Femoral Neck Strength Research Articles

Effects of Positioning and Notching of Resurfaced Femurs on Femoral Neck Strength: A Biomechanical Test

To assess the effects of positioning and notching of resurfaced femurs on the mechanical strength of third-generation saw bone (TGSB) femurs using an in vitro analogue bone model. 30 TGSB femurs were equally divided into 6 resurfaced femur groups (intact, anatomic, varus, valgus, anatomically notched, and valgus notched) for testing the load to failure, stiffness, and total energy. Compared to the intact femurs, the load to failure in all resurfaced femurs was significantly decreased by 29 to 57%. Among the resurfaced femurs, valgus and anatomic femurs had the highest load to failure, followed by valgus notched, varus, and anatomically notched femurs. Notching weakened the construct by a further 24 to 30%. To minimise the risk of femoral neck fracture, resurfaced femoral heads should be placed in an anatomic or valgus orientation, and the superior cortex of the femoral neck should remain intact.

Hip Fractures and the Contribution of Cortical Versus Trabecular Bone to Femoral Neck Strength

Osteoporotic fractures are caused by both cortical thinning and trabecular bone loss. Both are seen to be important for bone fragility. The relative contributions of cortical versus trabecular bone have not been established. The aim of this study was to test the contribution of cortical versus trabecular bone to femoral neck stability in bone strength. In one femur from each pair of 18 human cadaver femurs (5 female; 4 male), trabecular bone was completely removed from the femoral neck, providing one bone with intact and the other without any trabecular structure in the femoral neck. Geometrical, X-ray, and DXA measurements were carried out before biomechanical testing (forces to fracture). Femoral necks were osteotomized, slices were analyzed for cross-sectional area (CSA) and cross-sectional moment of inertia (CSMI), and results were compared with biomechanical testing data. Differences between forces needed to fracture excavated and intact femurs (DeltaF/F mean) was 7.0% on the average (range, 4.6-17.3%). CSA of removed spongiosa did not correlate with difference of fracture load (DeltaF/F mean), nor did BMD. The relative contribution of trabecular versus cortical bone in respect to bone strength in the femoral neck seems to be marginal and seems to explain the subordinate role of trabecular bone and its changes in fracture risk and the effects of treatment options in preventing fractures.

22 Sensitivity of Ultrasound to Indices of Femoral Neck Strength Investigated With Simulation of Wave Propagation in Cortical Bone

22 Sensitivity of Ultrasound to Indices of Femoral Neck Strength Investigated With Simulation of Wave Propagation in Cortical Bone

Effect of combined treatment with alendronate and calcitriol on femoral neck strength in osteopenic rats

BackgroundHip fracture is associated with pronounced morbidity and excess mortality in elderly women with postmenopausal osteoporosis. Many drugs have been developed to treat osteoporosis and to reduce the risk of osteoporotic fractures. We investigated the effects of combined alendronate and vitamin D3 treatment on bone mass and fracture load at the femoral neck in ovariectomized (OVX) rats, and evaluated the relationship between bone mass parameters and femoral neck strength.MethodsThirty 12-week-old female rats underwent either a sham-operation (n = 6) or OVX (n = 24). Twenty weeks later, OVX rats were further divided into four groups and received daily doses of either saline alone, 0.1 mg/kg alendronate, 0.1 μg/kg calcitriol, or a combination of both two drugs by continuous infusion via Alzet mini-osmotic pumps. The sham-control group received saline alone. After 12 weeks of treatment, femoral necks were examined using peripheral quantitative computed tomography (pQCT) densitometry and mechanical testing.ResultsSaline-treated OVX rats showed significant decreases in total bone mineral content (BMC) (by 28.1%), total bone mineral density (BMD) (by 9.5%), cortical BMC (by 26.3%), cancellous BMC (by 66.3%), cancellous BMD (by 29.0%) and total cross-sectional bone area (by 30.4%) compared with the sham-control group. The combined alendronate and calcitriol treatments improved bone loss owing to estrogen deficiency. On mechanical testing, although OVX significantly reduced bone strength of the femoral neck (by 29.3%) compared with the sham-control group, only the combined treatment significantly improved the fracture load at the femoral neck in OVX rats to the level of the sham-controls. The correlation of total BMC to fracture load was significant, but that of total BMD was not.ConclusionOur results showed that the combined treatment with alendronate and calcitriol significantly improved bone fragility of the femoral neck in OVX osteopenic rats.

