Articular geometry can affect joint kinematics, contact mechanics, and implant‐bone micromotion in total ankle arthroplasty

Abstract

Implant loosening and bearing surface wear remain the most common failure problems of total ankle arthroplasty (TAA). One of the main factors leading to these problems is the nonphysiologic design of articular surfaces. The goals of this study were to reveal the effects of the anatomical medial‐lateral borders height differences, coronal and sagittal radii on the joint kinematics, contact mechanics, and implant‐bone micromotion in TAA. A previously developed and validated musculoskeletal (MSK) multibody dynamics (MBD) modeling method of TAA based on AnyBody generic MSK MBD model (five simulations for each implant) was used by combining with a finite element analysis. Five ankle implant models with different articular surface morphologies were created according to the anatomic characteristics of Chinese measurement data, marked as Implant A to E. The total ankle forces and motions during walking simulation were predicted by MSK MBD models and the contact mechanics of the bearing surface and the micromotion of the implant‐bone interface of TAA were predicted by FE models. Compared with Implant A, the internal‐external rotation in Implant E increased by 12.14%, the maximum of anterior‐posterior translation in Implant E increased by 5.62%, the maximum reduction of tibial micromotion in Implant E was 59.98%, and for talar, micromotion was 15.36%. The ankle implant with similar anatomic articular surface has the potential to allow patients to recover better motions and reduce the risk of early loosening. This study would provide design guidance for the development of new ankle implants and further advance the development of TAA. Clinical Significance: This study promoted the improvement of ankle implant design and made contributions to improve the service life of ankle implant and patient satisfaction.

Effect of novel polyethylene insert configurations on bone-implant micromotion and contact stresses in total ankle replacement prostheses: a finite element analysis

“…For the insert-talar prothesis interface, which requires higher accuracy, the explicit contact pair algorithm was employed, set as hard contact with a friction coefficient of μ = 0.04, and the insert was in close contact with the tibial tray ( Sopher et al, 2017 ; González et al, 2020 ). Zhang et al ( Zhang et al, 2020 ; Zhang et al, 2023 ) collected gait data from patients and used them as motor inputs for specific musculoskeletal models. The corresponding prediction of musculoskeletal model data for total ankle arthroplasty included dorsiflexion-metatarsal flexion, varus-valgus, internal-external rotation, anterior-posterior translation, lower-upper translation, internal and external translation, ankle contact force, muscle activation and tendon force.…”

“…Compared to the data in other studies, the amplitude and trend of the predicted results are within a reasonable range. To simulate gait conditions, we referenced the research conducted by Zhang et al ( Zhang et al, 2020 ; Zhang et al, 2023 ) on gait experiments involving ankle implants and utilized ankle joint contact force and motion values based on the musculoskeletal (MSK) multibody dynamics (MBD) model used in that study. The entire gait cycle was divided into ten analysis steps, with gait parameters extracted at intervals of 10% and then subsequently used as the boundary and loading conditions for our TAR finite element models ( Figure 4 ).…”

“…Axial load, displacement, and interexternal rotation were applied to the tibial reference point. All the other degrees of freedom of the tibia and talus were constrained ( ISO, 2019 ; Zhang et al, 2023 , Standard Specification for Total Ankle Replacement Prosthesis, 2014 ), and an intact TAR FEA model was developed ( Figure 5 ).…”

“… Input functions based on musculoskeletal multibody dynamics model: (A) Total joint contact force; (B) Foot dorsi-plantarflexion; (C) Tibial internal-external rotation; (D) Tibial anterior-posterior displacement. Reprinted with permission from Zhang et al, 2023 . …”

The novel magnesium–titanium hybrid cannulated screws for the treatment of vertical femoral neck fractures: Biomechanical evaluation

“…The femur, the Mg–Ti hybrid cannulated screw and the conventional cannulated screw were meshed using the four-node tetrahedral elements (C3D4) [ 5 ]. The mesh size of all components was determined by convergence studies and the quality of all components was further checked [ 29 , 30 ]. A change of under 5% was utilized as the convergence criterion [ 29 , 30 ].…”