Three-dimensional finite element biomechanical analysis of stage II adult acquired flatfoot deformity after medial column stabilization / 中国组织工程研究

ABSTRACT

BACKGROUND: Flatfoot is a commonly seen disease in foot and ankle surgery, and stage II adult acquired flatfoot is mostly seen in clinic, so this stage is a key to treatment. However, medial column instability occurs in stage II adult acquired flatfoot, which is an important cause for arch collapse. Medial column stabilization can correct the deformity to great extent, but there is a lack of biomechanical study to assess the effect of medial column stabilization on the whole foot. OBJECTIVE: To investigate the biomechanical effects of medial column stabilization on stage II adult acquired flatfoot. METHODS: A three-dimensional finite element model of stage IIa and IIb adult acquired flatfoot was established. Geomagic software, Solidwork software and Abaqus software were used to simulate medial column stabilization operation (naviculocuniform joint fusion, tarsometatarsal joint fusion, and both fusion). The maximum pressure of plantar soft tissue, medial column bone and medial ligaments was compared before and after simulated single-foot weight loading. Meanwhile, the related parameters were measured to carry out a comprehensive comparison. RESULTS AND CONCLUSION: (1) The maximum plantar stress was located under the first metatarsal head after the simulated medial column stabilization operation. The maximum plantar stress increased significantly after the medial column stabilization in stage IIa flatfoot model, but did not change significantly after the medial column stabilization in stage IIb model. (2) After medial column fusion, the stress of the corresponding joint was reduced, but increased for the other joints of the first metatarsal column. (3) The stress of medial ligament and plantar fascia was not alleviated after medial column fusion. (4) These results indicate that simple medial column stabilization surgery cannot reduce the pressure of medial column of flatfoot in stage II acquired flatfoot adults. It can only be used as a combined surgery to stabilize joints with excessive motion and correct the deformity of supination of forefoot.