Finite element analysis of subtalar joint arthroereisis on adult-acquired flexible flatfoot deformity using customised sinus tarsi implant

Abstract

Background Subtalar arthroereisis may cause sinus tarsi pain complications. In this study, we aimed to introduce a customised implant that facilitated treatment effect and less impingement. The biomechanical outcome between the intact and implant conditions was compared using finite element analysis. Methods A female patient with flatfoot (age: 36 years, height: 156 ​cm, body mass: 51 ​kg) was recruited as the model patient. The customised implant was designed from the extracted geometry. Boundary and loading conditions were assumed from the data of a normal participant. Four gait instants, including the ground reaction force first peak (25% stance), valley (45%), initial push-off (60%) and second peak (75%) were analyzed. Results The navicular height was elevated by 4.2% at 25% stance, whereas the strain of the spring, plantar cuneonavicular and plantar cuboideonavicular ligaments were reduced. The talonavicular joint force decreased and the calcaneocuboid joint increased by half and 67%, respectively, representing a lateralised load pathway. There was a stress concentration at the sulcus tali reaching 15.29 ​MPa Conclusion Subtalar arthroereisis using a customised implant may produce some positive treatment effects in terms of navicular height elevation, ligament strain relief and lateralised joint loading pathway. Although the concentrated stress at the sulcus tali did not exceed the threshold of bone breakdown, we could not rule out the potential of vascular disturbance owing to the remarkable elevation of stress. Future study may enlarge the contact area of the bone–implant interface by considering customisation based on the dynamic change of the sinus tarsi during walking gait. The translational potential of this article Geometry mismatch of prefabricated implants could be the reason for complications. With the advancement of 3D printing, customising implant becomes possible and may improve treatment outcome. This study implemented a theoretical model approach to explore its potential under a simulation of walking.

Finite Element Analysis of Generalized Ligament Laxity on the Deterioration of Hallux Valgus Deformity (Bunion)

“…Implementing cohort studies with clearly defined and isolated exposure factors honed to an unspecific and long time is infeasible since the deterioration factors of hallux valgus could be multifactorial. Computational method using finite element (FE) analysis provides a versatile platform to evaluate the internal biomechanical environment with controlled and pre-assigned sets of conditions ( Morales-Orcajo et al, 2016 ; Wang et al, 2016 ; Behforootan et al, 2017 ), which was commonly used to understand foot pathology ( Wong et al, 2016 , 2018 ), assess the outcome of surgery ( Wang et al, 2019 ; Wong et al, 2020a ), and design implant ( Ni et al, 2019 ; Wong et al, 2020b ), etc. The biomechanical consequences of hallux valgus were examined by partial foot models (first ray models) regarding the stress of the medial capsule and the tarsometatarsal and MPJ forces ( Wong et al, 2014b ; Yu et al, 2020 ).…”

Abnormal Biomechanical Conditions of the Foot in Child with Down Syndrome During Standing: A Finite Element Study

“…There are still some limitations in this study. Mainly, this study was limited by the single-patient design, predefined set of loading conditions, which was commonly faced by FE study [21]. Given that differences existed in structure between the pathological and normal models, we reconstructed patient-specific DS foot model, which was different from our previous study that constructed the pathological model based on the normal one [33].…”

“…In the other way, the force of the foot intrinsic muscles was commonly calculated by inverse dynamics method in previous literatures [21]. However, the deficit of the relation that describes the character of hypotonia in DS children between the muscle length and joint angle makes it impossible to calculate the muscle force.…”

“…Biomechanical conditions of the foot in DS children will be explored by patient-specific FE analysis. The FE analysis, a non-invasive assessment, has been commonly used to investigate the biomechanics of foot and ankle, including pathomechanism, trauma and intervention outcomes [19][20][21].…”

Subtalar Arthroereisis for the Correction of the Adult Acquired Flatfoot

“…Radiographs show < 25% talar head uncoverage (AP view) (Figure 2a) and < 10 degrees of collapse of the talarfirst metatarsal angle (lateral view) (Figure 2b). Subtalar arthroereisis has a greater potential of hindfoot valgus correction than calcaneal osteotomy providing a 3-dimensional correction of the flatfoot deformity by repositioning the talus in its physiologic position [20] (Figure 3). Compared with medial displacement calcaneal osteotomy [21], subtalar arthroereisis (Figure 4) it is easy, quick to perform, and less invasive procedure with no risk of nonunion or malunion, no risk of damaging medial neurovascular structures, and it requires less immobilization time and shorter recovery time.…”