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Desai VM, Syed AN, Batley M, Wells L, Williams BA. Management of osteonecrosis of the humeral head in the pediatric population: A systematic review. J Child Orthop 2024; 18:432-440. [PMID: 39100979 PMCID: PMC11295367 DOI: 10.1177/18632521241254708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 04/25/2024] [Indexed: 08/06/2024] Open
Abstract
Purpose Humeral head osteonecrosis in the pediatric patients most often occurs in patients with underlying hemoglobinopathies, exposure to chronic corticosteroids, or after trauma. The purpose of this study was to perform a systematic review evaluating the prevalence, clinical characteristics, and management of humeral head osteonecrosis in the pediatric population. Methods PubMed, Ovid MEDLINE, and Scopus were screened with the terms "osteonecrosis," "avascular necrosis," "pediatric," and "proximal humerus" on January 10, 2024. A total of 218 studies were screened, and 74 studies were evaluated for eligibility. Studies that reported on the prevalence and/or management of pediatric humeral head osteonecrosis were included. The systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Results Twelve studies met inclusion criteria: four retrospective case series, three prospective case series, one retrospective cohort study, one retrospective case-control study, and three case reports. A majority of the studies (67%) discussed chemotherapy-induced osteonecrosis of the humeral head. A total of 77 patients (106 shoulders) with humeral head osteonecrosis were identified. The overall prevalence of osteonecrosis of the humeral head across eight studies examining at-risk populations (underlying hemoglobinopathies or undergoing chemotherapy) was 2%. Intra-articular steroid injections, physical therapy, and activity modification are effective conservative management strategies. Additionally, core decompression and hemiarthroplasty are surgical treatment options. Conclusions The prevalence of osteonecrosis of the humeral head is low even among at-risk populations with associated medical conditions. A variety of conservative and surgical treatment options have been described, but no comparative evaluations of these modalities has been conducted. Level of evidence IV.
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Affiliation(s)
- Vineet M Desai
- Department of Orthopaedics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Harvard Medical School, Boston, MA, USA
| | - Akbar N Syed
- Department of Orthopaedics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Morgan Batley
- Department of Orthopaedics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Lawrence Wells
- Department of Orthopaedics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brendan A Williams
- Department of Orthopaedics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
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Jung HJ, Mikdashi J. Systemic Sarcoidosis With Neurosarcoidosis Features as a Risk Factor for Multifocal Osteonecrosis. Cureus 2024; 16:e66791. [PMID: 39268259 PMCID: PMC11392397 DOI: 10.7759/cureus.66791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2024] [Indexed: 09/15/2024] Open
Abstract
Sarcoidosis is a systemic inflammatory disease that affects diverse organs such as the lungs, skin, eyes, and brain. Osseous involvement in sarcoidosis usually affects bones of the appendages with direct infiltration of non-caseating granulomas without bony infarcts. Symptoms of sarcoid bone lesions respond well to corticosteroid therapy. In contrast, corticosteroids act as a risk factor for the development of osteonecrosis resulting in pain and disability. Osteonecrosis that involves three or more different anatomic sites, defined as multifocal osteonecrosis (MFON), is rare. MFON has not been documented in the setting of sarcoidosis. We report a systemic sarcoidosis patient with predominant neuropsychiatric manifestations, who progressively developed MFON. Despite the limited use of corticosteroid treatment, the high burden of systemic sarcoidosis and its related neuropsychiatric involvementmay have collectively contributed to the development of MFON. This case highlights the rare association of MFON with systemic sarcoidosis and the need for further investigation into the underlying pathogenesis of MFON to prevent disability and morbidity.
