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Shim BJ, Won H, Kim SY, Baek SH. Surgical strategy of the treatment of atypical femoral fractures. World J Orthop 2023; 14:302-311. [PMID: 37304202 PMCID: PMC10251271 DOI: 10.5312/wjo.v14.i5.302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/16/2023] [Accepted: 04/19/2023] [Indexed: 05/18/2023] Open
Abstract
The atypical femoral fracture (AFF) has been attracting significant attention because of its increasing incidence; additionally, its treatment is challenging from biological and mechanical aspects. Although surgery is often required to manage complete AFFs, clear guidelines for the surgical treatment of AFFs are currently sparse. We reviewed and described the surgical treatment of AFFs and the surveillance of the contralateral femur. For complete AFFs, cephalomedullary intramedullary nailing spanning the entire length of the femur can be used. Various surgical techniques to overcome the femoral bowing common in AFFs include a lateral entry point, external rotation of the nail, and the use of a nail with a small radius of curvature, or a contralateral nail. In the case of a narrow medullary canal, severe femoral bowing, or pre-existing implants, plate fixation may be considered as an alternative. For incomplete AFFs, prophylactic fixation depends on several risk factors, such as a subtrochanteric location, presence of a radiolucent line, functional pain, and condition of the contralateral femur; the same surgical principles as those in complete AFFs can be applied. Finally, once AFF is diagnosed, clinicians should recognize the increased risk of contralateral AFFs, and close surveillance of the contralateral femur is recommended.
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Affiliation(s)
- Bum-Jin Shim
- Department of Orthopedic Surgery, Kyungpook National University Chilgok Hospital, Daegu 41404, South Korea
- Department of Orthopedic Surgery, Kyungpook National University, College of Medincine, Daegu 41944, South Korea
| | - Heejae Won
- Department of Orthopedic Surgery, Kyungpook National University Chilgok Hospital, Daegu 41404, South Korea
| | - Shin-Yoon Kim
- Department of Orthopedic Surgery, Kyungpook National University Hospital, Kyungpook National University, College of Medincine, Daegu 41944, South Korea
| | - Seung-Hoon Baek
- Department of Orthopedic Surgery, Kyungpook National University Hospital, Kyungpook National University, College of Medincine, Daegu 41944, South Korea
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2
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Inojosa AC, Mendes L, Bandeira L, Bandeira F. The Role of Bisphosphonates Prior to Denosumab Treatment on Rebound Fractures: A Mini Review. J Bone Metab 2022; 29:217-223. [PMID: 36529864 PMCID: PMC9760774 DOI: 10.11005/jbm.2022.29.4.217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/01/2022] [Indexed: 12/14/2022] Open
Abstract
Denosumab is a potent anti-resorptive medication used to treat patients at high risk for osteoporosis; however, its beneficial effects on the skeletal system are quickly reversed after discontinuation. In contrast, bisphosphonates (BPs) are anti-resorptive agents with residual effects on the bone matrix; thus, these are capable of preserving bone mass for a long time. Therefore, subsequent anti-resorptive treatment with BPs is mandatory to prevent rebound fractures. Furthermore, BP administration before denosumab treatment appears to be a reasonable strategy for reducing hyperactivation of bone remodeling. In this review, we summarize the effects of BP administration before denosumab treatment in preventing rebound fractures after denosumab discontinuation.
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Affiliation(s)
- Arthur Costa Inojosa
- Division of Endocrinology, Agamenon Magalhães Hospital, University of Pernambuco Medical School, Recife,
Brazil
| | - Laís Mendes
- Division of Endocrinology, Agamenon Magalhães Hospital, University of Pernambuco Medical School, Recife,
Brazil
| | | | - Francisco Bandeira
- Division of Endocrinology and Diabetes, FBandeira Endocrine Institute, Agamenon Magalhães Hospital, University of Pernambuco Medical School, Recife,
Brazil
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3
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Hussain MA, Joseph A, Cherian VM, Srivastava A, Cherian KE, Kapoor N, Paul TV. Bisphosphonate-induced atypical femoral fracture in tandem: long-term follow-up is warranted. Endocrinol Diabetes Metab Case Rep 2022; 2022:22-0249. [PMID: 36001019 PMCID: PMC9422258 DOI: 10.1530/edm-22-0249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/15/2022] [Indexed: 11/08/2022] Open
Abstract
Summary Although bisphosphonates (BPs) are mainly used for the treatment of osteoporosis and are generally safe, long-term use and more dosage as utilised in malignant conditions may be associated with the rare adverse event of an atypical femoral fracture (AFF). Occasionally, the risk of developing an AFF persists long after BPs are withdrawn. A 39-year-old woman who underwent chemotherapy and an autologous stem cell transplantation for multiple myeloma presented to us with history of pain in the left thigh. She had received multiple doses of oral and parenteral BPs for about 10 years in view of the underlying myeloma with osteoporosis. Her investigations showed a suppressed CTX of 192 pg/mL, and radiograph of pelvis displayed thickened cortices with beaking of the left femoral shaft, which was suggestive of an AFF. Following discontinuation of BPs, she underwent prophylactic intra-medullary nailing with which her symptoms improved. Five years later, she presented with similar complaints on the right side. Investigations showed that her bone turnover continued to be suppressed with Cross linked C- Telopeptide of type 1 collagen (CTX) of 165 pg/mL and an X-ray done showed AFF on the right side despite being off BPs. A second intra-medullary nailing was done and on follow-up, she has been symptom-free and independent in her daily activities. Discontinuation of BPs may not prevent the incident second AFF and, therefore, thus warranting long-term follow-up. Learning points Regular screening and follow-up of patients who receive long-term bisphosphonate (BP) therapy should be done. Discontinuation of BPs does not preclude the possibility of repeated occurrence of a second AFF. Long-term BP therapy warrants regular monitoring and follow-up should an AFF occur.