Physical determinants of three dimensional femoral neck structure and strength in older postmenopausal women

Physical determinants of three dimensional femoral neck structure and strength in older postmenopausal women

Objectively Measured Physical Activity and Bone Strength in 9-Year-Old Boys and Girls

The purpose of this work was to analyze the relationship between intensity and duration of physical activity and composite indices of femoral neck strength and bone-mineral content of the femoral neck, lumbar spine, and total body. Physical activity was assessed by accelerometry in 143 girls and 150 boys (mean age: 9.7 years). Measurement of bone-mineral content, femoral neck bone-mineral density, femoral neck width, hip axis length, and total body fat-free mass was performed with dual-energy radiograph absorptiometry. Compressive [(bone-mineral density x femoral neck width/weight)] and bending strength [(bone-mineral density x femoral neck width(2))/(hip axis length x weight)] express the forces that the femoral neck has to withstand in weight bearing, whereas impact strength [(bone-mineral density x femoral neck width x hip axis length)/(height x weight)] expresses the energy that the femoral neck has to absorb in an impact from standing height. Analysis of covariance (fat-free mass and age adjusted) showed differences between boys and girls of approximately 9% for compressive, 10% for bending, and 9% for impact strength. Stepwise regression analysis using time spent at sedentary, light, moderate, and vigorous physical activity as predictors revealed that vigorous physical activity explained 5% to 9% of femoral neck strength variable variance in both genders, except for bending strength in boys, and approximately 1% to 3% of total body and femoral neck bone-mineral content variance. Vigorous physical activity was then used to categorize boys and girls into quartiles. Pairwise comparison indicated that boys in the third and fourth quartiles (accumulation of >26 minutes/day) demonstrated higher compressive (11%-12%), bending (10%), and impact (14%) strength than boys in the first quartile. In girls, comparison revealed a difference between the fourth (accumulation of >25 minutes/day) and first quartiles for bending strength (11%). We did not observe any relationship between physical activity and lumbar spine strength. Femoral neck strength is higher in boys than girls. Vigorous intensity emerged as the main physical activity predictor of femoral neck strength but did not explain gender differences. Daily vigorous physical activity for at least approximately 25 minutes seems to improve femoral neck bone health in children.

Measuring femoral neck strength: Lost in translation?

Measuring femoral neck strength: Lost in translation?

Minodronic acid (ONO-5920/YM529) prevents decrease in bone mineral density and bone strength, and improves bone microarchitecture in ovariectomized cynomolgus monkeys

This study examined the effect of the highly potent nitrogen-containing bisphosphonate, minodronic acid (ONO-5920/YM529), on bone mineral density (BMD), bone turnover, bone microarchitecture and bone strength in ovariectomized (OVX) cynomolgus monkeys. Skeletally mature female cynomolgus monkeys, aged 9–17 years, were ovariectomized or sham-operated. Minodronic acid was administered orally once a day in doses of 0, 0.015, and 0.15 mg/kg from the day after surgery for 17 months. Bone resorption markers (urinary N-terminal cross-linking telopeptide of type I collagen and deoxypyridinoline), bone formation markers (serum osteocalcin and bone alkaline phosphatase) and lumbar vertebral BMD were measured at baseline and at 4, 8, 12 and 16 months after surgery. Treatment with minodronic acid dose-dependently inhibited OVX-induced increase in bone turnover markers and decrease in lumbar vertebral BMD, and minodronic acid at 0.15 mg/kg completely prevented these changes. At 17 months after surgery, minodronic acid also suppressed bone resorption (Oc.S/BS and N.Oc/BS) and bone formation (OS/BS, MS/BS, MAR, BFR/BS, and BFR/BV) in the lumbar vertebral bodies and tibia. In the mechanical tests, ultimate load on lumbar vertebral bodies and femoral neck of the OVX-control animals were significantly reduced compared to the sham animals. Minodronic acid prevented these reductions in bone strength at 0.15 mg/kg. There was significant correlation between BMD and bone strength, suggesting that the increase in bone strength was associated with the increase in BMD produced by minodronic acid. In micro-CT analysis of the lumbar vertebral bodies, minodronic acid improved trabecular architecture, converting rod structures into plate structures, and preventing the increase in trabecular disconnectivity at 0.15 mg/kg. In conclusion, similar to patients with postmenopausal osteoporosis, reduction in bone strength of lumbar vertebral bodies and femoral neck was clearly demonstrated in OVX cynomolgus monkeys. Minodronic acid prevented these reductions at a once-daily oral administration. Also, minodronic acid prevented OVX-induced changes in bone turnover, bone mass and bone microarchitecture. Long-term minodronic acid treatment was well tolerated and no adverse effects could be detected. These results suggest that minodronic acid may be a clinically useful drug for osteoporosis.

