Knee–ankle–foot orthoses (KAFOs) are prescribed to improve abnormal ambulation caused by quadriceps weakness. There are three major types of KAFOs: passive KAFOs, semidynamic KAFOs, and dynamic KAFOs. Dynamic KAFOs are the only type that enables to control knee motions throughout the entire walking gait cycle. However, those available in the market are heavy, bulky, and have limited functionality. The UT dynamic KAFO is developed to allow knee flexion and assist knee extension over the gait cycle by using a superelastic nitinol actuator, which has the potential to reduce volume and weight and reproduce normal knee behavior. In order to match the normal knee stiffness profile, the dynamic actuator consists of two actuating parts that work in the stance and swing phases, respectively. Each actuating part combines a superelastic torsional rod and a torsional spring in parallel. Geometries of the two superelastic rods were determined by matlab-based numerical simulations. The simulation response of the dynamic actuator was compared with the normal knee stiffness, verifying that the proposed design is able to mimic the normal knee performance. The surrounding parts of the dynamic knee joint have then been designed and modeled to house the two actuating parts. The dynamic knee joint was fabricated and mounted on a conventional passive KAFO, replacing its original knee joint on the lateral side. Motion analysis tests were conducted on a healthy subject to evaluate the feasibility of the UT dynamic KAFO. The results indicate that the UT dynamic KAFO allows knee flexion during the swing phase of gait and provides knee motion close to normal.

References

References
1.
Michael
,
J. W.
,
2006
, “
Summary From the Academy's Seventh State-of-the-Science Conference on Knee–Ankle–Foot Orthoses for Ambulation
,”
J. Prosthet. Orthotics
,
18
(
7
), pp.
132
136
.
2.
Zissimopoulos
,
A.
,
Fatone
,
S.
, and
Gard
,
S. A.
,
2007
, “
Biomechanical and Energetic Effects of a Stance-Control Orthotic Knee Joint
,”
J. Rehab. Res. Dev.
,
44
(
4
), pp.
503
513
.
3.
Bernhardt
,
K. A.
,
Oh
,
T. H.
, and
Kaufman
,
K. R.
,
2011
, “
Gait Patterns of Patients With Inclusion Body Myositis
,”
Gait Posture
,
33
(
3
), pp.
442
446
.
4.
Cullell
,
A.
,
Moreno
,
J. C.
,
Rocon
,
E.
,
Forner-Cordero
,
A.
, and
Pons
,
J. L.
,
2009
, “
Biologically Based Design of an Actuator System for a Knee–Ankle–Foot Orthosis
,”
Mech. Mach. Theory
,
44
(
4
), pp.
860
872
.
5.
Sawicki
,
G. S.
, and
Ferris
,
D. P.
,
2009
, “
A Pneumatically Powered Knee–Ankle–Foot Orthosis (KAFO) With Myoelectric Activation and Inhibition
,”
J. Neuroeng. Rehab.
,
6
(
23
), pp.
1
16
.
6.
Ottobock
,
2012
, “
World's First Orthotronic System
,”
Otto Bock Healthcare
, Duderstadt, Germany.
7.
Lagoudas
,
D. C.
,
2008
,
Shape Memory Alloys: Modeling and Engineering Applications
,
Springer
,
New York
.
8.
Hu
,
J. W.
,
2014
, “
Investigation on the Cyclic Response of Superelastic Shape Memory Alloy (SMA) Slit Damper Devices Simulated by Quasi-Static Finite Element (FE) Analyses
,”
Materials
,
7
(
2
), pp.
1122
1141
.
9.
Machado
,
L. G.
, and
Savi
,
M. A.
,
2003
, “
Medical Applications of Shape Memory Alloys
,”
Braz. J. Med. Biol. Res.
,
36
(
6
), pp.
683
691
.
10.
Pasparakis
,
D.
, and
Darras
,
N.
,
2009
, “
Normal Walking: Principles, Basic Concepts, Terminology 3-Dimensional Clinical Gait Analysis
,”
EEXOT
,
60
(
4
), pp.
183
194
.
11.
Winter
,
D. A.
,
2009
,
Biomechanics and Motor Control of Human Movement
,
Wiley
,
Hoboken, NJ
.
12.
Tian
,
F.
,
Hefzy
,
M. S.
, and
Elahinia
,
M.
,
2015
, “
State of the Art Review of Knee–Ankle–Foot Orthoses
,”
Ann. Biomed. Eng.
,
43
(
2
), pp.
427
441
.
13.
Deberg
,
L.
,
Taheri Andani
,
M.
,
Hosseinipour
,
M.
, and
Elahinia
,
M.
,
2014
, “
An SMA Passive Ankle Foot Orthosis: Design, Modeling, and Experimental Evaluation
,”
Smart Mater. Res.
,
2014
, p.
752094
.
14.
Andani
,
M. T.
,
Alipour
,
A.
, and
Elahinia
,
M.
,
2013
, “
Coupled Rate-Dependent Superelastic Behavior of Shape Memory Alloy Bars Induced by Combined Axial-Torsional Loading: A Semi-Analytic Modeling
,”
J. Intell. Mater. Syst. Struct
.,
15.
Tian
,
F.
,
Hefzy
,
M. S.
, and
Elahinia
,
M.
,
2014
, “
Development of a Dynamic Knee Actuator for a KAFO Using Superelastic Alloys
,”
ASME
Paper No. IMECE2014-40431.
16.
LifeModeler
,
2010
, “
Marker Placement Protocols
,”
LifeModeler Inc
., San Clemente, CA.
17.
Scheck and Siress,
2011
, “
KAFO (Knee-Ankle-Foot Orthosis)
,”
Scheck & Siress Inc.
, Chicago, IL.
18.
Becker Orthopedic,
2015
, “Ratchet Lock Joint KAFO,”
Becker Orthopedic
, Troy, MI.
19.
Braddom
,
R. L.
,
2010
,
Physical Medicine and Rehabilitation
,
Saunders
,
Philadelphia, PA
.
20.
Yakimovich
,
T.
,
Lemaire
,
E. D.
, and
Kofman
,
J.
,
2009
, “
Engineering Design Review of Stance-Control Knee–Ankle–Foot Orthoses
,”
J. Rehab. Res. Dev.
,
46
(
2
), pp.
257
267
.
21.
Arazpour
,
M.
,
Ahmadi
,
F.
,
Bani
,
M. A.
,
Hutchins
,
S. W.
,
Bahramizadeh
,
M.
,
Ghomshe
,
F. T.
, and
Kashani
,
R. V.
,
2014
, “
Gait Evaluation of New Powered Knee–Ankle–Foot Orthosis in Able-Bodied Persons: A Pilot Study
,”
Prosthet. Orthot. Int.
,
38
(
1
), pp.
39
45
.
22.
Tian
,
F.
,
Hefzy
,
M. S.
, and
Elahinia
,
M.
,
2013
, “
A Dynamic Knee–Ankle–Foot Orthosis With Superelastic Actuators
,”
ASME
Paper No. SMASIS2013-3044.
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