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Affiliation(s)
| | - Aneez Joseph
- Department of Endocrinology, Christian Medical College and Hospital, Vellore, India
| | - Vinoo Mathew Cherian
- Department of Orthopaedics, Christian Medical College and Hospital, Vellore, India
| | - Alok Srivastava
- Department of Haematology, Christian Medical College and Hospital, Vellore, India
| | | | - Nitin Kapoor
- Department of Endocrinology, Christian Medical College and Hospital, Vellore, India
| | - Thomas Vizhalil Paul
- Department of Endocrinology, Christian Medical College and Hospital, Vellore, India
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Singleton RC, Pharr GM, Nyman JS. Increased tissue-level storage modulus and hardness with age in male cortical bone and its association with decreased fracture toughness. Bone 2021; 148:115949. [PMID: 33862261 PMCID: PMC8102428 DOI: 10.1016/j.bone.2021.115949] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 11/19/2022]
Abstract
The incidence of bone fracture increases with age, due to both declining bone quantity and quality. Toward the goal of an improved understanding of the causes of the age-related decline in the fracture toughness of male cortical bone, nanoindentation experiments were performed on femoral diaphysis specimens from men aged 21-98 years. Because aged bone has less matrix-bound water and dry bone is less viscoelastic, we used a nanoindentation method that is sensitive to changes in viscoelasticity. Given the anisotropy of bone stiffness, longitudinal (n = 26) and transverse (n = 25) specimens relative to the long axis of the femur diaphysis were tested both dry in air and immersed in phosphate buffered saline solution. Indentation stiffness (storage modulus) and hardness increased with age, while viscoelasticity (loss modulus) was independent of donor age. The increases in indentation stiffness and hardness with age were best explained by increased mineralization with age. Indentation stiffness and hardness were negatively correlated with previously acquired fracture toughness parameters, which is consistent with a tradeoff between material strength and toughness. In keeping with the complex structure of bone, a combination of tissue-level storage modulus or hardness, bound water, and osteonal area in regression models best explained the variance in the fracture toughness of male human cortical bone. On the other hand, viscoelasticity was unchanged with age and was not associated with fracture toughness. In conclusion, the age-related increase in stiffness and hardness of male cortical bone may be one of the multiple tissue-level characteristics that contributes to decreased fracture toughness.
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Affiliation(s)
- Robert C Singleton
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN 37996, USA
| | - George M Pharr
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN 37996, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843-3003, USA
| | - Jeffry S Nyman
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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Bisphosphonate treatment and the risk of atypical femoral fracture among patients participating in a Fracture Liaison Service of a tertiary medical center. Arch Osteoporos 2021; 16:86. [PMID: 34089098 DOI: 10.1007/s11657-021-00944-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 04/01/2021] [Indexed: 02/03/2023]
Abstract
UNLABELLED Bisphosphonates are common treatment for osteoporosis. Among patients admitted with hip fracture, atypical femoral fractures (AFF) were more prevalent in those who were treated with Bisphosphonates for five or more years. Five years of Bisphosphonates treatment may signify an increased risk for AFF, though the absolute risk remains very low. PURPOSE Atypical femoral fractures (AFF) are a rare complication of bisphosphonate (BP) treatment. We evaluated the correlation between BP exposure and AFF risk among hip fracture patients. METHODS This retrospective nested case-control study included patients over age 50 years, operated for osteoporotic hip fracture between July 2014 and November 2018, who attended our Fracture Liaison Service. We classified fracture radiographs and compared demographic, clinical, biochemical, and drug purchase data between patients with AFF and those with typical osteoporotic hip fracture (controls). To correct for the younger age of patients with AFF, we matched each case (AFF) with three controls according to age ([Formula: see text] 1 year) and sex and performed a conditional logistic regression model. RESULTS Of 989 patients, 31 (3%) had AFF. Patients with AFF were younger than those with inter-trochanteric fractures (mean ± SD: 72.3 ± 10.3 vs. 80.2 ± 9.6 years, p < 0.001). Following matching, the mean Charlson's Comorbidity Index (CCI) was lower in the AFF than in the control group (2.9 ± 3.7 vs. 4.7 ± 4.2; p = 0.030) and a higher proportion of them were treated with BP for 5 years or more (58.1 vs. 16.0%; p < 0.001). Among patients admitted with hip fracture who were treated with BP for 5 years or more, the odds ratio of this fracture being atypical was significantly higher compared with no BP treatment (21.7; 95% CI-4.1-113.9). CONCLUSIONS Patients with AFF compared to typical hip fractures showed better baseline medical conditions irrespective of their younger age. Five years of BP treatment may be associated with an increased risk for AFF, though the absolute risk remains very low.
