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Effects of Ankle Arthrodesis on Biomechanical Performance of the Entire Foot.

Wang Y, Li Z, Wong DW, Zhang M - PLoS ONE (2015)

Bottom Line: An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray.The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes.Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Division of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.

ABSTRACT

Background/methodology: Ankle arthrodesis is one popular surgical treatment for ankle arthritis, chronic instability, and degenerative deformity. However, complications such as foot pain, joint arthritis, and bone fracture may cause patients to suffer other problems. Understanding the internal biomechanics of the foot is critical for assessing the effectiveness of ankle arthrodesis and provides a baseline for the surgical plan. This study aimed to understand the biomechanical effects of ankle arthrodesis on the entire foot and ankle using finite element analyses. A three-dimensional finite element model of the foot and ankle, involving 28 bones, 103 ligaments, the plantar fascia, major muscle groups, and encapsulated soft tissue, was developed and validated. The biomechanical performances of a normal foot and a foot with ankle arthrodesis were compared at three gait instants, first-peak, mid-stance, and second-peak.

Principal findings/conclusions: Changes in plantar pressure distribution, joint contact pressure and forces, von Mises stress on bone and foot deformation were predicted. Compared with those in the normal foot, the peak plantar pressure was increased and the center of pressure moved anteriorly in the foot with ankle arthrodesis. The talonavicular joint and joints of the first to third rays in the hind- and mid-foot bore the majority of the loading and sustained substantially increased loading after ankle arthrodesis. An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray. The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes. Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery. These variations can provide indications for outcome assessment of ankle arthrodesis surgery.

No MeSH data available.


Related in: MedlinePlus

Comparison of von Mises stress in five metatarsal bones in normal foot model and ankle arthrodesis foot model at three instants.
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pone.0134340.g010: Comparison of von Mises stress in five metatarsal bones in normal foot model and ankle arthrodesis foot model at three instants.

Mentions: The von Mises stress in bone generally increased due to the ankle arthrodesis, as shown in Fig 10. At the first-peak instant, the von Mises stress in the first and third metatarsal bones increased by 19% and 52%, respectively, due to ankle arthrodesis, whereas the stress in the other three metatarsals remained unchanged or slightly decreased. At the mid-stance and second-peak instants, stress in all five metatarsal bones showed an obvious increase. The maximum stress was found in the second metatarsal bone at the second-peak instant among all of the simulations. It was 42 MPa in the normal foot and increased to 52 MPa due to ankle arthrodesis. The stress in the third metatarsal bone was 20 MPa at mid-stance and 34 MPa at the second-peak instant in the normal foot and increased by 39% and 20%, respectively, in the ankle arthrodesis foot. The second and third metatarsals bore much greater stress than the other three metatarsals.


Effects of Ankle Arthrodesis on Biomechanical Performance of the Entire Foot.

Wang Y, Li Z, Wong DW, Zhang M - PLoS ONE (2015)

Comparison of von Mises stress in five metatarsal bones in normal foot model and ankle arthrodesis foot model at three instants.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519327&req=5

pone.0134340.g010: Comparison of von Mises stress in five metatarsal bones in normal foot model and ankle arthrodesis foot model at three instants.
Mentions: The von Mises stress in bone generally increased due to the ankle arthrodesis, as shown in Fig 10. At the first-peak instant, the von Mises stress in the first and third metatarsal bones increased by 19% and 52%, respectively, due to ankle arthrodesis, whereas the stress in the other three metatarsals remained unchanged or slightly decreased. At the mid-stance and second-peak instants, stress in all five metatarsal bones showed an obvious increase. The maximum stress was found in the second metatarsal bone at the second-peak instant among all of the simulations. It was 42 MPa in the normal foot and increased to 52 MPa due to ankle arthrodesis. The stress in the third metatarsal bone was 20 MPa at mid-stance and 34 MPa at the second-peak instant in the normal foot and increased by 39% and 20%, respectively, in the ankle arthrodesis foot. The second and third metatarsals bore much greater stress than the other three metatarsals.

Bottom Line: An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray.The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes.Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Division of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.

ABSTRACT

Background/methodology: Ankle arthrodesis is one popular surgical treatment for ankle arthritis, chronic instability, and degenerative deformity. However, complications such as foot pain, joint arthritis, and bone fracture may cause patients to suffer other problems. Understanding the internal biomechanics of the foot is critical for assessing the effectiveness of ankle arthrodesis and provides a baseline for the surgical plan. This study aimed to understand the biomechanical effects of ankle arthrodesis on the entire foot and ankle using finite element analyses. A three-dimensional finite element model of the foot and ankle, involving 28 bones, 103 ligaments, the plantar fascia, major muscle groups, and encapsulated soft tissue, was developed and validated. The biomechanical performances of a normal foot and a foot with ankle arthrodesis were compared at three gait instants, first-peak, mid-stance, and second-peak.

Principal findings/conclusions: Changes in plantar pressure distribution, joint contact pressure and forces, von Mises stress on bone and foot deformation were predicted. Compared with those in the normal foot, the peak plantar pressure was increased and the center of pressure moved anteriorly in the foot with ankle arthrodesis. The talonavicular joint and joints of the first to third rays in the hind- and mid-foot bore the majority of the loading and sustained substantially increased loading after ankle arthrodesis. An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray. The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes. Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery. These variations can provide indications for outcome assessment of ankle arthrodesis surgery.

No MeSH data available.


Related in: MedlinePlus