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Jepsen KJ, Bigelow EMR, Goulet RW, Nolan BT, Casden MA, Kennedy K, Hertz S, Kadur C, Clines GA, Leis AM, Karvonen-Gutierrez CA, Bredbenner TL. Structural differences contributing to sex-specific associations between FN BMD and whole-bone strength for adult White women and men. JBMR Plus 2024; 8:ziae013. [PMID: 38523663 PMCID: PMC10958990 DOI: 10.1093/jbmrpl/ziae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 03/26/2024] Open
Abstract
Hip areal BMD (aBMD) is widely used to identify individuals with increased fracture risk. Low aBMD indicates low strength, but this association differs by sex with men showing greater strength for a given aBMD than women. To better understand the structural basis giving rise to this sex-specific discrepancy, cadaveric proximal femurs from White female and male donors were imaged using nano-CT and loaded in a sideways fall configuration to assess strength. FN pseudoDXA images were generated to identify associations among structure, aBMD, and strength that differ by sex. Strength correlated significantly with pseudoDXA aBMD for females (R2 = 0.468, P < .001) and males (R2 = 0.393, P < .001), but the elevations (y-intercepts) of the linear regressions differed between sexes (P < .001). Male proximal femurs were 1045 N stronger than females for a given pseudoDXA aBMD. However, strength correlated with pseudoDXA BMC for females (R2 = 0.433, P < .001) and males (R2 = 0.443, P < .001) but without significant slope (P = .431) or elevation (P = .058) differences. Dividing pseudoDXA BMC by FN-width, total cross-sectional area, or FN-volume led to significantly different associations between strength and the size-adjusted BMC measures for women and men. Three structural differences were identified that differentially affected aBMD and strength for women and men: First, men had more bone mass per unit volume than women; second, different cross-sectional shapes resulted in larger proportions of bone mass orthogonal to the DXA image for men than women; and third, men and women had different proportions of cortical and trabecular bone relative to BMC. Thus, the proximal femurs of women were not smaller versions of men but were constructed in fundamentally different manners. Dividing BMC by a bone size measure was responsible for the sex-specific associations between hip aBMD and strength. Thus, a new approach for adjusting measures of bone mass for bone size and stature is warranted.
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Affiliation(s)
- Karl J Jepsen
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Erin M R Bigelow
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Robert W Goulet
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Bonnie T Nolan
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Michael A Casden
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Kathryn Kennedy
- Biomedical Engineering, Marquette University, Milwaukee, WI 53201 United States
| | - Samantha Hertz
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Chandan Kadur
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
- Biomedical Laboratory R&D, VA Medical Center, Ann Arbor, MI 48105 United States
| | - Gregory A Clines
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | - Aleda M Leis
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109 United States
| | | | - Todd L Bredbenner
- Department of Mechanical and Aerospace Engineering, University of Colorado Colorado Springs, Colorado Springs, CO 80918 United States
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Henry BW, Cruz CD, Goulet RW, Nolan BT, Locke C, Padmanabhan V, Moravek MB, Shikanov A, Killian ML. Bone quality following peripubertal growth in a mouse model of transmasculine gender-affirming hormone therapy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.08.570840. [PMID: 38106067 PMCID: PMC10723410 DOI: 10.1101/2023.12.08.570840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
During peri-puberty, bone growth and the attainment peak bone mass is driven predominantly by sex steroids. This is important when treating transgender and gender diverse youth, who have become increasingly present at pediatric clinics. Analogues of gonadotropin-releasing hormone (GnRH) are commonly prescribed to transgender and gender diverse youth prior to starting gender-affirming hormone therapy (GAHT). However, the impact of GnRH agonists on long bones with the addition of GAHT is relatively unknown. To explore this, we developed a trans-masculine model by introducing either GnRHa or vehicle treatment to female-born mice at a pre-pubertal age. This treatment was followed by male GAHT (testosterone, T) or control treatment three weeks later. Six weeks after T therapy, bone quality was compared between four treatment groups: Control (vehicle only), GnRHa-only, GnRHa + T, and T-only. Bone length/size, bone shape, mechanical properties, and trabecular morphology were modulated by GAHT. Independent of GnRHa administration, mice treated with T had shorter femurs, larger trabecular volume and increased trabecular number, higher trabecular bone mineral density, and wider superstructures on the surface of bone (e.g., third trochanters) when compared to control or GnRHa-only mice. In conclusion, prolonged treatment of GnRHa with subsequent GAHT treatment directly affect the composition, parameters, and morphology of the developing long bone. These findings provide insight to help guide clinical approaches to care for transgender and gender diverse youth.