Grip Strength May Facilitate Fracture Prediction in Perimenopausal Women with Normal BMD: A 15-Year Population-Based Study

The aim of the present study was to investigate the ability of grip strength measurements to predict fracture risk in perimenopausal women according to bone mineral density (BMD). A random sample of 971 perimenopausal women from the Kuopio Osteoporosis Risk Factor and Prevention study cohort was measured with dual-energy X-ray absorptiometry (DXA) at the femoral neck and grip strength with a pneumatic squeeze dynamometer in 5-year intervals from baseline (1989-1991). Fractures during the 15-year follow-up were recorded based on self-reports and validated from medical records. In the total sample and in osteopenic or osteoporotic women (T score < -1, n = 284) grip strength was not significantly associated with fracture-free survival rate (P = nonsignificant in Cox regression). In women with normal baseline BMD (N-BMD, T score > -1, n = 687) the lowest grip strength quartile had a significantly lower fracture-free survival rate in the Cox proportional hazard model (P = 0.005, hazard ratio [HR] = 2.0). In the multivariate Cox regression model, T score and grip strength were the only significant predictors of 15-year fracture-free survival in the N-BMD group and a risk index (RI) was formed according to HRs of these two variables. High RI (0-5 points) was associated with significantly lower 15-year fracture-free survival rate (P = 0.001, HR = 0.137) in the N-BMD group. In contrast, 5-year T score was no better a predictor of fractures in the baseline N-BMD group (P = 0.04, HR = 0.36). In conclusion, grip strength predicts 15-year fracture-free survival in perimenopausal women with N-BMD, while 5-year DXA does not seem to be any better a predictor of fracture risk. DXA measurements could be coupled with simple and cost-effective grip strength measurements. Controlling BMD in women with N-BMD could be abandoned.

Six-year longitudinal analysis shows physical activity impacts on lean mass development in adolescence

the study of physical activity effects on muscle and bone in youth is largely limited to cross-sectional comparisons among athletic and nonathletic groups and short-term intervention studies often less than one year. Critical to the field is the impact of physical activity throughout the

Sex-Specific Genetic Loci for Femoral Neck Bone Mass and Strength Identified in Inbred COP and DA Rats

