Three-Dimensional Distribution of Bone-Resorption Lesions in Osteonecrosis of the Femoral Head Based on the Three-Pillar Classification.

OBJECTIVE: To investigate three-dimensional distribution of bone-resorptive lesions based on the three-pillar classification and its effect on the disease progression of osteonecrosis of the femoral head (ONFH). METHODS: A total of 194 femoral head CT images from 117 patients diagnosed with ARCO stage II and III ONFH were retrospectively reviewed from April 2014 to February 2019. Three-dimensional structures of the femoral head and the bone-resorptive lesions were reconstructed. Using the three-pillar classification and coronal plane of the femoral head, we divided each femoral head into six regions to observe the location characteristics of bone-resorption lesions, and explore the destruction of different areas of the femoral head by the bone-resorptive lesions. Then the hips were divided into two groups based on whether they contained bone-resorption lesions and compared the difference of stage II and stage III between the two groups. RESULTS: The regional distribution revealed 39 (27.27%), 55 (38.46%), six (4.20%), 23 (16.08%), 17 (11.89%) and three (2.10%) bone-resorptive lesions in regions I, II, III, IV, V and VI respectively. The lateral pillar, AL (I + IV), contained 44.76% of the lesions, central pillar, C (II + V), 48.95%, and medial pillar, M (III + VI), 6.29%. Moreover, there were 81.82% bone-resorption lesions in anterolateral pillar, AL (I + II + IV), and 18.18% in posteromedial pillar, PM (III + V + VI). In all ONFH hips, the lateral pillar of 81(88.04%) femoral heads were affected, the central pillar of 84 (91.30%) femoral heads were affected, and the medical pillar of 29 (31.52%) femoral heads were affected. The ratio of ARCO stage III in the group with bone-resorption lesions was significantly higher than that of the group without bone-resorption lesions (76.09% vs 30.39%, P < 0.001). CONCLUSIONS: This study demonstrated that the bone-resorption lesions are mainly distributed in the lateral and central pillar of the femoral head, and the two pillars of the femoral head are usually involved by bone-resorption lesions. Furthermore, the ratio of ARCO stage III in the group with bone-resorption lesions was significantly higher than that of the group without bone-resorption lesions, suggesting that the bone-resorption lesions might accelerate the progression of ONFH.

Osteonecrosis of the Femoral Head: an Updated Review of ARCO on Pathogenesis, Staging and Treatment.

Non-traumatic osteonecrosis of the femoral head (ONFH) usually affects adults younger than 50 years and frequently leads to femoral head collapse and subsequent arthritis of the hip. It is becoming more prevalent along with increasing use of corticosteroids for the adjuvant therapy of leukemia and other myelogenous diseases as well as management of organ transplantation. This review updated knowledge on the pathogenesis, classification criteria, staging system, and treatment of ONFH.

The efficacy of acupuncture and moxibustion for early and middle-stage osteonecrosis of the femeral head: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Osteonecrosis of the femeral head (ONFH) occurs predominantly in young- and middle-aged people, and the disability rate is high in the late stage of the disease and most patients have to undergo total hip replacement. Clinically, increasing attention is paid to intervening early and middle-stage ONFH so as to delay its progress. Acupuncture and moxibustion (AM) is a unique method for treating ONFH in China. This study aims to summarize the advantages of AM for the treatment of ONFH. METHODS: A comprehensive literature search was conducted on the database with languages of English and Chinese. The medical subject titles used are "Osteonecrosis of the femoral head" and "acupuncture and moxibustion." Related words in the title or abstract including but were not limited to "necrosis of the femoral head," "avascular necrosis of the femoral head," "ischemic necrosis of the femoral head," "caput femoris necrosis," "bone paralysis," "bone erosion," and "bone atrophy." RESULTS: Nine randomized controlled trials were identified in this meta-analysis that included 630 subjects. Meta-analysis showed that the trial group that treated with conventional therapy combined with AM had a higher effective rate (Z = 2.27 P = 0.02) and excellent and good rate (Z = 4.85 P < 0.00001) and Harris hip function score (HHS) (Z = 2.31 P = 0.02) and lower incidence of related adverse reactions during treatment (Z = 2.82 P = 0.005) compared with the control group that treated with conventional therapy alone. CONCLUSIONS: AM for early and middle-stage ONFH is an effective and relatively safe intervention, which can improve the effective rate and excellent and good rate and HHS, and reduce the adverse reaction rate. Clinically, early and middle-stage ONFH can be intervened by combining with AM while taking conventional therapy to improve the efficacy.

