Classification of osteonecrosis of the femoral head. Reliability, reproducibility, and prognostic value

Collapse-related bone changes at multidetector CT in ARCO 1-2 osteonecrotic femoral heads: correlation with clinical and MRI data

OBJECTIVE

To assess the frequency of collapse-related bone changes at multi-detector CT (MDCT) in osteonecrotic femoral heads (ONFH) and to compare clinical parameters and MRI findings in Association Research Circulation Osseous (ARCO) 1-2 ONFH with or without collapse-related bone changes (CRBC) at MDCT.

MATERIALS AND METHODS

This is a secondary analysis of radiographic, MRI, and MDCT examinations of ONFH of patients eligible for a prospective clinical trial. Radiographs and MRI were analyzed to perform ARCO staging. Frequency of CRBC at MDCT including cortical interruption, trabecular interruption, impaction, and resorption was determined by two readers (R1, R2) blinded to radiographic, MRI, and clinical data. Baseline clinical and imaging data of ARCO 1-2 ONFH were compared between hips with or without CRBC at MDCT.

RESULTS

One hundred thirty-two hips of 77 participants were analyzed. There were 78 non-collapsed and 54 collapsed ONFH. For R1 and R2, 31/78 (40%) and 20/78 (26%) ARCO 1-2 ONFH and 54/54 (100%) and 53/54 (98%) ARCO 3-4 ONFH showed at least one CRBC at MDCT. For both readers, there was no significant difference in pain, functional impairment, size of lesion, and the presence of BME on MRI between ARCO 1-2 hips with or without CRBC at MDCT.

CONCLUSION

Twenty-six to forty percent of ARCO 1-2 ONFH demonstrate at least one collapse-related bone change at CT. Their clinical and MRI findings do not differ from those without collapse-related bone changes.

KEY POINTS

• Ninety-eight to one hundred percent of collapsed and 26-40% of non-collapsed osteonecrotic femoral heads presented at least one collapse-related bone change at CT (cortical or trabecular bone interruption, trabecular bone impaction, or resorption). • There was no significant difference in age, sex, pain, functional impairment, size of lesion, or frequency of marrow edema on MRI between non-collapsed hips with or without collapse-related bone changes at CT. • The significance of collapse-related bone changes at CT should be further assessed.

Steroid-induced osteonecrosis

Osteonecrosis associated with the use of glucocorticoids is a severe, potentially debilitating complication. In broader terms, it commonly involves the femoral head with secondary hip osteoarthritis. Osteonecrosis can also be caused by trauma and other non-traumatic factors besides steroid treatment. Nonetheless, glucocorticoid use is frequently observed in clinical settings in which this represents a common therapeutic option, including general practice, rheumatology and clinical immunology, among others. The pathogenesis involves genetic components, vascular impairment, adipocyte hypertrophy, and increased intraosseous pressure, ultimately leading to marrow and bone ischemia and necrosis and the process rapidly becomes irreversible. Osteonecrosis manifests with pain and impaired motility while the diagnosis is usually made with magnetic resonance imaging allowing early detection and potentially (dependent on the patient's needs for steroids and stage) timely management with conservative options, followed by joint replacement at late stages. In this review we discuss the pathogenesis, risk factors, diagnosis, staging, and management of this complication associated with glucocorticoid treatment.

Osteonecrosis of the Femoral Head: A Multidisciplinary Approach in Diagnostic Accuracy

Osteonecrosis of the Femoral Head (ONFH) is a disabling disease affecting up to 30,000 people yearly in the United States alone. Diagnosis and staging of this pathology are both technically and logistically challenging, usually relying on imaging studies. Even anatomopathological studies, considered the gold standard for identifying ONFH, are not exempt from problems. In addition, the diagnosis is often made by different healthcare specialists, including orthopedic surgeons and radiologists, using different imaging modes, macroscopic features, and stages. Therefore, it is not infrequent to find disagreements between different specialists. The aim of this paper is to clarify the association and accuracy of ONFH diagnosis between healthcare professionals. To this end, femoral head specimens from patients with a diagnosis of ONFH were collected from patients undergoing hip replacement surgery. These samples were later histologically analyzed to establish an ONFH diagnosis. We found that clinico-radiological diagnosis of ONFH evidences a high degree of histological confirmation, thus showing an acceptable diagnostic accuracy. However, when the diagnoses of radiologists and orthopedic surgeons are compared with each other, there is only a moderate agreement. Our results underscore the need to develop an effective diagnosis based on a multidisciplinary approach to enhance currently limited accuracy and reliability.

PCA-Assisted Raman Analysis of Osteonecrotic Human Femoral Heads

Osteonecrosis of the femoral head (ONFH) occurs frequently in adolescents and young adults and causes progressive deformation and destruction of the hip joint and impairs standing and walking, resulting in a significant decrease in the quality of life of patients. In addition, studies have shown that a history of corticosteroid administration and heavy alcohol consumption are closely related to the occurrence of ONFH. However, the detailed mechanism by which steroid administration and alcohol consumption are associated with the development of the disease is still unknown. With many researches still ongoing and without a clear biological pathway for osteonecrosis, effective preventive measures cannot be taken. Therefore, the current focus of ONFH treatment is to establish an early diagnosis and treatment strategy. We obtained the femoral heads of four patients with steroidal ONFH and three patients with alcoholic ONFH. We then compared the femoral heads of steroidal and alcoholic osteonecrosis by analyzing them at the molecular level by Raman spectroscopy. Crystallographic changes (deformations) in the mineral phase and fraction of organic material respect to the total mass were then plotted as a function. We found that changes in bone composition in ONFH were different in steroidal and alcoholic ONFH. We conclude that this suggests that the developmental mechanisms of steroidal and alcoholic ONFH may follow different paths. We also noticed that while steroid seem to lead to a more marked degradation of the tissue, alcohol seem to affect also the quality of the healthy tissue.