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Affiliation(s)
- Brandon W Henry
- Department of Orthopaedic Surgery, Michigan Medicine, Ann Arbor, Michigan
- College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Cynthia Dela Cruz
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Robert W Goulet
- Department of Orthopaedic Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Bonnie T Nolan
- Department of Orthopaedic Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Conor Locke
- Department of Orthopaedic Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Vasantha Padmanabhan
- Department of Pediatrics, Michigan Medicine, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, Michigan Medicine, Ann Arbor, Michigan
| | - Molly B Moravek
- Department of Obstetrics and Gynecology, Michigan Medicine, Ann Arbor, Michigan
| | - Ariella Shikanov
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, Michigan Medicine, Ann Arbor, Michigan
| | - Megan L Killian
- Department of Orthopaedic Surgery, Michigan Medicine, Ann Arbor, Michigan
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Jepsen KJ, Bigelow EMR, Casden MA, Goulet RW, Kennedy K, Hertz S, Kadur C, Nolan BT, Richards‐McCullough K, Merillat S, Karvonen‐Gutierrez CA, Clines G, Bredbenner TL. Associations Among Hip Structure, Bone Mineral Density, and Strength Vary With External Bone Size in White Women. JBMR Plus 2023; 7:e10715. [PMID: 36936363 PMCID: PMC10020918 DOI: 10.1002/jbm4.10715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/01/2022] [Accepted: 12/12/2022] [Indexed: 12/29/2022] Open
Abstract
Bone mineral density (BMD) is heavily relied upon to reflect structural changes affecting hip strength and fracture risk. Strong correlations between BMD and strength are needed to provide confidence that structural changes are reflected in BMD and, in turn, strength. This study investigated how variation in bone structure gives rise to variation in BMD and strength and tested whether these associations differ with external bone size. Cadaveric proximal femurs (n = 30, White women, 36-89+ years) were imaged using nanocomputed tomography (nano-CT) and loaded in a sideways fall configuration to assess bone strength and brittleness. Bone voxels within the nano-CT images were projected onto a plane to create pseudo dual-energy X-ray absorptiometry (pseudo-DXA) images consistent with a clinical DXA scan. A validation study using 19 samples confirmed pseudo-DXA measures correlated significantly with those measured from a commercially available DXA system, including bone mineral content (BMC) (R 2 = 0.95), area (R 2 = 0.58), and BMD (R 2 = 0.92). BMD-strength associations were conducted using multivariate linear regression analyses with the samples divided into narrow and wide groups by pseudo-DXA area. Nearly 80% of the variation in strength was explained by age, body weight, and pseudo-DXA BMD for the narrow subgroup. Including additional structural or density distribution information in regression models only modestly improved the correlations. In contrast, age, body weight, and pseudo-DXA BMD explained only half of the variation in strength for the wide subgroup. Including bone density distribution or structural details did not improve the correlations, but including post-yield deflection (PYD), a measure of bone material brittleness, did increase the coefficient of determination to more than 70% for the wide subgroup. This outcome suggested material level effects play an important role in the strength of wide femoral necks. Thus, the associations among structure, BMD, and strength differed with external bone size, providing evidence that structure-function relationships may be improved by judiciously sorting study cohorts into subgroups. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Karl J Jepsen
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Erin MR Bigelow
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Michael A Casden
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Robert W Goulet
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Kathryn Kennedy
- Department of Biomedical EngineeringMarquette UniversityMilwaukeeWIUSA
| | - Samantha Hertz
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Chandan Kadur
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Bonnie T Nolan
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Kerry Richards‐McCullough
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Steffenie Merillat
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Carrie A Karvonen‐Gutierrez
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
| | - Gregory Clines
- Department of Orthopaedic Surgery (Medical School) and Department of Epidemiology (Public Health)University of MichiganAnn ArborMIUSA
- EndocrinologyVA Medical CenterAnn ArborMIUSA
| | - Todd L Bredbenner
- Department of Mechanical and Aerospace EngineeringUniversity of Colorado Colorado SpringsColorado SpringsCOUSA
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Guo N, Tian J, Wang L, Sun K, Mi L, Ming H, Zhe Z, Sun F. Discussion on the possibility of multi-layer intelligent technologies to achieve the best recover of musculoskeletal injuries: Smart materials, variable structures, and intelligent therapeutic planning. Front Bioeng Biotechnol 2022; 10:1016598. [PMID: 36246357 PMCID: PMC9561816 DOI: 10.3389/fbioe.2022.1016598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Although intelligent technologies has facilitated the development of precise orthopaedic, simple internal fixation, ligament reconstruction or arthroplasty can only relieve pain of patients in short-term. To achieve the best recover of musculoskeletal injuries, three bottlenecks must be broken through, which includes scientific path planning, bioactive implants and personalized surgical channels building. As scientific surgical path can be planned and built by through AI technology, 4D printing technology can make more bioactive implants be manufactured, and variable structures can establish personalized channels precisely, it is possible to achieve satisfied and effective musculoskeletal injury recovery with the progress of multi-layer intelligent technologies (MLIT).