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Affiliation(s)
- Hee Jae Jung
- Internal Medicine, University of Maryland Medical Center, Baltimore, USA
| | - Jamal Mikdashi
- Rheumatology, University of Maryland School of Medicine, Baltimore, USA
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Krez A, Lane J, Heilbronner A, Park-Min KH, Kaneko K, Pannellini T, Mintz D, Hansen D, McMahon DJ, Kirou KA, Roboz G, Desai P, Bockman RS, Stein EM. Risk factors for multi-joint disease in patients with glucocorticoid-induced osteonecrosis. Osteoporos Int 2021; 32:2095-2103. [PMID: 33877383 PMCID: PMC8056829 DOI: 10.1007/s00198-021-05947-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 04/01/2021] [Indexed: 12/24/2022]
Abstract
UNLABELLED This study investigated risk factors for osteonecrosis involving multiple joints (MJON) among glucocorticoid-treated patients. The best predictor of MJON was cumulative oral glucocorticoid dose. Risk of MJON was 12-fold higher in patients who had a second risk factor for osteonecrosis. Further research is needed into strategies for prevention of MJON. INTRODUCTION Osteonecrosis (ON) is a debilitating musculoskeletal condition in which bone cell death can lead to mechanical failure. When multiple joints are affected, pain and disability are compounded. Glucocorticoid treatment is one of the most common predisposing factors for ON. This study investigated risk factors for ON involving multiple joints (MJON) among glucocorticoid-treated patients. METHODS Fifty-five adults with glucocorticoid-induced ON were prospectively enrolled. MJON was defined as ON in ≥ three joints. Route, dose, duration, and timing of glucocorticoid treatment were assessed. RESULTS Mean age of enrolled subjects was 44 years, 58% were women. Half had underlying conditions associated with increased ON risk: systemic lupus erythematosus (29%), acute lymphoblastic leukemia (11%), HIV (9%), and alcohol use (4%). Mean daily oral dose of glucocorticoids was 29 mg. Average cumulative oral dose was 30 g over 5 years. The best predictor of MJON was cumulative oral glucocorticoid dose. For each increase of 1,000 mg, risk of MJON increased by 3.2% (95% CI 1.03, 1.67). Glucocorticoid exposure in the first 6 months of therapy, peak dose (oral or IV), and mean daily dose did not independently increase risk of MJON. The risk of MJON was 12-fold in patients who had a second risk factor (95% CI 3.2, 44.4). CONCLUSIONS Among patients with glucocorticoid-induced ON, cumulative oral dose was the best predictor of multi-joint disease; initial doses of IV and oral glucocorticoids did not independently increase risk. Further research is needed to better define optimal strategies for prevention and treatment of MJON.
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Affiliation(s)
- A Krez
- Endocrinology Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY, USA
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
| | - J Lane
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
- Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - A Heilbronner
- Endocrinology Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY, USA
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
| | - K-H Park-Min
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomic Research Center, Hospital for Special Surgery, New York, NY, USA
| | - K Kaneko
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomic Research Center, Hospital for Special Surgery, New York, NY, USA
| | - T Pannellini
- Research Division, Hospital for Special Surgery, New York, NY, USA
| | - D Mintz
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA
| | - D Hansen
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
- Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - D J McMahon
- Endocrinology Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY, USA
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
| | - K A Kirou
- Division of Rheumatology, Hospital for Special Surgery, New York, NY, USA
| | - G Roboz
- Department of Hematology and Oncology, Weill Cornell Medical Center, New York, NY, USA
| | - P Desai
- Department of Hematology and Oncology, Weill Cornell Medical Center, New York, NY, USA
| | - R S Bockman
- Endocrinology Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY, USA
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA
| | - E M Stein
- Endocrinology Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY, USA.
- Metabolic Bone Disease Service, Hospital for Special Surgery, New York, NY, 10021, USA.
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Rocchi M, Del Piccolo N, Mazzotta A, Giavaresi G, Fini M, Facchini F, Stagni C, Dallari D. 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. Hip Int 2020; 30:3-12. [PMID: 33267692 DOI: 10.1177/1120700020964996] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
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.
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Affiliation(s)
- Martina Rocchi
- Reconstructive Orthopaedic Surgery Innovative Techniques - Musculoskeletal Tissue Bank, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Nicoladrea Del Piccolo
- Reconstructive Orthopaedic Surgery Innovative Techniques - Musculoskeletal Tissue Bank, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Alessandro Mazzotta
- Reconstructive Orthopaedic Surgery Innovative Techniques - Musculoskeletal Tissue Bank, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Gianluca Giavaresi
- Laboratory of Preclinical and Surgical Studies, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Milena Fini
- Laboratory of Preclinical and Surgical Studies, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Fabio Facchini
- Intensive Care and Pain Therapy, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Cesare Stagni
- Reconstructive Orthopaedic Surgery Innovative Techniques - Musculoskeletal Tissue Bank, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Dante Dallari
- Reconstructive Orthopaedic Surgery Innovative Techniques - Musculoskeletal Tissue Bank, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
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Sun W, Shi Z, Gao F, Wang B, Li Z. The pathogenesis of multifocal osteonecrosis. Sci Rep 2016; 6:29576. [PMID: 27404962 PMCID: PMC4941719 DOI: 10.1038/srep29576] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/20/2016] [Indexed: 12/14/2022] Open
Abstract
Our objective was to study the incidence, etiology, and diagnosis of multifocal osteonecrosis (MFON) and its treatment options to facilitate an earlier diagnosis and to optimize treatment. A radiological investigation was performed in osteonecrosis patients with a high risk of MFON for a more accurate diagnosis between January 2010 and June 2015. For patients with osteonecrosis of both the hip and knee joints or for patients with a history of corticosteroid use or alcohol abuse who had osteonecrosis of one or more joints in the shoulder, ankle, wrist or elbow, magnetic resonance imaging (MRI) was also performed on other joints, regardless of whether these joints were symptomatic. Furthermore, we performed a radiological screening of 102 patients who had a negative diagnosis of MFON but were at a high risk; among them, another 31 MFON cases were successfully identified (30.4%). Thus, the incidence of MFON during the study period increased from 3.1% to 5.2%. Patients diagnosed with osteonecrosis and who are at a high risk of MFON should have their other joints radiologically examined when necessary. This will reduce missed diagnosis of MFON and facilitate an earlier diagnosis and treatment to achieve an optimal outcome.