Treatment of aseptic osteonecrosis of the femoral head: Historical aspects

The treatment of aseptic osteonecrosis (ON) of the femoral head has been the subject of numerous therapeutic and surgical proposals due to the absence of medical treatment with proven efficacy. For many years, the goal of surgical treatment was to avoid total hip replacement (THR) with uncertain survival in patients considered too young (30-50 years) for this procedure. Numerous conservative treatments were thus proposed: core decompression with numerous variants, non-vascularized and vascularized bone grafts, intertrochanteric and rotational transtrochanteric osteotomies, cementing. The lack of a common classification and a lack of knowledge of natural history complicated the interpretation of the results for a long time. Nevertheless, it appeared that these treatments were effective only in the very early stages and among these in the limited ONs, medial rather than central and especially lateral, with discrepancies according to etiologies apart from sickle cell disease recognized by all as being pejorative. For the same reason, partial arthroplasties have been attempted and abandoned in turn: femoral head total and partial resurfacing and femoral prosthesis. The most recent advances are stem-cell-enhanced core decompression and progress in total arthroplasty, whose reliability has made it possible to extend the indications to increasingly younger patients seeking treatment with guaranteed or near-guaranteed efficacy. Most of the other interventions have disappeared or almost disappeared because of their lack of effectiveness especially in extensive and post-fracture ONs, sometimes because of their complexity and the length of their post-operative management, and also because they complicate and penalize a future total arthroplasty. This argues for early detection of ON at an early stage where the "head can be saved" by stem cell augmented core decompression, a minimally invasive treatment that leaves the chances of success of a THR intact.

Topology of microfractures in osteonecrotic femoral heads at μCT and histology

AIM

To assess the topology of bone and cartilage microfractures in osteonecrotic femoral heads.

METHOD

Sixteen resected human femoral heads with collapsed osteonecrosis (ON, n = 11) or osteoarthritis (OA, n = 5) were imaged at μCT with 12 μ nominal resolution. Forty-seven histological sections and μCT reformats with (n = 30) or without (8 from ON and 9 from OA femoral heads) osteonecrotic lesions were obtained and divided in 2 × 2 mm segments by a superposed grid. A radiologist and a pathologist separately assessed the presence of bone and cartilage microfractures in each segment on μCT and histological images, respectively. We determined the frequency and distribution of segments with bone microfractures according to a zonal distribution. Matrix analysis was performed by using Matlab to calculate the connectivity index and long/short axis ratios of clustered segments with microfractures.

RESULTS

Segments with bone microfractures but not with cartilage microfractures were found more frequently in ON than in OA femoral heads. In the 38 matched μCT and histological images from ON femoral heads, 86%/82% of segments with cortical microfracture, 91%/96% of segments with trabecular microfractures involved ON lesions at μCT/histology. At histology, 83% of segments with cartilage microfractures involved ON lesions. In the 30 paired μCT and histological images containing necrotic lesions, the frequency of segments with trabecular microfractures in the superficial layers (55% at μCT/51% at histology) was statistically significantly higher than in the deep layer (25% P < 0.0001/35%; P = 0.0006). Clustered segments with cortical/trabecular microfractures, exclusively found in osteonecrotic lesions, had a connectivity index >2.0/20.0 and mean long/short axis ratio > 2.35/2.2, respectively.

CONCLUSION

Segments with bone microfractures predominate in necrotic lesions. Segments with trabecular microfractures form elongated clusters near the femoral head surface.

Core decompression with bone chips allograft in combination with fibrin platelet-rich plasma and concentrated autologous mesenchymal stromal cells, isolated from bone marrow: results for the treatment of avascular necrosis of the femoral head after 2 years minimum follow-up

INTRODUCTION

Avascular necrosis of femoral head (AVN) is 1 of the main factors causing disability in young adults. Hip prosthesis can be considered an effective treatment of the painful symptoms but it is a major surgical intervention for this type of population. Thus, a large space should be left to therapeutic alternatives such as regenerative medicine.This retrospective study evaluates 52 AVN treated by core decompression, bone chips allograft, fibrin platelet-rich plasma (PRF) and concentrated autologous mesenchymal stromal cells (MSCs).

METHODS

The AVN was diagnosed using magnetic resonance imaging (MRI) and graded according to ARCO classification: a patient was classified stage 1 (21 patients), stage 3 (26 patients), and 4 patients were classified as stage 4. We evaluated patients with functional scores (Harris Hip Score) and radiological analysis at 3, 6, 12 and 24 months after the procedure. Patients requiring prosthetic replacement of the joint were included; in these cases, follow-up was interrupted at the time of the joint replacement procedure.

RESULTS

Our statistical analysis showed differences between survived and failed treatments, in terms of patient profile and ARCO radiological classification.The best result occurred in patients with ARCO grades 1 and 2, while the more advanced grades showed a high failure rate. It is interesting to note that ARCO quantification, conceived as the joint surface involved in the necrosis, has a negative influence on the outcome of the procedure. Indeed, patients affected by ARCO 3a, where necrosis involved a small portion of the femoral epiphysis and the collapse of the articular surface was limited to 2 mm, showed results similar to those obtained in patients with ARCO 1 and 2.

CONCLUSIONS

In conclusion, compared with the alternative technique of decompression, our data suggest that post-collapse cases with a small area of necrosis and the use of bone grafts may show better results compared to those of the literature.