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Affiliation(s)
- Na Guo
- Department of Computer Science and Technology, Tsinghua University, Beijing, China
- Institute of Precision Medicine, Tsinghua University, Beijing, China
| | - Jiawen Tian
- Department of Computer Science and Technology, Tsinghua University, Beijing, China
- Institute of Precision Medicine, Tsinghua University, Beijing, China
| | - Litao Wang
- College of Engineering, China Agricultural University, Beijing, China
| | - Kai Sun
- Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Lixin Mi
- Musculoskeletal Department, Beijing Rehabilitation Hospital, Beijing, China
| | - Hao Ming
- Orthopaedics, Chinese PLA General Hospital, Beijing, China
| | - Zhao Zhe
- Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Fuchun Sun
- Department of Computer Science and Technology, Tsinghua University, Beijing, China
- Institute of Precision Medicine, Tsinghua University, Beijing, China
- *Correspondence: Fuchun Sun,
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van 't Hof RJ, Rose L, Bassonga E, Daroszewska A. Open source software for semi-automated histomorphometry of bone resorption and formation parameters. Bone 2017; 99:69-79. [PMID: 28366796 DOI: 10.1016/j.bone.2017.03.051] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 10/19/2022]
Abstract
Micro-CT analysis has become the standard method for assessing bone volume and architecture in small animals. However, micro-CT does not allow the assessment of bone turnover parameters such as bone formation rate and osteoclast (OC) number and surface. For these crucial variables histomorphometric analysis is still an essential technique. Histomorphometry however, is time consuming and, especially in mouse bones, OCs can be difficult to detect. The main purpose of this study was to develop and validate a relatively easy and rapid method to measure static and dynamic bone histomorphometry parameters. Here we present the adaptation of established staining protocols and three novel open source image analysis packages: TrapHisto, OsteoidHisto and CalceinHisto that allow rapid, semi-automated analysis of histomorphometric bone resorption, osteoid, and calcein double labelling parameters respectively. These three programs are based on ImageJ, but use a relatively simple user interface that hides the underlying complexity of the image analysis.
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Affiliation(s)
- Rob J van 't Hof
- Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom.