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Affiliation(s)
- Wei Sun
- Centre for Osteonecrosis and Joint-preserving &Reconstruction, Orthopaedic Department, China-Japan Friendship Hospital, Beijing, 100029, China
| | - Zhencai Shi
- Centre for Osteonecrosis and Joint-preserving &Reconstruction, Orthopaedic Department, China-Japan Friendship Hospital, Beijing, 100029, China
| | - Fuqiang Gao
- Centre for Osteonecrosis and Joint-preserving &Reconstruction, Orthopaedic Department, China-Japan Friendship Hospital, Beijing, 100029, China
| | - Bailiang Wang
- Centre for Osteonecrosis and Joint-preserving &Reconstruction, Orthopaedic Department, China-Japan Friendship Hospital, Beijing, 100029, China
| | - Zirong Li
- Centre for Osteonecrosis and Joint-preserving &Reconstruction, Orthopaedic Department, China-Japan Friendship Hospital, Beijing, 100029, China
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Ilizarov hip reconstruction for the management of advanced osteonecrosis in an adolescent with leukemia. J Pediatr Orthop B 2012; 21:252-9. [PMID: 21753739 DOI: 10.1097/bpb.0b013e328348aac4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
With advances in chemotherapy, long-term survival for childhood leukemia is improving. However, chemotherapy-induced osteonecrosis of the proximal femur remains a challenging problem. We present a case of an adolescent female with advanced osteonecrosis of the proximal femur after chemotherapy for acute lymphoblastic leukemia. She underwent an Ilizarov hip reconstruction with a subtrochanteric valgus extension osteotomy and distal femoral lengthening with varus angulation using an external fixator. At a 3-year follow-up, her symptoms and gait had markedly improved. On the basis of this preliminary report, Ilizarov hip reconstruction is a viable alternative for advanced osteonecrosis of the proximal femur in an adolescent.
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Abstract
Skeletal manifestations are common in hematologic disorders. Benign entities such as Sickle cell disease develop microvascular embolization causing skeletal crisis. Leukemia, acute myeloblastic or lymphoblastic may develop bone marrow infarcts. Compromised immunity makes them susceptible to secondary infection leading to osteomyelitis or septic arthritis. Exposure to steroids may lead to osteonecrosis in these cases. Presented here is an atlas of various scintigraphic skeletal manifestations encountered over the past 10 years, in hematologic disorders.
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Affiliation(s)
| | - Ritu Bhandari
- Nuclear Medicine Services, Kothrud, Pune, Maharashtra, India
| | - Pallavi Solav
- Nuclear Medicine Services, Kothrud, Pune, Maharashtra, India
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Madadi F, Shamsian BS, Alavi S, Madadi F, Eajazi A, Aslani A. Avascular necrosis of the femoral head in children with acute lymphoblastic leukemia: a 4- to 9-year follow-up study. Orthopedics 2011; 34:e593-7. [PMID: 21956050 DOI: 10.3928/01477447-20110826-07] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Avascular necrosis of the femoral head is usually seen in children aged 1.5 to 10 years, reaching a peak incidence between the ages of 4 and 9. Avascular necrosis of the femoral head is a known complication of corticosteroid therapy in acute lymphoblastic leukemia. There are few reports in the literature regarding the natural history of this condition, and there is no consensus on its management. This study examined the natural history of avascular necrosis of the femoral head in children with leukemia. From 1993 to 2006, a total of 865 children with acute lymphoblastic leukemia were admitted to the hematology-oncology ward of a children's hospital. The diagnosis of acute lymphoblastic leukemia was established by bone marrow aspiration. Based on clinical and radiographic findings, avascular necrosis of the femoral head was found in 7 patients; these patients underwent follow-up for 4 to 9 years. Avascular necrosis of the femoral head was clinically symptomatic in all of the children, and they had advanced radiographic collapse of the femoral head. However, the head of the femur was not at risk in any patient based on clinical and radiographic findings. Patients received supportive treatment such as abduction brace and physiotherapy. After 4 to 9 years of follow-up, clinical and radiographic results were satisfactory. Provided that the head of the femur is not at risk, avascular necrosis of the femoral head in children with acute lymphoblastic leukemia may be successfully managed with nonoperative care.
