Cortical aging differences and fracture implications for the human femoral neck

Boyce, T. M.; Bloebaum, Roy D.

doi:10.1016/8756-3282(93)90209-s

Cited by 127 publications

(105 citation statements)

References 26 publications

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“…The higher value of cBMD at the FN in the elderly women, compared to the TR (which decreased with age), may be due to the presence of highly mineralized areas in the FN cortex of elderly women. These results are consistent with findings reporting increased mineralized tissue, areas of higher mineral content than the adjacent cortex, at the FN in elderly populations [4,5,37]. The origin of these highly mineralized areas may be due to subperiosteal calcification derived from the periosteum [11], necrotic tissue where minerals continue to accumulate [5] or calcified fibrocartilagenous tissue at points of attachments of tendons or capsules [5,37].…”

Section: Discussionsupporting

confidence: 91%

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Meta

Lü

Keyak

et al. 2006

Bone

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Fragility fractures at the trochanter (TR) and the femoral neck (FN) have distinct etiologies, but the underlying age-related structural changes at these proximal femoral sub-regions are poorly understood. 28 young (41 ± 3 years) and 124 elderly (74 ± 3 years) healthy Caucasian women underwent volumetric quantitative computed tomography at the hip. Integral (i), cortical (c) and trabecular (t) bone mineral density and content (BMD, BMC) were measured. Geometric parameters included cross sectional area (CSA), and volumes of the integral, cortical and trabecular regions (VOL). Structural measures included indices of compressive (Compstr) and bending (BSI) strength. After adjusting for height and weight, an F-test was used to compare the TR and the FN mean values between young and elderly and to test for interaction to compare logarithmic difference of young and elderly (log(Young)-log(Elderly), Y/E d ) between the FN and the TR in an ANOCOVA model. All BMC, iBMD and tBMD values were significantly lower in elderly than in young women, with the largest Y/E d in the FN tBMC and tBMD (P < 0.0011 and P < 0.0001). cBMD in young and elderly groups was not significantly different at the TR while at the FN it was greater (P = 0.0075) in elderly than young women, showing significant Y/E d (P = 0.0003) dependence on skeletal site. Elderly women had significantly larger iVOL and CSA values (0.0001 < P < 0.0051), except for the FN iVOL. cVOL values were smaller in elderly than young women (P < 0.0001). Y/E d in bone geometry differed by sub-region only for cVOL measures (P = 0.0267). Despite larger CSA and iVOL measures in elderly, the younger women had greater Compstr (P < 0.0001) and BSI (P = 0.0051). Thus, although both the TR and the FN appear to increase in size with age, this enlargement is insufficient to protect against loss of bone strength.

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Section: Discussionsupporting

confidence: 91%

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Experimental confirmation of the sheep model for studying the role of calcified fibrocartilage in hip fractures and tendon attachments

Shea¹,

Hallows²,

Bloebaum³

2002

Anat. Rec.

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Research has shown that there is a dramatic increase in the fractional area of calcified fibrocartilage from tendon and capsular insertions on the human femoral neck Shea et al., 2001b). Additional information regarding the properties of the proximal femur's cortical shell, gained from the use of an animal model, may result in a better understanding of elderly hip fracture since the cortical shell is a significant contributor to the strength of the proximal femur. The objective of the present study was to determine if the greater trochanter's tendon insertions of the human, rat, and sheep differ in terms of morphology and mineralization. The tendons of the greater trochanter of the human, rat, and sheep were observed to insert via a fibrocartilage insertion. The mineral content of the human and sheep calcified fibrocartilage was significantly higher than that of the rat calcified fibrocartilage (P Ͻ 0.01). Additionally, the mineral content of the rat cortical bone was significantly higher than that of the human cortical bone (P Ͻ 0.01). The mineral content of the calcified fibrocartilage and bone of the human and sheep were not statistically different from each other. There were also more similarities between the bone structure and lacunae density of the human and sheep than between the human and the rat. This suggests that the tendon insertions of the sheep are a better model than the tendon insertions of the rat for the investigation of calcified fibrocartilage in elderly hip fractures.

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“…These observations could have implications for hip fracture since it has been demonstrated that even small changes in mineral content can have a great effect on the mechanical properties of bone (Leichter et al, 1982;Mosekilde et al, 1987;Currey, 1988). Individuals with hypermineralized bone tissue would be at an increased risk for fracture because their high level of mineralization causes increased brittleness (Boyce and Bloebaum, 1993). Individuals with hypomineralized tissue have lower compressive strength (Leichter et al, 1982;Martens et al, 1983;McCalden et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…It has also been suggested that further explanation for these discrepancies in the literature may be found at a microscopic level. Boyce and Bloebaum (1993) suggested that fracture toughness of cortical bone is directly related to mineral content at a microscopic level based on the age-related changes they found. There is also interest in the properties of trabecular bone at a microstructural level to help explain the decrease in strength with age (Goldstein, 1987;Mosekilde et al, 1987).…”

mentioning

confidence: 98%

Age‐Related mineralization heterogeneity changes in trabecular bone of the proximal femur

et al. 2004

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Although there is extensive documentation in the literature regarding the importance of trabecular bone for proximal femoral integrity and fracture resistance, there remain gaps in our understanding of the basic mineral changes that may occur in trabecular bone attributable to aging. It is unclear what age-related changes take place in the trabecular bone of the proximal femur, a common fracture site in the elderly. It has been suggested that some explanation for conflicting reports on cancellous bone may be found at a microscopic level. The goal of this study was to document age-related changes in micromineralization in the proximal femur of Caucasian females using backscattered electron imaging technology. Proximal femurs were obtained from 11 young and 11 elderly females. Sections of bone from the superior and inferior neck and superior and inferior trochanter were analyzed in a scanning electron microscope using the backscatter technique to determine ash percent. Mean ash percent did not change with age in any of the four regions (P Ͼ 0.05). However, while the mean ash percent did not change, there was a dramatic increase in variability elderly age group and loss of mineral heterogeneity. This indicates that there are subpopulations with higher or lower ash percents than the mean in the elderly study group in this investigation. While variance changed dramatically, variance within individuals did not change significantly with age (P Ͼ 0.05). The results of this study suggest that changes in micromineralization may occur within an individual, adding a possible new dimension to our understanding of fracture risk in the elderly. Future studies should examine a longer population base to confirm this observation. Published 2004 Wiley-Liss, Inc. †

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Cortical aging differences and fracture implications for the human femoral neck

Cited by 127 publications

References 26 publications

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Experimental confirmation of the sheep model for studying the role of calcified fibrocartilage in hip fractures and tendon attachments

Age‐Related mineralization heterogeneity changes in trabecular bone of the proximal femur

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