Note: Descriptions are shown in the official language in which they were submitted.
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THERAPEUTIC DEVICE FOR POST-OPERATIVE KNEE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of United States
Patent
Application No. 12/797,065 filed June 9, 2010 (issued as U.S. Patent No.
8,333,722 B2), which is a continuation-in-part of United States Patent
Application
No. 11/585,427 filed October 24, 2006 (issued as U.S. Patent No. 7,762,963),
which claims the benefit of United States Patent Application No. 60/729,698
filed
on October 24, 2005.
FIELD
[0002] The present disclosure relates to a therapeutic device for
a post-
operative knee.
BACKGROUND
[0003] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0004] More than 500,000 patients underwent total knee replacement
(TKA) in 2012 in the United States alone, a number that is expected to exceed
three million by the year 2025. The rehabilitation process for TKA patients is
extensive, costly, and does not always yield optimal results. Many patients
struggle to re-gain full mobility following TKA because stiffness in the knee
joint
can quickly progress to scar tissue in a short time. If this process is not
prevented, scar tissue may impede flexibility in the future. Lack of full
range of
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motion not only affects gait and mobility, but can also lead to future back,
hip,
and joint pain.
[0005] The process of inhibited flexibility and accumulation of fluid
following TKA progresses through four stages: bleeding, edema, granulation
tissue, and fibrosis. Cytokines in the inflammatory cells draw in fibroblasts,
which
begin to lay down collagen tissue. As the collagen hardens it becomes more and
more difficult to eliminate. Scar tissue is basically all collagen and will
eventually
become fibrosis. This progression typically begins soon after surgery and is
well
on its way to permanently impeding mobility within 2-4 weeks when outpatient
physical therapy typically begins. Lack of range of motion is not normally a
focus
during the first few weeks of therapy. By the time outpatient physical therapy
begins (on average 3-4 weeks post-TKA), it is often not possible to prevent
and
treat the accumulation of fluid in the periarticular tissue. Failure to
achieve a full
range of motion in the immediate or early postoperative period, combined with
permitting the accumulation of even relatively small amounts of periarticular
blood and edema, naturally permits extracellular matrix and collagenous scar
tissue to be deposited, such that full range of motion may never be fully
recovered. A device and method for removing fluid containing fibroblasts from
the periarticular tissue before collagen begins to form would therefore be
desirable.
[0006] Patients and therapists often resist early rehabilitation because
they believe that early manipulation of the joint is exceedingly painful. By
limiting
the force or pressure used to move a patient's joint to below the patient's
comfort
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threshold, it is possible to decrease or eliminate pain while focusing on
terminal
extension and flexion.
[0007] Patients and physical therapists often delay range of motion
therapy after TKA because patients typically experience too much pain if the
leg
is manipulated toward full range of motion soon after surgery. Existing
methods
for treating a lack of range of motion include manually pushing and pulling
just
above and below the knee by a trained physical therapist in an effort to gain
better extension and flexion. If the pressure applied is overdone, a risk of
doing
more damage exists and the inflammatory cycle that started the problem may be
repeated. On the other hand, too little pressure results in insufficient
progress.
[0008] Another issue with existing TKA rehabilitation procedures is that
not all patients are the same in terms of their response to therapy. Some
patients tend to form scar tissue more rapidly, thicker, and more densely than
others. Patients that develop hypertrophic scar and keloids will exhibit loss
of
function at a faster pace than normal.
[0009] Continuous passive motion machines (CPM) are often used in
existing TKA therapies. CPM machines depend on flexion and extension values
to determine motion. CPM machines push blindly and have no pressure
feedback and no pressure variability. CPM machines also cannot stop in mid-
cycle, such as to allow for fluid to exit the joint. CPM machines further are
not
able to provide a high or low amplitude stretch at the extremes of the
patient's
range of motion, such as by holding the leg in a flexed or extended position.
It
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would therefore be desirable to provide a device and method capable of
increasing a patient's range of motion more quickly while minimizing pain.
[0010] CPM machines undesirably set limits on extension and flexion
and operate only within these limits. If the limits are set too aggressively,
the
joint can experience excess stress, leading to pain and potentially additional
injury. Typically, CPM machines are used to exercise a pre-specified range of
motion limited by fixing the target angles within the patient's existing range
of
motion, which is already achievable by the patient. This becomes self-limiting
and can undesirably leave periarticular fluid in the joint, reinforcing
existing limits
of extension and flexion, and preventing meaningful progress.
SUMMARY
[0011] This section provides a general summary of the disclosure, and
is not a comprehensive disclosure of its full scope or all of its features.
[0012] The present teachings provide for an exercise device for
exercising a joint and a limb. The device includes a controller, an actuation
member, a load cell, and a motor. The actuation member is controlled by the
controller and is configured to move between a first position and a second
position. The load cell is mounted to the actuation member and configured to
measure force between the limb and the actuation member. The motor is
configured to control movement of the actuation member in response to inputs
from the controller.