The clinical and radiographic characteristics of avascular necrosis after pediatric femoral neck fracture: a systematic review and retrospective study of 115 patients.

BACKGROUND: Avascular necrosis (AVN) after pediatric femoral neck fracture (PFNF) showed poor prognosis, but its clinical and radiographic characteristics remained unclear. METHODS: A systematic review and a retrospective study were performed to evaluate the clinical and radiographic characteristics of patients with AVN after PFNF. RESULTS: A total of 686 patients with PFNF and 203 patients with AVN from 21 articles were analyzed. Ratliff's classification was used in 178 patients, with types I, II, and III AVN accounting for 58.4%, 25.3%, and 16.3%, respectively. Ratliff's assessment was used in 147 patients, of whom 88.4% had an unsatisfactory prognosis. In retrospective study, 115 patients with a mean age of 13.6 ± 2.0 years were included. The mean interval between AVN and PFNF was 13.7 ± 9.5 months. At the time of diagnosis, 59.1% cases were symptomatic and 65.2% progressed to collapsed stage. Fifty (43.5%), 61 (53.0%), and 4 patients (3.5%) were defined as types I, II, and III , respectively, via Ratliff's classification. Thirteen (11.3%), 40 (34.8%), and 62 patients (53.9%) showed types A/B, C1, and C2 disease, respectively, via the JIC classification. Multivariate analysis demonstrated a strong relation between collapsed stage and symptomatic cases (OR = 6.25, 95% CI = 2.39-16.36) and JIC classification (OR = 3.41, 95% CI = 1.62-7.17). CONCLUSION: AVN after PFNF showed a tendency toward extensive necrotic lesions, presumably resulting in a rapid progression of femoral head collapse. And the symptoms and the JIC classification are other two risk factors of collapse progression.

Extracorporeal shockwave therapy combined with multiple drilling and intramedullary drug injection for treating early-stage Femur Head Necrosis: Protocol for a randomized controlled trial.

BACKGROUND: Early diagnosis and treatment of the osteonecrosis of the femoral head (ONFH), a refractory disease, is imperative to prevent femoral head collapse; however, the existing solutions remain controversial. This study assessed the safety and efficacy of extracorporeal shock wave therapy (ESWT) combined with multiple drilling and intramedullary drug injection, a novel cocktail therapy, as a randomized controlled trial (RCT) model to postulate an alternative therapy for patients with early-stage ONFH. METHODS: Femoral head necrosis patients aged 20 to 60 years with stage ARCO I-II were recruited. One hundred twenty eligible participants were randomized into four groups in a 1:1:1:1 ratio: extracorporeal shock wave therapy combined with multiple drilling and intramedullary drug injection (group EMI), extracorporeal shock wave therapy (group E), multiple drilling combined with intramedullary drug injection (group MI), and multiple drilling ("positive" control group; group M). The primary outcomes included effective rate, subchondral collapse rate of the femoral head, lesion size, and grade of bone marrow edema. Secondary outcomes included the Harris Hip Score and the visual analog scale. All outcomes were measured at the screening visit (baseline) and at the planned time intervals during treatment and follow-up, and the efficacy was statistically analyzed according to the intention-to-treat sub-populations and per-protocol sub-populations. OBJECTIVES: To examine the clinical efficacy of ESWT combined with multiple drilling and intramedullary drug injection to provide a safe and more effective method for treating early-stage ONFH. TRIAL REGISTRATION NUMBER: ChiCTR1900020888; Pre-results.