Bone marrow lesion on magnetic resonance imaging indicates the last chance for hip osteonecrosis treated with vascularized fibular grafting before collapse

PURPOSE

Timing of surgery is the most critical prognostic factor for hip osteonecrosis treated with free vascularized fibular grafting (FVFG). Bone marrow lesion (BML) on MRI usually occurs immediately before femoral head collapse. We conducted a retrospective cohort study to evaluate whether the noncollapsed hips with BML can benefit from FVFG.

METHODS

Consecutive patients undergoing modified FVFG were identified from our clinical repository between January 2014 and December 2014. Based on whether BML was pre-operatively detected, the four year radiographic and clinical outcomes were compared.

RESULTS

In the BML cohort, 22 of 53 hips (42%) showed radiographic signs of osteonecrosis progression, which was significantly higher than that in the control cohort (8 of 49, 16%; P = 0.005). The BML hips showed a significantly lower pre-operative Harris Hip Score (HHS) than those without BML (77.8 vs. 85.5, P = 0.046), whereas no such difference was observed in the final HHS or its post-operative improvement (HHS 90 vs. 94, P = 0.397; HHS improvement 12 vs. 8, P = 0.067). In the subgroup of patients with a pre-operative HHS lower than 80, BML hips were associated with a slightly lower final HHS than hips without BML. Four of 5 (80%) failed hips with BML had a poor pre-operative hip function.

CONCLUSION

BML indicates the last chance for a reproducible improvement in the treatment of hip osteonecrosis with FVFG before collapse. However, the concomitant lower pre-operative HHS (< 80) is a poor prognostic factor for BML-positive hips.

Comparison of core decompression and porous tantalum rod implantation with conservative treatment for avascular necrosis of the femoral head: A minimum 18 month follow-up study

Porous tantalum rod implantation is a novel surgical method that is used to treat avascular necrosis (AVN) of the femoral head (hip). In the present study, the results of core decompression and tantalum rod implantation were compared with non-surgical treatment for AVN, and the survivorship of the femoral head was evaluated. In total, 60 patients with AVN femoral head were recruited and analysed. Non-surgical treatment was selected by 30 patients (41 hips), 7 with a Ficat score of I and 23 with a score of II. Non-surgical treatment included celecoxib, salvia miltiorrhiza and tetramethylypyrazine and a reduction in weight-bearing activities. Surgical treatment and porous tantalum rod implantation were selected by 30 patients (41 hips), 10 with a Ficat score of I and 20 with a score of II. After follow-up (average: 33.5 months), patients were evaluated by assessing post-operative complications, radiology, hip survivorship and Harris hip score. In the surgical group, pre-operative symptoms were significantly alleviated. No complications, including infection, delayed healing or fractures were reported. Final follow-up rates of femoral head survivorship were 4.9% in the non-surgical group and 36.7% in the surgical group. The Harris hip score was significantly improved following surgery when compared with non-surgical treatment (P<0.05). The results indicated that core decompression and porous tantalum rod implantation are beneficial short- and mid-term treatment methods for AVN of the femoral head.

The 2019 Revised Version of Association Research Circulation Osseous Staging System of Osteonecrosis of the Femoral Head

BACKGROUND

The Association Research Circulation Osseous (ARCO) presents the 2019 revised staging system of osteonecrosis of the femoral head (ONFH) based on the 1994 ARCO classification.

METHODS

In October 2018, ARCO established a task force to revise the staging system of ONFH. The task force involved 29 experts who used a web-based survey for international collaboration. Content validity ratios for each answer were calculated to identify the levels of agreement. For the rating queries, a consensus was defined when more than 70% of the panel members scored a 4 or 5 rating on a 5-point scale.

RESULTS

Response rates were 93.1%-100%, and through the 4-round Delphi study, the 1994 ARCO classification for ONFH was successfully revised. The final consensus resulted in the following 4-staged system: stage I-X-ray is normal, but either magnetic resonance imaging or bone scan is positive; stage II-X-ray is abnormal (subtle signs of osteosclerosis, focal osteoporosis, or cystic change in the femoral head) but without any evidence of subchondral fracture, fracture in the necrotic portion, or flattening of the femoral head; stage III-fracture in the subchondral or necrotic zone as seen on X-ray or computed tomography scans. This stage is further divided into stage IIIA (early, femoral head depression ≤2 mm) and stage IIIB (late, femoral head depression >2 mm); and stage IV-X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes, and/or joint destruction. This revised staging system does not incorporate the previous subclassification or quantitation parameters, but the panels agreed on the future development of a separate grading system for predicting disease progression.

CONCLUSION

A staging system has been developed to revise the 1994 ARCO classification for ONFH by an expert panel-based Delphi survey. ARCO approved and recommends this revised system as a universal staging of ONFH.

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.

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.

Fast sequences MR imaging at the investigation of painful skeletal sites in patients with hip osteonecrosis

BACKGROUND

Multiple osteonecrotic foci can be clinically silent when located in metaphyses and becomes painful when it affects juxta-articular areas. The purpose of this study was to assess the value of fast MR imaging to depict the underlying pathology in cases with skeletal pain other than the already diagnosed hip osteonecrosis.

METHODS/DESIGN

Between 2008 and 2013, 49 patients with already diagnosed hip osteonecrosis reported symptoms of deep skeletal pain in an anatomical site different from the affected hip joint. All patients after thorough history & clinical examination underwent evaluation with x-rays and a single fat suppressed sequence with MR Imaging applying either T2-w TSE or STIR-TSE at the painful site. False positive and false negative findings were recorded for the conventional x-rays and compared to MRI.