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[0013] The present teachings also provide for a method for exercising
a joint and a limb. The method includes extending the limb with an actuation
member of an exercise device; slowing or stopping extension of the limb when a
measured extension force between the actuation member and the limb is at least
equal to a predetermined target extension force; flexing the limb with the
actuation member; and slowing or stopping flexion of the limb when a measured
flexion force between the actuation member and the limb is at least equal to a
predetermined target flexion force.
[0014] The present teachings further provide for a method that includes
preventing movement of an exercise device actuation member in a first
direction
unless force exerted by the limb against the actuation member is equal to or
greater than a predetermined first target force. The method further includes
preventing movement of the actuation member in a second direction unless force
exerted by the limb against the actuation member is equal to or greater than a
predetermined second target force.
[0015] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples in this
summary are intended for purposes of illustration only and are not intended to
limit the scope of the present disclosure.
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DRAWINGS
[0016] The drawings described herein are for illustrative purposes only
of selected embodiments and not all possible implementations, and are not
intended to limit the scope of the present disclosure.
[0017] Figure 1 is a perspective view of an exercise device according
to the present teachings;
[0018] Figure 2 is a perspective view of an actuation member of the
exercise device of Figure 1;
[0019] Figure 3 is a perspective view of a load cell coupled to the
actuation member;
[0020] Figure 4 is a side view of interior components of the exercise
device of Figure 1;
[0021] Figure 5 is a side view of another exercise device according to
the present teachings.
[0022] Figure 6 is a flow chart of a control method according to the
present teachings for an exercise device;
[0023] Figure 7 is a flow chart of another control method according to
the present teachings for an exercise device;
[0024] Figure 8 is a flow chart of yet an additional control method
according to the present teachings for an exercise device;
[0025] Figure 9A illustrates an additional exercise device according to
the present teachings in a first position; and
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[0026] Figure 9B illustrates the exercise device of Figure 9A in a
second position.
[0027] Corresponding reference numerals indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION
[0028] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0029] With initial referenced to Figure 1, an exercise device according
to the present teachings is illustrated at reference numeral 10. The exercise
device 10 generally includes a case 12 and a seat 14. The case 12 includes a
plurality of supports 16 extending from an undersurface thereof to support the
case 12 on a flat surface, such as a floor of a clinic or home. A post 18
extends
from an upper surface of the case 12, which is opposite to the undersurface
from
which the supports 16 extend. A display 20 is mounted to the post 18, as well
as
a tray 22. The display 20 can be any suitable display for use in operating the
device 10. For example, the display 20 can be a touchscreen capable of
accepting input commands for operating the device 10, and for displaying the
operational status of the device 10 to the user and operator, such as a
physical
therapist. Also at the upper surface of the case 12 proximate to the post 18
is a
first stop button 24A on a first side of the post 18 and a second stop button
24B
on a second side of the post 18. The stop buttons 24A and 24B can be used to
stop all operation of the exercise device.
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[0030] The exercise device further includes an actuation member or
actuation arm 26, which is rotatably mounted at a side of the case 12.
Connected to the actuation arm 26 is a limb coupling member 28. As described
herein, the limb coupling member 28 is configured to couple with a user's
ankle.
The limb coupling member 28 can also be configured to couple with any other
body portion to be exercised and actuated, such as a user's arm. Mounted to
the
case 12 on opposite sides of the actuation arm 26 is a first extension ruler
30A
and a second extension rule 30B. The extension rulers 30A and 30B include
indicia that allows the degree of extension of a user's limb to be visually
measured. The first extension ruler 30A can be used to measure extension
when the seat 14 is in the first position illustrated in Figure 1. The second
extension ruler 30B can be used to measure extension when the seat 14 is in a
second position in which the seat 14 is moved to an end of the case 12
opposite
to the end of the case 12 at which the seat 14 is positioned in Figure 1.
[0031] The exercise device 10 further includes a seat track 34
extending along a length of the case 12. At a first end of the case 12, the
seat
track 34 is mounted to the case 12 with a first mount 36. At a second end of
the
case 12, the seat track 34 is mounted to the case 12 with a second mount 38.
Each of the first mount 36 and the second mount 38 define a plurality of
apertures 40. The apertures 40 are configured to receive a coupling device to
lock the seat to either the first mount 36 or the second mount 38. When locked
to the second mount 38 at the second end of the case 12 for example, the seat
14 will be positioned to exercise the user's right leg. The seat 14 can be
moved
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along the seat track 34 to the first end and coupled to the first mount 36 to
exercise the user's left leg by turning the seat around to allow the left leg
to be
seated in the limb coupling member 28 of the actuation arm 26.
[0032] The seat 14 generally includes a floor support 50, a vertical
support 52 extending from the floor support 50, a vertical adjustment lever
for
adjusting the height of the vertical support 52, a base 56 mounted on top of
the
vertical support 52, and a back rest 58 mounted over the base 56 with a back
rest support 60. The back rest 58 can be moved horizontally relative to the
base
56 by sliding the back rest support 60 horizontally with respect to the base
56.
