OSTEONECROSIS OF THE HIP

Influence of avascular necrosis of the femoral head on hip prosthesis integration: a radiological analysis

BACKGROUND

Avascular osteonecrosis of the femoral head (AVN) often results in total hip arthroplasty (THA). The cause for increased THA revision rates among patients with AVN is not yet fully understood.

PURPOSE

To perform a comparative radiological analysis of implant integration between patients with AVN and osteoarthritis (OA).

MATERIAL AND METHODS

After a matched pair analysis of 58 patients, 30 received THA due to OA, 28 due to AVN. X-ray images were evaluated after one week ("baseline") and on average 37.58 months postoperatively ("endline"). The prosthesis was grouped into 10 regions of interest (ROI): seven femoral and three acetabular. Incidence, width, and extent of "radiolucent lines" were measured within each zone.

RESULTS

Between baseline and endline, width and extent progressed more noticeably in all femoral and acetabular zones among patients with AVN. In femoral ROI 1, the width increased in 40% of AVN cases compared to 6.7% of OA cases. For acetabular ROI 3, the width increased in 26.7% of AVN cases compared to no perceived changes in the OA group. No signs of prosthetic loosening were found in the AVN group.

CONCLUSION

The increase of width and extent of radiolucent lines over time in patients with AVN could be a sign of lack of osteointegration. However, prosthetic loosening in absence of clinical symptoms cannot be deduced from radiological findings after medium-term postoperative follow-up. Further long-term studies are required to monitor how radiolucent lines develop in respect to long-term implant loosening. Dependent on bone quality, individually adapted reaming and broaching of the implant site are recommended.

Attention fusion network with self-supervised learning for staging of osteonecrosis of the femoral head (ONFH) using multiple MR protocols

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is characterized as bone cell death in the hip joint, involving a severe pain in the groin. The staging of ONFH is commonly based on Magnetic resonance imaging and computed tomography (CT), which are important for establishing effective treatment plans. There have been some attempts to automate ONFH staging using deep learning, but few of them used only MR images.

PURPOSE

To propose a deep learning model for MR-only ONFH staging, which can reduce additional cost and radiation exposure from the acquisition of CT images.

METHODS

We integrated information from the MR images of five different imaging protocols by a newly proposed attention fusion method, which was composed of intra-modality attention and inter-modality attention. In addition, a self-supervised learning was used to learn deep representations from a large amount of paired MR-CT dataset. The encoder part of the MR-CT translation network was used as a pretraining network for the staging, which aimed to overcome the lack of annotated data for staging. Ablation studies were performed to investigate the contributions of each proposed method. The area under the receiver operating characteristic curve (AUROC) was used to evaluate the performance of the networks.

RESULTS

Our model improved the performance of the four-way classification of the association research circulation osseous (ARCO) stage using MR images of the multiple protocols by 6.8%p in AUROC over a plain VGG network. Each proposed method increased the performance by 4.7%p (self-supervised learning) and 2.6%p (attention fusion) in AUROC, which was demonstrated by the ablation experiments.

CONCLUSIONS

We have shown the feasibility of the MR-only ONFH staging by using self-supervised learning and attention fusion. A large amount of paired MR-CT data in hospitals can be used to further improve the performance of the staging, and the proposed method has potential to be used in the diagnosis of various diseases that require staging from multiple MR protocols.

Comparison of two joint-preserving treatments for osteonecrosis of the femoral head: core decompression and core decompression with additional cancellous bone grafting

OBJECTIVE

Femoral head necrosis (FHN) affects mostly young and active people. The most common operative therapy is core decompression (CD) with optional cancellous bone grafting (CBG). Because little information is available on the long-term results of these procedures, we investigated the effectiveness of CD and CD + CBG in patients with ARCO stage II FHN in terms of postoperative pain, range of motion, patient-reported outcome measures (Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, EuroQol 5D, and Short Form 36 Questionnaire), and disease progression.

METHODS

We retrospectively compared 11 patients treated with CD alone 48.0 months (range, 26.3-68.5 months) postoperatively versus 11 patients treated with CD + CBG 69.2 months (range, 38.0-92.9 months) postoperatively. All patients were assessed according to a routine clinical protocol involving a clinical examination, questionnaires, and radiological imaging (X-ray and magnetic resonance imaging).

RESULTS

The clinical and radiological results showed no significant differences between the two groups. Both interventions demonstrated equal results according to clinical scores.

CONCLUSIONS

Our data may encourage application of the less invasive technique of CD alone without CBG, which is more surgically demanding. Further prospective studies with longer follow-up are necessary to clarify the risk factors for therapy failure.

Avascular necrosis of the femoral head: three-dimensional measurement of drilling precision reveals high accuracy and no difference between fluoroscopically controlled core decompression and cancellous bone grafting

INTRODUCTION

Avascular osteonecrosis of the femoral head (AVN) is a widespread disease affecting mostly young and active people, often exacerbating in progressive stages, ending in joint replacement. The most common joint preserving operative therapy for early stages is core decompression (CD), optional with cancellous bone grafting (CBG). For success it is vital that the necrotic area is hit and the sclerotic rim is broken by drilling into the defect zone to relieve intraosseous pressure. The aim of this study was to investigate if both techniques are precise enough to hit the center of the necrosis and if there is a difference in precision between drilling with small pins (CD) and the trephine (CBG).

PATIENTS AND METHODS

10 patients underwent CD, 12 patients CBG with conventional C-arm imaging. Postoperatively 3D MRI reconstructions of the necrotic area and the drilling channels were compared. The deviation of the drilling channel from the center of the necrotic area was measured. PROMs (HHS, HOOS, EQ-5D, SF-36) were evaluated to compare the clinical success of these procedures.

RESULTS

Neither with CD nor with CBG the defect zone was missed. The drilling precision of both procedures did not differ significantly: distance to center 3.58 mm for CD (range 0.0-14.06, SD 4.2) versus 3.91 mm for CBG (range 0.0-15.27, SD 4.7). PROMs showed no significant difference.

CONCLUSION

Concerning the most important difference between the two procedures-the surgical higher demanding technique of CBG-we suggest applying the less invasive technique of CD alone.

Osteonecrosis in Inflammatory Bowel Disease: Clinical Features, Risk Factor Analysis, and Outcomes

BACKGROUND

Avascular necrosis (AVN) is a known adverse event associated with corticosteroid (CS) usage. Inflammatory bowel disease (IBD) is often treated with a CS for induction of remission. We sought to describe clinical features and outcomes of IBD patients with AVN.

METHODS

In this retrospective, single-center, case-control study, patients with IBD who had a diagnosis of osteonecrosis, aseptic necrosis, or AVN from 1976 to 2009 were included, and each was matched with up to 2 controls (IBD but no AVN) on age, sex, IBD subtype, geographic area of residence, and date of IBD diagnosis. We abstracted risk factor data from the medical records. Conditional logistic regression was performed accounting for minor differences in age and date of first IBD visit to assess the relationship between putative risk factors and AVN, expressed as odds ratio and 95% confidence interval.