DISCUSSION

Forty four (89.8%) patients were positive for osteonecrotic lesions in this study and 76 symptomatic osteonecrosis lesions were revealed at 14 distinct anatomic sites. The agreement between the x-ray findings and the MR imaging regarding osteonecrosis was 46.9%. Plain x-rays showed 43.4% sensitivity, 100% specificity, 100% positive predictive value and 10.4% negative predictive value. Fast MR imaging with fat suppressed sequences is necessary and adequate as a single method for the investigation of painful skeletal sites in patients with already diagnosed hip osteonecrosis. It allows early diagnosis of the potentially debilitating multiple juxta-articular lesions and consequently their prompt management.

Accuracy and limitations of diagnostic methods for avascular necrosis of the hip

INTRODUCTION

Femoral head avascular necrosis (FHAVN) is the result of irreversible anoxia of the subchondral bone. The death of bone cells can cause articular collapse and pain, and in turn usually leads to degenerative arthritis. FHAVN is a common disorder, affecting mainly young male adults. Reliability, accuracy and prognostic value of any classification system are important in evaluation and treatment of FHAVN.

AREAS COVERED

Although in the past, scintigraphy and CT and more recently PET have been used for diagnosing AVN, currently the most important imaging methods included in the most widely used classification systems, consist of radiographs and magnetic resonance imaging (MRI). The latter is used in major classification systems for early detection (pre-radiographic stage) of FHAVN and for assessing lesion size and location before collapse of the articular surface occurs. The purpose of this review is to present the current data regarding the accuracy of the X-rays and MRI in diagnosing, monitoring and postoperative evaluation of FHAVN.

EXPERT OPINION

The author's opinion is that MRI may contribute to improve staging, investigate radiologically occult collapse, depict other causes of disability and pain, assess prognosis and evaluate treatment. Newer MRI techniques, such as diffusion-weighted imaging and perfusion imaging, have not yet provided additional and clinically useful information.

Vascularized fibular grafts in patients with avascular necrosis of femoral head: a systematic review and meta-analysis

BACKGROUND

Vascularized fibular grafting (VFG) has been initiated to treat avascular necrosis of the femoral head (ANFH) since the late 1970s. There are a number of review articles updating the use of VFG to treat the ANFH. None of them applied statistical analysis for combining results from different studies to obtain a quantitative estimate of the overall effect and potential harm of VFG in comparison to other treatment.

METHODS

Several electronic databases were searched to find studies using VFG to treat ANFH. The outcomes sought included Harris Score, failure rate (conversion to total hip arthroplasty (THA) and/or femoral head collapse), and complications rate. Included studies were assessed for methodological bias and estimates of effect were calculated. Potential reasons for heterogeneity were explored.

RESULTS

The clinical results of 69.0 % of VFG-treated patients and 25.0 % of non-VFG-treated patients were good to excellent (OR 0.13; p < 0.01). The conversion rate to THA of VFG-treated and that of other methods treated hips was 16.5 % and 42.6 % (OR 0.19; p < 0.001). Collapse rate of VFG-treated and that of non-VFG-treated hips was 16.7 % and 63.6 % (OR 0.09; p < 0.05). The complication rate of VFG-treated and that of other methods treated patients was 23.8 % and 8.9 % (OR 3.44; p = 0.09). For Steinberg stage I, II ANFH, failure rate of VFG-treated and that of non-VFG-treated hips was 9.8 % and 40.2 % (OR 0.17; p < 0.001). For Steinberg stage II, III ANFH, failure rate of VFG-treated and that of non-VFG-treated hips was 16.5 % and 42.8 %, respectively (OR 0.17; p < 0.001).

CONCLUSIONS

VFG is a justified method that can prevent the ANFH from progressing to collapse, and that can retard or avoid hip replacement, especially in the hips of Steinberg stage I, II, and III.

Which factors influence preservation of the osteonecrotic femoral head?

BACKGROUND

Although surgeons use many procedures to preserve the femoral head in patients with hip osteonecrosis, there is no consensus regarding the best procedure.

QUESTIONS/PURPOSES

We raised the following questions: (1) Is one surgical treatment preferred based on published data? (2) What are the rates of radiographic progression or conversion to THA after treatment of pre- and postcollapse hips? (3) Does lesion size in the femoral head influence progression? And (4) does the extent of involvement of the weightbearing surface of the femoral head influence outcome?

METHODS

We searched MEDLINE and Scopus for articles published between 1998 and 2010. We included only articles assessing an operative intervention for hip osteonecrosis and having a level of evidence of I to IV. We included 54 of the 488 reviewed manuscripts.

RESULTS

No procedure was superior to others. In pre- and postcollapse hips, 264 of 864 hips (31%) and 419 of 850 hips (49%), respectively, exhibited radiographic disease progression. There were lower failure rates when the lesion involved less than 15% of the femoral head or had a necrotic angle of less than 200° (14%-25%) and when the osteonecrotic lesion involved only the medial 1/3 of the weightbearing surface (4.6%).

CONCLUSIONS

The best treatment of precollapse lesions is difficult to determine due to the limitations of the available literature. However, the data suggest operative intervention prevents collapse of small lesions of the femoral head or when there is a limited amount of the weightbearing surface involved. Patients with head collapse have a high progression rate after a femoral head-saving procedure.

