US20090017995A1

US20090017995A1 - Knee manipulating device

Info

Publication number: US20090017995A1
Application number: US11/777,658
Authority: US
Inventors: Richard A. Freiberg
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-07-13
Filing date: 2007-07-13
Publication date: 2009-01-15

Abstract

A device for exercising and manipulating a knee after reconstructive knee surgery has a seating portion and an angled bar pivotally coupled to the seating portion. A leg pad is provided at one end of the angled bar and a handle is provided at the other end. Manipulation of the handle rotates the angled bar through a pivot axis to move the leg pad and thereby manipulate or exercise the knee.

Description

TECHNICAL FIELD

This invention is a medical device designed to improve the mobility of the adult knee following reconstructive surgery of the knee.

BACKGROUND

After major knee operations, principally total knee replacement, regaining knee mobility is of primary importance. Customarily, this is a rather prolonged process. A physiotherapist instructs the patient to bend and straighten his knee, and, ordinarily assists in this process manually. The foremost goal in this process is to gain full knee straightening (extension), as this is required for patients to walk properly. Of almost equivalent importance is regaining knee bending (flexion) as this is necessary to allow patients to ascend and descend steps, sit properly with the knee bent appropriately, and to rise from the sitting position.
There are many existing devices for carrying the knee through its range of motion which includes flexion and extension and which are primarily designed to increase muscle power and flexibility. These are commonly used in gyms and are not useful for patients recuperating from rehabilitative knee surgery as they are large, prohibitively expensive, and involve applying high levels of force to the knee.
There are also devices designed specifically for post-operative use to regain flexion and extension after reconstructive knee surgery. These are generally referred to as continuous passive motion machines (CPM) and are applied to the supine patient following surgery. These machines are expensive, provoke pain during use, and are heavy and not readily transportable. There are also devices as described in U.S. Pat. No. 4,784,121 to Brooks that are patient controlled and designed to be used in a sitting position. The device of Brooks, however, does not fully straighten the knee. There remains a need for a device that overcomes these and other drawbacks of the prior art and provides an effective tool for mobilizing the post-operative knee after reconstructive surgery.

SUMMARY

In one embodiment, a device for patient powered manipulation of the knee includes a seating platform to be positioned on a chair. A mounting bar is attached to the platform, this bar having a pivot axis. The location of the pivot axis is adjustable so that it conforms to the length of the patient's thigh. An angled bar is rotatably coupled to the mounting bar at the pivot axis, the angled bar having a hand grasp at its upper end and a leg contact pad at its lower end. The position of the leg contact pad is adjustable along the lower end of the angled bar to fit the length of the patient's leg, and a portion of the leg contact pad can rotate to roll along the patient's leg to reduce the friction effect on the patient's skin where the leg contact pad engages the leg. This device can be configured to accomplish both knee flexion (bending) and knee extension (straightening) depending on the position of the leg pad in front of or behind the shin, respectively. The patient pushes on the handle to accomplish knee flexion or pulls on the handle for knee extension. A thigh strap holds the thigh to the seating platform so that full knee extension is possible. These and other features and advantages of this invention will be displayed and become more readily apparent in the following accompanying drawings. Detailed description of the principles and features of this invention will follow.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of one embodiment of a knee manipulation device in accordance with the present disclosure.

FIG. 2 is an exploded perspective view of a component of the device shown in FIG. 1.

FIG. 2A is an elevation view illustrating a range of motion of the component shown in FIG. 2.

FIG. 3 is a perspective detail view of a portion of the device of FIG. 1.

FIG. 4 is a partial elevation view of the device of FIG. 1, illustrating adjustability of a mounting bar.

FIG. 5 is a partial perspective view of a leg pad of the device of FIG. 1.

FIG. 6 is an elevation view illustrating use of the device of FIG. 1 to extend (straighten) a leg.

FIG. 7 is an elevation view illustrating use of the device of FIG. 1 to flex (bend) a leg.