RESULTS

Eighty-five patients were diagnosed with IBD-AVN and were matched with 163 controls. The mean age at AVN diagnosis was 47.5 years. AVN was diagnosed a median of 12.2 years after IBD diagnosis, and the control group was followed for a median of 15 years after IBD diagnosis to ensure that they did not have AVN. Ten percent of patients with AVN did not have any CS exposure. History of arthropathy or estrogen use in Crohn's disease and use of CS, osteoporosis, and history of arthropathy in ulcerative colitis were significantly associated with AVN.

CONCLUSIONS

Most patients with IBD-AVN had multifocal involvement. Most had received CS, but many patients had other risk factors including arthropathy.

Research Progress on Exosomes in Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a progressive disease that often necessitates hip replacement if hip preservation therapy fails. ONFH places a heavy economic burden and severe psychological pressure on patients. At present, ONFH is treated by either surgical or non‐surgical methods. In clinical practice, stem cells combined with surgery has achieved some positive results, but many problems remain to be resolved. Exosomes are small vesicles of 30–150 nm, which are rich in various nucleic acids, proteins, and small molecules depending on the cells from which they are derived. A growing number of studies have found that exosomes play an important role in tissue damage repair. In comparison with stem cells, exosomes have lower immunogenicity. Also, exosomes can promote cell proliferation and inhibit tumor growth. In addition, exosomes can also be used as natural carriers of drugs. Many studies have shown that exosomes have therapeutic effects in hormone‐induced ONFH. Exosomes have the effect of promoting vascular regeneration and show good application prospects in ONFH. Here, we present a review of studies on the application of exosomes in ONFH to provide a reference for future research.

Decreased Ankyrin Expression Is Associated with Repressed eNOS Signaling, Cell Proliferation, and Osteogenic Differentiation in Osteonecrosis of the Femoral Head

BACKGROUND

Reduced nitric oxide synthase (NOS) activity and decreased reparative potentials in stem cells may be involved in the pathogenesis of osteonecrosis of the femoral head (ONFH), but the underlying mechanism is not clear. Ankyrin, a cytoskeletal protein, can promote NOS expression and many cellular functions when it interacts with the CD44 receptors on the stem cells. This study investigated whether ankyrin is involved in the pathogenesis of ONFH.

MATERIALS AND METHODS

Bone marrow stem cells (BMSCs) from ONFH patients were compared with cells from patients with proximal femoral fracture and BMSC cell lines (PT-2501, Lonza, NC, USA). Differences in the expression levels and downstream signal pathway of ankyrin-Akt-eNOS in BMSCs were studied between ONFH and control. The involvement of ankyrin in the signal cascade, cell proliferation, and differentiation were further investigated by silencing ankyrin using small interfering (si)RNA.

RESULTS

We found the basal mRNA levels of ankyrin and CD44 in BMSCs from the ONFH group were significantly lower as compared with those from the control group. The signal transduction of CD44-ankyrin-Akt-eNOS was significantly repressed in the ONFH group as compared with the control group after hyaluronic acid treatment. Knockdown of ankyrin by siRNA could attenuate the eNOS signaling as well as the BMSCs proliferation and osteogenic differentiation. The proliferation ability and osteogenic differentiation potential of the BMSCs from the ONFH group were significantly reduced as compared with the control group, but they can be enhanced to the baseline levels of the control group by hyaluronic acid treatment.

CONCLUSION

The aberrant eNOS signaling, reduced cell proliferation, and osteogenic differentiation potential in BMSCs from ONFH patients are associated with the decreased ankyrin expression.

CLINICAL RELEVANCE

Altered signal transduction, proliferation, and osteogenic differentiation ability in BMSCs may be involved in the pathogenesis of ONFH. These need further studies especially in BMSC-based cell therapy.

A Dexterous Robotic System for Autonomous Debridement of Osteolytic Bone Lesions in Confined Spaces: Human Cadaver Studies

This article presents a dexterous robotic system for autonomous debridement of osteolytic bone lesions in confined spaces. The proposed system is distinguished from the state-of-the-art orthopedics systems because it combines a rigid-link robot with a continuum manipulator (CM) that enhances reach in difficult-to-access spaces often encountered in surgery. The CM is equipped with flexible debriding instruments and fiber Bragg grating sensors. The surgeon plans on the patient’s preoperative computed tomography and the robotic system performs the task autonomously under the surgeon’s supervision. An optimization-based controller generates control commands on the fly to execute the task while satisfying physical and safety constraints. The system design and controller are discussed and extensive simulation, phantom and human cadaver experiments are carried out to evaluate the performance, workspace, and dexterity in confined spaces. Mean and standard deviation of target placement are 0.5 and 0.18 mm, and the robotic system covers 91% of the workspace behind an acetabular implant in treatment of hip osteolysis, compared to the 54% that is achieved by conventional rigid tools.

Combination use of core decompression for osteonecrosis of the femoral head: A systematic review and meta-analysis using Forest and Funnel Plots

Objective

This study evaluated the efficacy and safety of CD combined with bone marrow stem cells in the treatment of femoral head necrosis by systematic review and meta-analysis. Methodology. PubMed, The Cochrane Library, Embase, CNKI, Google Scholar and MEDLINE, etc. databases were searched for clinical randomized controlled trials (RCTs) comparing core decompression combined with autologous bone marrow mesenchymal stem cells versus core decompression alone in the treatment of femoral head necrosis. The retrieval period is from the establishment of each database to May 20, 2021. After literature was extracted and literature quality was evaluated, meta-analysis was conducted by using RevMan5.3 software.

Results

A total of 420 osteonecrosis of the femoral head 452 patients' data were collected from all studies. Compared with the core decompression alone group, the CD combined with bone marrow stem cell showed marked reduction in the Visual analog scale (VAS), enhanced Harris hip score (HHS) at 12 months and 24 months, slowed down the progression of the disease, decreased the number of hips conversed to total hip arthroplasty (THA) in the future.

Conclusion

Core decompression therapy is a very effective and safe treatment process used for ONFH. Moreover, CD combined autologous bone marrow stem cell transplantation can improve the survival rate of the necrotic head, reduce hip pain and delay the disease progression, the rate of THA postoperatively.

Hip preserving procedures for osteonecrosis of the femoral head after collapse

Osteonecrosis of the femoral head (ONFH) affects mainly young patients and causes secondary hip osteoarthritis if remains untreated. Several operative treatments have been introduced with successful outcomes in the early stages. However, in late stages of ONFH treatment may be challenging due to the progressive nature of disease and many surgeons prefer arthroplasty option after collapse. Considering the size, age and etiology an effort should be made to preserve hip joint selected patients with early collapse or minimal arthritic changes. The purpose of the current review is to discuss the results of joint preserving procedures for late stages of ONFH.

