This paper describes a novel device to evaluate the mechanical properties of ankle foot orthoses (AFOs). The apparatus permits the application to AFOs of continuous three-dimensional (3D) movements between specified and settable endpoints. Using an x-y robot with a rotary stage and a six-component load cell, characteristic displacement versus reaction force curves can be generated and consequently the ankle moments can be determined as a function of dorsi/plantar flexion, inv/eversion and int/external rotation. Representative curves for two polypropylene lateral leaf AFOs, different in shape but produced for the same leg by a skilled orthotist, are presented to illustrate the capabilities of the novel testing system. The metrological investigation showed that the apparatus creates a highly repeatable data set (uncertainty ⩽1% FSO).

Issue Section:
Technical Briefs
Keywords:
orthotics, mechanical variables measurement, medical robotics, rotation measurement, biomechanics
Topics:
Orthotics, Rotation, Stiffness, Testing, Uncertainty, Robots, Stress
1.
International Organization for Standardization
, 1989, ISO 8549-3: Prosthetics and Orthotics–Vocabulary, Part 3: Terms relating to External Orthoses. ISO, Geneva.
2.
Knutson
,
L. M.
, and
Clark
,
D. E.
, 1991, “
Orthotic Devices for Ambulation in Children With Cerebral Palsy and Myelomeningocele
,”
Phys. Ther.
0031-9023,
71
, pp.
947
–
960
.
Crossref
Search ADS
PubMed
 
3.
Bower
,
E.
, 1999, “
A Guide to Physiotherapy Techniques in Cerebral Palsy
,”
Curr. Opin. Pediatr.
1040-8703,
9
, pp.
79
–
83
.
Crossref
Search ADS
 
4.
Mollan
,
R. B.
, and
James
,
W. V. A
, 1977, “
New Flexible Design of Drop-Foot Orthosis
,”
Injury
0020-1383,
8
(
4
), pp.
310
–
314
.
Crossref
Search ADS
PubMed
 
5.
Lehmann
,
J. F.
,
M.
,
S.
,
Condon
,
R.
, and
de Lateur
,
B. J. Price
, 1987, “
Gait Abnormalities in Hemiplegia: Their Correction by Ankle-Foot Orthoses
,”
Arch. Phys. Med. Rehabil.
0003-9993,
68
, pp.
763
–
771
.
PubMed
 
6.
Romkes
,
J.
, and
Brunner
,
R.
 2002, “
Comparison of a Dynamic and a Hinged Ankle–Foot Orthosis by Gait Analysis in Patients With Hemiplegic Cerebral Palsy
,”
Gait and Posture
,
15
, pp.
18
–
24
.
Crossref
Search ADS
PubMed
 
7.
D.
Leone
,
S.
Diemente
,
S.
Gustave
,
I.
Lopez
, 1988, “
Structural Analysis of Solid Ankle-Foot Orthoses
,”
Proceedings of the 14th Annual Northeast Bioengineering Conference
, 10–11 March, pp.
26
–
28
.
8.
D.
Leone
, 1987, “
A Structural Model for Molded Thermoplastic Ankle-Foot Orthosis Analysis
,”
ASME J. Biomech. Eng.
0148-0731,
109
, pp.
305
–
310
.
Crossref
Search ADS
 
9.
Deitz
,
D.
, 1997, “
Optimizing Orthotic Designs With FEA
,”
Mech. Eng. (Am. Soc. Mech. Eng.)
0025-6501, July,
119
(
7
), pp.
70
–
71
.
10.
Chu
,
T. M.
,
Reddy
,
N. P.
, and
Padovan
,
J.
, 1995, “
Three Dimensional Finite Element Stress Analysis of the Polypropylene, Ankle Foot Orthosis Static Analysis
,”
Med. Eng. Phys.
1350-4533,
17
, pp.
372
–
379
.
Crossref
Search ADS
PubMed
 
