Impact of first metatarsal shortening on forefoot loading pattern: a finite element model study
Impact of first metatarsal shortening on forefoot loading pattern: a finite element model study
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第一跖骨缩短对前脚负载模式的影响：有限元模型研究
DOI：
10.1186/s12891-019-2973-6
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发表时间：
2019-12-27
影响因子：
2.3
通讯作者：
Chen, Li
中科院分区：
文献类型：
--
作者：
Geng, Xiang;Shi, Jiaqi;Chen, Li
研究背景在拇外翻重建术中，第一跖骨短缩会导致移植跖骨术后疼痛，这一观点一直被认为是共识。然而，适当的缩短有时有利于矫正严重畸形或缓解关节僵硬。本研究从生物力学的角度探讨第一跖骨是否可以缩短以及缩短多少可以允许。MethodsA有限元模型的人脚模拟推离相的步态。将第一跖骨以2 mm的增量从2 mm逐渐缩短到8 mm，计算蹬离阶段前足载荷模式的相应变化，特别是中央射线处的载荷比。结果随着第一跖骨短缩程度的增加，第一跖排足底压力下降，而侧跖排足底压力持续上升。当缩短至6 mm时，中心线的负荷比超过55%的临界阈值，认为存在风险;但如果第一跖骨远端向足底侧移位3 mm，仍可以操作至正常。结论在第一跖骨截骨术中，最大缩短长度6 mm被认为是在安全范围内。当需要更高水平的缩短时，向下推远跖骨段可以是维持正常足底力分布的补偿程序。
BackgroundsThere has long been a consensus that shortening of the first metatarsal during hallux valgus reconstruction could lead to postoperative transfer metatarsalgia. However, appropriate shortening is sometimes beneficial for correcting severe deformities or relieving stiff joints. This study is to investigate, from the biomechanical perspective, whether and how much shortening of the first metatarsal could be allowed.MethodsA finite element model of the human foot simulating the push-off phase of the gait was established. Progressive shortening of the first metatarsal from 2 to 8 mm at an increment of 2 mm were sequentially applied to the model, and the corresponding changes in forefoot loading pattern during push-off phase, especially the loading ratio at the central rays, was calculated. The effect of depressing the first metatarsal head was also investigated.ResultsWith increasing shortening level of the first metatarsal, the plantar pressure of the first ray decreased, while that of the lateral rays continued to rise. When the shortening reaches 6 mm, the load ratio of the central rays exceeds a critical threshold of 55%, which was considered risky; but it could still be manipulated to normal if the distal end of the first metatarsal displaced to the plantar side by 3 mm.ConclusionsDuring the first metatarsal osteotomy, a maximum of 6 mm shortening length is considered to be within the safe range. Whenever a higher level of shortening is necessary, pushing down the distal metatarsal segment could be a compensatory procedure to maintain normal plantar force distributions.