"Sclerotic Band" type of classification system and measurement of necrotic area for osteonecrosis of the femoral head.

Osteonecrosis of the femoral head is a common orthopedic disease. Based on years of clinical experience and significant imaging data, this study aimed to elucidate a new type of it, to help improve prognosis in young adults and provide a basis for hip preservation treatment.From January 2014 to December 2016, a total of 211 patients undergoing hip preservation surgery for femoral head necrosis at our hospital were enrolled in this study. Coronal plane classification and cross-sectional area analysis were performed by nuclear magnetic resonance imaging (computed tomography optional) in cases meeting the inclusion criteria. Meanwhile, a new method of classification and calculating the necrotic area was proposed. The application simulation was conducted using sample cases. Additionally, treatment methods were recommended. We used our method to compare the outcome of the selected patients with the JIC classification so as to judge the advantages and disadvantages.The " pressure bone trabecular angle " of the femoral head was measured, and the "sclerotic band" (Zhang Ying) type of classification system and the "quartile" (Zhang Ying) method of measurement were used in 2 sample cases. After analysis, it is more accurate than JIC.The "Sclerotic band" type of classification system and 'quartile' methods are new methods to evaluate the stability of femoral head necrosis. They are convenient for clinical application and easily adopted.

Effect of a Specific Questionnaire Sheet on Subclassification of Osteonecrosis of the Femoral Head.

BACKGROUND This study examined whether use of a specific questionnaire sheet for nontraumatic osteonecrosis of the femoral head (ONFH) could affect the subclassification of ONFH compared with a conventional medical interview. MATERIAL AND METHODS Study participants consisted of 400 patients with ONFH who visited our hospital between February 2011 and March 2015. Data on history of systemic steroid therapy and habitual alcohol intake were obtained during a conventional medical interview at the first visit and were re-evaluated using a specific questionnaire sheet at another visit. Patients were subclassified into 4 groups: steroid-associated, alcohol-associated, steroid/alcohol-associated, or idiopathic ONFH. RESULTS Use of the specific questionnaire sheet resulted in a 4.0% increase in the proportion of patients with a history of systemic steroid therapy, from 57.3% (n=229) to 61.3% (n=245), and a 14.3% increase for history of habitual alcohol intake, from 35.0% (n=140) to 49.3% (n=197). The proportion of patients with steroid/alcohol-associated ONFH increased from 2.5% (n=10) to 17.8% (n=71), while the proportion in the other 3 groups decreased: steroid-associated ONFH from 54.8% (n=219) to 43.5% (n=174); alcohol-associated ONFH from 32.5% (n=130) to 31.5% (n=126); and idiopathic ONFH from 10.2% (n=41) to 7.2% (n=29). Ninety-six patients (24.0%) were classified into a different subgroup based on the specific questionnaire sheet. CONCLUSIONS The use of a specific questionnaire sheet can change the distribution of ONFH subclassifications compared with use of a conventional medical history interview. Use of a specific questionnaire sheet can allow for more detailed self-reporting regarding potential causative factors for nontraumatic ONFH, especially habitual alcohol intake.

[A review of avascular necrosis, of the hip and beyond]. / Ostéonécroses aseptiques, une revue générale des ostéonécroses de la hanche, et au-delà.

Avascular necrosis is an ischemic or cytotoxic necrosis of epiphyseal bone, responsible for joint pain, altered life quality and frequently affecting young patients. Avascular necrosis can be unifocal or multifocal, underlining the possibility of a systemic origin. Avascular necrosis involves the femoral head in more than 75% of cases. Although avascular necrosis is irreversible, many risk factors must be sought, including corticosteroid treatment, hypercholesterolemia, sickle cell disease or alcohol abuse. MRI imaging is the main exploration for the diagnostic and staging of the disease, and should be performed in unexplained hip pain in young patients with normal X-rays. In the earlier stages of the disease (stage I and II of the Arlet and Ficat classification), joint surface is preserved, and conservative treatment is recommended. In the more advanced stages (III and IV of the Arlet and Ficat classification), the articular surface collapses and joint arthroplasty is the main treatment. However, there are some recent therapeutic advances, based on mesenchymal stem cells, which may contribute, in the future, to improve the bad functional prognosis of the disease.

