauma, is a strong predictor of preserved talar vascularity. This study sought to assess the accuracy of the Hawkins sign in a contemporary cohort and assess factors associated with inaccuracy.

METHODS

A retrospective review of talar neck fractures at a level-I trauma center from 2008 to 2016 was conducted. Both the Hawkins sign and osteonecrosis were evaluated on radiographs. The Hawkins sign was determined on the basis of radiographs taken approximately 6 to 8 weeks after injury, whereas osteonecrosis was determined based on radiographs taken throughout follow-up. The Hawkins sign accuracy was assessed using proportions with 95% confidence intervals (CIs), and associations were examined with Fisher exact testing.

RESULTS

In total, 105 talar neck fractures were identified. The Hawkins sign was observed in 21 tali, 3 (14% [95% CI, 3% to 36%]) of which later developed osteonecrosis. In the remaining 84 tali without a Hawkins sign, 32 (38% [95% CI, 28% to 49%]) developed osteonecrosis. Of the 3 tali that developed osteonecrosis following observation of the Hawkins sign, all were in patients who smoked.

CONCLUSIONS

A positive Hawkins sign may not be a reliable predictor of preserved talar vascularity in all patients. We identified 3 patients with a positive Hawkins sign who developed osteonecrosis, all of whom were smokers. Factors impairing the restoration of microvascular blood supply to the talus may lead to osteonecrosis despite the presence of preserved macrovascular blood flow and an observed Hawkins sign. Further research is needed to understand the factors limiting Hawkins sign accuracy.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

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.

Correlation between ESR1 and APOE gene polymorphisms and risk of osteonecrosis of the femoral head: a case-control study

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a disease with a high disability rate, and genetic factors are closely related to its pathogenesis. This study aimed to investigate the possible correlation between ESR1 and APOE gene polymorphisms and the risk of ONFH.

METHODS

In this case-control study, the potential association between three genetic variants (rs2982573 C < T, rs10872678 C < T, and rs9322332 A < C) of the ESR1 gene and two genetic variants (rs7259620 A < G and rs769446 C < T) of the APOE gene with the risk of ONFH was investigated. Correlations between gene polymorphisms and ONFH risk were assessed using logistic regression analysis, with calculation of odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The overall analysis demonstrated that rs9322332 in the ESR1 gene exhibited a correlation with a decreased risk of ONFH under the homozygous (AA vs.CC: OR = 0.69, 95% CI [0.53-0.90], p = 0.006), dominant (CA + AA vs. CC: OR = 0.70, 95% CI [0.54-0.90], p = 0.006), and additive (OR = 0.79, 95% CI [0.66-0.95], p = 0.013) models. The stratification analysis revealed that rs9322332 was linked to a lower risk of ONFH in subgroups characterized by individuals aged over 51 years and non-smokers. Nevertheless, there were no notable correlations found between ESR1 rs2982573 and rs10872678, as well as APOE rs7259620 and rs769446, with the risk of ONFH.

CONCLUSION

ESR1-rs9322332 is closely linked to a decreased risk of ONFH, thereby enhancing our understanding of the relationship between gene polymorphisms and ONFH.

Did the COVID-19 Pandemic Coincide With an Increase in Osteonecrosis as Indication for Total Hip Arthroplasty in Older Patients?

BACKGROUND

Osteonecrosis of the femoral head is a common indication for total hip arthroplasty (THA). It is unclear to what extent the COVID-19 pandemic has impacted its incidence. Theoretically, the combination of microvascular thromboses and corticosteroid use in patients who have COVID-19 may increase the risk of osteonecrosis. We aimed to (1) assess recent osteonecrosis trends and (2) investigate if a history of COVID-19 diagnosis is associated with osteonecrosis.

METHODS

This retrospective cohort study utilized a large national database between 2016 and 2021. Osteonecrosis incidence in 2016 to 2019 was compared to 2020 to 2021. Secondly, utilizing a cohort from April 2020 through December 2021, we investigated whether a prior COVID-19 diagnosis was associated with osteonecrosis. For both comparisons, Chi-square tests were applied.

