A Retrospective Analysis Of Effects Of Age On Proximal Femoral Geometry In 466 Chinese Han Healthy Adults

Background:In recent years, the importance of Proximal femoral geometry(PFG) in the use of fracture risk prediction has acquired growing awareness by the majority of researchers, although studies and results are not consistent, or even has a completely opposite outcomes, which may in its study, this may due to the imparities in each sample size and the geographical differences or other differences regarding different research. Li et al. conducted Femoral neck local mechanical analysis to predict osteoporosis-related hip fractures, they found that the PFG is of great value in analyzing of the mechanical conditions of the proximal femur, and the combination analysis of the PFG and bone mineral density(BMD) may improve the prediction probability. Gundi et al. [1] have conducteda five-year cohort study To compare hip fracture incidence in post-menopausal females who were differently stratified for the fracture risk according to bone mineral density and proximal femur geometry. They found that The hip fracture incidence of the whole cohort was significantly higher in females with a wide NSA (8.52%) than in those with a narrow NSA (3.51%). The combination of wide NSA and low FNBMD had the highest hip fracture incidence in the whole cohort (17.61%) and each age category. The combinations of narrow/wide NSA with low/high FNBMD, respectively, gave a significantly higher fracture incidence in older than in younger women, whereas women with a combined wide NSA and low FNBMD had no significantly different fracture incidence in young (14.60%) or old age (21.62%). By comparing the above data, the authors concluded that NSA is effective at predicting the hip fracture risk and that the detection in early post-menopause of a wide NSA together with a low FNBMD should identify females at high probability of incident hip fracture. Kamath et al. [2] conducted A Retrospective Study in 135 Patients and found that Anatomical Variance in Acetabular Anteversion Does Not Predict Hip Fracture,. Im et al. [3] researched Proximal hip geometry and hip fracture risk assessment in a Korean population and found that HAL (p=0.046) and NSA (p=0.003) were significantly greater in the patients with IT fracture than in the control patients, while neither parameter was significantly greater in patients with FN fractures than the control patients. The femoral head offset was significantly shorter in the patients with FN fractures (p=0.003) compared with the control patients. In patients with IT fractures, the fracture risk increased 1.64-fold (p=0.048) with a 1 sd increase of the HAL, while it increased 2.32-fold (p=0.003) with alsd increase of the NSA. In FN fractures, the fracture risk increased 2.03-fold (p=0.012)with a 1 sd decrease in femoral head offset. They concluded that some PFG parameters as well as BMD values predict hip fractures in a Korean population, and their evaluation may be useful in the understanding of the biomechanics of hip fractures. Masako et al. [4] Analysis hip geometry by clinical CT for the assessment of hip fracture risk in elderly Japanese women and found that both the neck and trochanteric fracture cases had significantly lower total and cortical BMD, a significantly smaller cortical cross-sectional area (CSA), and a larger trabecular CSA. Both had significantly thinner cortex and smaller distance to center of bone mass, and women with trochanteric fracture had a significantly smaller cortical perimeter in the cross-sectional femoral neck. Women with neck fracture had a longer hip axis length (HAL) and women with trochanteric fracture had a significantly larger neck-shaft angle (NSA). Both groups had significantly lower cross-sectional moment of inertia (CSMI), and only women with neck fracture had a significantly higher buckling ratio (BR) compared to their respective controls. According to the multiple logistic regression analysis, women with neck fracture had a significantly longer HAL, lower CSMI, and higher BR, and women with trochanteric fracture had a significantly smaller cortical CSA of the femoral neck. So they concluded that clinical CT may be useful for the assessment of the risk of neck and trochanteric fracture. Frost et al. [5] investigated the influence of Acetabular and Femoral Version on Fractures of the Femoral Neck and found that no correlation between proximal femoral fracture type and the contralateral femoral version, femoral neck length, acetabular version, or Mckibbin’s instability index or between fracture type and age or gender. They concluded that there appears to be no correlation between proximal femoral fracture type and acetabular or femoral version. Wang et