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Papaioannou I, Pantazidou G, Baikousis A, Korovessis P. Femoral Bowing and Femoral Neck-Shaft Angle Evaluation Can Reduce Atypical Femoral Fractures in Osteoporotic Patients: A Scientific Report. Cureus 2020; 12:e10771. [PMID: 33154843 PMCID: PMC7606192 DOI: 10.7759/cureus.10771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bisphosphonates (BPs) are the mainstay of osteoporosis treatment due to their safety and efficacy. There is evidence that BPs medication may be complicated by atypical femoral fractures (AFFs). Prolonged administration of BPs is even more strongly associated with AFFs. AFF is a relatively rare complication of BPs when taking into account the huge population worldwide that benefits from this pharmacotherapy. AFF is, however, a serious complication of BPs treatment, which includes prolonged healing time and high revision rate when operative treatment is required. Less frequently, AFFs occur even without BPs administration, while these fractures have all the characteristics of “stress” or “insufficiency” fractures. The critical point of view in AFFs pathogenesis seems to be not only the biology of cortical bone, but also the mechanical issue. It has been proven that BPs, glucocorticoids and proton pump inhibitors (PPIs) can cause bone turnover suppression and affect the biological parameter of AFFs pathogenesis. Specific mechanical femoral bone properties predispose to AFFs pathogenesis. Several studies have already reported that increased femoral bowing > 5.250 degrees or decreased femoral neck-shaft angle <125 degrees, are associated with increased risk for diaphyseal and subtrochanteric AFFs respectively, regardless of BPs uptake. If these two parameters are simultaneously present, the probability for AFFs occurrence increases dramatically. Our scientific report, which is based on the current evidence about AFFs, is that if both femoral bowing angle and femoral neck-shaft angle are evaluated before BPs administration, this intervention may reduce the incidence of AFFs. Thus, in cases with excessive lateral femoral shaft bowing or very small femoral neck-shaft angle, the prescription of another anti-osteoporotic treatment than BPs should be recommended. If, however, BPs can’t be avoided, clinicians should be aware of the fact that long-term administration may be implicated with AFFs occurrence. In these cases, short term BPs administration with timely drug holiday between three and five years may be reasonable. Finally, roentgenographic evaluation of both femurs every six months and medical reference in case of any emerging thigh pain are also logical interventions to prevent and reduce AFFs.
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Affiliation(s)
- Ioannis Papaioannou
- Orthopedics and Traumatology and Spine Surgery, General Hospital of Patras, Patras, GRC
| | - Georgia Pantazidou
- Otolaryngology - Head and Neck Surgery, General Hospital of Patras, Patras, GRC
| | - Andreas Baikousis
- Orthopedics and Traumatology and Spine Surgery, General Hospital of Patras, Patras, GRC
| | - Panagiotis Korovessis
- Orthopedics and Traumatology and Spine Surgery, General Hospital of Patras, Patras, GRC
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Bahia M, Hecke M, Mercuri E, Pinheiro M. A bone remodeling model governed by cellular micromechanics and physiologically based pharmacokinetics. J Mech Behav Biomed Mater 2020; 104:103657. [DOI: 10.1016/j.jmbbm.2020.103657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/11/2020] [Accepted: 01/23/2020] [Indexed: 11/29/2022]
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Imamura T, Tsurumoto T, Saiki K, Nishi K, Okamoto K, Manabe Y, Oyamada J, Ogami-Takamura K. Morphological profile of atypical femoral fractures: age-related changes to the cross-sectional geometry of the diaphysis. J Anat 2019; 235:892-902. [PMID: 31355449 DOI: 10.1111/joa.13060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2019] [Indexed: 12/14/2022] Open
Abstract
The use of bisphosphonates for osteoporosis patients has markedly decreased the incidence of femoral neck or trochanteric fractures. However, anti-osteoporosis drugs have been reported to increase the incidence of atypical femoral fractures, which involve stress fractures in the subtrochanteric region or the proximal diaphysis. In this study, the morphological characteristics of the cortical bone in human femoral diaphysis samples were analyzed from individuals who lived before bisphosphonate drugs were available in Japan. A total of 90 right femoral bones were arbitrarily selected (46 males and 44 females) from modern Japanese skeletal specimens. Full-length images of these femurs were acquired using a computed tomography scanner. An image processing method for binarization was used to calculate the threshold values of individual bones for determining their contours. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain 10 planes. The mean value of cortical bone thickness, periosteal border length, and the cortical cross-sectional area was evaluated for all planes. Moreover, the ratio of the area of the cortical bone to the total area of cross-section at the mid-diaphysis was calculated. A comparison between males and females demonstrated that most females had lower cortical bone area ratios at the mid-diaphysis. The femoral outer shape did not differ markedly according to age or sex; however, substantial individual differences were observed in the shape of the inner surface of the cortical bone. The cortical bone thickness and the cross-sectional area decreased with age in the femoral diaphysis; furthermore, in females, the decrease was higher for the former than for the latter. This may be due to a compensatory increase in the circumference of the femoral diaphysis. In addition, in about half of the subjects there was a discrepancy between the region with maximal value of the cortical bone thickness and that of the total cross-sectional area. Biological responses to mechanical stresses to the femoral diaphysis are thought not to be uniform. Bisphosphonates inhibit bone resorption and may promote non-physiological bone remodeling. Thus, a nonhomogeneous decrease in cortical thickness may be related to the fracture occurrence in the femoral diaphysis in some cases. Thus, long-term administration of bisphosphonates in patients with morphological vulnerability in the femoral cortical bones may increase the occurrence of atypical femoral fractures.