[Relative factors and follow up research of asymptomatic osteonecrosis of the femoral head].

Objective: To evaluate the progress and influence factors of asymptomatic osteonecrosis of the femoral head(ONFH). Methods: MRI was performed on the contralateral hips of 174 patients with unilateral symptomatic ONFH who admitted at Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University from January 2012 to December 2018. Eighty-three of 174 patients with unilateral ONFH were found suffering from contralateral ONFH(47.7%), of which 77 patients were followed up.There were 28 males and 49 females with age of 48.6 years (range: 21-73 years). The pathogenesis, ARCO classfication, areas and position of osteonecrosis were collected.Independent sample t test, χ(2) test, Fisher exact test, multivariate Logistic regression were used to analyze the potential influence factors. Results: Patients were followed up for 36.7 months. During the following up period, ARCO classification of 28 patients (36.4%) progressed.The progress of asymptomatic ONFH was not related to the gender, age and original ARCO classification, but related to the pathogenesis, position and area of osteonecrosis (all P<0.05). Conclusion: The progress of asymptomatic osteonecrosis is related to the pathogenesis, position and area of osteonecrosis,but most of asymptomatic ONFH will not progress.

Classification systems of hip osteonecrosis: an updated review.

PURPOSE: Osteonecrosis of the femoral head (ONFH) typically impacts middle-aged patients who are typically more active and in whom many surgeons would try to delay performing a total hip arthroplasty (THA). This poses a clinical decision-making challenge. Therefore, several options for joint preservation have been advocated, but varying indications and success rates have led to debate on when to use the various procedures. This is due in part to the lack of a generalized system for assessing ONFH, as well as the absence of a standardized method of data collection for patient stratification. Due to the paucity of studies, in this review, we aimed to provide an up-to-date review of the most widely utilized classification systems and discuss the characteristics of each system. METHODS: A comprehensive literature review was conducted. Studies published between January 1st, 1975 and March 1st, 2018 were reviewed. The following key words were used in combination with Boolean operators AND or OR for the literature search: "osteonecrosis," "avascular necrosis," "hip," "femoral head," "classification," "reliability," and "validity." We defined the inclusion criteria for qualifying studies for this review as follows: (1) studies that reported on the classification systems for hip osteonecrosis, (2) studies that reported on the inter-observer reliability of the classification systems, and (3) studies that reported on the intra-observer reliability of any ONFH classification systems. In addition, we employed the following exclusion criteria: (1) studies that assessed classification systems for traumatic osteonecrosis, (2) Legg-Calvé-Perthes disease, or (3) Developmental Dysplasia of the Hip. Additionally, we excluded case reports and duplicate studies among searched databases. RESULTS: The following classification systems were the most commonly utilized: The Ficat and Arlet, Steinberg, the Association Research Circulation Osseous (ARCO), and the Japanese Investigation Committee (JIC) classification systems. The details of each system have been discussed and their inter- and intra-observer reliability has been compared. CONCLUSION: To this date, there is a lack of consensus on a universal and comprehensive system, and the use of any of the previous classification systems is a matter of dealer's choice. The Ficat and Arlet system was the earliest yet remains the most widely utilized system. Newer classification systems have been developed and some such as the JIC shows promising prognostic value while maintaining simplicity. However, larger validating studies are needed. While all of these systems have their strengths, the lack of a unified classification and staging system is still a problem in the diagnosis and prognosis ONFH. Further multi-center collaborative efforts among osteonecrosis experts are needed to adopt a universal classification system that may positively reflect on patient's outcomes.

Early diagnosis and treatment of steroid-induced osteonecrosis of the femoral head.