| | - Lorraine Rose
- Institute for Genetics and Molecular Medicine, University of Edinburgh, United Kingdom
| | - Euphemie Bassonga
- Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom
| | - Anna Daroszewska
- Institute of Ageing and Chronic Disease, University of Liverpool, United Kingdom
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Wang HD, Chen Z, Inoue I, Fu SJ, Shi XL, Tang L, Zhang FZ, Jiang Y, Jiang H. Effects of electroacupuncture at GB points on markers of osteoporosis and bodyweight in ovariectomised rats. Acupunct Med 2015; 33:465-71. [PMID: 26245584 PMCID: PMC4860971 DOI: 10.1136/acupmed-2014-010743] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2015] [Indexed: 12/20/2022]
Abstract
Background Based on a description of acupuncture to treat a bone disease resembling osteoporosis in the ancient text of Huangdi Neijing, we aimed to assess the effects of electroacupuncture (EA) at GB points in ovariectomised (OVX) rats. Methods 40 female Wistar rats were randomly divided into four groups (n=10 each): ovariectomised model group (OVX); ovariectomised group treated with EA at GB points (OVX+GB); ovariectomised group treated with EA at non-GB points (OVX+N) in the hindlimb; and a sham surgery group (Sham). Three months after ovariectomy, rats in the OVX+GB and OVX+N groups received EA treatment for 3 months. Urine, blood and femur samples were collected from each animal for analysis. Results Bodyweight (BW) in the OVX+GB group decreased after EA treatment, reaching a minimum of ∼12% below the OVX and OVX+N groups at 1 month. Concentrations of urine deoxypyridinoline, a bone resorption marker, were significantly elevated in the OVX and OVX+N groups but not the OVX+GB group. Concentrations of serum bone specific alkaline phosphatase, a bone formation marker, were significantly higher in the OVX+GB group versus the Sham and OVX groups. Bone mineral density (BMD) did not differ between the OVX, OVX+GB and OVX+N groups, but was ∼10% lower than the Sham group. However, BMD/BW in the OVX+GB group was significantly higher than in the OVX and OVX+N groups and similar to the Sham group. Histological assessment of the femur showed that EA at GB points improved the bone architecture. Conclusions EA treatment at GB points had anti-osteoporotic effects in a rat model of osteoporosis.
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Affiliation(s)
- Hong-Du Wang
- Department of Acupuncture, School of Traditional Chinese Medicine Combined with Western Medicine, Sichuan Medical University, Luzhou, Sichuan, China
| | - Zhuang Chen
- Laboratory of Infection and Immunology, Affiliated Hospital, Sichuan Medical University, Luzhou, Sichuan, China
| | - Isao Inoue
- Institute of Cardiovascular Research, Sichuan Medical University, Luzhou, Sichuan, China
| | - Shi-Jie Fu
- Department of Orthopaedics, Affiliated TCM Hospital, Sichuan Medical University, Luzhou, Sichuan, China
| | - Xiao-Lin Shi
- Laboratory of Infection and Immunology, Affiliated Hospital, Sichuan Medical University, Luzhou, Sichuan, China
| | - Li Tang
- Laboratory of Infection and Immunology, Affiliated Hospital, Sichuan Medical University, Luzhou, Sichuan, China
| | - Feng-Zheng Zhang
- Department of Acupuncture, School of Traditional Chinese Medicine Combined with Western Medicine, Sichuan Medical University, Luzhou, Sichuan, China
| | - Yang Jiang
- Department of Acupuncture, School of Traditional Chinese Medicine Combined with Western Medicine, Sichuan Medical University, Luzhou, Sichuan, China
| | - Hua Jiang
- Department of Acupuncture, School of Traditional Chinese Medicine Combined with Western Medicine, Sichuan Medical University, Luzhou, Sichuan, China
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Jerome CP, Vafai HT, Minetti KL, Kaplan K. Structural Histomorphometric Analysis of Cortical, Transitional, and Cancellous Vertebral Bone in Intact, Ovariectomized, and Nandrolone-Treated Cynomolgus Monkeys (Macaca fascicularis). J Histotechnol 2013. [DOI: 10.1179/his.1997.20.3.191] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Evaluating accuracy of structural geometry by DXA methods with an anthropometric proximal femur phantom. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2013; 36:279-87. [PMID: 23836197 DOI: 10.1007/s13246-013-0209-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/27/2013] [Indexed: 01/02/2023]
Abstract
DXA-derived bone structural geometry has been reported extensively but lacks an accuracy standard. In this study, we describe a novel anthropometric structural geometry phantom that simulates the proximal femur for use in assessing accuracy of geometry measurements by DXA or other X-ray methods. The phantom consists of seven different interchangeable neck modules with geometries that span the range of dimensions in an adult human proximal femur, including those representing osteoporosis. Ten repeated hip scans of each neck module using two current DXA scanner models were performed without repositioning. After scanner specific calibration, hip structure analysis was used to derive structural geometry. Scanner performance was similar for the two manufacturers. DXA-derived HSA geometric measurements were highly correlated with values derived directly from phantom geometry and position; R² between DXA and phantom measures were greater than 94% for all parameters, while precision error ranged between 0.3 and 3.9%. Despite high R² there were some systematic geometry errors for both scanners that were small for outer diameter, but increasing with complexity of geometrical parameter; e.g. buckling ratio. In summary, the anthropometric phantom and its fabrication concept were shown to be appropriate for evaluating proximal femoral structural geometry in two different DXA systems.
