A lower limb prosthesis is able to restore mobility to patients who have lost a limb; however, no current replacement is as moveable and adaptable as the limb that was lost. Therefore, all amputees suffer from a reduction in function at some level. Movement in the transverse plane of a lower limb prosthesis is often negated in a traditional prosthesis, and those devices that do allow for transverse plane motion are set to a single, fixed stiffness, and incapable of adapting to the varying activities of the user. A prototype device has been created that allows for varying stiffness in the transverse plane of a lower limb prosthesis. The variable stiffness torsion adapter (VSTA) functions by way of a movable pivot lever arm that can actively modify the mechanical advantage between the outer housing and the internal spring. The motion of the pivot is perpendicular to the external torque allowing for low power adjustments of the stiffness. Bench tests were performed and demonstrate the ability of the VSTA to vary torsional stiffness between 0.12 and 0.91 N m/deg over a ±30 deg rotational range of motion. The device also includes a mode for fully locked operation. The VSTA may improve the mobility of lower limb amputees by allowing for activity-dependent transverse plane stiffness.

References

1.
Ziegler-Graham
,
K.
,
MacKenzie
,
E. J.
,
Ephraim
,
P. L.
,
Travison
,
T. G.
, and
Brookmeyer
,
R.
,
2008
, “
Estimating the Prevalence of Limb Loss in the United States: 2005 to 2050
,”
Arch. Phys. Med. Rehabil.
,
89
(
3
), pp.
422
429
.10.1016/j.apmr.2007.11.005
2.
Rietman
,
J. S.
,
Postema
,
K.
, and
Geertzen
,
J. H. B.
,
2002
, “
Gait Analysis in Prosthetics: Opinions, Ideas and Conclusions
,”
Prosthet. Orthot. Int.
,
26
(
1
), pp.
50
57
.10.1080/03093640208726621
3.
Hafner
,
B. J.
,
Sanders
,
J. E.
,
Czerniecki
,
J. M.
, and
Fergason
,
J.
,
2002
, “
Transtibial Energy-Storage-and-Return Prosthetic Devices: A Review of Energy Concepts and a Proposed Nomenclature
,”
J. Rehabil. Res. Dev.
,
39
(
1
), pp.
1
11
.http://www.rehab.research.va.gov/jour/02/39/1/pdf/hafner.pdf
4.
Lamoureux
,
L. W.
, and
Radcliffe
,
C. W.
,
1977
, “
Functional Analysis of the UC-BL Shank Axial Rotation Device
,”
Prosthet. Orthot. Int.
,
1
(
2
), pp.
114
118
.10.3109/03093647709164619
5.
Levy
,
S. W.
,
1980
, “
Skin Problems of the Leg Amputee
,”
Prosthet. Orthot. Int.
,
4
(
1
), pp.
37
44
.10.1001/archderm.1962.01590010071009
6.
Dudek
,
N. L.
,
Marks
,
M. B.
, and
Marshall
,
S. C.
,
2006
, “
Skin Problems in an Amputee Clinic
,”
Am. J. Phys. Med. Rehabil.
,
85
(
5
), pp.
424
429
.10.1097/01.phm.0000214272.01147.5a
7.
van der Linden
,
M. L.
,
Twiste
,
N.
, and
Rithalia
,
S. V. S.
,
2002
, “
The Biomechanical Effects of the Inclusion of a Torque Absorber on Trans‐Femoral Amputee Gait, A Pilot Study
,”
Prosthet. Orthot. Int.
,
26
(
1
), pp.
35
43
.10.1080/03093640208726619
8.
Segal
,
A. D.
,
Orendurff
,
M. S.
,
Czerniecki
,
J. M.
,
Shofer
,
J. B.
, and
Klute
,
G. K.
,
2009
, “
Transtibial Amputee Joint Rotation Moments During Straight-Line Walking and a Common Turning Task With and Without a Torsion Adapter
,”
J. Rehabil. Res. Dev.
,
46
(
3
), pp.
375
383
.10.1682/JRRD.2008.06.0070
9.
Su
,
P.-F.
,
Gard
,
S. A.
,
Lipshutz
,
R. D.
, and
Kuiken
,
T. A.
,
2010
, “
The Effects of Increased Prosthetic Ankle Motions on the Gait of Persons With Bilateral Transtibial Amputations
,”
Am. J. Phys. Med. Rehabil.
,
89
(
1
), pp.
34
47
.10.1097/PHM.0b013e3181c55ad4
10.
Buckley
,
J. G.
,
Jones
,
S. F.
, and
Birch
,
K. M.
,
2002
, “
Oxygen Consumption During Ambulation: Comparison of Using a Prosthesis Fitted With and Without a Tele-Torsion Device
,”
Arch. Phys. Med. Rehabil.
,
83
(
4
), pp.
