Biomechanical application of finite elements in the orthopedics of stiff clubfoot

Abstract

Background The purpose of this study was to evaluate the effect of varying the different correction angles of hindfoot osteotomy orthosis on the biomechanical changes of the adjacent joints after triple arthrodesis in adult patients with stiff clubfoot to determine the optimal hindfoot correction angle and provide a biomechanical basis for the correction of hindfoot deformity in patients with stiff clubfoot. Methods A 26-year-old male patient with a stiff left clubfoot was selected for the study, and his ankle and foot were scanned using dual-source computed tomography. A three-dimensional finite element model of the ankle was established, and after the validity of the model was verified by plantar pressure experiments, triple arthrodesis was simulated to analyze the biomechanical changes of the adjacent joints under the same load with “3°” of posterior varus, “0°” of a neutral position and “3°, 6°, 9°” of valgus as the correction angles. Results The peak plantar pressure calculated by the finite element model of the clubfoot was in good agreement with the actual plantar pressure measurements, with an error of less than 1%. In triple arthrodesis, the peak von Mises stress in the adjacent articular cartilage was significantly different and less than the preoperative stress when the corrected angle of the hindfoot was valgus “6°”. In comparison, the peak von Mises stress in the adjacent articular cartilage was not significantly different in varus “3°”, neutral “0°”, valgus “3°” and valgus “9°” compared with the preoperative stress. Conclusion The results of this study showed that different angles of hindfoot correction in triple arthrodesis did not increase the peak von Mises stress in the adjacent joints, which may not lead to the development of arthritis in the adjacent joint, and a hindfoot correction angle of “6°” of valgus significantly reduced the peak von Mises stress in the adjacent joints after triple arthrodesis.

Cushioning mechanism of the metatarsals during landing for the skateboarding ollie maneuver

“…A static standing simulation was carried out using the FE model. In the standing state, each foot bears one-half of the gravitational force ( Bocanegra et al, 2021 ), and only the triceps of the calf has an obvious EMG signal ( Liu et al, 2022 ). Studies show that the force of the Achilles tendon is 50% of the force of the entire foot ( Sun et al, 2020 ).…”

Effects of Midsole Hardness on the Mechanical Response Characteristics of the Plantar Fascia during Running

“…The strength of the triceps surae muscle was estimated only by extracting the strength of the Achilles tendon in the sagittal plane of the foot from inverse dynamics data. However, according to EMG data [52,53], when standing with both feet balanced, except for the triceps crus, other foot and lower-limb muscles showed no evident activity, which could be considered a lack of active contraction. Moreover, Simonsen et al [54], and Croin et al [55] demonstrated that the triceps crus is the main part that exerts the plantar flexion moment of the foot at pushoff during running.…”