The back rest support 60 can include a series of suitable locking features to
lock
the back rest 58 in a desired position.
[0033] The seat 14 further includes a support sleeve 62 for a knee
support 64. The sleeve 62 is mounted proximate to the base, particularly in
front
of the base 56, and is configured to receive a knee support 64. In particular,
a
vertical portion 66 of the knee support 64 is slidably received within the
sleeve
62. A horizontal portion 68 of the knee support 64 is mounted to the vertical
portion 66, and is covered with a padded portion 68A. The knee support 64 can
be raised and lowered by sliding the vertical portion 66 to a desired position
within the sleeve 62. The knee support 64 can be moved to any suitable
position
or height to support a user's knee at a suitable height, with the knee being
positioned below the pad 68A. While the knee can be supported at any suitable
position, it is often desirable. to support the knee such that it is
vertically aligned
with a horizontal shaft 84 (Figures 1 and 2) to which the actuation arm 26 is
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coupled. A locator 124 (Figure 2) can be included with the actuation arm 26 at
the horizontal shaft 84 to facilitate alignment of the knee with the
horizontal shaft
84. Any suitable locator 124 can be used, such as a laser.
[0034] Extending from the floor support 50 of the seat 14 is a coupling
flange 70. The coupling flange 70 includes a series of apertures that can be
selectively aligned with the apertures 40 of either the first mount 36 or the
second
mount 38. To facilitate movement of the seat 14 between the first mount 36 and
the second mount 38, the floor support 50 includes wheels beneath it. When the
coupling flange 70 is arranged at a desired position at either the first mount
36 or
the second mount 38 with the aperture 40 of the first or second mount 36/38
aligned with the aperture of the coupling flange 70, a pin 72 can be inserted
through the apertures to lock the seat 14 in the desired position.
[0035] Figure 2 illustrates additional details of the actuation arm 26.
The actuation arm 26 includes an outer arm 80 and an inner arm 82. The outer
arm 80 is coupled to the horizontal shaft 84, which protrudes out from within
the
case 12. The inner arm 82 is slidably coupled to a track 86, which is mounted
within the outer arm 80. The outer arm 80 defines a series of outer apertures
88,
and the inner arm 82 defines a series of inner apertures 90, which are aligned
with the outer apertures 88. The inner arm 82 can telescope outward and inward
from within the outer arm 80 along the track 86. When the inner arm 82 is at a
desirable position, which typically depends on the length of the user's limb
being
exercised, the inner arm 82 can be locked in position with a pin 92 inserted
through the outer apertures 88 and the inner apertures 90.
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[0036] Mounted to
a distal end of the inner arm 82 is a load cell 96,
which will be described in further detail herein. The limb coupling member 28
is
coupled to the load cell 96 to mount the limb coupling member 28 to the
actuation arm 26 via the load cell 96. The limb coupling member 28 includes a
first support pad 102 and a second support pad 104. Each of the first and the
second support pads 102 and 104 are mounted to, and can be slidably
positioned along, a support rail 106. Extending from the first support pad 102
is
a first flange 108, and extending from the second support pad 104 is a second
flange 110. The first flange 108 includes a first pin 112, which can be
selectively
inserted in any one of first apertures 114 defined in the limb coupling member
28
to lock the first support pad 102 at a desired position along the support rail
106.
The second flange 110 includes a second pin 116, which can be selectively
inserted in any one of second apertures 118 defined in the limb coupling
member
28 to lock the second support pad 104 at a desired position along the support
rail
106. The first support pad 102 and the second support pad 104 are often
positioned depending on the size of the user's ankle to closely abut and
secure
the ankle therebetween.
[0037] An end plate 120 can be coupled to the limb coupling member
28 to serve as a foot support. The end plate 120 includes a pair of spaced
apart
end plate flanges 122, which are configured to couple with bosses 126
extending
from a rear side of the limb coupling member 28. The end plate 120 can be
removably mounted to the limb coupling member 28 and the exercise device 10
can fully function with or without the end plate 120.
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[0038] With continued reference to Figure 2 and additional reference to
Figure 3, the load cell 96 includes a proximal end 130 and a distal end 132.
Between the proximal end 130 and the distal end 132, the load cell 96 defines
an
aperture 134. The proximal end 130 of the load cell 96 is coupled to the
distal
end 94 of the inner arm 82 in any suitable manner, such as with a series of
fasteners to rigidly couple the proximal end 130 to the inner arm 82. The
distal
end 132 of the load cell 96 is rigidly coupled to the limb coupling member 28
with
a series of fasteners or screws 136. The load cell 96 can be any suitable load
cell, such as model AZL (serial no. NW020231) from Laumas Elettronica of
Italy.
