0
Research Papers

Assessment of Mechanical Characteristics of Ankle-Foot Orthoses

[+] Author and Article Information
Amanda Wach

Department of Biomedical Engineering,
Marquette University,
Olin Engineering Center,
Room 206, 1515 W. Wisconsin Avenue,
Milwaukee, WI 53233
e-mail: awach10@gmail.com

Linda McGrady, Mei Wang

Department of Orthopaedic Surgery,
Medical College of Wisconsin,
Milwaukee, WI 53226

Barbara Silver-Thorn

Department of Biomedical Engineering,
Marquette University,
Milwaukee, WI 53233

Manuscript received July 7, 2017; final manuscript received March 5, 2018; published online April 30, 2018. Assoc. Editor: Brian D. Stemper.

J Biomech Eng 140(7), 071007 (Apr 30, 2018) (6 pages) Paper No: BIO-17-1296; doi: 10.1115/1.4039816 History: Received July 07, 2017; Revised March 05, 2018

Recent designs of ankle-foot orthoses (AFOs) have been influenced by the increasing demand for higher function from active individuals. The biomechanical function of the individual and device is dependent upon the underlying mechanical characteristics of the AFO. Prior mechanical testing of AFOs has primarily focused on rotational stiffness to provide insight into expected functional outcomes; mechanical characteristics pertaining to energy storage and release have not yet been investigated. A pseudostatic bench testing method is introduced to characterize compressive stiffness, device deflection, and motion of solid-ankle, anterior floor reaction, posterior leaf spring, and the intrepid dynamic exoskeletal orthosis (IDEO) AFOs. Each of these four AFOs, donned over a surrogate limb, were compressively loaded at different joint angles to simulate the foot-shank orientation during various subphases of stance. In addition to force–displacement measurements, deflection of each AFO strut and rotation of proximal and supramalleolar segments were analyzed. Although similar compressive stiffness values were observed for AFOs designed to reduce ankle motion, the corresponding strut deflection profile differed based on the respective fabrication material. For example, strut deflection of carbon-fiber AFOs resembled column buckling. Expanded clinical test protocols to include quantification of AFO deflection and rotation during subject use may provide additional insight into design and material effects on performance and functional outcomes, such as energy storage and release.