RESULTS

Among 1,127,796 THAs performed between 2016 and 2021, we found an osteonecrosis incidence of 1.6% (n = 5,812) in 2020 to 2021 compared to 1.4% (n = 10,974) in 2016 to 2019; P < .0001. Furthermore, using April 2020 to December 2021 data from 248,183 THAs, we found that osteonecrosis was more common among those who had a history of COVID-19 (3.9%; 130 of 3,313) compared to patients who had no COVID-19 history (3.0%; 7,266 of 244,870); P = .001).

CONCLUSION

Osteonecrosis incidence was higher in 2020 to 2021 compared to previous years and a previous COVID-19 diagnosis was associated with a greater likelihood of osteonecrosis. These findings suggest a role of the COVID-19 pandemic on an increased osteonecrosis incidence. Continued monitoring is necessary to fully understand the impact of the COVID-19 pandemic on THA care and outcomes.

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.

Aseptic Necrosis of Femoral Head - Clinical Study

Femoral head osteonecrosis is a disease characterized by the decrease of blood vascularization in the femoral head, which leads to death of the osteocytes, demineralization and resorption of bone spans, change of trabecular architecture, with the reduction of the bone mechanical resistance and collapse of the articular surface in the femoral head. Left untreated, the disease may have a rapid progression, leading to severe symptoms, with significant articular dysfunction, functional impotence and a serious impact on the patient’s quality of life. The prevalence of the disease is ever growing all over the world, affecting mainly people in their 30s, 40s or 50s. In the present study, we analyzed a number of 76 patients with femoral head osteonecrosis with severe symptoms that required a surgical treatment. There was observed that more than ¾ of the investigated patients were males, while 81.58% were younger than 60 years old. Among the identified risk factors, smoking came first, followed by alcohol intake, obesity and chronic administration of corticosteroids. A very high percentage of patients (84.21%) were diagnosed in stages III and IV of the disease.

Gamma-Glutamyl Transferase: A Useful Marker of Habitual Drinking in Cases of Alcohol-Associated Osteonecrosis of the Femoral Head

AIMS

Alcohol intake is one of the factors associated with the occurrence of osteonecrosis of the femoral head (ONFH), and its epidemiological information regarding alcohol intake depends on patients' self-reports. Therefore, we analysed the efficacy of laboratory tests as an objective diagnostic tool to indicate habitual drinking in patients with alcohol-associated ONFH.

METHODS

This study included 109 consecutive patients diagnosed with ONFH who underwent primary hip surgery in our institution between 2010 and 2018. The patients were classified into group AL (alcohol-associated ONFH; n = 26) and group NO (alcohol-unassociated ONFH; n = 83), based on their self-reported information. Serum levels of gamma-glutamyl transferase (GGT), mean corpuscular volume (MCV), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol and triglycerides were compared between both groups. The sensitivities and specificities with the optimal cut-off values for detecting alcohol-associated ONFH were compared among these markers.

RESULTS

The median serum levels of GGT, AST and ALT were significantly higher in the AL group than in the NO group. The receiver operating characteristic curve analysis demonstrated an area under the curve of 0.795 for GGT, 0.731 for AST and 0.709 for ALT. The optimal cut-off level of GGT as a marker for alcohol-associated ONFH was 36.5 units/L, with a sensitivity of 76% and specificity of 80%, and it was found to be the best marker among the other examined laboratory markers.

CONCLUSION

Serum GGT level is a useful laboratory marker with moderate accuracy that indicates habitual drinking in patients with alcohol-associated ONFH.

Japanese Orthopaedic Association 2019 Guidelines for osteonecrosis of the femoral head

PURPOSE

The Clinical Practice Guidelines for Osteonecrosis of the Femoral Head (ONFH) 2019 Edition, written by the working group for ONFH guidelines of the Japanese Investigation Committee (JIC) for ONFH under the auspices of the Japanese Ministry of Health, Labour, and Welfare and endorsed by the Japanese Orthopaedic Association, were published in Japanese in October 2019. The objective of this guideline is to provide a support tool for decision-making between doctors and patients.