The load cell 96 can be configured for any suitable load, such as 50kg (about
1101bs.). The load cell 96 can be provided with any suitable sensitivity, such
as
about 1.945 mVN.
[0039] In response to force (or pressure) between the user's limb and
the limb coupling member 28, such as at either of the first support pad 102 or
the
second support pad 104, the load cell 96 will bend. For example, and as
illustrated in Figure 3, the distal end 132 of the load cell 96 can bend
relative to
the proximal end 130 from first position A to second position B in response to
force applied to the second support pad 104 by the user when the user flexes
his
or her leg, or in response to pressure exerted against the user's leg by the
actuation arm 26 at the second support pad 104 when the actuation arm 26 is
extending the leg. The distal end 132 may also bend in the opposite direction
to
a third position C, such as when the user applies force to the first support
pad
102 when the user extends his/her leg, or when the actuation arm 26 applies
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force to the user's leg at the first support pad 102 to flex the leg. The
distance
that the load cell 96 bends is proportional to the amount of force or pressure
between the limb coupling member 28 and the limb. The load cell 96 produces
an electrical output via connector 138 representative of the distance that the
load
cell 96 bends, and the amount of force or pressure between the limb coupling
member 28 and the limb.
[0040] With additional reference to Figure 4, internal components of the
case 12 will now be described. The case generally includes a base 140 and an
upper support 142. Mounted at the base 140 is a motor 144, a power supply
146, a controller 148, an inclinometer transmitter 150, a load cell sensor
152, and
a plurality of relays 154. The motor 144 can be any suitable motor for moving
the
actuation arm 26 and for providing resistance to movement of the actuation arm
26 as described herein. For example, the motor can be an Elektrimax 56C
1800RPM 3-phase rolled steel foot mounted motor. The motor 144 is powered
by the power supply 146, which can be any suitable power supply sufficient to
power the motor 144. For example, the power supply can be no. E225775 by
Reign Power Co. Ltd. of Taipei, Taiwan. Controller 148 can be any suitable
controller for controlling operation of the exercise device 10, such as the
FlexiLogics FL 010 and FL A0800A by Renu Electronics PVT, Ltd. of India. The
load cell sensor 152 can be any suitable sensor for receiving inputs from the
load
cell 96, such as Model 4710 Bridgesensor by Calex of Concord, California.
[0041] A suitable connection member, such as a belt or chain 160,
extends from about the base 140 of the case 12 to about the upper support 142.
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The chain 160 can be directly connected to an output shaft of the motor 144,
or
can be connected to an output shaft of gear box 162 at a first gear 164. From
the first gear 164 the chain 160 extends to a second gear 166 at the upper
support 142. The second gear 166 is mounted to the horizontal shaft 84, which
is mounted to the upper support 142. Therefore, the motor 144 drives the chain
160, which in turn rotates the horizontal shaft 84 to rotate the actuation arm
26
mounted to the horizontal shaft 84. The motor 144 can also be configured to
resist movement of the actuation arm 26 unless the user applies a preset force
to
the actuation arm 26. An inclinometer shaft 168 with an inclinometer 170
attached thereto is mounted to the horizontal shaft 84 and rotates with the
horizontal shaft 84. Because the actuation arm 26 is mounted to the horizontal
shaft 84, the incline and degree of rotation of the inclinometer will
correspond to
the position of the actuation arm 26. The inclinometer 170 is connected to the
inclinometer transmitter 150 to convey the position of the inclinometer 170,
and
thus the position of the actuation arm 26 as well, to the controller 148. Any
suitable inclinometer 170 can be used, such as Model 981HE by Vishay
Technology, Inc. of Malvern, Pennsylvania.
[0042] As
illustrated in Figure 1, the actuation arm 26 is configured to
rotate between a maximum extended position 180 and a maximum flexed
position 182 along an arc X (which includes X' and X" as illustrated). At the
maximum extended position 180, the actuation arm 26 will fully extend the
user's
leg, such that both the user's leg and the actuation arm 26 extend about
parallel
to the surface that the case 12 and the seat 14 are seated on. Thus, in the
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maximum extended position the user's leg is at about a 00 angle. In the
maximum flexed position 182, the user's leg will be flexed inward. The arc X
includes an extension arc portion X' and a flexion arc portion X". The
extension
portion X' extends from a neutral position 184, at which the actuation arm 26
is
about perpendicular to the surface that the case 12 is seated on (as
illustrated in
Figure 1), to the maximum extended position 180. In the neutral position the
user's leg is bent at about a 90 angle. The flexion portion X" extends from
the
neutral position 184 to the maximum flexed position 182, which can be about an
additional 35 from neutral position 184, which would position the user's leg
at
about a 135 angle. The range of motion arc X is provided for exemplary
purposes only, and thus the actuation arm 26 can be configured to rotate along
any suitable range. The case 12 can include hard stops for the actuation arm
26,
such as a bar protruding from the case 12, to prevent the actuation arm 26
from
rotating beyond each of the maximum extended position 180 and the maximum
flexed position 182.