Hip fracture is the most devastating osteoporotic fracture type with significant morbidity and mortality. Several studies in humans identified chromosomal regions linked to hip size and bone mass. Animal models, particularly the inbred rat, serve as complementary approaches for studying the genetic influence on hip fragility. The purpose of this study is to identify sex-independent and sex-specific quantitative trait loci (QTLs) for femoral neck density, structure, and strength in inbred Copenhagen 2331 (COP) and Dark Agouti (DA) rats. A total of 828 (405 males and 423 females) F(2) progeny derived from the inbred COP and DA strains of rats were phenotyped for femoral neck volumetric BMD (vBMD), cross-sectional area, polar moment of inertia (Ip), neck width, ultimate force, and energy to break. A whole genome screen was performed using 93 microsatellite markers with an average intermarker distance of 20 cM. Recombination-based marker maps were generated using MAPMAKER/EXP from the COP x DA F(2) data and compared with published Rat Genome Database (RGD) maps. These maps were used for genome-wide linkage analyses to detect sex-independent and sex-specific QTLs. Significant evidence of linkage (p < 0.01) for sex-independent QTLs were detected for (1) femoral neck vBMD on chromosomes (Chrs) 1, 6, 10, and 12, (2) femoral neck structure on Chrs 5, 7, 10, and 18, and (3) biomechanical properties on Chrs 1 and 4. Male-specific QTLs were discovered on Chrs 2, 9, and 18 for total vBMD, on Chr 17 for trabecular vBMD, on Chr 9 for total bone area, and on Chr 15 for ultimate force. A female-specific QTL was discovered on Chr 2 for ultimate force. The effect size of the individual QTL varied between 1% and 4%. We detected evidence that sex-independent and sex-specific QTLs contribute to hip fragility in the inbred rat. Several QTLs regions identified in this study are homologous to human chromosomal regions previously linked to QTLs contributing to femoral neck and related phenotypes.

Does a novel school-based physical activity model benefit femoral neck bone strength in pre- and early pubertal children?

The effects of physical activity on bone strength acquisition during growth are not well understood. In our cluster randomized trial, we found that participation in a novel school-based physical activity program enhanced bone strength acquisition and bone mass accrual by 2-5% at the femoral neck in girls; however, these benefits depended on teacher compliance with intervention delivery. Our intervention also enhanced bone mass accrual by 2-4% at the lumbar spine and total body in boys. We investigated the effects of a novel school-based physical activity program on femoral neck (FN) bone strength and mass in children aged 9-11 yrs. We used hip structure analysis to compare 16-month changes in FN bone strength, geometry and bone mineral content (BMC) between 293 children who participated in Action Schools! BC (AS! BC) and 117 controls. We assessed proximal femur (PF), lumbar spine (LS) and total body (TB) BMC using DXA. We compared change in bone outcomes between groups using linear regression accounting for the random school effect and select covariates. Change in FN strength (section modulus, Z), cross-sectional area (CSA), subperiosteal width and BMC was similar between control and intervention boys, but intervention boys had greater gains in BMC at the LS (+2.7%, p = 0.05) and TB (+1.7%, p = 0.03) than controls. For girls, change in FN-Z tended to be greater (+3.5%, p = 0.1) for intervention girls than controls. The difference in change increased to 5.4% (p = 0.05) in a per-protocol analysis that included girls whose teachers reported 80% compliance. AS! BC benefits bone strength and mass in school-aged children; however, our findings highlight the importance of accounting for teacher compliance in classroom-based physical activity interventions.

The relative importance of genetics and phenotypic plasticity in dictating bone morphology and mechanics in aged mice: Evidence from an artificial selection experiment

Both genetic and environmental factors are known to influence the structure of bone, contributing to its mechanical behavior during, and adaptive response to, loading. We introduce a novel approach to simultaneously address the genetically mediated, exercise-related effects on bone morphometrics and strength, using mice that had been selectively bred for high levels of voluntary wheel running (16 generations). Female mice from high running and control lines were either allowed ( n=12, 12, respectively) or denied ( n=11, 12, respectively) access to wheels for 20 months. Femoral shaft, neck, and head were measured with calipers and via micro-computed tomography. Fracture characteristics of the femoral head were assessed in cantilever bending. After adjusting for variation in body mass by two-way analysis of covariance, distal width of the femur increased as a result of selective breeding, and mediolateral femoral diameter was reduced by wheel access. Cross-sectional area of the femoral mid-shaft showed a significant linetype × activity effect, increasing with wheel access in high-running lines but decreasing in control lines. Body mass was significantly positively correlated with many of the morphometric traits studied. Fracture load of the femoral neck was strongly positively predicted by morphometric traits of the femoral neck ( r 2>0.30), but no significant effects of selective breeding or wheel access were found. The significant correlations of body mass with femoral morphometric traits underscore the importance of controlling for body size when analyzing the response of bone size and shape to experimental treatments. After controlling for body mass, measures of the femoral neck remain significant predictors of femoral neck strength.