FIGURES IN THIS ARTICLE
<>
Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Keeling, J. J. , Gwinn, D. E. , Tintle, S. M. , Andersen, R. C. , and McGuigan, F. X. , 2008, “ Short-Term Outcomes of Severe Open Wartime Tibial Fractures Treated With Ring External Fixation,” J. Bone Jt. Surg., Am., 90(12), pp. 2643–2651. [CrossRef]
Shawen, S. B. , Keeling, J. J. , Branstetter, J. , Kirk, K. L. , and Ficke, J. R. , 2010, “ The Mangled Foot and Leg: Salvage Versus Amputation,” Foot Ankle Clin., 15(1), pp. 63–75. [CrossRef] [PubMed]
Patzkowski, J. C. , Blanck, R. V. , Owens, J. G. , Wilken, J. M. , Blair, J. A. , and Hsu, J. R. , 2011, “ Can an Ankle-Foot Orthosis Change Hearts and Minds?,” J. Surg. Orthop. Adv., 20(1), pp. 8–18. [PubMed]
Bowker, P. , Condie, D. N. , Bader, B. L. , and Pratt, D. J. , 1993, Biomechanical Basis of Orthotic Management, Butterworth-Heinemann Ltd., Oxford, UK.
Lusardi, M. , Nielsen, C. C. , and Milagros, J. , 2013, “ Orthoses in Rehabilitation,” Orthotics and Prosthetics in Rehabilitation: A Multidisciplinary Approach, Elsevier, St. Louis, MO, pp. 181–455.
Bartonek, A. , Eriksson, M. , and Gutierrez-Farewik, E. M. , 2007, “ A New Carbon Fibre Spring Orthosis for Children With Plantarflexor Weakness,” Gait Posture, 25(4), pp. 652–656. [CrossRef] [PubMed]
Danielsson, A. , and Sunnerhagen, K. S. , 2004, “ Energy Expenditure in Stroke Subjects Walking With a Carbon Composite Ankle Foot Orthosis,” J. Rehabil. Med., 36(4), pp. 165–168. [CrossRef] [PubMed]
Patzkowski, J. C. , Blanck, R. V. , Owens, J. G. , Wilken, J. M. , Kirk, K. L. , Wenke, J. C. , and Hsu, J. R. , 2012, “ Comparative Effect of Orthosis Design on Functional Performance,” J. Bone Jt. Surg., Am., 94(6), pp. 507–515. [CrossRef]
Owens, J. G. , Blair, J. A. , Patzkowski, J. C. , Blanck, R. V. , and Hsu, J. R. , 2011, “ Return to Running and Sports Participation After Limb Salvage,” J. Trauma: Inj., Infect., Crit. Care, 71(Suppl.), pp. S120–S124. [CrossRef]
Wolf, S. I. , Alimusaj, M. , Rettig, O. , and Döderlein, L. , 2008, “ Dynamic Assist by Carbon Fiber Spring AFOs for Patients With Myelomeningocele,” Gait Posture, 28(1), pp. 175–177. [CrossRef] [PubMed]
Esposito, E. R. , Choi, H. S. , Owens, J. G. , Blanck, R. V. , and Wilken, J. M. , 2015, “ Biomechanical Response to Ankle-Foot Orthosis Stiffness During Running,” Clin. Biomech., 30(10), pp. 1125–1132. [CrossRef]
Esposito, E. R. , Ranz, E. C. , Schmidtbauer, K. A. , Neptune, R. R. , and Wilken, J. M. , 2017, “ Ankle-Foot Orthosis Bending Axis Influences Running Mechanics,” Gait Posture, 56, pp. 147–152. [CrossRef] [PubMed]
Bishop, D. , Moore, A. , and Chandrashekar, N. , 2009, “ A New Ankle Foot Orthosis for Running,” Prosthet. Orthot. Int., 33(3), pp. 192–197. [CrossRef] [PubMed]
Presuto, M. M. , Stickley, C. D. , Perlsweig, K. A. , Kimura, I. F. , and Antoine, G. M. , 2013, “ Long-Term Outcomes of a Dynamic Ankle-Foot Orthosis on Gait Characteristics of a Service Member With Incomplete Nerve Injury to the Lower Extremity: A Case Report,” Mil. Med., 178(7), pp. e870–e875. [CrossRef] [PubMed]
Bregman, D. J. J. , De Groot, V. , Van Diggele, P. , Meulman, H. , Houdijk, H. , and Harlaar, J. , 2010, “ Polypropylene Ankle Foot Orthoses to Overcome Drop-Foot Gait in Central Neurological Patients: A Mechanical and Functional Evaluation,” Prosthet. Orthot. Int., 34(3), pp. 293–304. [CrossRef] [PubMed]
Kobayashi, T. , Leung, A. K. L. , and Hutchins, S. W. , 2011, “ Techniques to Measure Rigidity of Ankle-Foot Orthosis: A Review,” J. Rehabil. Res. Dev., 48(5), pp. 565–576. [CrossRef] [PubMed]
Hawkins, M. C. , 2010, “Experimental and Computational Analysis of an Energy Storage Composite Ankle Foot Orthosis,” Doctoral thesis, University of Nevada, Las Vegas, NV.
Miller, L. A. , and Childress, D. S. , 1997, “ Analysis of a Vertical Compliance Prosthetic Foot,” J. Rehabil. Res. Dev., 34(1), pp. 52–57. [PubMed]
Wach, A. , 2015, “Mechanical Characterization of Carbon Fiber and Thermoplastic Ankle Foot Orthoses,” Master's thesis, Marquette University, Milwaukee, WI.
Kobayashi, T. , Leung, A. L. , Akazawa, Y. , Naito, H. , Tanaka, M. , and Hutchins, S. W. , 2010, “ Design of an Automated Device to Measure Sagittal Plane Stiffness of an Articulated Ankle-Foot Orthosis,” Proc. Inst. Mech. Eng.: Part H, 34(4), pp. 439–448.
Major, R. E. , Hewart, P. J. , and Macdonald, A. M. , 2004, “ A New Structural Concept in Moulded Fixed Ankle Foot Orthoses and Comparison of the Bending Stiffness of Four Constructions,” Prosthet. Orthot. Int., 28(1), pp. 44–48. [PubMed]
Bregman, D. J. J. , Rozumalski, A. , Koops, D. , de Groot, V. , Schwartz, M. , and Harlaar, J. , 2009, “ A New Method for Evaluating Ankle Foot Orthosis Characteristics: BRUCE,” Gait Posture, 30(2), pp. 144–149. [CrossRef] [PubMed]
Kobayashi, T. , Leung, A. K. , and Hutchins, S. W. , 2011, “ Design of a Manual Device to Measure Ankle Joint Stiffness and Range of Motion,” Prosthet. Orthot. Int., 35(4), pp. 478–481. [CrossRef] [PubMed]
Novacheck, T. F. , Beattie, C. , Rozumalski, A. , Gent, G. , and Kroll, G. , 2007, “ Quantifying the Spring-Like Properties of Ankle-Foot Orthoses (AFOs),” J. Prosthet. Orthot., 19(4), pp. 98–105. [CrossRef]
Singerman, R. , Hoy, D. J. , and Mansour, J. M. , 1999, “ Design Changes in Ankle-Foot Orthosis Intended to Alter Stiffness Also Alter Orthosis Kinematics,” J. Prosthet. Orthot., 11(3), pp. 48–55.
Dyer, B. , Sewell, P. , and Noroozi, S. , 2013, “ How Should We Assess the Mechanical Properties of Lower-Limb Prosthesis Technology Used in Elite Sport?—An Initial Investigation,” J. Biomed. Sci. Eng., 6(2), pp. 116–123. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Study AFOs: (a) solid-ankle AFO, (b) anterior floor reaction AFO, (c) PhatBrace AFO, and (d) IDEO

Grahic Jump Location
Fig. 2

Mechanical testing setup for (a) phase 1: strut deflection with posterior strut markers and (b) phase 2: AFO proximal and supramalleolar regional motion assessment with active markers (white). These two test configurations also illustrate the adjustable loading plate to simulate the different limb orientations corresponding to the various stance subphases.

Grahic Jump Location
Fig. 3

Mean (and SD) compressive stiffness of tested AFOs during latter subphases of stance (top) across the latter five loading cycles. The corresponding regressed force–displacement curves used to determine stiffness for the IDEO are also shown (bottom).

Grahic Jump Location
Fig. 4

Displacement of posterior strut markers in the sagittal plane during strut deflection testing. The strut marker positions during preload (midstance: circles; terminal stance: diamonds; preswing: squares) are shown in the inset figures; the strut displacement at the (reduced—see Table 2) target load for various subphases of stance is shown for each AFO.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In