[0043] With
additional reference to Figure 5, another exercise device
according to the present teachings is illustrated at reference numeral 202.
The
exercise device 202 includes a case 204, which is generally smaller than the
case 12 of the exercise device 10. The case 204 includes a base 206 with
wheels 208A and 208B mounted thereto. The exercise device 202 is thus a
portable device that can be, for example, delivered to a user's home for home
use. The internal components of the device 202 are similar to the internal
components of the device 10, and thus the same reference numbers are used to
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designate the similar components, and the description of the similar
components
in connection with the description of the exercise device 10 also describes
the
exercise device 202. The exercise device 202 is illustrated as including a
belt
210, but may alternatively include the chain 160 of the device 10, or any
other
suitable torque transfer member. The belt 210 is illustrated at being coupled
to a
first wheel 212 at the gear box 162, but can be connected directly to the
motor
144. The belt 210 is also coupled to second wheel 214, which is coupled to the
horizontal shaft 84 to thereby transfer torque from the motor 144 to the
horizontal
shaft 84 and the actuation arm 26, which is coupled to the horizontal shaft of
the
exercise device 202. Various interior components of the exercise device 202
that
were seated at the base 140 of the case 12 have been moved to an upper
support 240 of the exercise device 202, such as the controller 148, the load
cell
sensor 152, the inclinometer transmitter 150, and the relays 154.
[0044]
Mounted to the belt 210 is a clamp 216. The clamp 216
includes a first plate 218 and a second plate 220, each of which abut opposing
portions of the belt 210. The first plate 218 is connected to the second plate
220
with a spring 224. At least one of the first plate 218 and the second plate
220
can be in the form of a roller. The spring 224 biases the second plate 220
against the first plate 218. Therefore, when the motor 144 stops and the belt
210
stops rotating, the clamp 216 will pull the portion of the belt 210 abutting
the
second plate 220 toward the first plate, which will cause the actuation arm 26
to
rotate away from the base of the case 204 toward the maximum extended
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position 180. The clamp 216 can be included with the exercise device 10,
particularly when the exercise device 10 includes the belt 210.
[0045] With reference to Figure 6, a method, such as a therapy
method, of operation of the exercise device 10, the exercise device 202, or
any
other suitable exercise or therapy device is generally illustrated at
reference
number 302. The method 302 is generally a passive mode in which the user
does not positively exert force or pressure against the actuation arm 26, and
thus
does not contract his/her leg muscles. Rather, it is the actuation arm 26 that
moves the user's leg. The greater the force or pressure exerted by the
actuation
arm 26 against the leg, the further the leg will extend or flex.
[0046] At block 304, therapy parameters are set to customize the
method 302. A variety of different parameters can be set, such as one or more
the following: therapy time, target extension angle, target flexion angle,
start
angle, maximum extension force, maximum flexion force, and hold time. The
parameters can be input using the display 20, which can be a touch screen.
While the maximum extension and flexion forces are generally described herein
in terms of "force," they can also be described in terms of "pressure."
[0047] The
therapy time is typically the total time that the patient's limb
is exercised, such as about 30 minutes. The target extension angle is the
angle
to which the limb is to be extended along the arc X' away from the neutral
position 184 and in the direction of the maximum extended position 180. For
example, if the target is to straighten the leg and move the leg to the
maximum
extended position 180, then the target angle will be 0 . If the target is to
extend
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the leg to about halfway between the neutral position 184, in which the leg is
bent
at about 90 , and the maximum extended position 180, then the target extension
angle will be about 45 . The target flexion angle is the angle to which the
limb is
to be flexed along the arc X" from the neutral position 184 to the maximum
flexed
position 182. For example, if the target is to fully flex the leg, then the
target
flexion angle will be set to about 125 or more. The target extension and
flexion
angles can be determined by assessing the range of motion of the user's leg.
The start angle is the angle along the arc X (which is illustrated as
including arcs
X' and X") that the leg and the actuation arm 26 are desired to be started at.
For
example, if the actuation arm 26 is to start from the neutral position 184,
the start
angle will be about 90 .
[0048] The maximum extension force is the maximum force or
pressure to be applied to the user's leg by the actuation arm 26 as the user's
leg
is extended along the extension arc X' in the direction of the maximum
extended
position 180. The maximum flexion force is the maximum force or pressure to be
applied to the user's leg by the actuation arm 26 as the user's leg is flexed
along
the flexion arc X" in the direction of the maximum flexed position 182. The
maximum extension and the maximum flexion forces can be determined by
assessing the condition of the user's leg, and particularly the amount of
force that
the leg is able to withstand without the user incurring excessive pain. The
hold
time is the amount of time that the actuation arm 26 is to optionally hold the
leg at
the target extension angle, the target flexion angle, the point where the
maximum
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extension force is reached, or the point where the maximum flexion force is
reached.