576
581
.10.1053/apmr.2002.30624
11.
Miller
,
W. C.
,
Speechley
,
M.
, and
Deathe
,
B.
,
2001
, “
The Prevalence and Risk Factors of Falling and Fear of Falling Among Lower Extremity Amputees
,”
Arch. Phys. Med. Rehabil.
,
82
(
8
), pp.
1031
1037
.10.1053/apmr.2001.24295
12.
Orendurff
,
M. S.
,
Segal
,
A. D.
,
Berge
,
J. S.
,
Flick
,
K. C.
,
Spanier
,
D.
, and
Klute
,
G. K.
,
2006
, “
The Kinematics and Kinetics of Turning: Limb Asymmetries Associated With Walking a Circular Path
,”
Gait Posture
,
23
(
1
), pp.
106
111
.10.1016/j.gaitpost.2004.12.008
13.
Glaister
,
B. C.
,
Schoen
,
J. A.
,
Orendurff
,
M. S.
, and
Klute
,
G. K.
,
2007
, “
Mechanical Behavior of the Human Ankle in the Transverse Plane While Turning
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
15
(
4
), pp.
552
559
.10.1109/TNSRE.2007.908944
14.
Flick
,
K.
,
Orendurff
,
M.
,
Berge
,
J.
,
Segal
,
A.
, and
Klute
,
G.
,
2005
, “
Comparison of Human Turning Gait With the Mechanical Performance of Lower Limb Prosthetic Transverse Rotation Adapters
,”
Prosthet. Orthot. Int.
,
29
(
1
), pp.
73
81
.10.1080/03093640500088120
15.
Hansen
,
A. H.
,
Childress
,
D. S.
,
Miff
,
S. C.
,
Gard
,
S. A.
, and
Mesplay
,
K. P.
,
2004
, “
The Human Ankle During Walking: Implications for Design of Biomimetic Ankle Prostheses
,”
J. Biomech.
,
37
(
10
), pp.
1467
1474
.10.1016/j.jbiomech.2004.01.017
16.
Jafari
,
A.
,
Tsagarakis
,
N. G.
, and
Caldwell
,
D. G.
,
2011
, “
AwAS-II: A New Actuator With Adjustable Stiffness Based on the Novel Principle of Adaptable Pivot Point and Variable Lever Ratio
,”
2011 IEEE International Conference on Robotics and Automation
(
ICRA
), Shanghai, May 9–13, pp.
4638
4643
.10.1109/ICRA.2011.5979994
17.
Glaister
,
B. C.
,
Schoen
,
J. A.
,
Orendurff
,
M. S.
, and
Klute
,
G. K.
,
2009
, “
A Mechanical Model of the Human Ankle in the Transverse Plane During Straight Walking: Implications for Prosthetic Design
,”
ASME J. Biomech. Eng.
,
131
(
3
), p.
034501
.10.1115/1.3005153
18.
Lin-Chan
,
S. J.
,
Nielsen
,
D. H.
,
Yack
,
H. J.
,
Hsu
,
M. J.
, and
Shurr
,
D. G.
,
2003
, “
The Effects of Added Prosthetic Mass on Physiologic Responses and Stride Frequency During Multiple Speeds of Walking in Persons With Transtibial Amputation
,”
Arch. Phys. Med. Rehabil.
,
84
(
12
), pp.
1865
1871
.10.1016/j.apmr.2003.03.006
19.
Winter
,
D. A.
,
1991
,
The Biomechanics and Motor Control of Human Gait: Normal, Elderly and Pathological
, 2nd ed.,
University of Waterloo
,
Waterloo
, ON, Canada, pp.
11
12
.
20.
Juvinall
,
R. C.
, and
Marshek
,
K. M.
,
2012
,
Fundamentals of Machine Component Design
, 5th ed.,
Wiley
,
New York
, p.
411
.
21.
Taylor
,
M. J. D.
,
Dabnichki
,
P.
, and
Strike
,
S. C.
,
2005
, “
A Three-Dimensional Biomechanical Comparison Between Turning Strategies During the Stance Phase of Walking
,”
Hum. Mov. Sci.
,
24
(
4
), pp.
558
573
.10.1016/j.humov.2005.07.005
22.
Huxham
,
F.
,
Gong
,
J.
,
Baker
,
R.
,
Morris
,
M.
, and
Iansek
,
R.
,
2006
, “
Defining Spatial Parameters for Non-Linear Walking
,”
Gait Posture
,
23
(
2
), pp.
159
163
.10.1016/j.gaitpost.2005.01.001
23.
Waters
,
R. L.
, and
Mulroy
,
S.
,
1999
, “
The Energy Expenditure of Normal and Pathologic Gait
,”
Gait Posture
,
9
(
3
), pp.
207
231
.10.1016/S0966-6362(99)00009-0
You do not currently have access to this content.