Construction of the Femoral Neck During Growth Determines Its Strength in Old Age

Study of the design of the FN in vivo in 697 women and in vitro in 200 cross-sections of different sizes and shapes along each of 13 FN specimens revealed that strength in old age was largely achieved during growth by differences in the distribution rather than the amount of bone material in a given FN cross-section from individual to individual. We studied the design of the femoral neck (FN) to gain insight into the structural basis of FN strength in adulthood and FN fragility in old age. Studies in vivo were performed using densitometry in 697 women and in vitro using high-resolution microCT and direct measurements in 13 pairs of postmortem specimens. The contradictory needs of strength for loading yet lightness for mobility were met by varying FN size, shape, spatial distribution, and proportions of its trabecular and cortical bone in a cross-section, not its mass. Wider and narrower FNs were constructed with similar amounts of bone material. Wider FNs were relatively lighter: a 1 SD higher FN volume had a 0.67 (95% CI, 0.61-0.72) SD lower volumetric BMD (vBMD). A 1 SD increment in height was achieved by increasing FN volume by 0.32 (95% CI, 0.25-0.39) SD with only 0.15 (95% CI, 0.08-0.22) SD more bone, so taller individuals had a relatively lighter FN (vBMD was 0.13 [95% CI, 0.05-0.20 SD] SD lower). Greater periosteal apposition constructing a wider FN was offset by even greater endocortical resorption so that the same net amount of bone was distributed as a thinner cortex further from the neutral axis, increasing resistance to bending and lowering vBMD. This was recapitulated at each point along the FN; varying absolute and relative degrees of periosteal apposition and endocortical resorption focally used the same amount of material to fashion an elliptical FN of mainly cortical bone near the femoral shaft to offset bending but a more circular FN of proportionally more trabecular and less cortical bone to accommodate compressive loads adjacent to the pelvis. This structural heterogeneity was largely achieved by adaptive modeling and remodeling during growth-most of the variance in FN volume, BMC, and vBMD was growth related. Altering structural design while minimizing mass achieves FN strength and lightness. Bone fragility may be the result of failure to adapt bone's architecture to loading, not just low bone mass.

Interrelationships Between Bone Microarchitecture and Strength in Ovariectomized Monkeys Treated With Teriparatide

Bone microarchitecture measured at the iliac crest at 6 mo was confirmed to be a reasonable surrogate for, and a predictor of, architecture and strength of the femoral neck and lumbar vertebra after 18 mo of teriparatide treatment. However, the data taken together showed the importance of cortical bone volume for vertebra to assess pharmacological effects on bone quality. Improvements in bone architecture with teriparatide treatment are suggested to contribute to fracture risk reduction in osteoporotic patients. Teriparatide significantly improves microarchitecture in the iliac crest of humans by stimulating bone modeling and remodeling processes that differ dramatically from those induced by antiresorptives. The relationship between improvements of bone microarchitecture and improvements of bone strength with teriparatide treatment has not yet been fully studied. Ovariectomized monkeys were administered vehicle (n = 20); teriparatide 1.0 microg/kg/d (n = 19); or teriparatide 5.0 microg/kg/d (n = 21) for 18 mo. Iliac crest biopsies were obtained at 6 and 15 mo after initiation of treatment. Animals were killed after 18 mo of treatment, and adjacent vertebrae or contralateral proximal femora were processed for biomechanical or histomorphometric analyses. Pearson correlation analyses were performed to assess the relationship between biomechanical and static histomorphometric parameters of lumbar vertebra, femoral neck, and iliac crest biopsies. Static histomorphometric parameters of the 6- and 15-mo biopsies were significantly correlated with the vertebral and femoral neck parameters obtained at 18 mo of teriparatide treatment. Iliac crest biopsy parameters at 6 and 15 mo also correlated with vertebral and femoral neck strength at 18 mo. Static histomorphometry of the lumbar vertebra and femoral neck at 18 mo also significantly correlated with strength at these sites. However, cortical bone volume of the lumbar vertebrae had the strongest correlation with vertebral and femoral neck strength (r = 0.74 and 0.71, respectively). Teriparatide dose dependently improved cortical and trabecular microarchitecture of vertebra and femoral neck, as well as trabecular microarchitecture of the iliac crest. Bone microarchitecture at all sites was significantly correlated with lumbar vertebra and femoral neck strength. Cortical bone volume of vertebra had the strongest correlation with vertebral and femoral neck strength. Therefore, structural improvement seemed to be part of the mechanism for improved strength observed with teriparatide treatment. Trabecular bone architecture of the iliac crest at 6 mo also correlated with vertebral and femoral neck strength, as did femoral neck (cortical and trabecular) histomorphometry and trabecular histomorphometry of vertebra after 18 mo of treatment. Because clinical assessment of cortical bone volume is not readily possible for vertebra noninvasively, these findings confirm the importance of iliac crest biopsies to monitor skeletal health and show that biopsies are a reasonable surrogate to assess spine and femoral neck structure and function.