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Affiliation(s)
- Firooz Madadi
- Department of Orthopedic Surgery, Shahid Beheshti Medical University, Tehran, Iran
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Newland AM, Lawson AP, Adams VR. Complications associated with treatment of malignancies: a focus on avascular necrosis of the bone. Orthopedics 2010; 33:413-6. [PMID: 20806750 DOI: 10.3928/01477447-20100429-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Shirota T, Nakamura A, Matsui Y, Hatori M, Nakamura M, Shintani S. Bisphosphonate-related osteonecrosis of the jaw around dental implants in the maxilla: report of a case. Clin Oral Implants Res 2009; 20:1402-8. [PMID: 19793318 DOI: 10.1111/j.1600-0501.2009.01801.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We describe a patient who developed bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) around implants in the upper molar area. PATIENTS AND METHODS The patient was a 54-year-old woman with ulceration of the gum, bone exposure, and severe spontaneous pain around implants in the upper left molar area. She had received BPs intravenously for 2 years to treat bone metastases of breast cancer. She was diagnosed with BP-related ONJ. Sequestrum including implants was resected, and hyperbaric oxygen therapy was performed. Undecalcified ground sections were prepared from the resected bone around the implants and stained with toluidine blue. For the bone around the lesion, decalcified sections were prepared, and examined by histological and immunohistological analysis. RESULTS The surgical wound became completely covered with mucosal epithelia, and postoperative pain disappeared. No recurrence of ONJ was noted during a 6-month postoperative follow-up period. However, the patient died from metastatic disease. Although histopathological examination of the resected jaw bone revealed sequestrum, osseointegration of the implant was maintained. In the area around the lesion, there was no progression of bone necrosis, and reactive bone formation, fibrosis, and invasion of lymphoid cells into the marrow cavity were observed. CONCLUSION There is no effective treatment for ONJ caused by BPs, and conservative therapy based on clinicians' experience is recommended. However, if chemotherapy is planned, or if bone necrosis around implants is thought to harbor infection, the option of jaw resection should be considered.
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Affiliation(s)
- Tatsuo Shirota
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan.
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Kerachian MA, Séguin C, Harvey EJ. Glucocorticoids in osteonecrosis of the femoral head: a new understanding of the mechanisms of action. J Steroid Biochem Mol Biol 2009; 114:121-8. [PMID: 19429441 PMCID: PMC7126235 DOI: 10.1016/j.jsbmb.2009.02.007] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2008] [Revised: 02/10/2009] [Accepted: 02/11/2009] [Indexed: 01/15/2023]
Abstract
Glucocorticoid (GC) usage is the most common non-traumatic cause of osteonecrosis of the femoral head (ON). Despite the strong association of GC with ON, the underlying mechanisms have been unclear. Investigators have proposed both direct and indirect effects of GC on cells. Indirect and direct mechanisms remain intimately related and often result in positive feedback loops to potentiate the disease processes. However, the direct effects, in particular apoptosis, have recently been shown to be increasingly important. Suppression of osteoblast and osteoclast precursor production, increased apoptosis of osteoblasts and osteocytes, prolongation of the lifespan of osteoclasts and apoptosis of endothelial cells (EC) are all direct effects of GC usage. Elevated blood pressure through several pathways may raise the risk of clot formation. High-dose GC also decreases tissue plasminogen activator activity (t-PA) and increases plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels increasing the procoagulant potential of GC. Inhibited angiogenesis, altered bone repair and nitric oxide metabolism can also result. Also, GC treatment modulates other vasoactive mediators such as endothelin-1, noradrenalin and bradykinin. Thus, GCs act as a regulator of local blood flow by modulating vascular responsiveness to vasoactive substances. Vasoconstriction induced in intraosseous femoral head arteries causes femoral head ischemia. GCs also cause ischemia through increased intraosseous pressure, which subsequently decreases the blood flow to the femoral head by apoptosis of ECs as well as elevating the level of adipogenesis and fat hypertrophy in the bone marrow. It is difficult to predict which patients receiving a specific dose of GC will develop ON, indicating individual differences in steroid sensitivity and the potential of additional mechanisms. The textbook model of ON is a multiple hit theory in which, with a greater number of risk factors, the risk of ON increases. While more effort is needed to better comprehend the role of GC in ON, newer data on GC action upon the endothelial cell and the regional endothelial bed dysfunction theory sheds new light on particular GC mechanisms. Better understanding of GC pathomechanisms can lead to better treatment options.
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Affiliation(s)
| | - Chantal Séguin
- Department of Medicine, Division of Haematology, MUHC, Montreal, Canada
- Department of Oncology, MUHC, Montreal, Canada
| | - Edward J. Harvey
- Division of Orthopaedic Surgery, MUHC-Montreal General Site, 1650 Cedar Ave Room B5.159.5, Montreal, Quebec, Canada H3G1A4
- Corresponding author. Tel.: +1 514 934 1934x42734; fax: +1 514 934 8394.
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