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Affiliation(s)
- Takeshi Imamura
- Department of Macroscopic Anatomy, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Toshiyuki Tsurumoto
- Department of Macroscopic Anatomy, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Kazunobu Saiki
- Department of Macroscopic Anatomy, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Keita Nishi
- Department of Oral Anatomy and Dental Anthropology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Keishi Okamoto
- Department of Macroscopic Anatomy, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Yoshitaka Manabe
- Department of Oral Anatomy and Dental Anthropology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Joichi Oyamada
- Department of Oral Anatomy and Dental Anthropology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Keiko Ogami-Takamura
- Department of Macroscopic Anatomy, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
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Bahia MT, Hecke MB, Mercuri EG. Image-based anatomical reconstruction and pharmaco-mediated bone remodeling model applied to a femur with subtrochanteric fracture: A subject-specific finite element study. Med Eng Phys 2019; 69:58-71. [DOI: 10.1016/j.medengphy.2019.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 04/17/2019] [Accepted: 05/19/2019] [Indexed: 01/25/2023]
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10
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Buitendijk SKC, van de Laarschot DM, Smits AAA, Koromani F, Rivadeneira F, Beck TJ, Zillikens MC. Trabecular Bone Score and Hip Structural Analysis in Patients With Atypical Femur Fractures. J Clin Densitom 2019; 22:257-265. [PMID: 29661684 DOI: 10.1016/j.jocd.2018.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 03/13/2018] [Indexed: 01/03/2023]
Abstract
Bisphosphonate use has declined dramatically in recent years, partly because of fear of rare side effects like atypical femur fractures (AFFs). It is therefore desirable to have a diagnostic method to identify those at risk of AFF to prevent this serious complication. We compared trabecular microarchitecture and hip geometry between 30 patients with AFF and 141 controls of similar age and sex, using bisphosphonates. Trabecular bone score (TBS) and hip structural analysis (HSA) were used to assess trabecular microarchitecture and macroscopic hip geometry from dual-energy X-ray absorptiometry images of the lumbar spine and hip, respectively. General characteristics, TBS, and HSA were compared between patients with AFF and controls using Student's t tests and chi-square statistics. Associations between AFF and TBS and femur geometric characteristics by HSA were adjusted for sex, age, height, weight, ethnicity, duration of bisphosphonate use, and glucocorticoid use. Additionally, the analysis of TBS was adjusted for lumbar spine bone mineral density and the time difference between dual-energy X-ray absorptiometry scanning and the diagnosis of AFF. Patients with AFF had significantly higher body mass index than controls, had used bisphosphonates longer, and glucocorticoids and proton pump inhibitors more frequently. Sex-specific T-score was significantly higher in patients with AFF at the lumbar spine (p = 0.004), but not at the femoral neck (p = 0.190) after adjustment for age, height, and weight. TBS did not differ significantly between patients with AFF and controls. Neither neck shaft angle nor any geometric variables at the femoral shaft measured by HSA differed between patients with AFF and controls. At the narrow neck, patients with AFF had lower buckling ratio and higher centroid position, consistent with a lower risk of classical fragility hip fractures. The findings at narrow neck and higher bone mineral density might be explained by the fact that the majority of patients with AFF used bisphosphonates to prevent glucocorticoid-induced osteoporosis. Based on our results, TBS and HSA do not appear to have value in detecting patients at risk of AFF.
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Affiliation(s)
- Sanne K C Buitendijk
- Bone Center, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | | | - Alexandra A A Smits
- Bone Center, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Fjorda Koromani
- Bone Center, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
| | - Fernando Rivadeneira
- Bone Center, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
| | | | - M Carola Zillikens
- Bone Center, Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands.
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Abstract
We begin this chapter by describing normal characteristics of several pertinent connective tissue components, and some of the basic changes they undergo with ageing. These alterations are not necessarily tied to any specific disease or disorders, but rather an essential part of the normal ageing process. The general features of age-induced changes, such as skin wrinkles, in selected organs with high content of connective or soft tissues are discussed in the next part of the chapter. This is followed by a section dealing with age-related changes in specific diseases that fall into at least two categories. The first category encompasses common diseases with high prevalence among mostly ageing populations where both genetic and environmental factors play roles. They include but may not be limited to atherosclerosis and coronary heart disease, type II diabetes, osteopenia and osteoporosis, osteoarthritis, tendon dysfunction and injury, age-related disorders of spine and joints. Disorders where genetics plays the primary role in pathogenesis and progression include certain types of progeria, such as Werner syndrome and Hutchinson-Gilford progeria belong to the second category discussed in this chapter. These disorders are characterized by accelerated signs and symptoms of ageing. Other hereditary diseases or syndromes that arise from mutations of genes encoding for components of connective tissue and are less common than diseases included in the first group will be discussed briefly as well, though they may not be directly associated with ageing, but their connective tissue undergoes some changes compatible with ageing. Marfan and Ehlers-Danlos syndromes are primary examples of such disorders. We will probe the role of specific components of connective tissue and extracellular matrix if not in each of the diseases, then at least in the main representatives of these disorders.
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Affiliation(s)
- Carolyn Ann Sarbacher
- Department of Pathology, College of Veterinary Medicine, The University of Georgia and AU/UGA Medical Partnership, Athens, GA, USA
| | - Jaroslava T Halper
- Department of Pathology, College of Veterinary Medicine, The University of Georgia and AU/UGA Medical Partnership, Athens, GA, USA.
