Reduction in proximal femoral strength due to long-duration spaceflight
Reduction in proximal femoral strength due to long-duration spaceflight
复制标题
DOI：
10.1016/j.bone.2008.11.014
复制
发表时间：
2009-03-01
期刊：
影响因子：
4.1
通讯作者：
Lang, T. F.
中科院分区：
文献类型：
--
作者：
Keyak, J. H.;Koyama, A. K.;Lang, T. F.
骨量丢失是长时间航天飞行的一个众所周知的医学并发症。然而，我们不知道骨密度和几何形状的变化最终如何结合在一起影响股骨近端整体的强度。这项研究的目的是量化长期太空飞行导致的股骨近端力量的变化。建立了飞行前和飞行后基于CT扫描的13名宇航员左股骨近端的有限元模型，这些宇航员在国际空间站工作了4.3到6.5个月。模拟单肢站立和跌落到大粗隆后外侧的载荷条件，并计算股骨近端强度(F(FE))。平均F(FE)从飞行前的18.2倍体重(BW)下降到飞行后的15.6BW，下降到飞行前的3.5BW和飞行后的3.1BW。当飞行时间归一化后，原地踏步和坠落负荷下的F(FE)平均每月下降2.6%(0.6%至5.0%)和2.0%(0.6%至3.9%)。这些数值分别显著高于之前报道的DXA总股骨骨密度的降幅(每月0.4%至1.8%)。在一些受试者中，股骨近端强度降低的幅度与估计的与年龄相关的终生损失相当。虽然飞行后股骨近端的平均力量大于跌倒或正常活动的预期力量，但一些受试者的安全边际很小。如果股骨近端的力量没有恢复，一些机组人员在执行任务数十年后，可能会面临与年龄相关的髋部骨折的风险增加。(C)2008年爱思唯尔INS。版权所有。
Loss of bone mass is a well-known medical complication of long-duration spaceflight. However, we do not know how changes in bone density and geometry ultimately combine to affect the strength of the proximal femur as a whole. The goal of this study was to quantify the changes in proximal femoral strength that result from long-duration spaceflight. Pre-and post-flight CT scan-based patient-specific finite element models of the left proximal femur of 13 astronauts who spent 4.3 to 6.5 months on the International Space Station were generated. Loading conditions representing single-limb stance and a fall onto the posterolateral aspect of the greater trochanter were modeled, and proximal femoral strength (F(FE)) was computed. Mean F(FE) decreased from 18.2 times body weight (BW) pre-flight to 15.6 BW post-flight for stance loading and from 3.5 BW preflight to 3.1 BW post flight for fall loading. When normalized for flight duration, F(FE) under stance and fall loading decreased at mean rates of 2.6% (0.6% to 5.0%) per month and 2.0% (0.6% to 3.9%) per month. respectively, These values are notably greater than previously reported reductions in DXA total femoral bone mineral density (0.4 to 1.8% per month). In some subjects, the magnitudes of the reductions in proximal femoral strength were comparable to estimated lifetime losses associated with aging. Although average post flight proximal femoral strength is greater than forces expected to occur clue to falls or normal activities, some subjects have small margins of safety. If proximal femoral strength is not recovered, some crew members may be at increased risk for age-related hip fractures decades after their missions. (C) 2008 Elsevier Ins. All rights reserved.