[0049] After the therapy parameters are set at block 304, the
actuation arm 26 will rotate from the set start angle in either the extension
direction (towards the maximum extended position 180) or the flexion direction
(toward the maximum flexed position 182) to extend or flex the leg at block
306.
If initially moved in the extension direction for example, the actuation arm
26 will
slowly rotate and then slow further to a creep when either the target
extension
angle or the maximum extension force is about to be reached, as set forth at
block 308. By slowing to a creep, excess fluid, such as scar tissue forming
fibroblast fluid, is given the opportunity to exit the knee joint. Once the
target
extension angle or the maximum extension force is reached, the actuation arm
26 will hold the leg in position at block 310, which can further allow excess
fluid
drain from the knee joint, thereby making the buildup of scar tissue less
likely.
After the hold time has expired, the actuation arm 26 will rotate in the
opposite
direction at block 312, such as in the flexion direction (toward the maximum
flexed position 182), until the target flexion angle or the target flexion
force is
reached. As the actuation arm 26 approaches the target flexion angle or the
maximum force, the actuation arm 26 will again slow to a creep and then will
hold
the leg at the preset hold time, to again permit excess fluid to exit the knee
joint.
[0050] With reference to block 314, during operation of the method
302 the target extension and flexion angles, as well as the maximum extension
and flexion forces, can be modified, such as according to the user's progress.
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For example, as the leg is extended and flexed, excess fluid will drain from
the
knee and scar tissue will breakdown thereby increasing the range of motion of
the leg and increasing the amount of force or pressure that the user is able
to
withstand. Therefore, the target angles and maximum force can be increased.
[0051] The maximum
extension and maximum flexion force is
measured with the load cell 96. For example, as the actuation arm 26 moves to
the maximum extended position 180, the second support pad 104, which pushes
the leg upward, applies force, such as pressure, to the user's ankle, which is
between the first support pad 102 and the second support pad 104. The force is
generally applied at a single point in a single direction upward toward the
maximum extended position 180. As the actuation arm 26 moves toward the
maximum extended position 180, more and more force must be applied to flex
the leg, particularly when the range of motion of the leg is limited. If the
leg's
resistance to extension is great enough, the load cell 96 will bend from
position A
to position B of Figure 3. The load cell 96 will transmit the degree of bend
to the
load cell sensor 152 via the connector 138, and ultimately the controller 148.
The degree of bend is proportionate to the amount of force or pressure applied
by the actuation arm 26. Therefore, by monitoring the degree of bend of the
load
cell 96, the controller 148 can determine the amount of force or pressure
applied
by the actuation arm 26 and identify when the maximum extension force is
reached. The flexion pressure is monitored in a similar manner. As the
actuation
arm 26 moves from the neutral position 184, the first support pad 102 will
apply
force or pressure to the ankle, thereby causing the load cell 96 to bend in
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opposite direction to position C. At block 316 the results of the method 302
can
be recorded.
[0052] With reference to Figure 7, another method of operating an
exercise device, such as the exercise device 10 or the exercise device 202 for
example, is illustrated at reference numeral 350. The method 350 is an active
isotonic mode whereby the user contracts muscles of the leg through the entire
range of motion to move the actuation arm 26, which provides resistance and
will
not be permitted to move by the motor unless the user exerts sufficient force
against the actuation arm 26 to reach the extension target force or the
flexion
target force. For example, as the user moves the actuation arm towards the
maximum extended position 180, the quadriceps are exercised. As the user
moves the actuation arm toward the maximum flexed position 182, the
hamstrings are exercised. The actuation arm 26 thus provides resistance to the
user's leg both when the leg is being extended and flexed.
[0053] With initial reference to block 352, the parameters of the
active isotonic therapy are set. The therapy time is the total time of the
method
350. The extension target force is the force that the user must exert against
the
actuation arm 26 to cause the actuation arm 26 to move toward the maximum
extended position 180. The flexion target force is the force sure that the
user
must exert against the actuation arm 26 to cause the actuation arm 26 to move
toward the maximum flexed position 182. The start angle is the position along
the rotation arc X that the actuation arm 26 is to start at. The maximum
extension angle is the maximum distance that the actuation arm 26 is to extend
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along the extension arc X' from the neutral position 184. The maximum flexion
angle is the maximum distance that the actuation arm 26 is to flex along the
flexion arc X" towards the maximum flexed position 182. The maximum
extension and flexion angles are determined by the maximum distance that the
user's leg can be extended or flexed without the user experiencing undue pain.