METHODS

Procedures for developing this guideline were based on the Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014, which proposed an appropriate method for preparing clinical guidelines in Japan.

RESULTS

This clinical practice guideline consists of 7 chapters: epidemiology; pathology; diagnosis; conservative therapy; surgical treatment: bone transplantation/cell therapy; surgical treatment: osteotomy; and surgical treatment: hip replacement. Twelve background questions and 13 clinical questions were determined to define the basic features of the disease and to be addressed when deciding treatment in daily practice, respectively.

CONCLUSIONS

The clinical practice guidelines for the ONFH 2019 edition will be useful for physicians, investigators, and medical staff in clinical practice, as well as for patients, during the decision-making process when defining how to treat ONFH.

Correlation between an ABO Blood Group and Primary Femoral Head Necrosis: A Case-Control Study

Objective

To investigate the relationship between primary femoral head necrosis (ONFH) and an ABO blood group.

Methods

This study was a retrospective case–control trial. An analysis of the clinical data of an ABO blood group with 516 patients (case group) with ONFH and 489 limb‐fracture patients (control group) without previous hip pain was obtained from the Second Hospital of Shanxi Medical University from November 2015 to November 2018. The clinical data included gender, age, height, weight, a history of smoking, alcohol abuse, prior medical history, hormone use, and ABO blood type. A logistic regression model was used for univariate and multivariate analysis.

Results

From November 2015 to November 2018, there were 267 males and 249 females in the 516 cases of ONFH in the case group. The control group included 289 males and 200 females. In terms of age, the average age of the case group was significantly lower than that of the control group. In terms of body mass index (BMI), the BMI of the case group was significantly higher than that of the control group (P < 0.05). From the previous medical history of patients in the two groups (coronary heart disease, hypertension, cerebrovascular disease, diabetes, and peripheral vascular disease), there was no significant difference between the two groups from a statistical perspective (P < 0.05). However, according to the risk factors of ONFH (smoking, alcohol abuse, hyperlipidemia, and hormone‐use history), there were significant differences between the case group and the control group. There was no statistical difference in the quantitative distribution ratio of the four blood types – A, B, O, and AB – between the case group and the control group. The outcomes of logistic multiple regression analysis presented that there was no significant correlation between the occurrence of ONFH and blood type A, B, AB, and O (P > 0.05). However, there are significant differences in the disease progression between the different blood types. There was a significant difference in the progression of disease between type A and type O. Among them, patients with ONFH and type A blood had the fastest progression with an average of 2.318 years, and the slowest progression was found in type O blood with an average of 5.15 years.

Conclusions

The ABO blood group has no correlation with the occurrence of ONFH, but the ABO blood type is closely related to the disease progression of ONFH.

Guidelines for clinical diagnosis and treatment of osteonecrosis of the femoral head in adults (2019 version)

Osteonecrosis of the femoral head (ONFH) is a common and refractory disease in orthopaedic clinics. The number of patients with ONFH is increasing worldwide every year. There are an estimated 8.12 million patients with nontraumatic osteonecrosis in China alone. Treatment of nontraumatic osteonecrosis has always been a clinical challenge for orthopaedic surgeons. To further standardize diagnosis and treatment of ONFH, these guidelines provide not only basic diagnosis, treatment, and evaluation systems for ONFH but also expert advice and standards in many aspects, including epidemiology, aetiology, diagnostic criteria, pathological staging, prevention and treatment options, and postoperative rehabilitation. The aetiological factors of ONFH can currently be divided into two major categories: traumatic and nontraumatic; however, the specific pathological mechanism of ONFH is not completely clear. Currently, the staging system of ONFH formulated by the Association Research Circulation Osseous is widely used in clinical practice. Based on the changes in the intraosseous blood supply at different stages, the corresponding nonsurgical and surgical treatments are recommended, and when there are risk factors for possible ONFH, certain preventive measures to avoid the occurrence of osteonecrosis are recommended. These guidelines provide brief classification criteria and treatment regimen for osteonecrosis. Specification of the aetiology, treatment plan based on comprehensive consideration of the different stages of osteonecrosis, hip function, age, and occupation of the patients are important steps in diagnosis and developing treatment strategies.