Inter-observer and intra-observer reliabilities of the Japanese Ministry of Health, Labor and Welfare type classification system for osteonecrosis of the femoral head

The aim of this study was to clarify the reproducibility of the Japanese Ministry of Health, Labor and Welfare (JMHLW) type classification for osteonecrosis of the femoral head. We performed inter-observer and intra-observer trials using 40 sets of magnetic resonance imagings, 20 of which were produced by a 0.5 Tesla (T) superconductive unit and the other 20 produced by a 1.5 T unit, in patients with non-collapsed and asymptomatic osteonecrosis of the femoral head (JMHLW stage 1 or 2). The JMHLW type classification (A, B, C1, or C2) was determined from T1-weighted coronal images at the center of the femoral head. Six orthopedic surgeons independently assessed all 40 images twice, with an interval of 4-5 weeks between sessions. Regarding inter-observer reliability, the percent agreement was 85% and weighted kappa was 0.709 for 0.5 T, versus a percent agreement of 82% and weighted kappa of 0.724 for 1.5 T. Regarding intra-observer reliability, the percent agreement was 82% and weighted kappa was 0.780 for 0.5 T versus a percent agreement of 80% and weighted kappa of 0.800 for 1.5 T. Inter-observer and intra-observer reliabilities did not differ significantly between the 0.5 and 1.5 T units. The JMHLW type classification provided high inter-observer and intra-observer reliabilities.

To study the role of dynamic magnetic resonance imaging in assessing the femoral head vascularity in intracapsular femoral neck fractures

Intracapsular femoral neck fractures remain unsolved fractures even after improvement in techniques of diagnosis and internal fixation. Individuals who sustain displaced femoral neck fractures are at high risk of developing avascular necrosis and non-union. Although several methods for predicting the viability of femoral head have been reported, they are not effective or widely used because of unreliability, potential complications and technical difficulties. Dynamic MRI was introduced in the recent past as a simple, non-invasive technique to predict the femoral head viability after the femoral neck fractures. In this study role of dynamic MRI was studied in 30 patients with 31 intracapsular femoral neck fractures. Fractures were divided in to three types according to dynamic curve patterns on MRI evaluation and were followed up for 6 months to 2 years to observe the final outcome. Sensitivity, Specificity and the Accuracy of dynamic MRI in predicting vascularity after femoral neck fracture are 87%, 88% and 87%, respectively. Type A or Type B curve pattern is a positive factor to successful osteosynthesis with p value <0.0001 (Chi-square test). This is a statistically significant value. From this finding it can be suggested that the reliability of dynamic curves A and B in predicting maintained vascularity of femoral head is high. This investigation can be used to predict the vascularity of femoral head after intracapsular femoral neck fractures. There was a good correlation between the outcomes of fractures and dynamic MRI curves done within 48 h of injury. This signifies the role of dynamic MRI in predicting the vascularity of femoral head as early as 48 h. A treatment algorithm can be suggested on the basis of dynamic MRI curves. The fractures with Type C dynamic curve should be considered as fractures with poor vascularity of femoral head and measures to enhance the vascularity of femoral head along with rigid internal fixation should be undertaken to promote revascularization process and better healing of fractures. Patients with these fractures should be on longer non-weight bearing ambulation than other patients. To conclude, the dynamic MRI seems to be reliable, non-invasive, sensitive, specific and accurate method of assessing the femoral head vascularity after intracapsular femoral neck fractures as early as 48 h of injury and to predict the outcome of fractures and may be used as a guideline for management of intracapsular femoral neck fractures.

Outcome measures for evaluation of treatments for osteonecrosis

With the advent of cell-based therapies, biologics, and pharmaceuticals for the potential treatment of osteonecrosis, it is important to conduct evaluations using scientifically accepted outcomes measures. For the treatment of osteonecrosis, most studies have focused on pain relief, surgery, or the need for surgery, disease progression (advancing stage), and change in lesion size. Quantification of imaging techniques continue to gain in sophistication but have not yet been validated for use in clinical trials. Despite recent interest in using biomarkers or genetic markers in the diagnosis and analysis of disease progression, more research is needed to determine the sensitivity and specificity of these techniques with respect to osteonecrosis.

Outcome after tantalum rod implantation for treatment of femoral head osteonecrosis: 26 hips followed for an average of 3 years

BACKGROUND AND PURPOSE

Tantalum rod implantation has recently been proposed for treatment of early stages of femoral head osteonecrosis.The purpose of our study was to report the early results of its use in pre- and post-collapse stages of the disease.

METHODS

We studied prospectively 27 patients who underwent tantalum rod implantation for treatment of nontraumatic femoral head osteonecrosis between December 2000 and September 2005. Patients were evaluated radiologically and clinically using the Steinberg classification and the Harris hip score (HHS). Disease stage varied between stages II and IV. Mean follow-up time was 38 (15-71) months.

RESULTS

1 patient (1 hip) died 15 months after surgery for reasons unrelated to it. 13 of 26 hips remained at the same radiographic stage, and 13 deteriorated. Mean HHS improved from 49 to 85. 6 patients required conversion to total hip arthroplasty. When the procedure was used for stages III and IV, both radiological outcome and revision rates were worse than for the stage II hips. There was, however, no difference in postoperative HHS between patients at pre- and post-collapse stages at the time of initial evaluation. Survivorship, with revision to THA as the endpoint,was 70% at 6 years.

INTERPRETATION

The disease process does not appear to be interrupted,but there was a significant improvement in hip function initially in most hips. Tantalum rod implantation is a safe "buy-time" technique, especially when other joint salvage procedures are not an option. Appropriate patient selection and careful rod insertion are needed for favorable results.