[0054] With reference to block 354, once the user applies enough force
against the stationary actuation arm 26, particularly against the first
support pad
102, to reach the extension target force as measured by the degree of bend of
the load cell 96, the actuation arm 26 will move toward the maximum extended
position 180. As long as the user continues to exert force at or above the
extension target force, the actuation arm 26 will continue to move toward the
maximum extended position 180. As the actuation arm 26 nears the maximum
extension angle, which may be at the maximum extended position 180 or at any
other position along the extension arc X', the actuation arm may be configured
to
progressively apply resistance force to the user's leg to slow movement of the
actuation arm 26 to a creep, which facilitates drainage of fluid from the knee
and
breaks down scar tissue. The user's quads will be exercised as the actuation
arm 26 is moved along the flexion arc X' in the direction of the maximum
extended position 180.
[0055] With reference to block 356, the user exercises his/her
hamstrings by flexing his/her leg and moving the actuation arm 26 toward the
maximum flexed position 182. The actuation arm 26 will continue to move
toward the maximum flexed position 182 to the maximum flexion angle as long
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as the force exerted by the user is greater than the flexion target force as
measured by the load cell 96. At block 358, the actuation arm 26 will slow
further, such as to a creep, as the target pressure and or maximum angle is
approached. As set forth at block 360, the extension and flexion target force
and
angles can be modified during the therapy method 350. For example, the target
force and angles can be increased as the user's range of motion increases. The
results of the therapy can be recorded at block 362.
[0056] With reference to Figure 8, an additional method of operating an
exercise device, such as the exercise device 10 or the exercise device 202, is
illustrated at reference numeral 402. The method 402 is an active eccentric
method in which the actuation arm 26 moves until the user applies enough force
or pressure to stop the actuation arm 26 or slow the actuation arm 26 to a
creep.
To stop or slow the actuation arm 26, the user must apply force in a direction
opposite to the direction of movement of the actuation arm 26.
[0057] With
initial reference to block 404, therapy parameters of the
method 402 are set. For example, the following exemplary parameters are set:
therapy time, extension target resistance force, flexion target resistance
force,
target hold time, maximum extension angle, maximum flexion angle, and start
angle. The therapy time is the total time of the method 402, such as about 30
minutes. The extension target resistance force is the force that the user must
exert on the actuation arm 26 to stop or slow the actuation arm 26 as the
actuation arm 26 moves toward the maximum extended position 180 to extend
the leg. The flexion target resistance force is the force that the user must
exert
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,
on the actuation arm 26 to stop or slow the actuation arm 26 as the actuation
arm
26 moves toward the maximum flexed position 182. The target resistance force
are measured by the load cell 96. The target hold time is the target period of
time that the user is to apply the resistance forces. The maximum extension
angle is the maximum distance that the actuation arm 26 travels along the
extension arc X' toward the maximum extended position 180. The maximum
flexion angle is the maximum distance that the actuation arm 26 travels along
the
flexion arc X" toward the maximum flexion position 182. The maximum
extension and flexion angles are determined by the maximum range of motion
that the user is able to endure without experiencing undue pain and/or stress.
[0058] At block 406, the user's limb is extended with the actuation
arm
26. Although extension of the limb will be described first, flexion of the
limb with
the actuation arm 26 at block 412 may be performed first. With reference to
block 408, the actuation arm 26 will slow or stop when the user applies force
equal to or greater than the extension target resistance force. The goal of
the
user is to maintain the extension target resistance force for the target hold
time,
which can be displayed on the display 20, such as in the form of a countdown
timer. At block 410, the actuation arm 26 will resume its initial speed when
the
force applied by the user is below the extension target resistance force, and
proceed to the maximum extension angle. As the actuation arm 26 proceeds to
the maximum extension angle, the user will attempt to again apply the
extension
target resistance force at regular intervals. As the actuation arm 26 nears
the
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maximum extension angle, it will slow to a creep and then stop when it reaches
the maximum extension angle.
[0059] After reaching the maximum extension angle the actuation arm
26 will reverse to flex the user's limb, as set forth at block 412. The
actuation
arm 26 will slow or stop when the user applies force equal to or greater than
the
flexion target resistance force, as set forth at block 414. The user will
attempt to
hold the flexion target resistance force for the target hold time. At block
416, the
actuation arm 26 will resume its initial speed when the force applied by the
user
is below the flexion target resistance force, and proceed to the maximum
flexion
angle. As the actuation arm 26 proceeds to the maximum flexion angle, the user
will attempt to again apply the flexion target resistance force at regular
intervals.
As the actuation arm 26 nears the maximum flexion angle, it will slow to a
creep
and then stop when it reaches the maximum flexion angle. At block 418, the
results of the method 402 are recorded.
[0060] The results recorded at blocks 316, 362, and 418 can be used
to track the user's progress, and to customize future therapy or exercise to
best
suit the user. The results can also be conveyed to a therapist, doctor, or
other
healthcare provider, such as via the Internet, so that the healthcare provider
can
monitor the patient's progress remotely.
[0061] Each of
the exercise devices 10 and 202 can be configured to
provide any one or more of the methods 302, 350, and 402. For example the
portable exercise device 202 could only include the passive method set forth
at
302, such as to reduce costs.