TRANSLATIONAL POTENTIAL OF THIS ARTICLE

New advances in the epidemiology, etiology, pathophysiology, imaging, diagnosis and treatment of ONFH have been renewed in this revision. This guideline can be used for reference by orthopedic professionals and researchers, and for standardized diagnosis and treatment management under the clinical guidance, which is conducive to the prevention, treatment and further research of ONFH, improving the diagnosis and treatment level, making patients' symptoms under good control, and improving their quality of life.

Correlational analysis between neutrophil granulocyte levels and osteonecrosis of the femoral head

Background

The correlation between peripheral blood neutrophil level and osteonecrosis of the femoral head (ONFH) has not been extensively studied. Thus, we aimed to investigate the correlation between neutrophil level in the peripheral blood (neutrophil granulocyte) and ONFH.

Methods

A total of 984 cases of ONFH and femoral neck fractures (non-ONFH) diagnosed at the Department of Orthopedics at our institution between January 1, 2011 and December 31, 2016 were retrospectively reviewed. The ONFH and non-ONFH groups comprised 488 and 496 cases, respectively. Basic information and peripheral blood cell levels of the two groups were compared.

Results

The patients’ mean age was 59.89 ± 17.06 years (range: 38–82 years). There were 457 male and 527 female patients, with a male-to-female ratio of 1:1.15. We found that neutrophil granulocyte levels and percentage of neutrophil granulocytes were significantly different between the ONFH and non-ONFH groups. Multimodal regression analysis showed that the percentage of neutrophil granulocytes was an independent protective factor against ONFH.

Conclusions

The factors influencing ONFH are neutrophil granulocyte levels and percentage of neutrophil granulocytes. Percentage of neutrophil granulocytes has a significant correlation with aseptic femoral head necrosis, providing a new perspective and direction for further study of femoral head necrosis.

Epidemiology, Cause, and Anatomy of Osteonecrosis of the Foot and Ankle

Osteonecrosis arises throughout the foot and ankle in various forms and due to numerous causes, with a thousand US cases per year estimated for the ankle alone. Although research continues to elucidate specific mechanisms at work, the pathophysiology remains poorly understood. Nevertheless, the various osteonecrosis pathways converge on osteocyte death, and bony lesions follow a pattern of progression. Understanding the specific anatomy and biomechanics associated with common forms of foot and ankle osteonecrosis should help guide diagnosis and interventions, particularly at earlier stages of disease where etiology-specific approaches might become optimal.

Chinese Guideline for the Diagnosis and Treatment of Osteonecrosis of the Femoral Head in Adults

The treatment of adult osteonecrosis of the femoral head (ONFH), with 8.12 million patients in China, remains a challenge to surgeons. To standardize and improve the efficacy of the treatment of ONFH, Chinese specialists updated the experts' suggestions in March 2015, and an experts' consensus was given to provide a current basis for the diagnosis, treatment and evaluation of ONFH. The current guideline provides recommendations for ONFH with respect to epidemiology, etiology, diagnostic criteria, differential diagnosis, staging, treatment, as well as rehabilitation. Risk factors of non-traumatic ONFH include corticosteroid use, alcohol abuse, dysbarism, sickle cell disease and autoimmune disease and others, but the etiology remains unclear. The Association Research Circulation Osseous (ARCO) staging system, including plain radiograph, magnetic resonance imaging, radionuclide examination, and histological findings, is frequently used in staging ONFH. A staging and classification system was proposed by Chinese scholars in recent years. The major differential diagnoses include mid-late term osteoarthritis, transient osteoporosis, and subchondral insufficiency fracture. Management alternatives for ONFH consist of non-operative treatment and operative treatment. Core decompression is currently the most common procedure used in the early stages of ONFH. Vascularized bone grafting is the recommended treatment for ARCO early stage III ONFH. This guideline gives a brief account of principles for selection of treatment for ONFH, and stage, classification, volume of necrosis, joint function, age of the patient, patient occupation, and other factors should be taken into consideration.