DETAILED DESCRIPTION

FIG. 1 depicts one embodiment of a knee manipulating device 10. A seating platform 12 is made from rugged molded plastic to support the weight of a user, with a top surface 14 and bottom surface 16, a forward edge 20, a back edge 18, and side edges 22 and 24. A centerline 26 extends along the seating platform 12, generally between the side edges 22, 24. The bottom surface 16 has appropriate surface texturing to allow the seating platform 12 to be stable on a surface such as a chair. The top surface 14 is contoured to allow stable and comfortable seating on the seating platform 12.
A receptacle 28 molded into the seating platform 12 extends upward from the top surface 14 and is aligned with the centerline 26. The receptacle 28 is open at one end 30 and is closed at an opposite end 32 to enhance the rigidity of the receptacle 28. However, alternatively, end 32 may be partially or fully opened if rigidity were provided by other rigidity enhancing features such as gussets or increased wall thickness of receptacle 28. End 30 is open at its lower end so that the motion of angled bar 50 is not restricted in flexion and extension. Receptacle 28 has an internal channel 34 with a rectangular cross section. A series of holes 38 is arrayed along the top surface 36 of the receptacle 28. The holes 38 extend from the outside surface of receptacle 28 to the internal channel 34.
A mounting bar 40, made of rectangular tubing in this embodiment, is inserted into internal channel 34 and extends forward from the seating platform 12. The mounting bar 40 has a rectangular cross section slightly smaller than the cross section of channel 34, so that the mounting bar 40 and the channel 34 have a sliding fit. The matching rectangular shapes of channel 34 and mounting bar 40 prevent rotation of the mounting bar 40 and provide a sufficiently large surface area to distribute torque that may be applied to the mounting bar 40 during its intended use, as will be described below. One end 41 of the mounting bar 40 has a hole 42 (FIG. 4) on its top surface. By aligning hole 42 with one of the series of holes 38 on receptacle 28, and inserting a pin 44 into the aligned holes 38, 42, the extended length L1, L2, (FIG. 4) of the mounting bar 40 may be adjusted to the size of a patient using the device 10. As an alternative to the above adjustment feature of mounting bar 40, the series of holes 38 along a top area 36 of receptacle 28 may be replaced with a single hole, and the end 41 of mounting bar 40 may include a plurality of holes for selective alignment with the hole in receptacle 28 to facilitate adjustment of mounting bar 40 in a manner similar to that described above. It will be appreciated that various other hardware, such as for example, clamps, screws, telescoping ratchet or collet assemblies, or other devices suitable to adjustably couple mounting bar 40 relative to seating platform 12 may alternatively be used.
Mounting bar 40 has a pivot axis 48 (FIG. 2) where it attaches to an angled bar 50. In this embodiment angled bar 50 is also made of rectangular tubing, although a solid rectangular bar, or a tube or bar of other cross sectional shape, could alternatively be used. Angled bar 50 comprises first and second portions 51, 53 disposed at an angle α relative to one another. In the embodiment shown angle α is about 135 degrees. In this arrangement the device can provide both full extension and full flexion of a patient's leg for therapeutic purposes, as demonstrated in FIGS. 6 and 7. While this embodiment utilizes an angle α of approximately 135 degrees, angles ranging between approximately 120 and approximately 150 degrees may also be used.
A strap 80 is made of one piece of VELCRO® type material. This material has a surface with hooks and a surface with loops. The loops surface is secured with screws and washers (not shown) against the bottom surface 16 of the seating platform 12. The contour and recesses of bottom surface 16 are such that the screw heads and strap do not bear the load of the patient's weight, and thereby forcefully contact and damage a surface such as a chair. Although this strap 80 is one piece of material, uniformly covered with hooks and loops, it will be understood that various other configurations for this strap, and methods of attachment, can be used. For example the strap could be two pieces, and have hooks and loops only on specific areas. Alternatively, buckles snaps, or other fastening devices could be used instead of hooks and loops. Fastening to seating platform 12 can be by any suitable method such as riveting, bonding, or molding within the structure of the seating platform 12.