Managing femoral head osteonecrosis in patients with sickle cell disease

With an increasing number of people immigrating between different countries, sickle cell disease (SCD) is spreading all over the world. Due to improved health care, the life span of SCD patients has increased and many of them live to adulthood and middle-age. Osteonecrosis of the femoral head is one of the most common musculo-skeletal problems in SCD patients. Once osteonecrosis starts in the femoral head, it can progress from early to late stages in just a few years. Managing osteonecrosis of the femoral head in young-adults is a challenging problem and, in many situations, it requires major surgical procedures. In the early stages of the disease it is advisable to treat it by femoral head preserving procedures. In advanced stages, hip replacement arthroplasty (HPA) is indicated. In SCD patients, the incidence of operative complications and failure rates are higher than that for osteonecrosis due to other causes. Understanding the problems of SCD patients; appropriate diagnosis, prognosis, implications of the procedure performed and taking the necessary precautions, can reduce the complications and delay the failure of surgical procedures.

The role of MR imaging in staging femoral head osteonecrosis

Reliability, accuracy and prognostic value of any classification system are important in evaluation and treatment of femoral head osteonecrosis. The purpose of the present study was to correlate the plain radiographs with MRI in femoral head osteonecrosis. Between 2000 and 2005, 115 hips (72 patients) were evaluated and classified according to the ARCO classification criteria with the use of plain radiographs and additional application of MRI. Classification was performed by consensus between a musculoskeletal radiologist and an orthopaedic surgeon. Sensitivity (SEN), specificity (SP), positive (PPV) and negative (NPV) predictive value of X-rays were estimated. According to MRI, 17 hips were classified as stage I, 25 as stage II, 48 as stage III and 25 as stage IV. The SEN, SP, PPV and NPV of plain radiographs were for stage II 88%, 90.5%, 78.6% and 95%; for stage III 79.2% 82%, 80.8% and 87.2%; for stage IV 76%, 100%, 100% and 90.9%, respectively. The agreement between plain radiographs and MRI was 80.6% for staging the disease, 71.2% for recording the location of the osteonecrotic lesion, 67.1% for evaluating the size of the lesion, 79.2% for the presence of collapse of the articular surface and 56.3% for the degree of collapse. In conclusion, the ARCO classification could miss important information in stages II and III, where treatment aims at preservation of the hip joint integrity. The results of the present study suggest that MRI should be incorporated in the classification of osteonecrosis (stages II and III), to add accuracy and prognostic value.

Femoral head osteonecrosis: volumetric MRI assessment and outcome

Effective treatment of femoral head osteonecrosis (FHON) requires early diagnosis and accurate assessment of the disease severity. The ability to predict in the early stages the risk of collapse is important for selecting a joint salvage procedure. The aim of the present study was to evaluate the outcome in patients treated with vascularized fibular grafts in relation to preoperative MR imaging volumetry. We studied 58 patients (87 hips) with FHON. A semi-automated octant-based lesion measurement method, previously described, was performed on the T1-w MR images. The mean time of postoperative follow-up was 7.8 years. Sixty-three hips were successful and 24 failed and converted to total hip arthroplasty within a period of 2-4 years after the initial operation. The rate of failures for hips of male patients was higher than in female patients. The mean lesion size was 28% of the sphere equivalent of the femoral head, 24+/-12% for the successful hips and 37+/-9% for the failed (p<0.001). The most affected octants were antero-supero-medial (58+/-26%) and postero-supero-medial (54+/-31%). All but postero-infero-medial and postero-infero-lateral octants, showed statistically significant differences in the lesion size between patients with successful and failed hips. In conclusion, the volumetric analysis of preoperative MRI provides useful information with regard to a successful outcome in patients treated with vascularized fibular grafts.

Osteonecrosis of the femoral head: etiology, imaging and treatment

Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usually leads to destruction of the hip joint. A high index of suspicion is necessary for the diagnosis due to the insidious onset of the bone infarcts and the lack of specific clinical signs at the early stages. Many etiology-associated factors have been identified reducing thus the number of idiopathic cases. A number of joint salvaging treatment options are available if early diagnosis can be achieved. MR imaging has been proved to be a highly accurate method both for early diagnosis and for staging of the disease. Replacement of the hip joint is the last resort for pain relief and function, although non-desirable because of the young age of the affected population.

[Differential diagnoses of avascular necrosis of the femoral head. Articular groin pain in adults]

Early diagnosis and therapy of hip joint complaints in the young adult are often crucial for the prognosis of the joint. Besides avascular necrosis of the femoral head several differential diagnoses are possible, which if left untreated frequently lead to early osteoarthritis. The necessity of joint replacement in middle age often could be avoided by initiating adequate therapy as early as possible. The early diagnosis of aseptic necrosis of the femoral head at an early stage is possible with MRI. Especially in consideration of decreasing budgets MRI is dispensable for other diagnosis, e.g. hip dysplasia, femoroacetabular impingement or coxitis. On the other hand para-articular causes and non-orthopaedic diseases must also be considered, which remain hidden to classic orthopaedic diagnostics. Important differential diagnoses of groin pain in the adult, with emphasis on articular illnesses, are described.