Spontaneous subcapital femoral neck fracture complicating osteonecrosis of femoral head

Spontaneous subcapital fracture (SSF) of femoral neck in pre-existent osteonecrosis of femoral head (ONFH) is a rare presentation. Only a few cases have been reported so far and majority of them have been reported to have unilateral hip involvement. We retrospectively reviewed clinical-radiological data of 10 patients (12 hips) with SSF complicating ONFH. All of them underwent uncemented total hip arthroplasty. All the available publications in the English language based medical literature were critically reviewed and results were summarized. The median age of presentation was 32 years (range : 24 years to 61 years). They were followed up for a mean duration of 25 months (range : 12 months to 59 months). The most common risk factor was corticosteroid consumption (7 out of 10 patients). All except one (modified Ficat and Arlet stage II) belonged to advanced stage of ONFH {stage III 3 patients (3 hips), stage IV 6 patients (8 hips)}. The mean time lag of ONFH to presentation was 22.3 months (range : 5 months to 60 months), and SSF to presentation was 13.8 days (range : 1 day to 28 days). Mean pre- operative Harris Hip Score was 10.8 (range : 8 to 14), which improved to 93 (range : 91 to 96) after total hip arthroplasty when last followed up (p<0.05). Corticosteroids induced ONFH has a propensity to develop SSF. This entity should find a place in existing classification system.

Bone Microarchitecture and Biomechanics of the Necrotic Femoral Head

The mechanism behind osteonecrosis of the femoral head (ONFH) remains unclear. The aim of this study was to explore the pathogenesis of ONFH from a biomechanical standpoint to provide a theoretical basis for improved treatments. We compared the bone structure of fractured femoral heads with that of necrotic femoral heads by Micro-CT scanning and histological evaluation. In addition, we compared the biomechanical properties of each zone in fractured femoral heads with those in necrotic femoral heads by using biomechanical tests. Compared with fractured femoral heads, bone microarchitecture and bone morphometry in necrotic zone and sclerotic zone of necrotic femoral heads have altered markedly. In addition, the biomechanical properties of the necrotic zone in femoral heads weaken markedly, while those of the sclerotic zone strengthen. We hypothesize that discordance between bone structure and function of the femoral head may be involved in the pathogenesis of ONFH and that more attention should be paid to the prevention and treatment of such discordance.

Atraumatic Femoral Head Necrosis in Adults

BACKGROUND

Atraumatic necrosis of the femoral head is a common cause of hip arthrosis in middle age. In Germany, it affects 5000-7000 patients per year, corresponding to an incidence of 0.01%. Though rarer than primary hip arthrosis, it is still of major clinical and socio-economic significance. Patients with this problem should be diagnosed early and given stage-appropriate treatment.

METHODS

This review is based on pertinent publications that were retrieved by a selective search in the PubMed, Embase, Medline, and Cochrane Library databases using the terms "osteonecrosis," "femoral head necrosis," "diagnosis," "classification," "conservative treatment," "surgical treatment," "joint preservation," "osteotomy," and "arthroplasty," as well as a recent guideline on atraumatic necrosis of the femoral head in adults.

RESULTS

The etiology and pathogenesis of atraumatic femoral head necrosis in adults are not yet fully clear. The main risk factor is prolonged corticosteroid treatment. Nonspecific complaints and an initially normal plain x-ray of the hip can delay the diagnosis. The diagnosis is established by plain x-ray, computerized tomography, magnetic resonance tomography, and scintigraphy. Conservative treatment alone is not considered adequate. The range of surgical treatments includes joint-preserving and (for more severe necrosis) joint-resecting methods.

CONCLUSION

Atraumatic femoral head necrosis in adults is a disease that progresses in stages; depending on its stage, it can either be cured or lead to hip arthrosis. A full cure is possible only in early stages. Current research focuses on the effect of new drugs on the intermediateand long-term outcome.

Bone regeneration strategies with bone marrow stromal cells in orthopaedic surgery

Bone is the most transplanted tissue human with 1 million procedures every year in Europe. Surgical interventions for bone repair are required for varied reasons such as trauma resulting non-union fractures, or diseases including osteoporosis or osteonecrosis. Autologous bone grafting is the gold standard in bone regeneration but it requires a second surgery with associated pain and complications, and is also limited by harvested bone quantity. Synthetic bone substitutes lack the osteoinductive properties to heal large bone defects. Cell therapies based on bone marrow or ex vivo expanded mesenchymal stromal stem cells (MSCs) in association with synthetic calcium phosphate (CaP) bone substitutes may be alternatives to autologous bone grafting. This manuscript reviews the different conventional biological and synthetic bone grafting procedures as well as the more recently introduced cell therapy approaches used in orthopaedic surgery for bone regeneration. Some clinical studies have demonstrated safety and efficacy of these approaches but regeneration of large bone defects remain challenging due to the absence of rapid and adequate vascularisation. Future directions in the field of bone regeneration are presented, such as testing alternative cell sources or in situ fabrication of vascularized bone grafts in patients.

Guideline for Diagnostic and Treatment of Osteonecrosis of the Femoral Head

There is a new knowledge for clinical presentations and findings of imagine in patients with osteonecrosis of the femoral head (ONFH) in recent more than ten years. According to clinical data in Chinese huge patients with ONFH, the guideline for diagnosis and treatment of ONFH has been put forward by Chinese specialists. The newer contents of guideline include the definition for predisposing risk factors of ONFH, the new knowledge for clinical manifestations, the new interpretation for changes of imagine, important differential diagnosis. Based on the supplementary and revision for widely used staging and classification system, the new Chinese staging and classification system have been established. The advantages of Chinese staging and classification system accord with clinical and pathological features, it could be predicted the prognosis, and clinical applications are convenient. The guideline gives a brief account of principles for treatment selection and treatment methods for enhancement of diagnosis and treatment for ONFH.

Hip resurfacing arthroplasty in treatment of avascular necrosis of the femoral head

Background

Hip resurfacing is a conservative type of total hip arthroplasty but its use is controversial, especially in patients with osteonecrosis. The aim of this study was analysis of the clinical and radiographic outcomes of hip resurfacing in patients with osteonecrosis.

Material/Methods

Between 2007 and 2008, 30 hip resurfacing arthroplasties were performed due to osteoarthritis secondary to avascular necrosis of femoral head staged as Ficat III and IV.

Patients were qualified to resurfacing arthroplasty when the extent of avascular necrosis using Kerboul’s method was <200° and the angle between avascular necrosis and head-neck junction was >20°. All patients were evaluated clinically and radiologically before and 60 months after the operation.

Results

The mean Harris Hip Score (HHS) score increased from 47.8 to 94.25 (p<0.05). Physical activity level (University of California, Los Angeles activity score – UCLA activity score) improved from 3.7 to 7.55 (p<0.05). No implant migration was observed.

Conclusions

Management of osteonecrosis of the hip with resurfacing arthroplasty seems to be effective in strictly-selected patients.

Relationship between the Apolipoprotein AI, B gene polymorphism and the risk of non-traumatic osteonecrosis

BACKGROUND

Previous studies suggested that Apolipoprotein AI (ApoAI) and apolipoprotein B (ApoB) gene polymorphisms may result in lipid metabolism disorders. Genetic polymorphisms in these genes may be associated with the occurrence of osteonecrosis.