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Del Rio LM, Winzenrieth R, Cormier C, Di Gregorio S. Is bone microarchitecture status of the lumbar spine assessed by TBS related to femoral neck fracture? A Spanish case-control study. Osteoporos Int 2013; 24:991-8. [PMID: 22581295 DOI: 10.1007/s00198-012-2008-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 04/05/2012] [Indexed: 11/29/2022]
Abstract
UNLABELLED Bone mineral density (BMD) as assessed by dual energy X-ray absorptiometry (DXA) constitutes the gold standard for osteoporosis diagnosis. However, DXA does not take into account bone microarchitecture alterations. INTRODUCTION The aim of our study was to evaluate the ability of trabecular bone score (TBS) at lumbar spine to discriminate subjects with hip fracture. METHODS We presented a case-control study of 191 Spanish women aged 50 years and older. Women presented transcervical fractures only. BMD was measured at lumbar spine (LS-BMD) using a Prodigy densitometer. TBS was calculated directly on the same spine image. Descriptive statistics, tests of difference and univariate and multivariate backward regressions were used. Odds ratio (OR) and the ROC curve area of discriminating parameters were calculated. RESULTS The study population consisted of 83 subjects with a fracture and 108 control subjects. Significant lower spine and hip BMD and TBS values were found for subjects with fractures (p < 0.0001). Correlation between LS-BMD and spine TBS was modest (r = 0.41, p < 0.05). LS-BMD and TBS independently discriminate fractures equally well (OR = 2.21 [1.56-3.13] and 2.05 [1.45-2.89], respectively) but remain lower than BMD at neck or at total femur (OR = 5.86 [3.39-10.14] and 6.06 [3.55-10.34], respectively). After adjusting for age, LS-BMD and TBS remain significant for transcervical fracture discrimination (OR = 1.94 [1.35-2.79] and 1.71 [1.15-2.55], respectively). TBS and LS-BMD combination (OR = 2.39[1.70-3.37]) improved fracture risk prediction by 25 %. CONCLUSION This study shows the potential of TBS to discriminate subjects with and without hip fracture. TBS and LS-BMD combination improves fracture risk prediction. Nevertheless, BMD at hip remains the best predictor of hip fracture.
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Gayzik FS, Moreno DP, Geer CP, Wuertzer SD, Martin RS, Stitzel JD. Development of a Full Body CAD Dataset for Computational Modeling: A Multi-modality Approach. Ann Biomed Eng 2011; 39:2568-83. [DOI: 10.1007/s10439-011-0359-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 07/13/2011] [Indexed: 11/28/2022]
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11
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Wang X, Nyman J, Dong X, Leng H, Reyes M. Fundamental Biomechanics in Bone Tissue Engineering. ACTA ACUST UNITED AC 2010. [DOI: 10.2200/s00246ed1v01y200912tis004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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12
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A cortical-bone structural geometry phantom: dental plaster as a convenient and radiologically similar fabrication material. ACTA ACUST UNITED AC 2007; 30:200-10. [DOI: 10.1007/bf03178427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Clarke SA, Brooks RA, Lee PTH, Rushton N. The effect of osteogenic growth factors on bone growth into a ceramic filled defect around an implant. J Orthop Res 2004; 22:1016-24. [PMID: 15304274 DOI: 10.1016/j.orthres.2004.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Accepted: 01/21/2004] [Indexed: 02/04/2023]
Abstract
Currently available synthetic bone substitutes perform poorly compared to autograft. It is hoped that by adding osteogenic growth factors to the materials, new bone formation could be increased and the clinical outcome improved. In this study, IGF-1, bFGF and TGFbeta1, alone and in combination, were absorbed onto a carrier of beta-tricalcium phosphate (betaTCP) and implanted into a defect around a hydroxyapatite-coated, stainless steel implant in the proximal tibia of rat in a model of revision arthroplasty. Animals were sacrificed at 6 and 26 weeks for routine histology and histomorphometry and mechanical push out tests. The results show that only bFGF had a significant effect on ceramic resorption. The groups that received bFGF and bFGF in combination with TGFbeta1 had smaller and fewer betaTCP particles remaining in the defect at 6 and 26 weeks. No growth factor combination significantly enhanced new bone formation or the mechanical strength of the implant. These results indicate that, of the growth factors tested, only bFGF had any beneficial effect on the host response to the implant, perhaps by delaying osteoblast differentiation and thereby prolonging osteoclast access to the ceramic.