OBJECTIVE: This study aims to investigate the early diagnosis and treatment of steroid-induced osteonecrosis of the femoral head. PATIENTS AND METHODS: From January 2010 to January 2014, a total of 350 patients, who required the use of large amounts of hormones, were enrolled into the study. These patients were followed up every three months after starting the hormone therapy. A total of 62 cases were screened, among which nine cases were asymptomatic. Furthermore, 38 patients were diagnosed as stage I and were given low-molecular weight heparin (LMWH) and vasodilator drugs. Moreover, 22 cases were diagnosed as stage IIa/b and underwent core decompression. In addition, two cases were diagnosed as stage IIc and underwent pedicled bone transplantation. During the follow-up period, ARCO staging was used for radiological evaluation, the HHS score was applied to evaluate for clinical efficacy, and SPSS 22.0 statistical software was used for the data analysis. RESULTS: A total of 60 patients were followed up for 24 months. Among these patients, 38 patients were diagnosed with ARCO stage I and underwent systematic therapy. No progress was found in 29 cases (76.3%). Furthermore, three cases progressed to stage IIb (7.8%), four cases progressed to stage IIc (10.5%), two cases progressed to stage III and IV, respectively (2.6%), and 16 cases (80%) did not progress after core decompression. In the 16 cases at stage IIa and four cases at stage IIb, and four cases (20%) progressed in stage III. The HHS score of stage I was 80.42 ± 3.25 before follow-up, while the HHS score was 86.46 ± 8.54 after follow-up, and the difference was statistically significant (P < 0.05). Furthermore, the HHS score of patients with stage IIa/b was 70.38 ± 4.62 before follow-up, while the HHS score was 80.28 ± 6.72 after follow-up, and the difference was statistically significant (P < 0.01). CONCLUSION: MRI remains as the most effective method for the non-invasive diagnosis of osteonecrosis, at present. Enhanced MRI may be able to detect early osteonecrosis, but further research is needed. Drug treatment and core decompression can achieve satisfactory results at the early stage.

Etiologic Classification Criteria of ARCO on Femoral Head Osteonecrosis Part 1: Glucocorticoid-Associated Osteonecrosis.

BACKGROUND: Glucocorticoid usage, a leading cause of osteonecrosis of the femoral head (ONFH), and its prevalence was reported in 25%-50% of non-traumatic ONFH patients. Nevertheless, there have been no unified criteria to classify glucocorticoid-associated ONFH (GA-ONFH). In 2015, the Association Research Circulation Osseous addressed the issue of developing a classification scheme. METHODS: In June 2017, a task force was set up to conduct a Delphi survey concerning ONFH. The task force invited 28 experts in osteonecrosis/bone circulation from 8 countries. Each round of the Delphi survey consists of questionnaires, analysis of replies, and feedback reports to the panel. After 3 rounds of the survey, the panel reached a consensus on the classification criteria. The response rates were 100% (Round 1), 96% (Round 2), and 100% (Round 3), respectively. RESULTS: The consensus on the classification criteria of GA-ONFH included the following: (1) patients should have a history of glucocorticoid use >2 g of prednisolone or its equivalent within a 3-month period; (2) osteonecrosis should be diagnosed within 2 years after glucocorticoid usage, and (3) patients should not have other risk factor(s) besides glucocorticoids. CONCLUSION: Association Research Circulation Osseous established classification criteria to standardize clinical studies concerning GA-ONFH.

Etiologic Classification Criteria of ARCO on Femoral Head Osteonecrosis Part 2: Alcohol-Associated Osteonecrosis.