METHODS

We designed a case-control study including 429 patients of osteonecrosis and 368 age- and sex-matched control subjects. Polymerase chain reaction was used to amplify the DNA fragments in promoter -75 G > A of ApoAI gene and EcoR I, Xba I and 3'-VNTR of ApoB gene in osteonecrosis patients and healthy controls. We utilized polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to genotype these four single nucleotide polymorphisms (SNPs).

RESULTS

For -75 G > A polymorphism of ApoAI, AA genotype frequency (0.501) was significantly higher in patients with osteonecrosis than that in control (0.462) subjects (P <0.001), GA genotype frequency (0.170) was significantly lower than that in the control (0.310) group (P <0.0001). In osteonecrosis patients, the odds ratio (OR) of A allele was 3.932 (95% CI: 3.0847 ~ 5.0123), which suggested that subjects carrying A allele of promoter region -75 G > A of ApoAI gene had higher susceptibility to osteonecrosis than G allele carriers. The genotype and allele frequency distributions showed no significant difference in EcoR I, Xba Iand 3'-VNTR loci of ApoB gene between the osteonecrosis group and control group.

CONCLUSION

Our study suggested that ApoAI gene -75G > A polymorphism may be associated with susceptibility to osteonecrosis in Chinese population. However, our results need further investigation with large sample size and various populations.

[Autologous concentrated bone marrow graft in the treatment of femoral head avascular necrosis: clinical outcome after two years of follow up in a non-controlled prospective study]

OBJECTIVE

To assess the efficacy of implanting concentrated bone marrow rich in mesenchymal stem cells (MSC) for the treatment of femoral head avascular necrosis (AVN) to prevent or delay total hip replacement (THR).

MATERIAL AND METHODS

A single-centre, prospective, non-controlled clinical study was conducted on patients with a diagnosis of AVN. The parameters assessed were, patient demographics, Harris Hip Score (HHS), imaging test (X-ray and NMR), and staging using the Arlet-Ficat scale. The patients were followed up for 1, 6, 12 and 24 months. The bone marrow was aspirated from the iliac crest, concentrated with the Harvest SmartPReP 2 system, and infused into the necrotic area by means of core decompression.

RESULTS

A total of 22 hips in 17 patients were recruited between the years 2006 to 2012, with a minimum follow-up of 2 years. A mean of 119.5 mL of aspirate was extracted, with 15.25 ml of MSC being implanted. During the first 2 years of the infusion, 5 hips (24.7%) required THR, with no differences in the baseline Arlet-Ficat stage, and 4 of these (80%) had femoral head involvement equal to or higher than 30%. A significant increase of 14.27 (P=.026) in the HHS and a 0.98 (P=.089) decrease in the VAS was observed two years after the infusion in the remaining 17 hips. The results suggest that the infusion of concentrated bone marrow rich in MSC, combined with surgical decompression of the nucleus, improves hip function (HHS), and avoids THR in 75.3% of patients with AVN treated during the first 2 years.

Vascularized pedicle bone grafting for nonunions of the tarsal navicular

BACKGROUND

Osteonecrosis and nonunions of the tarsal navicular remain a challenging clinical problem. This article presents a series of patients treated with local vascularized pedicle bone grafting to the navicular. The purpose of this study was to determine the early clinical and radiographic outcomes of this technique.

METHODS

Patients who underwent local vascularized pedicle bone grafting for osteonecrosis of the navicular from 2002 to 2007 were included in this study. The Ankle Osteoarthritis Scale (AOS), the Revised Foot Function Index (FFI-R), and the Short-Form 36 (SF-36) outcomes questionnaires were administered at most recent followup. Postoperative imaging was reviewed for evidence of healing. Eight patients with a mean age of 47.5 (range, 18 to 68) years were included in this study. The mean followup time was 61 (range, 32 to 72) months.

RESULTS

Two patients underwent concomitant talonavicular arthrodesis. Two patients underwent additional procedures to address continued nonunion of the navicular. Neither patient elected to complete the outcomes questionnaires. The mean postoperative FFI score was 35.2 (range, 16.6 to 59). SF-36 subscales were as follows: bodily pain, 53; general health, 55; mental health, 75; physical function, 56; role emotional, 61; role physical, 37.5; social function, 71; and vitality, 56. The mean postoperative AOS pain score was 27.9 (range, 0 to 46.2) and the average disability score was 31.4 (range, 0 to 78.2). Postoperative imaging revealed consolidation and full healing in six of eight patients.

CONCLUSION

Vascularized pedicle bone grafting is a treatment option for patients with chronic nonunion or osteonecrosis of the navicular. Additionally, it may serve as an adjunct procedure to provide increased vascularity to talonavicular arthrodesis in cases of navicular osteonecrosis and talonavicular arthritis.

Nontraumatic osteonecrosis of the femoral head: endoscopic visualization of its avascular burden

The purpose of this study was to evaluate the intraosseous use of a flexible endoscope during core decompression in identifying avascular bone in the femoral head that did not meet magnetic resonance imaging diagnostic criteria for osteonecrosis. The flexible endoscope was used to visually examine and locate avascular bone in the entire core track. A high-speed burr was then used to debride the avascular bone. This debridement process was continued until a host bed of porous bleeding cancellous bone was observed, comprising thorough debridement of the femoral head. Autologous cancellous bone graft was then packed into the residual cavity and stabilized. Ten patients (13 hips total) with an average age of 49 years (range, 34-58 years) were included in the study. Eight patients were fully ambulatory at 3 weeks (range, 1-3 weeks). For all 13 hips, the mean preoperative Harris Hip Score was 43 (range, 30-75) and improved to a mean of 93 (range, 60-100) postoperatively. Eighty-five percent of patients (11 of 13 hips) demonstrated a good to excellent outcome at a minimum 2-year follow-up (range, 27-45 months). Flexible intraosseous endoscopy helped identify avascular bone that did not appear on the preoperative magnetic resonance imaging, safely widen the surgical margins of the core decompression track, and achieve thorough debridement of the femoral head using a minimally invasive technique.

Results of Conserve Plus® metal-on-metal hip resurfacing for post-traumatic arthritis and osteonecrosis

The safety and efficacy of metal-on-metal surface arthroplasty in post-traumatic arthritis and post-traumatic osteonecrosis (PT OA and PT ON) cases has not previously been thoroughly investigated. This study compared the outcomes of metal-on-metal hip resurfacing (HR) in patients performed for an indication of OA secondary to trauma to compared to PT ON. Metal-on-metal resurfacing arthroplasties were performed on 62 hips, 43 with PT OA and 19 with PT ON with secondary osteoarthritis. There were 51 males and 11 females. All patients were followed up clinically and radiographically with a mean follow-up of 87.2 months. Clinical outcome scores, survivorship, and radiographs were compared between the PT OA and PT ON group. The clinical outcomes for the PT ON and PT OA groups were similar with a survival rate of 95% (95% CI 82.1% to 98.8%) for the PT OA group alone at 8 years and 91% for those with PT OA with ON at 8 years (95% CI 50.8%-98.7%). The Kaplan-Meier survivorship curves for the cohorts of PT OA and PT ON patients were not statistically significantly different (Log rank, p=0.6036). Metal-on-metal hip resurfacing appears to be a safe and effective procedure for the treatment of both post-traumatic osteoarthritis and osteonecrosis.

