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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

Cadaveric specimen of the foot and ankle.
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pone.0134340.g003: Cadaveric specimen of the foot and ankle.

Mentions: A male cadaveric specimen consisting of part of the tibia and the entire foot sized of 42 was used in the cadaveric experiment. The contact pressure at the talonavicular joint was measured using a K-Scan sensor (TekScan Inc., Boston, MA, USA) under specific boundary and loading conditions implemented via a mechanical testing system (ElectroForce 3510, Bose, MT, USA). After the insertion of the K-Scan sensor from an incision on the dorsal aspect of the foot over the talonavicular joint (Fig 3), the tibia and fibula bones of the cadaveric foot were fixed on the testing machine in 10 degrees of dorsiflexion position through the adjustment of the rotational plate beneath the plantar foot. The tendons of extrinsic muscles were sutured to pulley lines for the convenience of muscle loading application. A compressive force of 100 N was applied vertically to the tibia and fibula cross-section, and muscle forces of 250 N for the Achilles tendon, 50 N for the tibialis posterior, 50 N for the flexor hallux longus, 50 N for the flexor digital longus, and 50 N for the peroneus longus were applied to the corresponding tendons. Simulations under the same boundary and loading conditions were executed in the finite element model.


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

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

Cadaveric specimen of the foot and ankle.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0134340.g003: Cadaveric specimen of the foot and ankle.
Mentions: A male cadaveric specimen consisting of part of the tibia and the entire foot sized of 42 was used in the cadaveric experiment. The contact pressure at the talonavicular joint was measured using a K-Scan sensor (TekScan Inc., Boston, MA, USA) under specific boundary and loading conditions implemented via a mechanical testing system (ElectroForce 3510, Bose, MT, USA). After the insertion of the K-Scan sensor from an incision on the dorsal aspect of the foot over the talonavicular joint (Fig 3), the tibia and fibula bones of the cadaveric foot were fixed on the testing machine in 10 degrees of dorsiflexion position through the adjustment of the rotational plate beneath the plantar foot. The tendons of extrinsic muscles were sutured to pulley lines for the convenience of muscle loading application. A compressive force of 100 N was applied vertically to the tibia and fibula cross-section, and muscle forces of 250 N for the Achilles tendon, 50 N for the tibialis posterior, 50 N for the flexor hallux longus, 50 N for the flexor digital longus, and 50 N for the peroneus longus were applied to the corresponding tendons. Simulations under the same boundary and loading conditions were executed in the finite element model.

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