From marrow oedema to osteonecrosis: common paths in the development of post-transplant bone pain

Osteonecrosis, the calcineurin-inhibitor-induced pain syndrome and transient marrow oedema may occur after renal transplantation, are generally painful and can be diagnosed by X-ray, radionuclide scan or magnetic resonance imaging. They share features of increased intraosseous pressure, compromised vascular supply, marrow oedema and the development of a 'bone compartment syndrome'. Glucocorticoid dosage is the most commonly implicated risk factor for osteonecrosis. Mechanisms may include the differentiation of mesenchymal stem cells to adipocytes causing increased intraosseous pressure and collapse of marrow sinusoids, as well as increased osteoblast and osteocyte apoptosis. Some of these effects may be ameliorated by lipid lowering drugs. Calcineurin-inhibitors, particularly cyclosporine, may increase the risk of osteonecrosis because of vasoconstrictive effects and sirolimus may influence the development of osteonecrosis by potentiating the effects of calcineurin inhibitors or by influencing the lipid profile. For osteonecrosis, early stages are generally managed conservatively or with core decompression sometimes accompanied by bone grafting and more recently the injection of bone morphogenic protein. The use of iloprost to improve blood flow and bisphosphonates and RANK-ligand inhibition to reduce osteoclastic resorption of remaining trabecular structures are as yet unproven strategies. Unfortunately, the rate of total hip arthroplasty remains high. For the calcineurin-inhibitor-induced pain syndrome and transient marrow oedema, calcium channel blockers, the reduction or withdrawal of calcineurin-inhibitors and core decompression have been used. Although a lack of randomized controlled trials makes management decisions difficult, early recognition of these bone pain syndromes affords the best opportunity for avoiding prolonged pain or joint replacement surgery.

Physical therapy alone compared with core decompression and physical therapy for femoral head osteonecrosis in sickle cell disease. Results of a multicenter study at a mean of three years after treatment

BACKGROUND

Osteonecrosis of the femoral head is a common complication in patients with sickle cell disease, and collapse of the femoral head occurs in 90% of patients within five years after the diagnosis of the osteonecrosis. However, the efficacy of hip core decompression to prevent the progression of osteonecrosis in these patients is still controversial.

METHODS

In a prospective multicenter study, we evaluated the safety of hip core decompression and compared the results of decompression and physical therapy with those of physical therapy alone for the treatment of osteonecrosis of the femoral head in patients with sickle cell disease. Forty-six patients (forty-six hips) with sickle cell disease and Steinberg Stage-I, II, or III osteonecrosis of the femoral head were randomized to one of two treatment arms: (1) hip core decompression followed by a physical therapy program or (2) a physical therapy program alone. Eight patients withdrew from the study, leaving thirty-eight who participated.

RESULTS

Seventeen patients (seventeen hips) underwent decompression combined with physical therapy, and no intraoperative or immediate postoperative complications occurred. Twenty-one patients (twenty-one hips) were treated with physical therapy alone. After a mean of three years, the hip survival rate was 82% in the group treated with decompression and physical therapy and 86% in the group treated with physical therapy alone. According to a modification of the Harris hip score, the mean clinical improvement was 18.1 points for the patients treated with hip core decompression and physical therapy compared with 15.7 points for those treated with physical therapy alone. With the numbers studied, the differences were not significant.

CONCLUSIONS

In this randomized prospective study, physical therapy alone appeared to be as effective as hip core decompression followed by physical therapy in improving hip function and postponing the need for additional surgical intervention at a mean of three years after treatment.

Osteoarticular Manifestations of Antiphospholipid Syndrome

In conclusion, arthralgias represent a rather common osteoarticular manifestation of primary and secondary APS, while arthritis is mainly described in SLE-related APS. Osteonecrosis is frequently described in association with aPL in patients with and without autoimmune disorders. The presence of osteonecrosis in primary APS patients in the absence of corticosteroid use suggests an association between osteonecrosis and APS. Clinicians should be aware of this possible clinical manifestation of APS, because early diagnosis may lead to early management. A systematic screening for aPL in all cases with diagnosed osteonecrosis in the absence of precipitating factors should be considered.

Fractures of the hip in children

Fractures of the hip are uncommon in children, and their importance is related not to the frequency of the injury but to the frequency of complications. Many of these complications can be minimized or avoided by anatomic reduction and internal fixation. Open reduction frequently is necessary to obtain a stable, anatomic reduction. Regardless of the age of the child, stable fixation of the fracture must be given priority over preservation of the proximal femoral physis. The development of osteonecrosis, however, is most likely related to the severity of the initial injury and is largely unaffected by treatment of the fracture.

Classification systems for osteonecrosis: an overview

Currently a number of classification systems for osteonecrosis are in use. The use of different systems often leads to confusion and makes it difficult to compare the results of different methods of treatment. Because the management of osteonecrosis is determined in large part by the stage of the disease, it is important to use an effective and reliable method of staging and classification. This article provides an overview of the systems most commonly used so the reader can better understand and compare the outcome of studies that report their results using different methods of classification. The essential features of the ideal system are outlined to enable the reader to decide which of the available classification systems best meets these goals.

Treatment of femoral head osteonecrosis using bone impaction grafting

Even in extensive osteonecrosis of the femoral head in younger patients, a femoral head-preserving method is preferable. We developed a new technique using the lateral approach as used in traditional core biopsy; the osteonecrotic lesion was removed and impacted bone grafts were used to regain sphericity and prevent collapse. In this prospective one surgeon study, we included 28 consecutive hips in 27 patients with extensive osteonecrotic lesions (ARCO classification Stage 2 [11 hips], Stage 3 [14 hips]; and Stage 4 [three hips]); 14 hips had preoperative collapse. The mean age of the patients was 33 years (range, 15-55 years). At a mean followup of 42 months (range, 24-119 months), eight hips (29%) were converted to a total hip arthroplasty (THA). Of the 20 reconstructions that were in situ, 18 were clinically successful (90%) and 70% were radiologically successful. Patients who were younger than 30 years at surgery had a radiologically significant better outcome, even patients with higher stages of osteonecrosis. Patients with preoperative collapse and use of corticosteroids had disappointing results. This method is attractive as a salvage procedure, is relatively simple and quick, and it does not interfere with an eventual future hip arthroplasty.