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Affiliation(s)
- S A Clarke
- Orthopaedic Research Unit, University of Cambridge, Box 180, Addenbrooke's Hospital, Hill's Road, Cambridge CB2 2QQ, UK
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Jordan GR, Loveridge N, Bell KL, Power J, Dickson GR, Vedi S, Rushton N, Clarke MT, Reeve J. Increased femoral neck cancellous bone and connectivity in coxarthrosis (hip osteoarthritis). Bone 2003; 32:86-95. [PMID: 12584040 DOI: 10.1016/s8756-3282(02)00920-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Patients with coxarthrosis (cOA) have a reduced incidence of intracapsular femoral neck fracture, suggesting that cOA offers protection. The distribution of bone in the femoral neck was compared in cases of coxarthrosis and postmortem controls to assess the possibility that disease-associated changes might contribute to reduced fragility. Whole cross-section femoral neck biopsies were obtained from 17 patients with cOA and 22 age- and sex-matched cadaveric controls. Densitometry was performed using peripheral quantitated computed tomography (pQCT) and histomorphometry on 10-microm plastic-embedded sections. Cortical bone mass was not different between cases and controls (P > 0.23), but cancellous bone mass was increased by 75% in cOA (P = 0.014) and histomorphometric cancellous bone area by 71% (P < 0.0001). This was principally the result of an increase of apparent density (mass/vol) of cancellous bone (+45%, P = 0.001). Whereas cortical porosity was increased in the cases (P < 0.0001), trabecular width was also increased overall in the cases by 52% (P < 0.001), as was cancellous connectivity measured by strut analysis (P < 0.01). Where osteophytic bone was present (n = 9) there was a positive relationship between the amount of osteophyte and the percentage of cancellous area (P < 0.05). Since cancellous bone buttresses and stiffens the cortex so reducing the risk of buckling, the increased cancellous bone mass and connectivity seen in cases of cOA probably explain, at least in part, the ability of patients with cOA to resist intracapsular fracture of the femoral neck during a fall.
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Affiliation(s)
- G R Jordan
- Bone Research Group (MRC), Department of Medicine, (Box 157), University of Cambridge Clinical School, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
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Abstract
It is well established that bones functionally adapt by mechanisms that control tissue density, whole bone geometry, and trabecular orientation. In this study, we propose the existence of another such powerful mechanism, namely, trabecular eccentricity, i.e. non-central placement of trabecular bone within a cortical envelope. In the human femoral neck, trabecular eccentricity results in a thicker cortical shell on the inferior than superior aspect. In an overall context of expanding understanding of bone adaptation, the goal of this study was to demonstrate the biomechanical significance of, and provide a mechanistic explanation for, the relationship between trabecular eccentricity and stresses in the human femoral neck. Using composite beam theory, we showed that the biomechanical effects of eccentricity during a habitual loading situation were to increase the stress at the superior aspect of the neck and decrease the stress at the inferior aspect, resulting in an overall protective effect. Further, increasing eccentricity had a stress-reducing effect equivalent to that of increasing cortical thickness or increasing trabecular modulus. We conclude that an asymmetric placement of trabecular bone within a cortical bone envelope represents yet another mechanism by which whole bones can adapt to mechanical demands.
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Affiliation(s)
- J C Fox
- Orthopaedic Biomechanics Laboratory, Department of Mechanical Engineering, 2166 Etcheverry Hall, University of California, Berkeley, CA 94720-1740, USA.