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[0062] The exercise devices 10 and 202, as well as the methods 302,
350, and 402 can be modified in any suitable manner to exercise and/or
rehabilitate any joint or limb, including but not limited to an elbow, a
shoulder, a
hip, an ankle, a neck, fingers, toes, arms, etc.
[0063] The exercise devices 10 and 202, and the methods 302, 350,
and 402 can be included not only in a physical therapy device to rehabilitate
a
total knee replacement, for example, but can also be included in an exercise
machine found in a gym or workout area to be used to increase strength and
stamina. For example, the methods 302, 250, and 402 can be implemented in
any exercise machine with an actuation arm, such as by outfitting the exercise
machine with the load cell 96 on the actuation arm and including with the
machine the motor 144, inclinometer 170, controller 148, power supply 146, and
other components of the exercise devices 10 and 202.
[0064] An exemplary exercise device is illustrated in Figures 9A and
9B in the form of a bench press at reference numeral 502. The bench press 502
generally includes vertical supports 504 and a crossbar 506 extending
therebetween. Mounted to the crossbar 506 is a control module 508. The
control module 508 includes the motor 144, the power supply 146, the
controller
148, the inclinometer 170, and the load cell sensor 152 for receiving inputs
from
the load cell 96. Each of these components is generally similar to those
described above with the same reference numbers. While the control module
508 is illustrated as mounted to the crossbar 506, one or more components of
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the control module 508 can be positioned elsewhere, such as on a floor
proximate to the bench press 502.
[0065] The motor 144 is configured to resist movement of actuation
member 510 between the first position of Figure 9A and the second position of
Figure 9B, as well as resist movement between the second position and the
first
position, such as according to the method 350 of Figure 7. The actuation
member 510 is illustrated as a bar with a vertical portion 512 extending
therefrom. The vertical portion 512 is in cooperation with the control module
508
and the motor 144.
[0066] The load cell 96 is positioned at any suitable location to be
able to sense the force applied to the actuation member 510 by a user seated
on
or lying on seat 514, such as on the actuation member 510 itself. For the user
to
move the actuation member 510 from the first position of Figure 9A to the
second
position of Figure 9B, the user must pull on the actuation member 510 and
apply
sufficient force as measured by the load cell 96 to overcome a first target
force
entered into the control module 508, such as via the display 20 mounted at or
near the bench press 502. When the actuation member 510 is pulled proximate
to a first target distance, the resistance provided by the motor 144 can be
increased to slow movement of the actuation member 510, such as to a creep,
which will enhance working of the user's muscles. When the actuation member
510 reaches the first target distance, the motor 144 will prevent the
actuation
member 510 from moving further. The user can then return the actuation
member 510 to the first position of Figure 9A by pushing upward and applying
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enough force, as measured by the load cell 96, to reach or overcome a second
target force. The motor 144 will allow the actuation member 510 to be moved
upward to the first position of Figure 9A as long as the user applies force
equal to
or greater than the second target force. As the actuation member 510 nears the
second target distance of Figure 9A, the resistance provided by the motor 144
can increase to slow movement of the actuation member 510, such as to a
creep, which will enhance working of the muscles. Although the actuation
member 510 is illustrated as an actuation bar for a bench press, the actuation
member 510 can be any suitable actuation member for working any suitable
body part, such as an actuation plate for a leg press.
[0067] The exercise devices 10 and 202, as well as the methods
302, 350, and 402 differ in a number of ways from prior rehabilitation and
strength building techniques, such as continuous passive motion machines. With
respect to the passive mode 302 for example, by fixing the force applied by
the
actuation arm 26 below the patient's pain tolerance, excessive pain and
further
strain on the joint can be avoided while allowing the body to naturally
increase
range of motion, such as by breaking down scar tissue and allowing excess
fluid
to drain from the knee. The maximum flexion and extension force can be
increased during the therapy, and the maximum extension and flexion angles can
be set outside of the user's natural range of motion to enable a natural,
progressive increase in the patient's effective range of motion without
exceeding
the patient's pain threshold, which can result in greater lasting range of
motion
improvements.
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[0068] Because continuous passive motion machine therapy is
limited in its ability to increase range of motion, total knee replacement
rehabilitation is often performed using manual manipulation ¨ one-on-one with
a
licensed physical therapist. The exercise device 10 and 202 described herein,
as
well as the methods 302, 350, and 402, provide more precision and control than
manual manipulation, and require less direct intervention on behalf of a
therapist,
which provides an efficient and effective way to rehabilitate patients in an
inpatient and outpatient setting while enabling significant labor productivity
gains.
[0069] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not intended to
be
exhaustive or to limit the disclosure. Individual elements or features of a
particular embodiment are generally not limited to that particular embodiment,
but, where applicable, are interchangeable and can be used in a selected
embodiment, even if not specifically shown or described. The same may also be
varied in many ways. Such variations are not to be regarded as a departure
from
the disclosure, and all such modifications are intended to be included within
the
scope of the disclosure.
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