Hospital for Special Surgery, New York, New York, USA.
University of São Paulo, São Paulo, Brazil.
Am J Sports Med. 2022 May;50(6):1659-1667. doi: 10.1177/03635465221079652. Epub 2022 Mar 18.
Fractures of the proximal fifth metatarsal bone are common injuries in elite athletes and are associated with high rates of delayed union and nonunion. Structural features of the foot may increase fracture risk in some individuals, emphasizing the need for intervention strategies to prevent fracture. Although orthotic devices have shown promise in reducing fractures of the fifth metatarsal bone, the effect of orthosis on fifth metatarsal strains is not well understood.
To quantify the effects of different foot orthotic constructs on principal tensile strains in the proximal fifth metatarsal bone during cadaveric simulations of level walking. An additional purpose was to investigate the relationships between structural features of the foot and corresponding strains on the fifth metatarsal bone during level walking.
Controlled laboratory study.
A total of 10 midtibial cadaveric specimens were attached to a 6 degrees of freedom robotic gait simulator. Strain gauges were placed at the metaphyseal-diaphyseal junction (zone II) and the proximal diaphysis (zone III) during level walking simulations using 11 different foot orthotic configurations. Images of each specimen were used to measure structural features of the foot in an axially loaded position. The peak tensile strains were measured and reported relative to the sneaker-only condition for each orthotic condition and orthotic-specific association between structural features and principal strains of both zones.
In total, 2 of the 11 orthotic conditions significantly reduced strain relative to the sneaker-only condition in zone II. Further, 6 orthotic conditions significantly reduced strain relative to the sneaker-only condition in zone III. Increased zone II principal strain incurred during level walking in the sneaker-only condition showed a significant association with increases in the Meary's angle. Changes in zone III principal strain relative to the sneaker-only condition were significantly associated with increases in the Meary's angle and fourth-fifth intermetatarsal angle.
The use of orthotic devices reduced principal strain relative to the condition of a sneaker without any orthosis in zone II and zone III. The ability to reduce strain relative to the sneaker-only condition in zone III was indicated by increasing values of the Meary's angle and levels of the fourth-fifth intermetatarsal angle.
Clinicians can use characteristics of foot structure to determine the proper foot orthosis to potentially reduce stress fracture risk in high-risk individuals.
第五跖骨近端骨折是精英运动员常见的损伤，其延迟愈合和不愈合的发生率很高。足部的结构特征可能会增加某些个体的骨折风险，因此需要采取干预策略来预防骨折。尽管矫形器已被证明可以减少第五跖骨骨折，但矫形器对第五跖骨应变的影响尚不清楚。
在模拟平地行走的尸体模拟中，定量研究不同足矫形器结构对近侧第五跖骨主拉伸应变的影响。另一个目的是研究在平地行走过程中，足部的结构特征与第五跖骨相应应变之间的关系。
对照实验室研究。
将 10 个中胫骨尸体标本附着在 6 自由度机器人步态模拟器上。在模拟平地行走过程中，使用 11 种不同的足矫形器配置，在骺干交界处（区 II）和近骨干（区 III）放置应变计。使用每个标本的图像来测量轴向加载位置下足部的结构特征。测量并报告每个矫形器条件下的峰值拉伸应变，以及每个矫形器的结构特征与两个区的主应变之间的特定关联。
总共有 2 种矫形器条件与仅穿运动鞋条件相比，在区 II 显著降低了应变。此外，6 种矫形器条件与仅穿运动鞋条件相比，在区 III 显著降低了应变。在仅穿运动鞋条件下，平地行走时区 II 主应变的增加与 Meary 角的增加呈显著相关性。与仅穿运动鞋条件相比，区 III 主应变的变化与 Meary 角和第四至第五跖骨间角的增加呈显著相关性。
与仅穿运动鞋的条件相比，矫形器的使用降低了区 II 和区 III 的主应变。通过增加 Meary 角和第四至第五跖骨间角的水平，可以降低区 III 相对于仅穿运动鞋的条件下的应变。
临床医生可以使用足部结构特征来确定适当的足部矫形器，以降低高风险个体应力性骨折的风险。