BACKGROUND: Although alcohol is a leading risk factor for osteonecrosis of the femoral head (ONFH) and its prevalence reportedly ranges from 20% to 45%, there are no unified classification criteria for this subpopulation. In 2015, Association Research Circulation Osseous decided to develop classification criteria for alcohol-associated ONFH. METHODS: In June of 2017, Association Research Circulation Osseous formed a task force to conduct a Delphi survey. The task force invited 28 experts in osteonecrosis/bone circulation from 8 countries. Each round of the Delphi survey included questionnaires, analysis of replies, and feedback reports to the panel. After 3 rounds of the survey, consensus was reached on the classification criteria. The response rates for the 3 Delphi rounds were 100% (round 1), 96% (round 2), and 100% (round 3). RESULTS: The consensus on the classification criteria of alcohol-associated ONFH included the following: (1) patients should have a history of alcohol intake >400 mL/wk (320 g/wk, any type of alcoholic beverage) of pure ethanol for more than 6 months; (2) ONFH should be diagnosed within 1 year after alcohol intake of this dose; and (3) patients should not have other risk factor(s). CONCLUSION: ARCO-established classification criteria to standardize clinical studies concerning AA-ONFH.

[Imaging and classification of avascular femoral head necrosis]. / Bildgebung und Klassifikation der aseptischen Hüftkopfnekrose.

Avascular femoral head necrosis (AVNFH) is difficult to diagnose on plain radiographs in early stages of the disease. Since early stages are often clinically occult, early use of MRI is required to rule out or verify a clinical suspicion. MRI and, in some cases, additional CT are the cornerstones of AVNFH diagnosis and classification. Anteroposterior radiography of the pelvis and a second plane of the involved hip remains the primary basic imaging examination for follow-up and to rule out other pathologies. Correct staging of adult disease has been shown to be the key factor in therapeutic decision-making. According to the German S3 guideline on diagnosis and treatment of AVNFH, use of the ARCO classification is recommended for staging. This paper presents the current status of diagnosis and classification of adult AVNFH. The criteria for ascribing disease to a particular ARCO stage are defined and critically discussed.

A new 3D printed titanium metal trabecular bone reconstruction system for early osteonecrosis of the femoral head.

Presently, biomechanical support therapy for the femoral head has become an important approach in the treatment of early osteonecrosis of the femoral head (ONFH). Previous studies have reported that the titanium metal trabecular bone reconstruction systems (TMTBRS) achieved satisfactory clinical results for the treatment of early femoral head necrosis. Electron beam melting technology (EBMT) is an important branch of 3D printing technology, which enables the construction of an interface that is required for support of bone in-growth. However, the effect of TMTBRS created using EBMT for clinical applications for early ONFH is still unknown. At present, there are no reports on this topic worldwide. The purpose of this study was to assess the safety of a new 3D printed TMTBRS implant and to evaluate its clinical efficacy in early ONFH.Thirty patients who underwent surgery for ONFH were selected. The stages of ONFH were classified according to the Association Research Circulation Osseus (ARCO) classification. They were followed-up and radiological examination was performed at 6, 12, and 24 months post-surgery to assess TMTBRS stability and bone growth in the bone trabecular holder portion surface. To evaluate hip function, postoperative Harris and Visual Analogue Scale (VAS) scores were used.The postoperative Harris score increased significantly and VAS score decreased significantly at the 12-month follow-up compared to the 24-month follow-up, wherein the Harris score declined slightly and the VAS score was slightly elevated with the aggravation of ONFH. With the passage of time, postoperative improvement rates were 100% for IIA, 70% for IIB, and 0% for IIC. Hip-preserving rates were 100% for IIA, 100% for IIB, and 50% for IIC.The effect of TMTBRS treatment for early ONFH in ARCO IIA and ARCO IIB is satisfactory. However, it is not recommended for a relatively large area of necrosis such as in ARCO IIC.

A simple, precocious, and reliable way to assess future clinical outcome in children with Perthes disease and mild femoral head involvement: correlation between MRI with diffusion-weighted and dynamic gadolinium-enhanced subtraction and Catterall and Herring classifications.

