Periosteal expansion and bone loss have opposite effects on femur strength. Their combined effect has not been fully understood. Our investigation using a recently developed beam model suggested that periosteal expansion may maintain femur bending stiffness among elderly women, but not help preserve femoral strength and reduce hip fracture risk. INTRODUCTION Periosteal expansion and bone loss are two accompanying biological phenomena in old population. Their combined effect on bone stiffness, strength, and fracture risk is still not clear, because previous studies have reported contradictory results. METHODS A recently developed DXA (dual-energy X-ray absorptiometry)-based beam model was applied to study the effect at the femoral neck. We first made a theoretical analysis. Then, a clinical cohort consisting of 961 women (316 hip fractures and 645 controls, age of 75.9 ± 7.1) was used to investigate the associations quantitatively. We investigated (1) correlations of femoral-neck width and bone mineral density with femoral stiffness and strength; (2) correlations of femoral stiffness, strength, and hip fracture risk index with age; (3) associations of femoral stiffness, strength and fracture risk index with actual fracture status, measured by the area under the curve (AUC) and odds ratio (OR). RESULTS The investigation results showed that (i) femoral-neck width had stronger correlation with femoral bending stiffness (r = 0.61-0.82, p < 0.001) than with the other stiffness components, while bone mineral density had stronger correlation with axial/shearing stiffness (r = 0.84-0.97, p < 0.001), strength (r = 0.85-0.92, p < 0.001), and fracture risk index (r = -0.61-0.62, p < 0.001) than with bending stiffness. (ii) The association between femoral bending stiffness and age was insignificant (r = - 0.06-0.05, r > 0.05); The associations of axial/shearing stiffness (r = - 0.27--0.20, p < 0.001), strength (r = - 0.28, p < 0.001), and fracture risk index (r = 0.38, p < 0.001) with age were significant. (iii) Fracture risk index had the strongest association with actual fracture status (AUC = 0.75, OR = 3.19), followed by strength (AUC = 0.74, OR = 2.84) and axial/shearing stiffness (AUC = 0.56-0.65, OR = 2.39-2.49). Femoral bending stiffness had the weakest association (AUC = 0.48-0.69, OR = 1.42-2.09). CONCLUSION We concluded that periosteal expansion may be adequate to maintain femoral bending stiffness among elderly women, but it may not help preserve strength and reduce hip fracture risk.

中文翻译：

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老年女性在股骨颈上与年龄相关的骨膜扩张可能维持弯曲刚度，但不能保持股骨强度。

骨膜扩张和骨质流失对股骨强度有相反的影响。它们的综合作用尚未完全了解。我们使用最近开发的光束模型进行的研究表明，骨膜扩张可以维持老年女性的股骨弯曲刚度，但无助于保持股骨强度并降低髋部骨折的风险。引言骨膜扩张和骨丢失是老年人群中两个伴随的生物学现象。由于先前的研究报道了相互矛盾的结果，因此它们对骨硬度，强度和骨折风险的综合影响尚不清楚。方法采用最近开发的基于DXA（双能X射线吸收法）的射线束模型研究股骨颈处的效果。我们首先进行了理论分析。然后，一项由961名女性（316名髋部骨折和645名对照，年龄75.9±7.1岁）组成的临床队列用于定量研究这种关联。我们研究（1）股骨颈宽度和骨矿物质密度与股骨刚度和强度的相关性；（2）股骨刚度，强度和髋部骨折风险指数与年龄的相关性；（3）股骨刚度，强度和骨折危险指数与实际骨折状态之间的关系，通过曲线下面积（AUC）和比值比（OR）进行衡量。结果研究结果表明：（i）股骨颈宽度与股骨弯曲刚度的相关性更强（r = 0.61-0.82，p <0.001），而与其他刚度成分相比，骨矿物质密度与轴向/剪切刚度的关联性更强（r = 0.84-0.97，p <0.001），强度（r = 0.85-0.92，p <0.001）和骨折风险指数（r = -0.61-0.62，p <0.001）大于弯曲刚度。（ii）股骨弯曲刚度与年龄之间的关系不明显（r =-0.06-0.05，r> 0.05）；轴向/剪切刚度（r =-0.27--0.20，p <0.001），强度（r =-0.28，p <0.001）和骨折风险指数（r = 0.38，p <0.001）与年龄的相关性显着。（iii）骨折风险指数与实际骨折状态（AUC = 0.75，OR = 3.19）的关联最大，其次是强度（AUC = 0.74，OR = 2.84）和轴向/剪切刚度（AUC = 0.56-0.65，OR = 2.39-2.49）。股骨弯曲刚度的关联最弱（AUC = 0.48-0.69，OR = 1.42-2.09）。结论我们得出结论，老年妇女的骨膜扩张可能足以维持股骨弯曲刚度，