Effects of severe hallux valgus on metatarsal stress and the metatarsophalangeal loading during balanced standing: A finite element analysis

Abstract

The internal stress of the human foot enables efficient parametric evaluation of structural and functional impairments associated with foot deformities, such as hallux valgus (HV). However, the status of the internal stress of such a deformed foot remains insufficiently addressed due to the difficulties and limitations of experimental approaches. This study, using finite element (FE) methodology, investigated the influence of severe HV deformity on the metatarsal stress and the metatarsophalangeal (MTP) joint loading during balanced standing. FE models of a normal foot and a severe HV were constructed and validated. Each FE model involves 28 bones and various cartilaginous structures, ligaments, and plantar fascia, as well as encapsulated soft tissue. All the materials except for the encapsulated soft tissue were considered isotropic and linearly elastic, while the encapsulated soft tissue was set as nonlinear hyperelastic. Hexahedral elements were assigned to the solid parts of bones, cartilage, and the encapsulated soft tissue. Link elements were assigned to ligaments and plantar fascia. A plate was created for simulating ground support. A vertical force of a half-body weight was applied on the bottom of the plate for simulating balanced standing loading. The superior surfaces of the encapsulated soft tissue, distal tibia, and distal fibula were fixed. Stress distribution in the metatarsals, contact pressure, and force at the MTP joints were comparatively analysed. Compared to the normal foot, the HV foot showed higher stress concentration in the metatarsals but lower magnitude of MTP joint loading. In addition, the region with high contact pressure at the first MTP joint shifted medially in the HV foot. Knowledge of this study indicates that patients with severe HV deformity are at higher risk of metatarsal injuries and functional impairment of the MTP joints while weight bearing.

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

“…The weakened windlass mechanism contributed by the deformity impaired the load-carrying capacity of the first metatarsal, which was also substantiated by the lower plantar pressure and shear of the medial forefoot in some studies though inconsistent ( Yavuz et al, 2009 ; Nix et al, 2013 ; Hida et al, 2017 ). In addition, Zhang et al (2018) simulated a balanced standing condition on a severe hallux valgus participant and found a significantly lower metatarsal joint load. Although higher stress was also found on the metatarsals, the stress was concentrated at the joint regions which could be caused by joint incongruency of the deformity.…”

“…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). Moreover, Zhang et al (2018) predicted the metatarsal stress and pressure of a severe hallux valgus patient under a balanced standing condition using a comprehensive FE model of the foot and ankle complex. On the other hand, using a FE foot model reconstructed from a normal participant, Wong et al (2014c) predicted the alteration of joint load transfer resulted from the reduction of ligament stiffness and attempted to reveal the potential relationship to hallux valgus.…”

Effect of Displacement Degree of Distal Chevron Osteotomy on Metatarsal Stress: A Finite Element Method

“…The FE method has been widely used in the study of HV. Zhang et al [ 21 ] predicted the metatarsal stress and pressure of a severe HV patient under a balanced standing condition using a comprehensive FE model of the foot and ankle complex. Wong et al [ 22 ] established a musculoskeletal model to explore the effect of ligament relaxation on the etiology of HV.…”

Biomechanical evaluation of different hallux valgus treatment with plate fixations using single first metatarsal bone model and musculoskeletal lower extremity model

“…The effect of generalized ligament laxity on the stress pattern of the first ray had been studied. Zhang et al (Zhang et al, 2018) had investigated the effects of severe hallux valgus on metatarsal stress and the metatarsophalangeal loading during balanced standing using finite element method. Matzaroglou et al (Matzaroglou et al, 2010) analyzed both sixty-degree Chevron osteotomy and ninety-degree Chevron osteotomy for correction of hallux valgus deformity using finite element method.…”