al. [6] studied 41 female (77.2±9.9 years) and 22 male (76.2±12.1 years) patients with hip fractures and 40 female (85.7±6.0 years) and 17 male (84.3±10.1 years) controls. Hip geometry was analyzed on the nonfracture hip in patients and left hip in controls using dual-energy X-ray absorptiometry. They found that There was no difference in areal bone mineral density (aBMD), hip axis length, femoral neck axis length, or neck-shaft angle between cases and controls. However, the moment arm of the force on the hip during a sideways fall was 7.3% and 9.5% longer resulting in 5.6% and 9.1% greater moment in such a fall in female and male cases relative to their respective controls independent of height and weight (all p<0.056). In multivariate logistic regression analysis, only the moment arm length in a sideways fall was associated with increased risk of hip fracture in females (odds ratio=1.91, 95%CI:1.14-3.20 for each SD increase in moment arm length of sideways fall, p=0.02) and males (odds ratio=2.69,95%CI,1.19-6.09, p=0.01). and they concluded A longer moment arm in the sideways fall increases the resultant force applied to the hip predisposing to hip fracture. Nissen et al. [7-9] analysis proximal femur geometry parameters at the level of gene in pridicting risk of hip fracture and found only body height in the MTHFR TT genotype group was significantly different from the combined CT/CC genotype group (P\0.05). The geometric dimensions of the proximal femur in peri-menopausal women are not associated with the MTHFR c.677C[T, P2X7 (Glu496Ala), P2X7 (Ile568Asn), and LRP5 exon 9 (c.266A[G) polymorphisms. Pulkkinen et al. [10] reported that structural parameters of trabecular bone and bone geometry predict in vitro failure loads of the proximal femur with similar accuracy as DXA, when using appropriate image analysis technology. predicts in vitro failure load with similar accuracy as DXA. Dincel et al. [12] aimed to discuss the risk assessments of patients with hip fractures due to the fall-related moderate or minimal trauma and compare them with non-fractured control patients by bone mineral density (BMD) and proximal femur geometric measurements to assess whether geometric measurements of femoral dimensions were associated with femoral strength and hip fracture risk. Forty two osteoporotic patients with proximal femur fracture and 40 osteoporotic non-fractured age and gender-matched controls were included in the study.Lunar DXA was used for BMD measurements and proximal femur geometric measurements were performed manually on direct X-rays as hip axial length (HAL), femoral length (FL), and femoral neck width (FW). The trochanteric and total BMD values of the fracture group were significantly lower than the control group. There was a significant increase in FW/FL ratio in the fracture group that would be of specific importance for guidance:if FL values did not increase as did FW, it would point out a risk for fracture. The trochanteric BMD values were correlated with all increased measurements in the control group. There are genetically determined adaptive differences among individuals concerning bone morphology and bone mineral distribution. These different adaptations result in different bone strengths and fracture formation risk, proximal femur geometry parameters used in combination to predict risk of hip fracture study found that decreased bone density and proximal femoral intertrochanteric geometric morphometric parameters can provide a good prediction of fracture risk. Mikhail et al. [13], who found that the mechanical properties of the proximal femur geometry parameters and characteristics are closely related to bones and proximal femur geometry parameters and can be used alone to predict fracture risk in the case does not combined with bone mineral density. However, proximal femur bone mineral density and geometry parameters combine to predict fracture risk more accurately. Cheng et al. [14] reported that All vQCT measurements discriminated between fractured subjects and age-matched controls. There was no significant difference in predictive strength between volumetric and areal representations of BMD and trabecular and integral vBMD showed comparable discriminatory power, although both of these measures were more correlated to fracture status than cortical vBMD. We found that fractured subjects had larger femoral neck cross-sectional areas, consistent with adaptation to lower BMD in these osteoporotic subjects. The larger neck cross-sectional areas resulted in bending strength indices in the fractured subjects that were comparable or larger than those of the control subjects. In multi-variate analyses, reduced femoral neck cortical thickness and buckling ratio indices were associated with