BACKGROUND Surgical treatment of adult acquired flatfoot deformity can involve arthrodesis of the midfoot to stabilize the medial column. Few experimental studies have assessed the biomechanical effects of these fusions, because of the difficulty of measuring these parameters in cadavers. Our objective was to quantify the biomechanical stress caused by various types of midfoot arthrodesis on the Spring ligament. To date this is not known. METHODS An innovative finite element model was used to evaluate flatfoot scenarios treated with various combinations of midfoot arthrodesis. All the bones, cartilages and tissues related to adult acquired flatfoot deformity were included, respecting their biomechanical characteristics. The stress changes on the Spring ligament were quantified. Both foot arch lengthening and falling were measured for each of the midfoot arthrodeses evaluated. FINDINGS Arthrodesis performed for stabilization of the talonavicular joint leads to a higher decrease in stress on the Spring ligament. Talonavicular fusion generated a Spring ligament stress decrease of about 61% with respect to the reference case (without any fusion). However, fusing the naviculocuneiform joints leads to an increase in the stress on the Spring ligament. INTERPRETATION This important finding has been unknown to date. We advocate caution regarding fusion of the naviculocuneiform joint as it leads to increased stresses across the Spring ligament and therefore accelerates the development of planovalgus.

中文翻译：

---

成人足后天扁平足处理中足融合对弹簧韧带继发影响的有限元分析。

背景技术成人后天扁平足畸形的外科手术治疗可能涉及中足的关节固定术以稳定内侧柱。很少有实验研究评估这些融合的生物力学效果，因为很难在尸体中测量这些参数。我们的目的是量化由弹簧韧带上的各种类型的中足关节固定术引起的生物力学应力。迄今为止，这还未知。方法采用创新的有限元模型评估用足中关节固定术组合治疗的扁平足情况。考虑到它们的生物力学特征，所有与成年人后天扁平足畸形有关的骨骼，软骨和组织都包括在内。量化了春季韧带上的应力变化。对于评估的每个中足关节，均测量了足弓的伸长和下降。研究结果发现，为稳定距骨眼关节而进行的关节固定术可以使弹簧韧带的应力降低更大。相较于参考病例（无任何融合），足管融合术使春季韧带应力降低了约61％。但是，融合鼻唇形关节会导致弹簧韧带的应力增加。解释迄今为止，这一重要发现尚不清楚。我们提倡对鼻腔楔形关节融合保持警惕，因为它会导致整个春季韧带应力增加，从而加速扁平卵巢的发育。研究结果表明，为稳定距骨眼关节而进行的关节固定术可导致弹簧韧带应力的更大降低。相较于参考病例（无任何融合），足管融合术使春季韧带应力降低了约61％。但是，融合鼻唇形关节会导致弹簧韧带的应力增加。解释迄今为止，这一重要发现尚不清楚。我们提倡对鼻腔楔形关节融合保持警惕，因为它会导致整个春季韧带应力增加，从而加速扁平卵巢的发育。研究结果发现，为稳定距骨眼关节而进行的关节固定术可以使弹簧韧带的应力降低更大。相较于参考病例（无任何融合），足管融合术使春季韧带应力降低了约61％。但是，融合鼻唇形关节会导致弹簧韧带的应力增加。解释迄今为止，这一重要发现尚不清楚。我们提倡对鼻腔楔形关节融合保持警惕，因为它会导致整个春季韧带应力增加，从而加速扁平卵巢的发育。融合鼻腔楔形关节会导致弹簧韧带应力增加。解释迄今为止，这一重要发现尚不清楚。我们提倡对鼻腔楔形关节融合保持警惕，因为它会导致整个春季韧带应力增加，从而加速扁平卵巢的发育。融合鼻腔楔形关节会导致弹簧韧带应力增加。解释迄今为止，这一重要发现尚不清楚。我们提倡对鼻腔楔形关节融合保持警惕，因为它会导致整个春季韧带应力增加，从而加速扁平卵巢的发育。