With reference to FIGS. 2 and 2A, the attachment of mounting bar 40 to angled bar 50 is accomplished by aligning hole 52 through the mounting bar 40 with a hole 54 through the angled bar 50. A roll pin 56 inserted through holes 52 and 54 couples the bars 40 and 50 and keeps them aligned. The roll pin 56 is just one option for coupling mounting bar 40 and angled bar 50 at pivot axis 48. It will be understood that various other devices, such as for example cylindrical roller bearings or bushings, or other devices suitable to rotatably couple the two bars may alternatively be used. Mounting bar 40 has a notch 58 on its top surface and a notch 60 on its bottom surface. In the embodiment shown, these two notches 58, 60 allow the angled bar 50 sufficient rotational excursion to permit full movement, as seen in FIG. 2A, corresponding with flexion and extension of a leg, as seen in FIGS. 6 and 7. In the fully assembled device 10, the area near the notches 58, 60 is isolated by appropriate pinch guards 62 and 63 (FIG. 3). Pinch guard 62 is attached to and rotates with angled bar 50 and is shaped to pass through notches 58, 60 in mounting bar 40. The clearance space between mounting bar 40 and guard 62 is very small to prevent objects such as fingers from entering. Two guards 63 are attached to device 10, one on each side of mounting bar 40. Pinch guards 63 remain stationary relative to mounting bar 40 while angled bar 50 passes between them.
With reference to FIGS. 1 and 2, angled bar 50 has a hole 64 (FIG. 2) to which a handle 66 can be fitted and held, such as by a fastener pin 67. Handle 66 is preferably padded and able to be gripped by both hands of a patient. In the embodiment shown, handle 66 has a small diameter so that it does not prematurely contact a patient's legs or abdomen and thereby prevent the device from moving through its full range of motion as shown in FIGS. 6 and 7. It will be appreciated that handle 66 may alternatively comprise various other structure and configurations. For example, handle 66 could comprise a strap that could be used pulling, but not for pushing.
As seen in FIG. 5, the lower end 55 of the angled bar 50 has a series of holes 68 to facilitate adjustment of a leg pad 70 according to the length of a patient's shin. The leg pad 70 comprises a hard, plastic, cylindrical axle 75 surrounded by a cylindrical plastic bushing 76 covered by a cylindrical foam pad 78. The bushing 76 and foam pad 78 are retained on the cylindrical axle 75 by a retainer 79 attached to one end 73 of the axle 75. On the other end 77 of the axle 75 is channel 74 that includes a retained and spring-loaded pin 72. The leg pad 70 can be selectively positioned along the angled bar 50 by extracting pin 72 from one of the holes 68 and then sliding leg pad 70 up or down the angled bar to a new hole 68. Leg pad 70 may also be fully removed from the angled bar 50 by extracting the pin 72 from the holes 68 and sliding the leg pad 70 off the angled bar 50. The leg pad 70 can then be rotated (as shown in phantom lines 70 a) and reassembled for use on the opposite side of angled bar 50 for use with a patient's other leg. Although this embodiment uses a retained spring-loaded pin 72 and a series of holes 68, it will be appreciated that various other fastening hardware, for example, nuts, bolts, and clamps, may be used to attach the leg-engaging pad 70 at a variety of positions on the lower component of the angled bar 50.
In use, the bushing 76 on cylindrical axle 75 permits easy rotation of the cylindrical foam pad 78. This arrangement reduces any chafing or discomfort that might be encountered when the leg pad 70 travels up and down a patient's leg as the device 10 is used to mobilize and manipulate the knee.