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Abstract
Atypical femoral fractures (AFF) are stress or ‘insufficiency’ fractures, often complicated by the use of bisphosphonates or other bone turnover inhibitors. While these drugs are beneficial for the intact osteoporotic bone, they probably prevent a stress fracture from healing which thus progresses to a complete fracture. Key features of atypical femoral fractures, essential for the diagnosis, are: location in the subtrochanteric region and diaphysis; lack of trauma history and comminution; and a transverse or short oblique configuration. The relative risk of patients developing an atypical femoral fracture when taking bisphosphonates is high; however, the absolute risk of these fractures in patients on bisphosphonates is low, ranging from 3.2 to 50 cases per 100,000 person-years. Treatment strategy in patients with AFF involves: radiograph of the contralateral side (computed tomography and magnetic resonance imaging should also be considered); dietary calcium and vitamin D supplementation should be prescribed following assessment; bisphosphonates or other potent antiresorptive agents should be discontinued; prophylactic surgical treatment of incomplete AFF with cephalomedullary nail, unless pain free; cephalomedullary nailing for surgical fixation of complete fractures; avoidance of gaps in the lateral and anterior cortex; avoidance of varus malreduction.
Cite this article: EFORT Open Rev 2018;3:494-500. DOI: 10.1302/2058-5241.3.170070.
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Affiliation(s)
| | - Hagen Schmal
- Department of Orthopaedics and Traumatology, Odense University Hospital, Denmark
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13
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A Cross-Sectional Study of the Association between Autoantibodies and Qualitative Ultrasound Index of Bone in an Elderly Sample without Clinical Autoimmune Disease. J Immunol Res 2018; 2018:9407971. [PMID: 29854851 PMCID: PMC5952466 DOI: 10.1155/2018/9407971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/05/2018] [Accepted: 03/17/2018] [Indexed: 12/15/2022] Open
Abstract
Bone loss is characteristic of the ageing process and a common complication of many autoimmune diseases. Research has highlighted a potential role of autoantibodies in pathologic bone loss. The confounding effects of immunomodulatory drugs make it difficult to establish the contribution of autoantibodies amongst autoimmune disease sufferers. We attempted to examine the relationship between autoantibodies and bone mass in a population of 2812 elderly participants without clinical autoimmune disease. Serum samples were assayed for a panel of autoantibodies (anti-nuclear, extractable nuclear antigen, anti-neutrophil cytoplasmic, thyroid peroxidase, tissue transglutaminase, anti-cardiolipin, rheumatoid factor, and cyclic citrullinated peptide). Bone mass was measured using quantitative ultrasound (QUS) of the calcaneus. The relationship between each autoantibody and bone mass was determined using linear regression models. Anti-nuclear autoantibodies were the most prevalent, positive in approximately 11%, and borderline in roughly 23% of our sample. They were also the only autoantibody observed to be significantly associated with QUS index in the univariate analysis (n = 1628; r = -0.20; 95% CI: -0.40-0.00; p = 0.046). However, statistical significance was lost after adjustment for various other potential confounders. None of the other autoantibodies was associated with QUS index in either univariate or multivariate analysis. We are limited by the cross-sectional nature of the study and the low prevalence of autoantibodies in our nonclinical sample.
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14
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Oh Y, Fujita K, Wakabayashi Y, Kurosa Y, Okawa A. Location of atypical femoral fracture can be determined by tensile stress distribution influenced by femoral bowing and neck-shaft angle: a CT-based nonlinear finite element analysis model for the assessment of femoral shaft loading stress. Injury 2017; 48:2736-2743. [PMID: 28982480 DOI: 10.1016/j.injury.2017.09.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/25/2017] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Loading stress due to individual variations in femoral morphology is thought to be strongly associated with the pathogenesis of atypical femoral fracture (AFF). In Japan, studies on AFF regarding pathogenesis in the mid-shaft are well-documented and a key factor in the injury is thought to be femoral shaft bowing deformity. Thus, we developed a CT-based finite element analysis (CT/FEA) model to assess distribution of loading stress in the femoral shaft. PATIENTS AND METHODS A multicenter prospective study was performed at 12 hospitals in Japan from August 2015 to February 2017. We assembled three study groups-the mid-shaft AFF group (n=12), the subtrochanteric AFF group (n=10), and the control group (n=11)-and analyzed femoral morphology and loading stress in the femoral shaft by nonlinear CT/FEA. RESULTS Femoral bowing in the mid-shaft AFF group was significantly greater (lateral bowing, p<0.0001; anterior bowing, p<0.01). Femoral neck-shaft angle in the subtrochanteric AFF group was significantly smaller (p<0.001). On CT/FEA, both the mid-shaft and subtrochanteric AFF group showed maximum tensile stress located adjacent to the fracture site. Quantitatively, there was a correlation between femoral bowing and the ratio of tensile stress, which was calculated between the mid-shaft and subtrochanteric region (lateral bowing, r=0.6373, p<0.0001; anterior bowing, r=-0.5825, p<0.001). CONCLUSIONS CT/FEA demonstrated that tensile stress by loading stress can cause AFF. The location of AFF injury could be determined by individual stress distribution influenced by femoral bowing and neck-shaft angle.