Total hip arthroplasty in advanced osteonecrosis: the short-term results by metal-on-metal hip resurfacing

BACKGROUND

Characteristically, osteonecrosis affects younger patients who typically refer to the orthopedic surgeon for the first time in the third to fifth decades of life, in the late stages of the disease. Femoral metal-on-metal hip resurfacing is as an alternative to conventional total hip arthroplasty in treating osteoarthritis of the hip. Since there are already many reports regarding the successful outcome of resurfacing in advanced osteoarthritis, the purpose of this study was to analyze the clinical outcomes of this procedure in patients with osteonecrosis of the femoral head and to compare them with a matched group of patients with osteoarthritis.

MATERIAL/METHODS

This retrospective cohort study evaluated a consecutive series of 52 patients with end-stage osteonecrosis (28 patients) and osteoarthritis (24 patients) of the femoral head, managed by metal-on-metal hip resurfacing in a referral orthopedic center from Feb 2002 to May 2007. Pain, function and deformity were evaluated with the use of the Harris hip score after the operation. Patients were clinically followed for a mean of 41 months.

RESULTS

The patients in the osteoarthritis group had a significantly higher mean age than those in the osteonecrosis group (47.88 ± 12.6 vs 30.86 ± 7.5, p=0.003). The clinical outcomes were similar for both groups. There was no significant difference in mean Harris hip score (p=0.347) and hip joint range of motion (p=0.346) between osteonecrosis and osteoarthritis groups after surgery.

CONCLUSIONS

On the basis of these initial findings, we recommend MOM resurfacing as a viable treatment option for patients with advanced stages of osteonecrosis.

Spontaneous repair of asymptomatic osteonecrosis associated with corticosteroid therapy in systemic lupus erythematosus: 10-year minimum follow-up with MRI

Systemic lupus erythematosus (SLE) patients are at high risk of developing osteonecrosis. This study utilized MRI to document the long-term natural history of asymptomatic osteonecrosis associated with corticosteroid therapy in SLE patients. Two hundred and one SLE patients treated with high-dose corticosteroids were prospectively observed from 1986 to 1997. The inclusion criterion was that patients had received periodic MRI examinations of all their hip and knee joints for ≥10 years. Joints that were already collapsed and symptomatic at the first examination were excluded. Five hundred and thirty-seven joints (251 hips and 286 knees) were identified in 144 patients, with a mean follow-up period of 13.6 years (range, 10—20 years) and a follow-up rate of 73%. Mean age of SLE onset was 26 years, and the mean highest oral corticosteroid dosage was 57 mg/day. Osteonecrosis developed in 238 (44%) of 537 joints. At final follow-up, 117 (49%) of these 238 joints demonstrated spontaneous repair in the necrotic area. Osteonecrosis completely disappeared in 21 joints. Enlargement of osteonecrosis was noted in 35 joints (15%) following increased steroid dosage because of SLE recurrence. Finally, 52 joints (22%) were collapsed. Spontaneous repair of asymptomatic osteonecrosis was observed, whereas enlargement occurred only after corticosteroid dosage increases. Lupus (2010) 19, 1307—1314.

Effects of an anticoagulant and a lipid-lowering agent on the prevention of steroid-induced osteonecrosis in rabbits

This study was designed to evaluate the effects of the combined treatment with an anti-coagulant (enoxaparin) agent and a lipid-lowering agent (lovastatin) on prevention or decrease in the occurrence of steroid-induced osteonecrosis in rabbits. A total of 112 rabbits, which were injected intramuscularly with 20 mg/kg of methylprednisolone acetate were divided into four groups and treated as follows: one group received enoxaparin combined with lovastatin (EL; n = 30), another received enoxaparin alone (EA; n = 28), another received lovastatin alone (LA; n = 28) and the last received no treatment (non-prophylactic; NP, n = 26). Haematological examination for serum lipid levels and prothrombin time was carried out and both femora and humeri were examined histopathologically for the presence of osteonecrosis (ON) before injection and at 2, 4, 8 and 12 weeks after the injection. The incidence of ON in the EL group (15%) was significantly lower than that observed in the NP group (68%). The incidence in the EA and LA groups was also significantly lower than that in the NP group (31%, 35%vs. 68%). The fat cell sizes of the bone marrow in both EL (46.49 +/- 1.27 microm) and LA (50.8 +/- 2.31 microm) groups were lower than in the NP group (59.89 +/- 6.33 microm). The prothrombin time was prolonged and plasma lipid levels were reduced in the EL group during the study. Combination treatment with an anti-coagulant agent and a lipid-lowering agent can reduce the incidence of steroid-induced ON in rabbits. Future evaluation in clinical practice is necessary.

Cytotherapy of osteonecrosis of the femoral head: a mini review

The pathogenesis and aetiology of nontraumatic osteonecrosis of the femoral head has not been revealed completely. However, with advances in stem cell research and regenerative medicine, it is believed that the onset of osteonecrosis of the femoral head probably has a cellular origin, and the possible therapy of osteonecrosis of the femoral head based on cytotherapy has great potential. In this review, the aetiology of osteonecrosis of the femoral head, animal experiments and clinical applications of cytotherapy are summarized and analysed. Current problems and future challenges are discussed.

Vascularized iliac bone-grafting for osteonecrosis with segmental collapse of the femoral head

BACKGROUND

Vascularized iliac bone-grafting has been reported to be successful for patients with osteonecrosis of the femoral head. However, its benefit in patients with segmental collapse of the femoral head has not been determined. The purpose of this study was to analyze the results of vascularized iliac grafting in osteonecrotic femoral heads with segmental collapse.

METHODS

We retrospectively analyzed thirty-three hips in thirty-two patients in whom an osteonecrotic femoral head with segmental collapse (Association Research Circulation Osseous [ARCO] stage IIIA [<2-mm collapse] or stage IIIB [2 to 4-mm collapse]) had been treated with vascularized iliac bone-grafting between 1994 and 1999. The average age of the patients at the time of surgery was thirty-seven years. Twenty-six patients (twenty-seven hips) overused alcohol, five patients (five hips) had no known risk factor, and one patient (one hip) used corticosteroids for refractory bronchial asthma. Clinical outcomes were evaluated with the Harris hip score. We defined clinical failure as conversion to total hip replacement for any reason and radiographic failure as progressive femoral head collapse or secondary osteoarthritis of the involved hip.

RESULTS

At the conclusion of the study, only eight (24%) of the thirty-three hips were preserved. The mean survival time for the series as a whole was seventy-four months (95% confidence interval, fifty-four to ninety-five months) after the surgery. Eighteen of the twenty-six ARCO stage-IIIA hips were converted to a total hip replacement, and the mean survival time for the stage-IIIA hips was eighty-five months (95% confidence interval, sixty-one to 108 months). All of the seven ARCO stage-IIIB hips were converted to a total hip replacement, and the mean survival time for the stage-IIIB hips was thirty-five months (95% confidence interval, eleven to fifty-eight months). The mean Harris hip score for the eight hips that still survived at the time of follow-up had improved from 62 points to 80 points. However, all of them had progressive collapse of the femoral head-i.e., radiographic failure-at the time of final follow-up.