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16
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Jordan GR, Loveridge N, Bell KL, Power J, Rushton N, Reeve J. Spatial clustering of remodeling osteons in the femoral neck cortex: a cause of weakness in hip fracture? Bone 2000; 26:305-13. [PMID: 10710006 DOI: 10.1016/s8756-3282(99)00272-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Intracapsular femoral neck fractures are associated with decreased cortical width and increased proportions of Haversian canals with diameters greater than the normal mean plus 3 SD (i.e., >385 microm). Such canals might be formed if closely associated resorbing osteons merge; a cortical event analogous with the loss of cancellous connectivity. To test this, we investigated the pattern of osteon distribution in the aging femoral neck to determine if remodeling osteons were distributed in anatomical clusters. Femoral neck biopsies from female patients with intracapsular hip fractures (n = 13) were compared with age/gender-matched cadaveric controls (n = 13). Solochrome-stained sections were analyzed for Haversian canal location, canal diameter, and the presence of an osteoid surface. Clustering was investigated using statistical software with a cluster defined as two or more osteoid-bearing osteon centers within 0.75 mm of each other. Clusters occurred more frequently than would be expected by chance (p < 0.001). Fracture cases had more clusters per unit area (3.14 +/- 0.31 clusters/25 mm2 of cortical bone) than controls (1.89 +/- 0.22) (p = 0.002). In fracture cases, the antero-inferior, antero-superior, and infero-anterior regions had more clusters per 25 mm2 than comparable control regions (ant/inf: 4.12 +/- 0.79, 1.70 +/- 0.60,p = 0.025; ant/sup: 5.31 +/- 1.1, 1.80 +/- 0.59,p = 0.013; inf/ant: 3.15 +/- 0.49, 1.27 +/-0.29, p = 0.004). The mean number of clusters per 25 mm2 per region correlated with the mean porosity per region (adjusted r2 = 0.60;p = 0.014), and the total number of giant canals per region correlated with the total number of clusters per region (adjusted r2 = 0.58; p = 0.011). In conclusion, remodeling osteons are clustered or grouped anatomically, and fracture cases have more clusters than controls. Our data suggest that merging of adjacent, clustered osteons during resorption could lead to the rapid development of canals with excessive diameters and focal weakness. Clustering is greatest in those regions that we have previously shown to have the largest relative reductions in bone strength compared with controls and known to be maximally loaded during a sideways fall. This implicates the remodeling process underlying clustering of remodeling osteons in the aetiology of hip fracture.
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Affiliation(s)
- G R Jordan
- Bone Research Group (MRC), Department of Medicine, University of Cambridge Clinical School, UK.
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17
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Prevrhal S, Engelke K, Kalender WA. Accuracy limits for the determination of cortical width and density: the influence of object size and CT imaging parameters. Phys Med Biol 1999; 44:751-64. [PMID: 10211808 DOI: 10.1088/0031-9155/44/3/017] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study we analysed the accuracy of computed tomography (CT) measurements in assessing cortical bone. We determined the dependency of thickness and density measurements on the true width and density of the cortex and on the spatial resolution in the CT images using two optimized segmentation methods. As a secondary goal, we assessed the ability of CT to reflect small changes in cortical thickness. Two different bone-mimicking phantoms with varying cortical thickness were scanned with single-slice CT on a Somatom Plus 4 scanner. Images were reconstructed with both a standard and a high-resolution convolution kernel. Two special operator-independent segmentation methods were used to automatically detect the edges of the cortical shell. We measured cortical thickness and density and compared the phantom measurements with theoretical computations by simulating a cross-sectional shape of the cortical shell. Based on the simulations, we calculated CT's power to detect small changes in cortical thickness. Simulations and phantom measurements were in very good agreement. Cortical thickness could be measured with an error of less than 10% if the true thickness was larger than 0.9 (0.7) mm for the standard (high-resolution) kernel which is close to the full width at half maximum (FWHM) of the point spread functions for these kernels and our scanner. Density measurements yielded errors of less than 10% for true cortical thickness values above two to three times the FWHM corresponding to 2.5 (2) mm in our case. The simulations showed that a 10% change in cortical width would not be detected with satisfying probability in bones with a cortical shell thinner than 1.2 mm. An accurate determination of the cortical thickness is limited to bones with a thickness higher than the FWHM of the scanner's point spread function. Therefore, the use of a high-resolution reconstruction kernel is crucial. Cortical bone mineral density can only be measured accurately in bones two to three times thicker than this number. In thinner bones, the measured density becomes dependent on the thickness. Changes in cortical thickness can only be assessed if the change is rather large or if the measured bone has sufficient thickness. Therefore, assessing density or thickness of the vertebral shell by CT should be treated with caution.