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Affiliation(s)
- Yoto Oh
- Department of Orthopaedic and Trauma Research, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Koji Fujita
- Department of Orthopaedic and Spinal Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshiaki Wakabayashi
- Department of Orthopaedic Surgery, Yokohama City Minato Red Cross Hospital, Kanagawa, Japan
| | - Yoshiro Kurosa
- Department of Orthopaedic Surgery, Saku Central Hospital, Nagano, Japan
| | - Atsushi Okawa
- Department of Orthopaedic and Spinal Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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15
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Zeng Y, Wu J, He X, Li L, Liu X, Liu X. Mechanical microenvironment regulation of age-related diseases involving degeneration of human skeletal and cardiovascular systems. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 148:54-59. [PMID: 28958683 DOI: 10.1016/j.pbiomolbio.2017.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/24/2017] [Accepted: 09/25/2017] [Indexed: 02/05/2023]
Abstract
Age-related diseases involving degeneration of human skeletal and cardiovascular systems are now critical problems worldwide. The current review focuses on a common pathophysiological association between primary osteoporosis and vascular calcification, and reviews the mechanical response of bone cells and vascular cells to mechanical stress, as well as the coordination mechanism for intercellular signaling. With aging, calcium is lost from bones but deposited in the cardiovascular system. Bone metabolism-related molecules, such as alkaline phosphatase, matrix Gla protein, osteocalcin, osteopontin, and collagen type I; inflammatory cytokines, such as interleukin-1, -6, and tumor necrosis factor; and lipid metabolism related molecules, such as oxidized low density lipoprotein; mediate signaling in primary osteoporosis and vascular calcification. The mechanical microenvironment is a common pathophysiological basis for primary osteoporosis and vascular calcification. Mobilization of calcium from bone to vessel determines the regression rate, which could be controlled using a mechanical microenvironment. We highlight several issues: (1) linked features between primary osteoporosis and vascular calcification, and detailed changes of the mechanical microenvironment in degenerative bone or blood vessels, (2) signaling coordination mechanism between bone and vascular wall cells, and (3) calcium translocation mechanism. The degree to which these issues can be solved will help develop prevention and treatment strategies for age-related regression.
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Affiliation(s)
- Ye Zeng
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
| | - Jiang Wu
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China
| | - Xueling He
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China; Laboratory Animal Center of Sichuan University, Chengdu 610041, China
| | - Liang Li
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
| | - Xiaojing Liu
- Laboratory of Cardiovascular Diseases, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiaoheng Liu
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
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Kim HY, Choi S, Yoon JH, Lim HJ, Lee H, Choi J, Ro EJ, Heo JN, Lee W, No KT, Choi KY. Small molecule inhibitors of the Dishevelled-CXXC5 interaction are new drug candidates for bone anabolic osteoporosis therapy. EMBO Mol Med 2017; 8:375-87. [PMID: 26941261 PMCID: PMC4818757 DOI: 10.15252/emmm.201505714] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bone anabolic agents promoting bone formation and rebuilding damaged bones would ideally overcome the limitations of anti‐resorptive therapy, the current standard prescription for osteoporosis. However, the currently prescribed parathyroid hormone (PTH)‐based anabolic drugs present limitations and adverse effects including osteosarcoma during long‐term use. Also, the antibody‐based anabolic drugs that are currently being developed present the potential limits in clinical application typical of macromolecule drugs. We previously identified that CXXC5 is a negative feedback regulator of the Wnt/β‐catenin pathway via its interaction with Dishevelled (Dvl) and suggested the Dvl–CXXC5 interaction as a potential target for anabolic therapy of osteoporosis. Here, we screened small‐molecule inhibitors of the Dvl–CXXC5 interaction via a newly established in vitro assay system. The screened compounds were found to activate the Wnt/β‐catenin pathway and enhance osteoblast differentiation in primary osteoblasts. The bone anabolic effects of the compounds were shown using ex vivo‐cultured calvaria. Nuclear magnetic resonance (NMR) titration analysis confirmed interaction between Dvl PDZ domain and KY‐02061, a representative of the screened compounds. Oral administration of KY‐02327, one of 55 newly synthesized KY‐02061 analogs, successfully rescued bone loss in the ovariectomized (OVX) mouse model. In conclusion, small‐molecule inhibitors of the Dvl–CXXC5 interaction that block negative feedback regulation of Wnt/β‐catenin signaling are potential candidates for the development of bone anabolic anti‐osteoporosis drugs.