CONCLUSIONS

Vascularized iliac bone-grafting with use of the technique described in this study is not indicated for the treatment of osteonecrotic femoral heads with segmental collapse.

One-stage hip arthroplasty and bone grafting for bilateral femoral head osteonecrosis

One-stage hip arthroplasty and contralateral core decompression with bone grafting were performed for 30 patients with bilateral femoral head osteonecrosis between April 2002 and June 2005. The treatment course, clinical and radiographic outcomes, and medical costs were compared with another 30 age-, gender-, etiology-, and disease extent-matched patients undergoing two-stage treatment during the same period. The two groups had similar clinical data and few complications. Total hospital stay and associated costs were reduced for patients who had one-stage treatment. These patients also returned to work faster (6.0 versus 10.8 months). At an average followup of 46 months, progression to greater than 2 mm of collapse of the salvaged femoral head was observed in seven patients (23%) who had one-stage treatment and 14 patients (47%) who had two-stage treatment. Conversion to hip arthroplasty was performed in five patients (17%) in the one-stage group and 12 patients (40%) in the two-stage group. A special group of patients with bilateral osteonecrosis of the femoral head seemed to benefit from one-stage hip arthroplasty and contralateral core decompression with bone grafting and had better survival of the salvaged femoral head. One-stage hip arthroplasty and core decompression with bone grafting proved to be a cost-effective method that did not increase perioperative morbidity.

LEVEL OF EVIDENCE

Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Total hip arthroplasty with a cementless acetabular component and a cemented femoral component in the treatment of Chinese patients with femoral head necrosis

The purpose of this study was to evaluate midterm clinical and radiographic outcomes associated with hybrid total hip arthroplasty in a consecutive series of 86 Chinese patients (93 hips) with osteonecrosis of the femoral head, which revealed that the mean Harris hip score increased from 39 +/- 6.0 points before operation to 90.4 +/- 4.6 points at the latest follow-up. There was pelvic osteolysis in one hip (1%), which required revision, and some small focal areas of femoral osteolysis in 12 hips (13%) were observed. The mean linear wear rate was 0.143 +/- 0.05 mm/y (0.02-0.45 mm/y). No loosening of the components was observed radiographically. The survival rate of the acetabular and femoral components for revision was 98% (95% confidence interval, 0.96-1.0) and 100% (95% confidence interval, 0.95-1.0). Hybrid total hip arthroplasty in patients with osteonecrosis of the femoral head had a satisfactory clinical and radiographic outcome at a minimum 5 years of follow-up. Because polyethylene wear and osteolysis cannot be avoided, the long-term effect should be further studied.

Osteonecrosis of the femoral head following an electrical injury to the leg

We report a case of osteonecrosis of the femoral head in a young man who is a carrier of the prothrombin gene mutation. We suggest that an electrical injury to his lower limb may have triggered intravascular thrombosis as a result of this mutation with subsequent osteonecrosis of the femoral head. No case of osteonecrosis of the femoral head secondary to a distant electrical injury has previously been reported.

Circulating platelet-derived microparticles and endothelium-derived microparticles may be a potential cause of microthrombosis in patients with osteonecrosis of the femoral head

INTRODUCTION

To test the hypothesis that the platelet microparticle (PMP) and endothelial microparticle (EMP) may contribute to the hypercoagulability associated with microvascular thrombosis in patients with nontraumatc osteonecrosis of the femoral head (ONFH).

MATERIALS AND METHODS

The study comprised 46 patients who had been diagnosed with ONFH and 20 control subjects. The plasma was ultracentrifuged, and then PMPs and EMPs were examined by the flow cytometry. The thrombotic and fibrinolytic disorders were investigated.

RESULTS

The numbers of PMPs expressing P-selectin and CD42a and EMPs expressing E-selectin and CD31 in the ONFH patients were significantly higher than those in the controls (P<0.001). The number of MPs was correlated with the level of the serum C-reactive protein (CRP) (r=0.661, P<0.001), but there was a poor correlation between the MPs counts and the risk factors for ONFH (P>0.05). The mean levels PAI-1, F1+2, and TAT were higher in the patients with ONFH than in the controls (P<0.05).

CONCLUSIONS

The elevated numbers of PMPs and EMPs may contribute to hypercoagulability in the ONFH patients. This may provide important pathophysiological insights into the hypercoagulability associated with nontraumatic ONFH and have implications for pharmacological prevention and treatment of ONFH.

[Cell based therapy for the treatment of femoral head necrosis]

The goal of the therapy for necrosis of the femoral head in adults is the preservation of the femoral head and, therefore, avoidance of total joint replacement. Core decompression is known to reduce the intraosseous pressure and additionally provides the opportunity to introduce bioactive materials, substances and cells into the core tract. These include vascularized and non-vascularized bone grafts, allogenic and synthetic bone substitutes, osteogenic and angiogenic growth factors, as well as different progenitor cells. In particular, the use of cell-based strategies has great therapeutic potential and could play an important role in the treatment of femoral head necrosis in adults in the future. In this article, we summarize the existing clinical experience of current cell-based strategies for the treatment of femoral head necrosis in adults, and present a therapeutic approach using bone marrow stem cells (TRCs: tissue repair cells). in combination with a beta-TCP matrix.

Health-related quality of life in patients with systemic lupus erythematosus after medium to long-term follow-up of hip arthroplasty

Health-related quality of life (HRQOL) of systemic lupus erythematosus (SLE) patients with hip arthroplasty after medium to long-term follow-up has not been reported. We conducted a retrospective study for SLE patients with osteonecrosis of the femoral head (ONF). Forty-seven consecutive arthroplasties were performed in 36 patients. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Medical Outcome Survey Short Form 36 (SF-36) and Harris hip score were evaluated. Two patients died before the four-year follow-up and two patients were lost to follow-up. The remaining 43 hips in 32 patients with an average age at surgery of 35 years and an average follow-up of 12.0 years (range 4.0-25.0) were assessed. Bipolar hemiarthroplasty was performed for 18 hips in 12 patients, and total hip arthroplasty (THA) was performed for 25 hips in 20 patients. The mean WOMAC scores for pain and function at the recent followup were 90.8 +/- 8.5points and 79.0 +/- 18.3 points. Patients with THA had significantly high scores in SF-36 physical functioning (P < 0.05) and bodily pain (P < 0.03) compared to those with bipolar hemiarthroplasty. Although improvement could not reach the level of general population, the hip arthroplasty contributed to support HRQOL of SLE patients.

Die konservative Therapie der aseptischen Femurkopfnekrose

Osteonecrosis of the femoral head is a locally destructive disease with a multifactorial genesis. The majority of patients are men between 35 and 45 years of age, who are increasingly reduced in their quality of life and career. As these patients are in the middle of their careers, osteonecrosis of the femoral head is even of increasing interest for the national economy. It is therefore of major interest to reduce the costs as well as the time for its therapy. Since conservative treatment is discussed controversially, it was the aim to focus on the current literature according to the criteria of evidence-based medicine and to prove the importance of conservative treatment of femoral head osteonecrosis.