High Dietary Phosphate Intake Reduces Bone Strength in the Growing Rat Skeleton

Nutrition influences peak bone mass development in early adulthood. The effect of high dietary phosphate intake on the growing skeleton of 1-month-old male rats (n = 30) was assessed in an 8-week intervention. High dietary phosphate intake increased bone remodeling and impaired bone material properties, diminishing bone mechanical strength. High dietary phosphate intake is typical in the Western diet. Abundant phosphate intake enhances parathyroid secretion and bone metabolism. To study the influence of high dietary phosphate intake on growing bone homeostasis and structure, we submitted growing rats to experimental diets that varied in their phosphate content. One-month-old intact male rats (n = 30) were fed a control diet (Ca:P 1:1) or an experimental diet of either Ca:P 1:2 or Ca:P 1:3 for 8 weeks. At the beginning and the end of the study period, the right femurs were measured using DXA. Double labeling with tetracycline injection was performed 12 and 2 days before death. After death, hind legs were cut loose. Left femurs were processed for histomorphometry. Right femurs were measured with pQCT. Mechanical testing was performed on the right femoral neck and tibial shaft. Six right tibias were analyzed with microCT. Serum PTH, calcium, and phosphate contents were analyzed. High-phosphate intake impaired growth of the animal, limited bone longitudinal growth, and restricted femur BMC and BMD build-up. Osteoclast number, osteoblast perimeter, and mineral apposition rate were increased, and trabecular area and width were decreased. Phosphate decreased femur midshaft total bone BMD, cortical bone BMD, and mean cortical thickness. High-phosphate diet reduced femoral neck and tibial shaft ultimate strength and tibia stiffness and toughness. In addition, serum PTH increased. High dietary phosphate intake reduced growth, skeletal material, and structural properties and decreased bone strength in growing male rats. Adequate calcium could not overcome this.

Femoral neck structure in hip fracture

Hip fracture occurs relating to fall and decreased mechanical integrity of the femoral neck. Mechanical strength of the femoral neck is determined by both bone mineral density and other factors such as bone quality and hip geometry. Histomorphometrical studies show that cortical thinning, regional hyper-mineralization, decreased osteocyte lacunae and microdamage accumulation occur in aged or fractured subjects, suggesting that bone quality contributes mechanical integrity of femoral neck. Recent dual energy X-ray absorptiometry (DXA) studies revealed that hip axis length, longer in femoral neck fracture patients may contribute to the risk of femoral neck fracture.