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Affiliation(s)
- Hyun-Yi Kim
- Translational Research Center for Protein Function Control, Yonsei University, Seoul, Korea Department of Biotechnology, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
| | - Sehee Choi
- Translational Research Center for Protein Function Control, Yonsei University, Seoul, Korea Department of Biotechnology, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
| | - Ji-Hye Yoon
- Department of Biochemistry, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
| | - Hwan Jung Lim
- Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Hyuk Lee
- Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Jiwon Choi
- Bioinformatics & Molecular Design Research Center, Yonsei University, Seoul, Korea
| | - Eun Ji Ro
- Translational Research Center for Protein Function Control, Yonsei University, Seoul, Korea Department of Biotechnology, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
| | - Jung-Nyoung Heo
- Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Weontae Lee
- Department of Biochemistry, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
| | - Kyoung Tai No
- Department of Biotechnology, College of Life Science and Biotechnology Yonsei University, Seoul, Korea Bioinformatics & Molecular Design Research Center, Yonsei University, Seoul, Korea
| | - Kang-Yell Choi
- Translational Research Center for Protein Function Control, Yonsei University, Seoul, Korea Department of Biotechnology, College of Life Science and Biotechnology Yonsei University, Seoul, Korea
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17
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Pellegrino G, Roman M, Fritton JC. Effects of the basic multicellular unit and lamellar thickness on osteonal fatigue life. J Biomech 2017; 60:116-123. [PMID: 28711163 DOI: 10.1016/j.jbiomech.2017.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/08/2017] [Accepted: 06/13/2017] [Indexed: 11/25/2022]
Abstract
A remodeling cycle sets the size of the osteon and associated lamellae in the basic multicellular unit. Treatments and aging affect these micro-structural features. We previously demonstrated decreased fatigue life with an unexplained mechanism and decreased osteon size in cortical bone treated with high-dose bisphosphonate. Here, three finite element models were examined: type-1: a single osteon, as a homogeneous unit and with heterogeneous lamellae and interlamellae, type-2: a control, interstitial-only tissue and type-3: the osteon with cement line, set within the interstitial tissue. Models were loaded in simulated, sinusoidal bending fatigue. As osteon size was decreased, lamellar number and lamellar thickness were incrementally adjusted for each model. As hypothesized, lamellae within the larger type-1 models attained greater cycles to failure and the addition of an osteon to type-2 models (generating a type-3 model set) yielded increased fatigue life. However, as the osteon size was decreased, the potential for compressive damage nucleation was increased within the lamellae of the osteons versus the interstitium. Also, osteons with fewer, thicker lamellae displayed increased fatigue life. Osteonal microstructure plays a role in damage initiation location, especially when BMU size is smaller. Previous findings by us and others could partially be explained by this further understanding of increased probability for damage nucleation in smaller osteons.
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Affiliation(s)
- George Pellegrino
- Department of Orthopaedics & Graduate School of Biomedical Sciences, New Jersey Medical School, Rutgers University, 205 South Orange Avenue, Newark, NJ 07103, USA
| | - Max Roman
- Department of Biomedical Engineering, New Jersey Institute of Technology, 323 Martin Luther King, Jr. Boulevard, University Heights, Newark, NJ 07102, USA
| | - J Christopher Fritton
- Department of Orthopaedics & Graduate School of Biomedical Sciences, New Jersey Medical School, Rutgers University, 205 South Orange Avenue, Newark, NJ 07103, USA; Department of Biomedical Engineering, School of Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, USA.
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18
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Role of cortical bone in hip fracture. BONEKEY REPORTS 2017; 6:867. [PMID: 28277562 DOI: 10.1038/bonekey.2016.82] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/03/2016] [Indexed: 12/23/2022]
Abstract
In this review, I consider the varied mechanisms in cortical bone that help preserve its integrity and how they deteriorate with aging. Aging affects cortical bone in two ways: extrinsically through its effects on the individual that modify its mechanical loading experience and 'milieu interieur'; and intrinsically through the prolonged cycle of remodelling and renewal extending to an estimated 20 years in the proximal femur. Healthy femoral cortex incorporates multiple mechanisms that help prevent fracture. These have been described at multiple length scales from the individual bone mineral crystal to the scale of the femur itself and appear to operate hierarchically. Each cortical bone fracture begins as a sub-microscopic crack that enlarges under mechanical load, for example, that imposed by a fall. In these conditions, a crack will enlarge explosively unless the cortical bone is intrinsically tough (the opposite of brittle). Toughness leads to microscopic crack deflection and bridging and may be increased by adequate regulation of both mineral crystal size and the heterogeneity of mineral and matrix phases. The role of osteocytes in optimising toughness is beginning to be worked out; but many osteocytes die in situ without triggering bone renewal over a 20-year cycle, with potential for increasing brittleness. Furthermore, the superolateral cortex of the proximal femur thins progressively during life, so increasing the risk of buckling during a fall. Besides preserving or increasing hip BMD, pharmaceutical treatments have class-specific effects on the toughness of cortical bone, although dietary and exercise-based interventions show early promise.
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19
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Sharp K. Atypical Femoral Fractures: Implications for the Advanced Practitioner in Oncology. J Adv Pract Oncol 2017; 8:395-399. [PMID: 30018845 PMCID: PMC6040875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Bone-health issues may arise for oncology patients as a side effect of their treatments. One of these may be the development of an atypical femoral fracture. Advanced practitioners should be aware of the risk factors for atypical femoral fractures, and be able to promptly recognize signs, provide patient education, and manage them competently.