fracture status independently of trabecular vBMD. Patron et al. [15] studied the geometry parameters proximal femur and hip fractures relationship, found that increased length of the neck can lead to the higher hip fracture incidence. Gnudi et al. [16] reported the association of BMD with proximal femur fracture and support the evidence that PFG plays a significant role only in neck fracture prediction, since NSA is the best predictive parameter among those tested. Crabtree et al. [17] pointed out that HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more proactive approach to identifying women at high risk of hip fracture in the community. Bergot et al. Discuss the relationship between the geometry parameters and the risk of hip fracture by exploring the proximal femur DXA images, they found that a single measurement of the length of the femoral neck without bone mineral density can be a good predictor of fracture risk, hip femoral neck fracture patients was significantly longer than the control group. Gatti et al. [18], reported that the bending resistance of the mirror can predict the risk of femoral neck fracture. Yang et al. [19] studied the China Taiwan’s female proximal femur geometry parameters, and found that only the length of the femoral neck was positively correlated with the risk of hip fracture, which indicate that increased length of the femoral neck will result in higher hip fracture risk, stocks bone diameter and neck diameter presence no significant correlation with hip fracture risk. Nakumara et al. [20] compared the Japanese and white Americans’proximal femur geometry parameters, they found that although the Japanese has a significantly lower bone mineral density in the proximal femur than white Americans, but the Japanese hip fracture the incidence indeed significantly less than white Americans, so they concluded that despite lower bone mass, Japanese women have lower risks of structural failure in the femoral neck, attributable primarily to shorter femoral necks and, to a lesser degree, a smaller femoral neck angle. Geometric characteristics of the femoral neck in Japanese women are associated with their lower hip fracture risk, and the measurement of proximal femoral geometry, combined with bone mass, may provide further clinical information about the risk of hip fracture. Faulkner et al. [21] through a single measurement of the proximal femur geometry parameters to predict hip fracture, hip axis length and concluded the value of PFG in predict risk of hip fracture independently. With the improvement of living standards and the medical technology, people become more and more longevity, resulting in the increasing number of elderly people. Improved knowledge regarding the effects of age on PFG will help surgeon better reconstruct PFG during hip surgeries, especially for the aged. Our data may be used as a reference to design more suitable implants for the aged in Chinese population. Furthermore, the assessment for the effects of age on PFG may partly account for the higher incidence of hip fractures in older people.Methods:PFG of femoral version (FV), neck-shaft angle (NSA), acetabular anteversion (AA), femoral offset (FO), femoral head diameter (FHD), femoral neck diameter (FND) and femoral neck length (FNL) were measured in 466 Chinese Han healthy adults (353 males and 113 females). Included adults were divided into seven groups based on age of 18 to 29 years,30 to 39 years,40 to 49 years,50 to 59 years, 60 to 69 years,70 to 79 years and over 80 years, respectively. Analyses for all and stratified analyses by gender and laterality were performed.Results:Analyses for all and stratified analyses by gender and laterality were performed. We found significant differences of NSA (P= 0.000) and AA (P= 0.000) among the age groups, which indicated that NSA may decrease while AA may increase with age. However, no significant differences were found regarding FV (P= 0.616), FO (P= 0.631), FHD (P= 0.807), FND (P= 0.993) or FNL (P= 0.070). Outcomes of Pearson correlation analysis showed a negative relationship between NSA and age (P= 0.000) but a positive association between AA and age (P= 0.000). In the stratified analysis by gender, statistical differences were identified in males regarding NSA (P= 0.003), AA (P= 0.000) and FNL (P= 0.043). With respect to females, significant differences were found in FV (P= 0.014), AA (P= 0.024), FND (P= 0.041) and FNL (P= 0.038). Stratified analyses by body laterality revealed similar outcomes with those for all.Conclusions:Our outcomes suggest a negative association between NSA and age but a positive association between AA and age in the Chinese cohort we reviewed. Additionally, gender differences may exist regarding changes of PFG with age.