Influence of cigarette smoking on osteonecrosis of the femoral head (ONFH): a systematic review and meta-analysis

BACKGROUND

Current studies demonstrate controversy regarding the relationship between cigarette smoking and osteonecrosis of the femoral head (ONFH).

METHODS

We conducted a meta-analysis to evaluate the association between smoking and ONFH. Relevant articles published before September 2016 were identified by a systematic search of EMBASE and MEDLINE via Ovid. Summary odds ratios (OR) were calculated using random effects models, and study quality was assessed using a modified Newcastle-Ottawa scale.

RESULTS

102 citations were screened and 7 case-control studies were identified and included in the review. When compared with nonsmokers, current smokers had a higher risk of developing ONFH (OR 2.53; 95% confidence interval [CI] 1.68-3.79), as did former smokers (OR 1.82; 95% CI, 1.10-3.00). Within the group of current smokers, those classified as heavy smokers (with a daily number >20 cigarettes/day) demonstrated higher risks of ONFH (OR 2.03; 95% CI, 1.29-3.19), and light smokers classified as smoking <20 cigarettes/day, also demonstrated a higher risk of ONFH when compared with nonsmokers (OR 1.73; 95% CI, 1.06-2.83). When smoking was classified by pack-years, heavy smokers (>20 pack-years) were at a higher risk of ONFH (OR 2.26; 95% CI, 1.24-4.13), but no significant difference in risk was identified in light smokers (<20 pack-years) (OR 1.81; 95% CI, 0.88-3.71) when compared with nonsmokers.

CONCLUSIONS

Our meta-analysis showed that current smokers were at a higher risk of ONFH, this high risk can also be found in former smokers. And heavy cigarette smoking showed a higher risk of ONFH than light smoking.

Prevalence of Nontraumatic Osteonecrosis of the Femoral Head and its Associated Risk Factors in the Chinese Population: Results from a Nationally Representative Survey

Background:

Nontraumatic osteonecrosis of the femoral head (NONFH) is a debilitating disease that represents a significant financial burden for both individuals and healthcare systems. Despite its significance, however, its prevalence in the Chinese general population remains unknown. This study aimed to investigate the prevalence of NONFH and its associated risk factors in the Chinese population.

Methods:

A nationally representative survey of 30,030 respondents was undertaken from June 2012 to August 2013. All participants underwent a questionnaire investigation, physical examination of hip, and bilateral hip joint X-ray and/or magnetic resonance imaging examination. Blood samples were taken after overnight fasting to test serum total cholesterol, triglyceride, and high-density lipoprotein (HDL) and low-density lipoprotein (LDL) levels. We then used multivariate logistic regression analysis to investigate the associations between various metabolic, demographic, and lifestyle-related variables and NONFH.

Results:

NONFH was diagnosed in 218 subjects (0.725%) and the estimated NONFH cases were 8.12 million among Chinese people aged 15 years and over. The prevalence of NONFH was significantly higher in males than in females (1.02% vs. 0.51%, χ² = 24.997, P < 0.001). Among NONFH patients, North residents were subjected to higher prevalence of NONFH than that of South residents (0.85% vs. 0.61%, χ² = 5.847, P = 0.016). Our multivariate regression analysis showed that high blood levels of triglycerides, total cholesterol, LDL-cholesterol, and non-HDL-cholesterol, male, urban residence, family history of osteonecrosis of the femoral head, heavy smoking, alcohol abuse and glucocorticoid intake, overweight, and obesity were all significantly associated with an increased risk of NONFH.

Conclusions:

Our findings highlight that NONFH is a significant public health challenge in China and underscore the need for policy measures on the national level. Furthermore, NONFH shares a number of risk factors with atherosclerosis.