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20
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Jakob F, Genest F, Baron G, Stumpf U, Rudert M, Seefried L. [Regulation of bone metabolism in osteoporosis : novel drugs for osteoporosis in development]. Unfallchirurg 2016; 118:925-32. [PMID: 26471379 DOI: 10.1007/s00113-015-0085-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Bone is continuously regenerated and remodeled as an adaptation to mechanical load. Bone mass and fracture resistance are maintained by a balanced equilibrium between bone formation and bone resorption. Regeneration and response to mechanical load are, however, impaired in osteoporosis and during aging. Bone resorption is enhanced by chronic inflammation while bone formation is altered by rising levels of inhibitors in the aging organism. Core molecular principles of the regulation of bone metabolism in health and disease have been characterized and developed as therapeutic targets. The receptor activator of nuclear factor kappaB ligand (RANKL) and osteoclast-derived protease cathepsin K are important regulators and effectors of osteoclast differentiation and bone resorption. Bone formation is stimulated by bone morphogenetic proteins (BMP) and via the parathyroid hormone receptor and the Wnt signaling pathway. The principles of osteoclast inhibition using bisphosphonates have now been known for almost three decades. Based on more recent knowledge RANKL and cathepsin K have been developed as new therapeutic targets to inhibit bone resorption. While denosumab, a RANKL antibody, has already been introduced into routine treatment strategies, the cathepsin K antagonist odanacatib is currently in the licensing process. Bone formation can also be stimulated by local administration of BMPs, by systemic treatment with the parathyroid hormone fragment teriparatide and by using antibodies targeting the Wnt inhibitor sclerostin. The latter are presently being tested in phase III clinical studies. In the near future a panel of traditional and novel treatment strategies will be available that will enable us to meet the individual clinical needs during aging and for the treatment of osteoporosis.
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Affiliation(s)
- F Jakob
- Experimentelle und Klinische Osteologie, Orthopädie und Orthopädische Klinik König-Ludwig-Haus, Universität Würzburg, Brettreichstraße 11, 97074, Würzburg, Deutschland.
| | - F Genest
- Experimentelle und Klinische Osteologie, Orthopädie und Orthopädische Klinik König-Ludwig-Haus, Universität Würzburg, Brettreichstraße 11, 97074, Würzburg, Deutschland
| | - G Baron
- Experimentelle und Klinische Osteologie, Orthopädie und Orthopädische Klinik König-Ludwig-Haus, Universität Würzburg, Brettreichstraße 11, 97074, Würzburg, Deutschland
| | - U Stumpf
- Osteologisches Schwerpunktzentrum, Chirurgische Klinik und Poliklinik, Nußbaumstr. 20, 80336, München, Deutschland
| | - M Rudert
- Experimentelle und Klinische Osteologie, Orthopädie und Orthopädische Klinik König-Ludwig-Haus, Universität Würzburg, Brettreichstraße 11, 97074, Würzburg, Deutschland
| | - L Seefried
- Experimentelle und Klinische Osteologie, Orthopädie und Orthopädische Klinik König-Ludwig-Haus, Universität Würzburg, Brettreichstraße 11, 97074, Würzburg, Deutschland
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21
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Pittman K, Antill YC, Goldrick A, Goh J, de Boer RH. Denosumab: Prevention and management of hypocalcemia, osteonecrosis of the jaw and atypical fractures. Asia Pac J Clin Oncol 2016; 13:266-276. [DOI: 10.1111/ajco.12517] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/11/2016] [Indexed: 01/07/2023]
Affiliation(s)
| | - Yoland C Antill
- Cabrini Institute, Cabrini Health, and Department of Oncology; Frankston Hospital; Victoria Australia
| | - Amanda Goldrick
- Department of Haematology and Oncology; Amgen Australia Australia
| | - Jeffrey Goh
- Royal Brisbane & Women's Hospital; Queensland Australia
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22
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Popp AW, Zysset PK, Lippuner K. Rebound-associated vertebral fractures after discontinuation of denosumab-from clinic and biomechanics. Osteoporos Int 2016; 27:1917-21. [PMID: 26694598 DOI: 10.1007/s00198-015-3458-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 12/10/2015] [Indexed: 10/22/2022]
Abstract
UNLABELLED Rebound-associated vertebral fractures may follow treatment discontinuation of highly potent reversible bone antiresorptives, resulting from the synergy of rapid bone resorption and accelerated microdamage accumulation in trabecular bone. INTRODUCTION The purposes of this study are to characterize rebound-associated vertebral fractures following the discontinuation of a highly potent reversible antiresorptive therapy based on clinical observation and propose a pathophysiological rationale. METHODS This study is a case report of multiple vertebral fractures early after discontinuation of denosumab therapy in a patient with hormone receptor-positive non-metastatic breast cancer treated with an aromatase inhibitor. RESULTS Discontinuation of highly potent reversible bone antiresorptives such as denosumab may expose patients to an increased fracture risk due to the joined effects of absent microdamage repair during therapy followed by synchronous excess activation of multiple bone remodelling units at the time of loss-of-effect. We suggest the term rebound-associated vertebral fractures (RVF) for this phenomenon characterized by the presence of multiple new clinical vertebral fractures, associated with either no or low trauma, in a context consistent with the presence of high bone turnover and rapid loss of lumbar spine bone mineral density (BMD) occurring within 3 to 12 months after discontinuation (loss-of-effect) of a reversible antiresorptive therapy in the absence of secondary causes of bone loss or fractures. Unlike atypical femoral fractures that emerge from failure of microdamage repair in cortical bone with long-term antiresorptive treatment, RVF originate from the synergy of rapid bone resorption and accelerated microdamage accumulation in trabecular bone triggered by the discontinuation of highly potent reversible antiresorptives. CONCLUSIONS Studies are urgently needed to i) prove the underlying pathophysiological processes suggested above, ii) establish the predictive criteria exposing patients to an increased risk of RVF, and iii) determine appropriate treatment regimens to be applied in such patients.
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Affiliation(s)
- A W Popp
- Department of Osteoporosis, Inselspital, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
| | - P K Zysset
- Institute for Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland
| | - K Lippuner
- Department of Osteoporosis, Inselspital, Bern University Hospital and University of Bern, 3010, Bern, Switzerland.
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