目的采用三维有限元数值模拟方法分析比较骨水泥棒外固定支架与交叉克氏针在力学稳定性方面的差异,为手术治疗第五掌骨颈骨折(特别是第五掌骨颈开放性骨折)提供理论依据。方法选取1名健康志愿者,采集其手腕关节的三维CT图像数据,首先利...目的采用三维有限元数值模拟方法分析比较骨水泥棒外固定支架与交叉克氏针在力学稳定性方面的差异,为手术治疗第五掌骨颈骨折(特别是第五掌骨颈开放性骨折)提供理论依据。方法选取1名健康志愿者,采集其手腕关节的三维CT图像数据,首先利用Mimics Research 21.0、Geomagic Studio 2021软件进行三维图形数据处理,在此基础上应用Solidworks 2020软件构建第五掌骨颈骨折骨水泥棒外固定支架模型(A模型)和第五掌骨颈骨折交叉克氏针固定模型(B模型)。在ANSYS Workbench 17.0中对各模型的材料属性进行赋值、划分网格,建立三维有限元模型。最后通过在第五掌骨头远端关节面进行轴向施加和第五掌骨三点弯曲实验,计算得出两种施压方式的远端骨折块的最大位移,以此评价骨水泥棒外固定支架治疗第五掌骨颈骨折的稳定性。结果(1)轴向施压时,A模型远端骨折块的最大位移、最小位移和平均位移的值大于B模型,A模型近端骨折块的最大位移、最小位移和平均位移的值小于B模型,A模型最大相对位移、最小相对位移和平均相对位移大于B模型。(2)在三点折弯给力时,A模型远端骨折块最大位移小于B模型,远端骨折块最小位移等于B模型,近端骨折块的最大位移和最小位移的均值大于B模型,A模型最大相对位移、最小相对位移和平均相对位移大于B模型。(3)与B模型相比较,A模型的总体应力、固定物应力均明显较小。结论骨水泥棒外固定支架及克氏针交叉固定在治疗第五掌骨颈骨折方面,在轴向和纵向上的位移及总位移均未超过1 mm,差异较小;但骨水泥棒外固定支架在两种施力方式中与交叉克氏针相比应力更小,提示骨水泥棒外固定支架能提供可靠的力学稳定性。展开更多
Background: Many older adults fall while turning. During the turning maneuver, rotation of the head precedes the rest of the body, creating a spatial frame of reference. Limitations of the neck rotation, may interfere...Background: Many older adults fall while turning. During the turning maneuver, rotation of the head precedes the rest of the body, creating a spatial frame of reference. Limitations of the neck rotation, may interfere with the turning mechanism, affect stability, and lead to recurrent falls. However, the association between the range of the neck rotation and turning stability was not explored yet. Purpose: To compare the impact of restricting the neck rotation by a brace, on the turning stability of adults with and without a history of falls. Methods: An observational, cross-sectional study consisting of 59 adults (average age 76 ± 6.9). A group (N = 29) with at least 2 falls (FL) in the last year and a group (N = 30) without a history of falls in the last year (NFL). All participants performed three tests: Timed up and Go (TUG), 180° Turn Test (180 TT) and 360° Turn Test (360 TT) with and without a neck brace. Results: All the scores of the FL were lower than those of the NFL (p Application of the brace worsened the performance of the 180 TT and the 360 TT of both groups (p < 0.05) but there was no interaction between group and bracing. The TUG score of only the NFL was affected by the brace (p < 0.004). Interestingly, only the range of the right neck rotation was correlated with balance tests and number of falls (r = 0.272;p Conclusions: Restricting of the neck mobility worsened the turning stability of both groups but without interaction. The study reinforces the need of considering the neck range of motion when addressing adult stability. A decrease in the range of right neck rotation was identified as a risk factor for loss of balance.展开更多
文摘目的采用三维有限元数值模拟方法分析比较骨水泥棒外固定支架与交叉克氏针在力学稳定性方面的差异,为手术治疗第五掌骨颈骨折(特别是第五掌骨颈开放性骨折)提供理论依据。方法选取1名健康志愿者,采集其手腕关节的三维CT图像数据,首先利用Mimics Research 21.0、Geomagic Studio 2021软件进行三维图形数据处理,在此基础上应用Solidworks 2020软件构建第五掌骨颈骨折骨水泥棒外固定支架模型(A模型)和第五掌骨颈骨折交叉克氏针固定模型(B模型)。在ANSYS Workbench 17.0中对各模型的材料属性进行赋值、划分网格,建立三维有限元模型。最后通过在第五掌骨头远端关节面进行轴向施加和第五掌骨三点弯曲实验,计算得出两种施压方式的远端骨折块的最大位移,以此评价骨水泥棒外固定支架治疗第五掌骨颈骨折的稳定性。结果(1)轴向施压时,A模型远端骨折块的最大位移、最小位移和平均位移的值大于B模型,A模型近端骨折块的最大位移、最小位移和平均位移的值小于B模型,A模型最大相对位移、最小相对位移和平均相对位移大于B模型。(2)在三点折弯给力时,A模型远端骨折块最大位移小于B模型,远端骨折块最小位移等于B模型,近端骨折块的最大位移和最小位移的均值大于B模型,A模型最大相对位移、最小相对位移和平均相对位移大于B模型。(3)与B模型相比较,A模型的总体应力、固定物应力均明显较小。结论骨水泥棒外固定支架及克氏针交叉固定在治疗第五掌骨颈骨折方面,在轴向和纵向上的位移及总位移均未超过1 mm,差异较小;但骨水泥棒外固定支架在两种施力方式中与交叉克氏针相比应力更小,提示骨水泥棒外固定支架能提供可靠的力学稳定性。
文摘Background: Many older adults fall while turning. During the turning maneuver, rotation of the head precedes the rest of the body, creating a spatial frame of reference. Limitations of the neck rotation, may interfere with the turning mechanism, affect stability, and lead to recurrent falls. However, the association between the range of the neck rotation and turning stability was not explored yet. Purpose: To compare the impact of restricting the neck rotation by a brace, on the turning stability of adults with and without a history of falls. Methods: An observational, cross-sectional study consisting of 59 adults (average age 76 ± 6.9). A group (N = 29) with at least 2 falls (FL) in the last year and a group (N = 30) without a history of falls in the last year (NFL). All participants performed three tests: Timed up and Go (TUG), 180° Turn Test (180 TT) and 360° Turn Test (360 TT) with and without a neck brace. Results: All the scores of the FL were lower than those of the NFL (p Application of the brace worsened the performance of the 180 TT and the 360 TT of both groups (p < 0.05) but there was no interaction between group and bracing. The TUG score of only the NFL was affected by the brace (p < 0.004). Interestingly, only the range of the right neck rotation was correlated with balance tests and number of falls (r = 0.272;p Conclusions: Restricting of the neck mobility worsened the turning stability of both groups but without interaction. The study reinforces the need of considering the neck range of motion when addressing adult stability. A decrease in the range of right neck rotation was identified as a risk factor for loss of balance.