11.
Chu
,
T. M.
,
Reddy
,
N. P.
, and
Padovan
,
J.
, 1995, “
Stress Distribution in the Ankle-Foot Orthosis Used to Correct Pathological Gait
,”
J. Rehabil. Res. Dev.
0748-7711
32
(
4
), p.
349
.
PubMed
 
12.
Chu
,
T. M.
, and
Gent
, 1996, “
A Bonding Methods of Strain Gages to the Polypropylene Ankle-Foot Orthosis
,”
Exp. Tech.
0732-8818
20
(
5
), p.
29
.
Crossref
Search ADS
 
13.
Chu
,
T. M.
, 2000, “
Determination of Peak Stress on Polypropylene Ankle-Foot Orthoses due to Weight Change Using Strain Gage Technology
,”
Exp. Tech.
0732-8818,
24
(
2
), pp.
28
–
30
.
Crossref
Search ADS
 
14.
Yamamoto
,
S.
,
Ebina
,
M.
,
Iwasaki
,
M.
,
Kubo
,
S.
,
Kawai
,
H.
, and
Kayashi
,
R.
, 1993, “
Comparative Study of Mechanical Characteristics of Plastic AFOs
,”
Prosthet. Orthot Int.
0309-3646,
5
, pp.
259
–
264
.
15.
Lunsford
,
T. R.
,
Ramm
,
T.
, and
Miller
,
J.
, 1994, “
Viscoelastic Properties of Plastic Paediatric AFOs
,”
Prosthet. Orthot Int.
0309-3646,
6
, pp.
3
–
9
.
Crossref
Search ADS
 
16.
Singerman
,
R.
,
Hoy
,
D. J.
, and
Mansour
,
J.
, 1999, “
Design Changes in Ankle-Foot Orthosis Intended to Alter Stiffness Also Alter Orthosis Kinematics
,”
Prosthet. Orthot Int.
0309-3646,
11
, pp.
48
–
56
.
Crossref
Search ADS
 
17.
Nagaya
,
M.
, 1997, “
Shoehorn-Type Ankle-Foot Orthoses: Prediction of Flexibility
,” 1997
Arch. Phys. Med. Rehabil.
0003-9993;
78
(
1
), pp.
82
–
84
.
Crossref
Search ADS
PubMed
 
18.
Klasson
,
B.
,
Convery
,
P.
, and
Raschke
,
S.
, 1998, “
Test Apparatus for the Measurement of the Flexibility of Ankle-Foot Orthoses in Planes Other Than the Loaded Plane
,”
Prosthet. Orthot Int.
0309-3646, Apr;
22
(
1
), pp.
45
–
53
.
PubMed
 
19.
Sykes
,
N.
,
Peacock
.
J. C.
, and
Johnson
,
G. R.
, 1998, “
A Method for the Measurement of Three-Dimensional Geometry of Casts Used for the Manufacture of Ankle Foot Orthoses
,”
Clin. Biomech. (Los Angel. Calif.)
0191-7870,
13
, pp.
542
–
547
.
Crossref
Search ADS
 
20.
Cappa
,
P.
,
Patanè
,
F.
, and
Pierro
,
M. M.
, 2003, “
A Novel Device to Evaluate the Stiffness of Ankle-Foot Orthosis Devices
,”
ASME J. Biomech. Eng.
0148-0731, December
125
, pp.
1
–
5
.
21.
Letter to the editor, 2002, “
ISB Recommendation on Definitions of Joint Coordinate System of Various Joints for the Reporting of Human Joint Motion Part I: Ankle, Hip, and Spine
”
J. Biomech.
0021-9290,
35
, pp.
543
–
554
.
Crossref
Search ADS
PubMed
 
22.
http://www.itl.nist.gov/div898/handbook/index.htmhttp://www.itl.nist.gov/div898/handbook/index.htm NIST Statistical Engineering Handbook, “Type B Evaluations,” section 2.5.4.
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 by American Society of Mechanical Engineers
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