Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement

Category: Hindfoot; Ankle Arthritis Introduction/Purpose: Clinical studies have shown 32% of patients with a TAR progress to subtalar OA within 5 years, whereas 78% of patients with a tibiotalar arthrodesis presented with subtalar OA by 7.5 years. Higher rates of subtalar OA after arthrodesis may be...

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Main Authors: Rich Lisonbee MS, Kevin Dibbern PhD, Andrew E. Anderson PhD, Karen Kruger PhD, Amy Lenz PhD
Format: Article
Language:English
Published: SAGE Publishing 2023-12-01
Series:Foot & Ankle Orthopaedics
Online Access:https://doi.org/10.1177/2473011423S00106
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author Rich Lisonbee MS
Kevin Dibbern PhD
Andrew E. Anderson PhD
Karen Kruger PhD
Amy Lenz PhD
author_facet Rich Lisonbee MS
Kevin Dibbern PhD
Andrew E. Anderson PhD
Karen Kruger PhD
Amy Lenz PhD
author_sort Rich Lisonbee MS
collection DOAJ
description Category: Hindfoot; Ankle Arthritis Introduction/Purpose: Clinical studies have shown 32% of patients with a TAR progress to subtalar OA within 5 years, whereas 78% of patients with a tibiotalar arthrodesis presented with subtalar OA by 7.5 years. Higher rates of subtalar OA after arthrodesis may be explained by a transfer of ankle forces and stress through the adjacent subtalar joint while TAR may mitigate these changes. The objective of this study was to compare subtalar joint contact stresses between patients treated with tibiotalar arthrodesis and total ankle replacement (TAR) during an overground walking activity using correspondence particles to enable regional analysis. Methods: With IRB approval, ten individuals with unilateral tibiotalar arthrodesis and six individuals with unilateral TAR were imaged with biplane fluoroscopy during overground walking. Discrete element analysis (DEA) was performed to estimate subtalar joint contact stress using the tracked bone models. Cartilage was modeled using linear-elastic material properties (E=12 MPa, v=0.42) and uniformly extruded compressible surfaces from rigid subchondral bone (0.98 mm talar side, 0.75 mm calcaneal side1). A calcaneal statistical shape model (SSM) was created and resulting correspondence particles served as registered locations for comparison of cumulative stress across three phases of normalized stance (loading-response 0-24%, mid 25-54%, and terminal 55- 87%). Two-sample t-tests or Wilcoxon rank-sum tests were used to evaluate differences (p < 0.05) in cumulative contact stresses at each correspondence particle within the 3 phases based upon Shapiro-Wilk findings of normality. Results: There were significant differences in contact stress exposure across all three phases of gait. Differences were identified along the superior-medial aspect of the posterior facet and within the anterior facet (Figure 1). Higher cumulative stresses were observed along the border of the posterior facet and in the medial facet. This model is limited by a lack of validation, uniform cartilage thickness assumptions applied across groups, and that DEA only estimates contact stress without consideration of shear. Conclusion: This study was the first to localize regional differences in subtalar joint stress for patients having undergone TAR and tibiotalar arthrodesis. Interestingly, TAR patients experienced higher stress in this study compared to those with arthrodeses. These ostensibly counterintuitive findings of higher TAR stress may relate to the pre-existence of subtalar OA which is a common indication of TAR versus fusion.
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spelling doaj.art-598a057568024aca9bd438a73dc9391c2025-03-04T09:03:45ZengSAGE PublishingFoot & Ankle Orthopaedics2473-01142023-12-01810.1177/2473011423S00106Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle ReplacementRich Lisonbee MSKevin Dibbern PhDAndrew E. Anderson PhDKaren Kruger PhDAmy Lenz PhDCategory: Hindfoot; Ankle Arthritis Introduction/Purpose: Clinical studies have shown 32% of patients with a TAR progress to subtalar OA within 5 years, whereas 78% of patients with a tibiotalar arthrodesis presented with subtalar OA by 7.5 years. Higher rates of subtalar OA after arthrodesis may be explained by a transfer of ankle forces and stress through the adjacent subtalar joint while TAR may mitigate these changes. The objective of this study was to compare subtalar joint contact stresses between patients treated with tibiotalar arthrodesis and total ankle replacement (TAR) during an overground walking activity using correspondence particles to enable regional analysis. Methods: With IRB approval, ten individuals with unilateral tibiotalar arthrodesis and six individuals with unilateral TAR were imaged with biplane fluoroscopy during overground walking. Discrete element analysis (DEA) was performed to estimate subtalar joint contact stress using the tracked bone models. Cartilage was modeled using linear-elastic material properties (E=12 MPa, v=0.42) and uniformly extruded compressible surfaces from rigid subchondral bone (0.98 mm talar side, 0.75 mm calcaneal side1). A calcaneal statistical shape model (SSM) was created and resulting correspondence particles served as registered locations for comparison of cumulative stress across three phases of normalized stance (loading-response 0-24%, mid 25-54%, and terminal 55- 87%). Two-sample t-tests or Wilcoxon rank-sum tests were used to evaluate differences (p < 0.05) in cumulative contact stresses at each correspondence particle within the 3 phases based upon Shapiro-Wilk findings of normality. Results: There were significant differences in contact stress exposure across all three phases of gait. Differences were identified along the superior-medial aspect of the posterior facet and within the anterior facet (Figure 1). Higher cumulative stresses were observed along the border of the posterior facet and in the medial facet. This model is limited by a lack of validation, uniform cartilage thickness assumptions applied across groups, and that DEA only estimates contact stress without consideration of shear. Conclusion: This study was the first to localize regional differences in subtalar joint stress for patients having undergone TAR and tibiotalar arthrodesis. Interestingly, TAR patients experienced higher stress in this study compared to those with arthrodeses. These ostensibly counterintuitive findings of higher TAR stress may relate to the pre-existence of subtalar OA which is a common indication of TAR versus fusion.https://doi.org/10.1177/2473011423S00106
spellingShingle Rich Lisonbee MS
Kevin Dibbern PhD
Andrew E. Anderson PhD
Karen Kruger PhD
Amy Lenz PhD
Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
Foot & Ankle Orthopaedics
title Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
title_full Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
title_fullStr Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
title_full_unstemmed Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
title_short Statistical Shape Modeling Enables Identification of Subtalar Contact Stress Differences Following Tibiotalar Arthrodesis and Total Ankle Replacement
title_sort statistical shape modeling enables identification of subtalar contact stress differences following tibiotalar arthrodesis and total ankle replacement
url https://doi.org/10.1177/2473011423S00106
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