BACKGROUND: In children older than 5 years with a mild form of Legg-Calvé-Perthes disease, the outcome is difficult to predict. In this study, we retrospectively correlated gadolinium-enhanced subtracted (DGS) and diffusion (DWI) MRI findings to the radiographic assessment according to the Catterall and Herring et al. classifications and to the final score according to Stulberg et al.: the aim was to identify a precocious, simple, and objective criterion to differentiate between forms evolving favourably and forms requiring an early surgical treatment in order to avoid femoral head deformity and subsequent osteoarthritis. METHODS: Twelve boys with unilateral mild femoral head involvement (Catterall grade 2 or grade 3) underwent DSG and DWI MR during the early phase of the disease. The absence of enhancement of the external pillar on DSG MRI and the presence of metaphyseal hyperintensity on DWI were considered to be the signs of poor outcome. These findings were correlated with the Catterall and Herring et al. classifications at the initial sclerotic stage and early fragmentation phase and with the Stulberg et al. classifications at least 5 years after the onset of the disease. RESULTS: DSG MRI findings correctly discriminated three out of four patients with a good outcome but underestimated two out of eight patients with a poor outcome. DWI findings correlated with the Catterall and Herring et al. classifications in 12 out of 12 cases. In only one case, DWI findings did not correlate with the Stulberg et al. classification. CONCLUSION: DWI MR provides an objective and accurate prognostic criterion that is relatively easy to recognise. DGS MR findings are less accurate, thus underestimating the gravity of the disease in one-fourth of the patients with a poor outcome.

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.

Osteonecrosis of the Femoral Head and Hip Arthritis in an Adolescent Following an Isolated Fracture of the Greater Trochanter: A Case Report and Review of the Literature.

CASE: A healthy adolescent sustained an isolated fracture of the greater trochanter after falling from a height. He was treated nonoperatively. After 10 weeks of improvement, the pain recurred, and osteonecrosis of the femoral head was diagnosed. Core decompression and a bone-marrow injection were performed. Transient relief was achieved, followed by deterioration to end-stage hip arthritis. CONCLUSION: To our knowledge, 19 other cases of isolated fractures of the greater trochanter in adolescents have been reported since 1905. All high-energy injuries (10 cases) progressed to osteonecrosis, independent of the intervention; none of the low-energy cases progressed to osteonecrosis. We advocate vigilance and early magnetic resonance imaging for these injuries to detect and treat osteonecrosis in its early stages.

Imaging of osteonecrosis of the femoral head.

Osteonecrosis of the femoral head is a common disease affecting both children and adults causing acute hip pain and functional impairment. Among the various techniques allowing a correct diagnosis, MRI represents the gold standard for an early detection, the latter being useful for a positive outcome. The purpose of this review is to describe the imaging findings of the osteonecrosis of the femoral head.

Hip resurfacing for osteonecrosis: two- to 18-year results of the Conserve Plus design and technique.

AIMS: Hip resurfacing arthroplasty (HRA) is an alternative to conventional total hip arthroplasty for patients with osteonecrosis (ON) of the femoral head. Our aim was to report the long-term outcome of HRA, which is not currently known. PATIENTS AND METHODS: Long-term survivorship, clinical scores and radiographic results for 82 patients (99 hips) treated with HRA for ON over a period of 18 years were reviewed retrospectively. The mean age of the 67 men and 15 women at the time of surgery was 40.8 years (14 to 64). Patients were resurfaced regardless of the size of the osteonecrotic lesion. RESULTS: The mean clinical follow-up was 10.8 years (2 to 18). The mean University of California, Los Angeles hip scores at the last follow-up were 9.3, 9.4, 9.2 and 6.8 for pain, walking, function and activity, respectively. A total of six hips underwent revision surgery, four for loosening of the femoral component and two for loosening of the acetabular component. Using any revision as an end point, the 15-year Kaplan-Meier survivorship was 90.3%. There were no wear-related failures. There were no femoral failures among the hips reconstructed with a cemented metaphyseal stem. A total of five hips showed narrowing of the femoral neck; all stabilised and remain asymptomatic, 21 showed signs of femoral neck impingement. CONCLUSION: To our knowledge, this is the first report of a series of HRA performed for ON with 15-year survivorship. Our data confirm that patients with advanced stages of ON of the femoral head are excellent candidates for HRA. Cite this article: Bone Joint J 2016;98-B:901-9.