Bildgebung der aseptischen Femurkopfnekrose des Erwachsenen

The aim of diagnostic imaging procedures in avascular femoral head necrosis is to provide the patient with a stage-adapted therapy. Therefore, a differentiated diagnostic work-up is needed. Native radiography of the hip in two planes is still the first step. Over the past years, the diagnosis of femoral head necrosis has experienced tremendous improvement due to the use of MRI and CT scans. Because of these improvements the correct stage can be diagnosed early and the appropriate therapy can be initiated immediately. Today, MRI is the most sensitive diagnostic imaging procedure. CT scans can be particularly useful to exclude subchondral fractures. The use of bone scintigraphy is restricted to exceptional cases. In Europe, the ARCO classification of avascular femoral head necrosis has been widely accepted. It is essential here to define subtypes according to the localisation and the extent of the necrosis, because both have major influence on the prognosis of the disease and therefore also for the therapeutic strategy. In this overview, we describe the specific characteristics of the different diagnostic imaging procedures and illustrate them with appropriate imaging material. At the end of the article an algorithm for diagnostic imaging procedures in avascular femoral head necrosis for daily orthopaedic practice is proposed.

Avascular necrosis of the femoral head in pertrochanteric fractures: a report of 8 cases and a review of the literature

OBJECTIVE

To evaluate patients with pertrochanteric fractures (Type 31A1 + 2 ASIF/OTA classification) treated surgically and who subsequently developed avascular necrosis of the femoral head (ANFH).

SETTING

University hospital.

DESIGN

Retrospective clinical study and analysis of the literature.

PATIENTS

From 1995 to 2003 the authors operated on 1,373 patients with pertrochanteric fractures. Eight patients with a mean age of 69 years (range, 52-78 years) subsequently developed ANFH.

INTERVENTION

Five patients were treated with a dynamic hip screw (DHS), and 3 were treated with an intramedullary hip nail (IMHN).

RESULTS

All fractures in these 8 patients healed without complications in 3 to 4 months. Avascular necrosis of the femoral head developed 4 months to 4 years after the operation. Detailed analysis of these cases did not reveal any risk factors or errors in surgical technique to account for the ANFH. Results of a literature review of 41 cases in addition to our 8 cases give us reason to believe the etiology of postoperative AFNH following surgical treatment of pertrochanteric fractures is probable injury to the deep branch of the medial circumflex artery at time of fracture. Other possible risk factors include high-energy trauma, comminution, displacement of the fragments, and atypical fracture line.

CONCLUSIONS

ANFH develops in approximately 0.5-1% of all pertrochanteric fractures, mostly within 4 years after the injury and predominantly in patients older than 50 years of age. The diagnosis should be considered in patients who have undergone an operation previously and have symptoms that are unclear. Prevention of ANFH in these fractures includes an early reduction, stable fixation, and correct surgical technique.

Repairing defect and preventing collapse of canine femoral head using titanium implant enhanced by autogenous bone graft and rhBMP-2

There is a direct relationship between mechanical stress and the progressive collapse of the necrotic region in osteonecrosis of the femoral head. The titanium implant combined with autogenous bone graft and recombinant human bone morphogenetic protein (rhBMP)-2 to repair the defect and prevent collapse of the femoral head was investigated. The femoral head defects were made by the trapdoor procedure and then the defects were filled, respectively, with the titanium implant combined with autogenous bone graft and rhBMP-2, with autogenous bone graft and rhBMP-2, and with autogenous bone graft alone. Roentgenographic and histological examinations were performed at various times postoperatively. The defects were repaired completely and the titanium implant was integrated with the surrounding bone tissues. The defects healed faster than did without rhBMP-2. No trapdoor cartilage collapsed and joint space narrowed. The titanium implant combined with autogenous bone graft and rhBMP-2 can enhance the repairing procedure and prevent the collapse of the femoral head.

Contrast-Enhanced MRI and Micro-CT Adopted for Evaluation of a Lipid-Lowering and Anticoagulant Herbal Epimedium-Derived Phytoestrogenic Extract for Prevention of Steroid-Associated Osteonecrosis

We developed an alternative steroid-associated osteonecrosis (ON) rabbit model using a combination of a single injection of low-dose lipopolysaccharide (LPS) and three subsequent injections of pulsed high-dose methylprednisolone (MPS).The usefulness of this experimental ON model was evaluated using both conventional and advanced bio-imaging techniques, including contrast-enhanced dynamic MRI and a high-resolution micro-CT. Details on establishment of methodology are described, which were adopted into an efficacy study on a herbal Epimedium-derived phytoestrogenic extract (HEPE) developed for prevention of steroid-associated ON using an established rabbit model. The underlying mechanisms of HEPE for prevention of steroid-associated ON were found to be associated with inhibition of both intravascular thrombosis and extravascular bone marrow lipid deposition, the two known mechanistic pathways in pathogenesis of ON. Our experimental results provide for potential clinical trials or applications of HEPE in the prevention of ON among hig-hrisk patients undergoing steroid treatment.

Use of metal-on-metal total hip resurfacing for the treatment of osteonecrosis of the femoral head

BACKGROUND

Recently, with the advent of improved metal-on-metal prostheses, total hip resurfacing has emerged as a viable arthroplasty option. However, it remains controversial whether this procedure should be used in patients with osteonecrosis when the femoral resurfacing component is cemented onto dead bone. The purpose of this study was to analyze the clinical and radiographic outcomes of metal-on-metal total hip resurfacing arthroplasty in patients with osteonecrosis of the femoral head. In addition, this group was compared with a matched group of patients who were diagnosed as having osteoarthritis.

METHODS

Forty-two osteonecrotic hips that were treated with a metal-on-metal total hip resurfacing arthroplasty were studied. They were matched by gender, age, prosthesis, surgeon, and surgical approach to forty-two osteoarthritic hips that were treated with the same metal-on-metal prosthesis. In the osteonecrosis group, there were twenty-five men and eleven women, and in the osteoarthritis group, there were twenty-eight men and thirteen women. The mean age at the time of surgery was forty-two years. Patients were followed both clinically and radiographically for a mean of forty-one months.

RESULTS

The clinical outcomes were similar for both groups, with a good or excellent outcome in thirty-nine hips (93%) with osteonecrosis and a good or excellent outcome in forty-one hips (98%) with osteoarthritis. In each of the two groups, there were two failures that required conversion to a standard total hip arthroplasty. Survivorship curves were similar for the two patient groups.

CONCLUSIONS

The short-term results for metal-on-metal total hip resurfacing for this challenging patient population with osteonecrosis were excellent and comparable with those seen in patients with osteoarthritis. We await long-term results to see if these early results are maintained.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Cost-effectiveness analysis of core decompression

Core decompression is widely used to treat the early stages of osteonecrosis of the hip. The purpose of this analysis is to assist orthopedic surgeons in judging whether currently available data support the use of core decompression as cost-effective. A decision model was created for the treatment of osteonecrosis of the femoral head. Literature review was used to identify possible outcomes and their probability after initial treatment with either observation or core decompression. This model demonstrates core decompression must delay the need for total hip arthroplasty for a minimum of 5 years to maintain an incremental cost-effectiveness ratio lower than 50,000 dollars per quality-adjusted life year gained. Treatment options with ratios higher than 50,000 dollars per quality-adjusted life year are generally considered to have limited cost-effectiveness. This study demonstrates that core decompression has the potential to be a highly cost-effective alternative if it is leads to a delay in the need for total hip arthroplasty of 5 years or longer.