Assessment of Femoral Neck Strength by 3-Dimensional X-ray Absorptiometry

Hip fractures due to osteoporosis are accompanied with increased mortality and morbidity. Bone mineral density (BMD [g/cm(2)]) measured by dual-energy X-ray absorptiometry (DXA) is the most important risk factor. However, an overlap exists between results of fractured and nonfractured populations. Macro-architectural parameters of the femur are independent risk factors of fracture. They have been evaluated in two dimensions using X-ray films or DXA scans; therefore, they are highly dependent on patient positioning and interindividual anatomical variations. To overcome this problem, we have previously shown the possibility to reconstruct human femurs using two perpendicular DXA scans and to calculate 3-dimensional (3D) geometric parameters from these reconstructions by a method called 3-dimensional X-ray absorptiometry (3D-XA). The aim of this article is to assess whether the combination of areal BMD and 3D geometric parameters calculated from 3D-XA improves failure load prediction of human proximal femurs in stance phase configuration. Twelve femurs (11 women, 1 man; aged 88+/-9 yr; range: 72-103 yr) were included in this study. The BMD was measured using a Hologic Delphi-W device (Hologic, Waltham, MA) and 3D reconstruction of the femurs was done using two perpendicular DXA scans as previously published. The calculated 3D geometric parameters included femoral neck axis length (FNAL), mid-femoral neck cross-sectional area (mid-FN CSA), neck shaft angle (NSA), and femoral head diameter (FHD). Mechanical testing was performed using stance phase configuration, which resulted in subcapital fractures. The FHD was correlated to mid-FN CSA and FNAL (r=0.68 and 0.76, respectively; p<0.001). Failure load was correlated to age, FHD, NSA, and BMD measurements. Multiple regression analysis showed that femoral neck BMD, FHD, and mid-FN CSA gave the best statistical model for failure load prediction (r(2)=0.84; p<0.002). This is the first study suggesting that combining areal BMD to 3D geometric parameters obtained by 3D-XA improve failure load prediction in human femurs.

Assessment of bone strength at differentially-loaded skeletal regions in adolescent middle-distance runners

Bone adaptations to loading extend beyond mineral accrual to geometric markers of bone strength. Available technology and regional differences in cortical bone dictate how bone strength is reported. Examination of bone strength at two differentially-loaded skeletal sites using hip structure analysis (HSA) and bone strength index (BSI) is under-explored in adolescent sporting populations. The purpose of this study was to compare HSA at the femoral neck and BSI at the distal tibia in adolescent middle-distance runners and age- and gender-matched controls. Four groups of 20 adolescents aged 14-18 years were composed of male and female middle-distance runners, and male and female controls. Distal tibial BSI was calculated using data from dual energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI). Calculations for femoral neck strength were acquired from DXA-derived HSA software. Female athletes displayed greater distal tibial BSI than controls t(38)=3.4, p=0.002, but femoral neck bone measures did not differ. In males, no group differences were found at either the distal tibia or femoral neck. In conclusion, exposure to similar high training loads may advantage female adolescent athletes more than male adolescent athletes compared with less active peers in bone strength at the distal tibia.

Association of Grip Strength Change with Menopausal Bone Loss and Related Fractures: A Population-Based Follow-Up Study

The aim of the present study was to investigate the association between grip strength change and bone health according to menopausal status. A random sample of 971 pre- to postmenopausal women from the Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort was measured with dual X-ray absorptiometry in the lumbar spine (LS) and femoral neck (FN) and grip strength with pneumatic squeeze dynamometer at baseline (1989-1991), 5 years (1994-1997), and 10 years (1999-2001). Fractures were recorded based on self-reports and validated from medical records. Women were divided into two groups according to change in grip strength quartile from baseline to 5-year follow-up: not improved (n = 735) and improved (n = 236). In the total population, the greatest bone loss was observed in perimenopausal (beginning of menopause during follow-up, n = 311) women [P < 0.001 vs. premenopausal women (n = 139)], and it declined in postmenopausal (n = 521) women [P < 0.001 by analysis of covariance (ANCOVA)]. The perimenopausal bone loss rate was significantly lower in women in the improved group in comparison to the not improved group (P < 0.01) in contrast to the pre- and postmenopausal groups (P > 0.05). Accordingly, there was a greater decline in perimenopausal LS and FN T-scores in the improved group vs. the not improved group over the first 5-year follow-up interval (P < 0.05 by ANCOVA) and remained unchanged over the 10-year follow-up. In perimenopausal women, there was a trend toward higher fracture-free survival rate in the improved group (82%) vs. the not improved group (88%) after 10 years. Adjustments did not change the results. In conclusion, maintenance of grip strength is associated with menopausal bone loss and future fractures.