High triglyceride is a risk factor for silent osteonecrosis of the femoral head in systemic lupus erythematosus

The purpose of this study was to clarify the factors related to silent osteonecrosis of the femoral head (ONFH) in patients with systemic lupus erythematosus (SLE). Seventy-eight patients with SLE were selected on the basis of having been newly diagnosed and requiring high-dose prednisolone, including pulse therapy with methylprednisolone, as the initial treatment. All the patients initially underwent MRI at 3 months after the start of corticosteroid treatment to detect any early changes in the femoral head. These examinations were then performed again 3 months later. Laboratory parameters were evaluated at the start of steroid treatment and at 1 month thereafter. By 3 months after the start of corticosteroid treatment, silent ONFH was diagnosed by MRI in 21 patients (26.9 %), being bilateral in 11 patients and unilateral in 10. The occurrence of silent ONFH was not related to SLE disease activity index, serological activity, or renal function; it was also unrelated to body mass index (BMI), body surface area (BSA), and the initial dose of prednisolone per unit body weight. However, the total cholesterol level at 4 weeks after the start of steroid treatment tended to be higher in patients with silent ONFH. Patients with a higher triglyceride level showed a significantly higher frequency of silent ONFH both before (p = 0.002) and 4 weeks after (p = 0.036) steroid initiation.A high triglyceride level is an important risk factor for silent ONFH in patients with SLE, and large-scale epidemiologic surveys of such early events are needed in this patient population.

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

BACKGROUND

Nontraumatic osteonecrosis of the femoral head (ONFH) is a rare disorder caused by ischemic necrosis of unknown etiology. A few studies have demonstrated trends in the number of patients with ONFH. However, there are no data on temporal trends in characteristics such as age, gender, and causative factors. To investigate this, we examined data from a multicenter hospital-based sentinel monitoring system in Japan.

METHODS

A total of 3041 newly-diagnosed ONFH patients from 34 participating hospitals who were reported to the system from 1997-2011 were analyzed. We examined age at diagnosis, potential causative factors, and underlying diseases for which patients received systemic steroid administration. Their temporal trends were assessed according to date of diagnosis in 5-year intervals (1997-2001, 2002-2006, and 2007-2011).

RESULTS

The gender ratio and distribution of potential causative factors did not change. Regarding underlying diseases requiring steroid administration, the proportion of patients with systemic lupus erythematosus decreased in males (10% to 6.4%) and in females (37% to 29%). Proportion of patients with renal transplantation fell consistently across the study period in both males (3.8% to 1.2%) and females (3.2% to 0.8%). In contrast, the proportion of patients receiving steroids for pulmonary disease (except asthma) significantly increased in both males (0.5% to 5.5%) and females (0.5% to 3.6%).

CONCLUSIONS

This large descriptive study is the first to investigate temporal trends in the characteristics of ONFH, which provide useful information for future studies.

Epidemiology of nontraumatic osteonecrosis of the femoral head in Japan

OBJECTIVES

To elucidate the epidemiology of nontraumatic osteonecrosis of the femoral head (ONFH), and to estimate the annual incidence rate in Japan.

METHODS

We examined, over the course of 3 years, personal records and radiographic images from the national registry of documents used for the study of nontraumatic ONFH in patients in Aichi Prefecture, Japan (population: 7.4 million). Those patients not meeting the diagnostic criteria according to the Japanese Investigation Committee for nontraumatic ONFH were excluded from this study.

RESULTS

A total of 285 out of the 327 patients who applied for the national registration of nontraumatic ONFH during the 3-year study met the diagnostic criteria for personal records, radiographic images, and magnetic resonance images. Forty-two patients (12.8%) were not considered to have nontraumatic ONFH. The mean age of patients was 50.4 years, and the male-female ratio was 2.1:1. Nontraumatic ONFH was steroid-induced in 135 cases (47.4%), alcohol-associated in 87 cases (30.5%), steroid-induced and alcohol- associated in 14 cases (4.9%), and idiopathic in 49 cases (17.2%).

CONCLUSIONS

The age-adjusted annual incidence of nontraumatic ONFH in Aichi Prefecture was estimated at 138.5 patients.Thus the annual incidence rate in Japan (population 128 million) was 1.91/100,000.