Multiple bioimaging modalities in evaluation of an experimental osteonecrosis induced by a combination of lipopolysaccharide and methylprednisolone

Aims:

The present study employed both static and dynamic imaging modalities to study both intra- and extravascular events attributing to steroid-associated osteonecrosis (ON) using an experimental protocol with a single low-dose lipopolysaccharide (LPS) injection and subsequently three injections of high-dose methylprednisolone (MPS).

Methods:

Fourteen 28-week-old male New Zealand white rabbits received one intravenous injection of LPS (10 μg/kg). 24 h later, three injections of 20 mg/kg of MPS were given intramuscularly at a time interval of 24 h. Additional 6 rabbits were used as controls. Dynamic MRI was performed on bilateral femora for local intraosseous perfusion before and after LPS injection. Blood samples were collected for hematological examinations before and after LPS injection. Bilateral femora were dissected and decalcified for microCT-based microangiography. ON lesion, intravascular thrombus and extravascular marrow fat cell size were examined histopathologically.

Results:

Intravascular thrombus was observed in all ON rabbits. Extravascular marrow fat cell size was significantly increased in ON rabbits than that of the controls (P < 0.05). Compared to baseline, a significant decrease in ratio of tissue-type plasminogen activator/plasminogen activator inhibitor 1, activated partial thromboplatin time and a significant increase in ratio of low-density lipoprotein/high-density lipoprotein were only found in ON rabbits (P < 0.05). Dynamic MRI showed a significant decrease in the perfusion index ‘maximum enhancement’ in the ON rabbits (P < 0.05), and microCT-based microangiography showed blocked stem vessels in ON samples. Overall, 93% of the rabbits (13/14) developed ON, and no rabbits died throughout the experiment period.

Conclusion:

Both intra- and extravascular events were found attributing to the steroid-associated ON based on our experimental protocol with a single low-dose LPS injection and subsequent three injections of high-dose MPS. Both high ON incidence and no mortality in rabbits treated with this inductive protocol suggested its effectiveness for future studies on evaluation of therapeutic efficacy of interventions developed for prevention of steroid-associated ON.

Does alendronate prevent collapse in osteonecrosis of the femoral head?

Progression of collapse in osteonecrosis of the femoral head is related to the repair response, especially bone resorption around the necrotic region. A preliminary clinical study was done to determine whether systemic alendronate would prevent collapse and lead to pain relief in patients with osteonecrosis of the femoral head. Fourteen patients (20 hips) with osteonecrosis of the femoral head received daily administration of 5 mg alendronate (alendronate group) for 1 year. Eight patients (13 hips) with osteonecrosis of the femoral head did not receive alendronate (control group). All patients had measurements of biochemical markers of bone turnover at entry into the study, and the patients in the alendronate group repeated the measurements at 3 months, 6 months, and 12 months. All patients had clinical and plain radiographic examinations at entry into the study and at 3 months, 6 months, and 12 months. The alendronate group showed a greater decrease of biochemical marker of bone resorption than biochemical marker of bone formation. The alendronate group showed a lower frequency of collapse of the femoral head and reported less hip pain than the control group. Our results suggest alendronate has the potential to prevent collapse of the femoral head, even with extensive necrosis, presumably by inhibiting bone resorption in the necrotic region.

LEVEL OF EVIDENCE

Therapeutic study, level II (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

[Core decompression of the femoral head for avascular necrosis]

PURPOSE OF THE STUDY

Core decompression of the femoral head is a conservative surgical treatment with controversial efficacy. We studied retrospectively a series of 32 cases of femoral head osteonecrosis treated by core decompression between 1988 and 2000 in 25 patients. We examined the epidemiological and clinical features as well as the laboratory findings, comparing cases requiring secondary hip replacement and those who had a favorable outcome. We search for prognostic factors.

MATERIAL AND METHODS

The series included 32 hips, one case was lost to follow-up. Mean age at decompression was 41.3 years (22-55). In eight hips, osteonecrosis was favored by corticosteroid treatment, in three by chronic alcoholism, and in one by hypertriglyceridemia. No favoring factors were present for 20 hips. According to the ARCO classification there were 15 stage I hips, 13 stage II, 3 stage III, and one stage IV. Core decompression was centered in 24 hips and mean time to decompression was 6.4 months (14 days to 40 months). We reviewed hips without a total prosthesis using the Postel-Merle-d'Aubigne function score and for the radiological assessment the ARCO stage and the Koo index.

RESULTS

Favorable outcome was noted in 12 hips. Total hip arthroplasty was required for 19, one hip was lost to follow-up. Mean follow-up in the success group was 82 months (26-176) and mean "time of participation" in the failure group was 11 months (1-38). Mean survival after core decompression was 14 months. Time between onset of symptoms and decompression did not influence outcome. Lesions which remained asymptomatic before decompression remained stable. The stage I hips did not have more favorable outcome than the stage II hips (p < 0.05). Stage III or IV hips had unfavorable outcome. Hips with a Koo index > 40 had a poor outcome (p < 0.05).

DISCUSSION

Epidemiological factors which can worsen outcome after core decompression for osteonecrosis are controversial in the literature. Early stage disease (I or II) is considered as an ideal indication for decompression, but is insufficient alone to guarantee success. As other authors, we consider that ARCO stage III and IV and a Koo index > 40 are contraindications for decompression. Improved outcome after core decompression can only be achieved by limiting indications.

Osteoporosis associated with excess glucocorticoids

Excess glucocorticoids, whether endogenous or exogenous, can cause osteoporosis and fractures. Even low doses of oral glucocorticoids and mild endogenous hypercortisolism may be associated with bone loss. Patients treated with glucocorticoids, however, often are not evaluated and treated for this problem. Patients on chronic glucocorticoids or initiating these drugs should have their bone density measured and appropriate laboratory studies. They should be treated with adequate calcium and vitamin D, and antiresorptive therapy (particularly bisphosphonates) should be considered.

[Bilateral femoral cephalic osteonecrosis in a human immunodeficiency virus-infected child taking HAART]

Musculoskeletal complications are uncommon in HIV-infected patients. In adults, one manifestation is osteonecrosis which can be associated with risk factors such as alcohol consumption, smoking or use of corticosteroids. Such risk factors are rare in children. Over the last decade musculoskeletal complications have been observed in patients with advanced-stage disease or whose immune system has been reconstituted with highly active antiretroviral therapy (HAART). This complication has been reported in adults but to date not in children. We present the case of a 5-year-old child with AIDS (C stage 3) who developed osteonecrosis related to the advanced stage of the illness and to HAART. No risk factors were found.