Cementation for femoral head osteonecrosis: a preliminary clinic study

Treatment for femoral head osteonecrosis has been less successful in late stages of the disease, after progression to collapse. The current authors treated 21 patients (22 hips) with Stage III osteonecrosis by a technique of open reduction and fixation with methylmethacrylate cement (cementation). The followup ranged from 1 to 3 years (average, 1.7 years). Patient progress was followed using preoperative and postoperative Harris hip scores, Western Ontario and McMaster Universities Osteoarthritis Index, and a health status questionnaire (Short Form-36). Patients were staged preoperatively using the Association Research Circulation Osseous international classification system and radiographic evaluation was done intraoperatively and postoperatively. The Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index, and Short Form-36 physical health scores improved significantly from 53.5 to 78.0, 66.0 to 48.1, and 27.0 to 40.0, respectively. The outcome was worse for patients with more advanced disease. Six patients, all with severe disease, had total hip arthroplasty. Cementation is technically simple, enables patients' immediate postoperative pain relief and improvement in mobility, and has the potential to restore and maintain the sphericity of the femoral head after collapse. The high failure rate (27%) at short-term followup, although comparable with other reported techniques, does not support generalized use for Stage III disease. Currently the use of this procedure is restricted to symptomatic, young patients (younger than 40 years), preferably with mild to moderate Stage III disease (degree of head involvement < 30% and degree of collapse < 4 mm).

Free vascularized fibular grafting for the treatment of postcollapse osteonecrosis of the femoral head

BACKGROUND

Osteonecrosis of the femoral head, a disease primarily affecting young adults, is often associated with collapse of the articular surface and subsequent arthrosis. Free vascularized fibular grafting has been reported to be successful for patients with early stages of osteonecrosis, but little is known about its efficacy after the femoral head has collapsed.

METHODS

We retrospectively reviewed the results in a consecutive series of 188 patients (224 hips) who had undergone free vascularized fibular grafting, between 1989 and 1999, for the treatment of osteonecrosis of the hip that had led to collapse of the femoral head but not to arthrosis. The average duration of follow-up was 4.3 years (range, two to twelve years). We defined conversion to total hip arthroplasty as the failure end point, and we analyzed the contribution, to failure, of the size of the lesion, amount of preoperative collapse of the femoral head, etiology of the osteonecrosis, age of the patient, and bilaterality of the lesion. We used the Harris hip score to evaluate clinical status preoperatively and at the time of the most recent follow-up.

RESULTS

The overall rate of survival was 67.4% for the hips followed for a minimum of two years and 64.5% for those followed for a minimum of five years. The mean preoperative Harris hip score was 54.5 points, and it increased to 81 points for the patients in whom the surgery succeeded; 63% of the patients in that group had a good or excellent result. There was a significant relationship between the outcome of the grafting procedure and the etiology of the osteonecrosis (p = 0.017). Patients in whom the osteonecrosis was idiopathic, associated with alcohol abuse, or posttraumatic fared worse than did those with other causes, including steroid use. Survival of the joint was not significantly related to the size of the femoral head lesion, but there was an increased relative risk of conversion to total hip arthroplasty with increasing lesion size and amount of collapse. Neither patient age nor bilaterality significantly affected outcome.

CONCLUSIONS

Patients with postcollapse, predegenerative osteonecrosis of the femoral head appear to benefit from free vascularized fibular grafting, with good overall survival of the joint and significant improvement in the Harris hip score. The results of this femoral head-preserving procedure in patients with postcollapse osteonecrosis are superior to those of core decompression and nonoperative treatment, as reported in the literature. Patients with larger lesions and certain diagnoses, such as idiopathic and alcohol-related osteonecrosis, have worse outcomes.

Vascularized compared with nonvascularized fibular grafting for the treatment of osteonecrosis of the femoral head

BACKGROUND

We are not aware of any clinical studies in the literature comparing the results of vascularized and nonvascularized fibular grafting for the treatment of osteonecrosis of the femoral head. The purpose of this study was to compare the clinical results of free vascularized fibular grafting with those of nonvascularized fibular grafting.

METHODS

Two hundred patients (220 hips) with osteonecrosis of the femoral head were treated with free vascularized fibular grafting at the University of Pittsburgh Medical Center, and ninety-nine patients (123 hips) were treated with nonvascularized fibular grafting at the Kyungpook National University Hospital in Korea. From these populations, two groups of fifty hips each, followed for a minimum of three years (average, five years), were matched by the stage, size, and etiology of the lesion and by the mean preoperative Harris hip score. A retrospective case-control study of these groups was then performed to compare the postoperative Harris hip scores as well as the prevalences of radiographic progression and collapse of the femoral head following free vascularized fibular grafting with those measures following nonvascularized fibular grafting.

RESULTS

The mean Harris hip score improved for 70% of the hips treated with free vascularized fibular grafting: seventeen hips (34%) were rated excellent, fourteen (28%) were rated good, nine (18%) were rated fair, and ten (20%) were rated poor. The mean Harris hip score improved for 36% of the hips treated with nonvascularized fibular grafting: five hips (10%) were rated excellent; nine (18%), good; sixteen (32%), fair; and twenty (40%), poor. The rate of survival at seven years for the Stage-I and II hips (precollapse) was 86% after treatment with free vascularized fibular grafting compared with 30% after nonvascularized fibular grafting.

CONCLUSIONS

The results of this study strongly suggest that vascularized fibular grafting is associated with better clinical and radiographic results.