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Affiliation(s)
- S Prevrhal
- Institute of Medical Physics, University of Erlangen, Germany
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18
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Bell KL, Loveridge N, Power J, Garrahan N, Stanton M, Lunt M, Meggitt BF, Reeve J. Structure of the femoral neck in hip fracture: cortical bone loss in the inferoanterior to superoposterior axis. J Bone Miner Res 1999; 14:111-9. [PMID: 9893072 DOI: 10.1359/jbmr.1999.14.1.111] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although bone mass is a contributory risk factor for hip fracture, its distribution about the femoral neck is also important. Femoral neck biopsies were obtained from 13 females with intracapsular hip fracture (fracture: mean age 74.3 +/- 2.3 years [SEM]) and 19 cadaveric samples (control: 9 males and 10 females 79.4 +/- 1.7 years) and the areas of cortical and cancellous bone were quantitated in octants. In the control group, although males had larger bones than females, the proportions of cortical and cancellous bone were not different (p > 0.05) between the genders. The total amount of bone, as a proportion of bone + marrow, was significantly reduced in the fractures compared with the female controls (%Tt.Ar: fracture 27.83 +/- 1.18, female control 33.62 +/- 1.47; p = 0.0054). Reductions in cortical bone area occurred in all regions but particularly in the inferior, inferoanterior, and anterior octants (p < 0.05). There were no differences between cases and controls in the regional amount of cancellous bone (all regions, p > 0.178). Marked reductions in mean cortical bone width between the fracture and female control group occurred in the anterior, inferoanterior (31%), and superoposterior (25%) regions. Representing cortical widths as simple Fourier functions of the angle about the center of area (R2adj = 0.79) showed in the cases that there was preservation of the cortical bone in the inferior region, with the proportional loss of cortical bone being greatest in the inferoanterior and superoposterior regions. It is concluded that loss of cortical, rather than cancellous, bone predominates in cases of femoral neck fracture. This loss occurs primarily along the inferoanterior to superoposterior axis. As this axis bears the greatest strain during a fall, it is hypothesized that specific thinning of the cortex in these regions leads to an exaggerated propensity to fracture in those so affected, above that resulting from an equivalent general decrease in bone mass.
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Affiliation(s)
- K L Bell
- Bone Research Group (MRC), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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19
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Bagi CM, Wilkie D, Georgelos K, Williams D, Bertolini D. Morphological and structural characteristics of the proximal femur in human and rat. Bone 1997; 21:261-7. [PMID: 9276091 DOI: 10.1016/s8756-3282(97)00121-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because the ovariectomized rat model of postmenopausal osteoporosis is the most commonly used small animal model to investigate consequences of bone loss on bone structure and strength, or to assess benefits of the various therapeutic strategies to improve bone mass and strength, the attempt was made to compare histoanatomical and structural characteristics of the femoral neck between human and rat models. In addition to different biomechanics, there is a significant difference in gross- and microanatomy of the proximal femur between humans and rats. Percent of the cortical bone component is much higher in rats (72.5%) relative to humans (12.5%). Also, cortical bone at the femoral neck in rats is evenly distributed, whereas in humans there is a considerable difference in the amount of the cortical bone between the superior half of the femoral neck with cortical thickness being only 0.3 mm, and the inferior half of the neck having 6-mm-thick cortex. Humans have far more cancellous bone at the femoral neck (22.7% average) relative to rats (6.8%). In addition, cancellous bone at the femoral neck in humans is unevenly distributed between the bone center and its periphery. Human samples exhibited striking differences in the cancellous bone structure between weight-bearing and tensile trabecular groups exhibiting clear trabecular orientation consisting of plates and rods, and trabeculae around the neutral bone axis with little mechanical activity exhibiting rod-like trabeculae only. Although humans and rats have a periosteum covering the femoral neck, and each lacks the muscular attachment at intracapsular portions of the femoral neck, rats, in contrast to humans, have the ability to quickly adapt cortical thickness and increase inertia to meet mechanical needs via modeling-dependent periosteal apposition.
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Affiliation(s)
- C M Bagi
- Institute of Bone, Joint Disorders, and Cancer, Bayer Corporation, West Haven, CT 06516, USA.
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20
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Reeve J, Silman A. Epidemiology of Osteoporotic Fractures in Europe: towards biologic mechanisms. The European Prospective Osteoporosis Study Group. Osteoporos Int 1997; 7 Suppl 3:S78-83. [PMID: 9536308 DOI: 10.1007/bf03194348] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- J Reeve
- University of Cambridge Department of Medicine and Institute of Public Health, UK
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