FIG. 6 depicts use of the device 10 to extend the knee, as shown by the arrow in the figure. The patient places the device 10 on a surface, usually a chair 81, sufficiently high to allow the knees to flex fully without the patient's feet being constrained by the floor. The leg pad 70 is positioned on the side of the angled bar 50 towards the leg having the knee to be manipulated. The patient sits on the seating platform 12 with the receptacle 28 and the mounting bar 40 situated between the thighs. The mounting bar 40 is adjusted so that the pivot axis 48 is approximately aligned with the axis of rotation of the knee to permit maximum application of torque through the knee when the device 10 is used. The patient straps the leg to be exercised in extension to the seating platform 12 by taking both ends of strap 80 and connecting them together such that the loop portion, being relatively smooth, contacts the patient's leg while the hook portion, being relatively rough, does not make contact with the patient's leg. This strap 80 constrains the thigh so that, when force is exerted to extend the knee, the knee straightens rather than the thigh coming off of the seat 12. As seen in FIG. 6 the leg pad 70 is placed behind the shin. The patient pulls on the handle 66 to straighten the knee. The primary purpose of the use of the device 10 in extension mode is passive extension of the knee, motivated by the patient's arms. The patient is in full control of the device and can exert force to move his knee up to his own tolerance of discomfort. In the early phases of the patient's rehabilitation, a physiotherapist can assist the patient by pushing on the handle 66 in addition to the pulling effort of the patient. After the physiotherapist has shown the patient how to use the device 10 in this manner, a family member can be instructed to assist the patient similarly to gain extension more rapidly. Later in the rehabilitation process the patient may move the leg pad 70 to in front of the shin, and may use his hands to resist active (thigh muscle motivated) extension of the knee to thereby strengthen the knee extending muscles. The unique angle α of the angled bar 50 coupled with securing the thigh to the seating platform 12 using the strap 80, allows the leg to be fully straightened before the handle 66 reaches the abdomen or thighs, yet the angle α is not so small that the user is unable to reach the handle 66 to initiate extension.
FIG. 7 depicts the use of the device 10 for accomplishing knee flexion. In this mode, the leg pad 70 is positioned in contact with the front of the shin. The mounting bar 40 is again adjusted so that pivot axis 48 is approximately at the axis of rotation of the knee. To flex the knee, the patient pushes forward on the handle 66. The primary purpose of the use of the device 10 in flexion mode is passive (motivated by the patient's arms) flexion of the knee. The patient is in full control of the device 10 and can exert force to flex his knee up to his own tolerance of discomfort. In the early phases of the rehabilitation, a physiotherapist can assist the patient by pulling on the handle 66 in addition to the pushing effort of the patient. After a physiotherapist has shown the patient how to use the device 10 in this manner, a family member can be instructed to carry out the same assistive measures to gain flexion more rapidly. The unique angle α of the angled bar 50 allows the knee to be fully flexed without exceeding the reach of the patient.
The device 10 can also be used as an exerciser for the muscles that straighten the knee (knee extensors) and flex the knee (knee flexors). The patient may use his hands on the handle 66 to resist active (thigh muscle motivated) extension of the knee which allows for strengthening of the knee straightening muscles. This may be important in the later phases of rehabilitation in which strength is needed for walking, and in particular, in ascending and descending steps. Further, the device 10 can be utilized as an exerciser for the muscles that bend the knee (knee flexors). The patient uses his hands on the handle 66 to resist active (hamstring muscle motivated) flexion of the knee which allows for strengthening of the knee bending muscles. This also is of significance later in the rehabilitation process.
The embodiment shown and described herein has been made from hollow tube of rectangular cross section which is one type of a non-circular cross section that could be used. A similar device could be constructed from circular tubing; however, rectangular cross sections or other non-circular cross sections provide an abundance of surfaces to resist twisting motion on the angled bar 50 and mounting bar 40 which could cause loosening or breakage or otherwise impair the use of the components.
The embodiment shown and described herein has included notches 58, 60 in the top and bottom surfaces of mounting bar 40 so that the angled bar 50 can rotate within the mounting bar 40. However, one skilled in the art could achieve appropriate rotatable coupling between the mounting bar 40 and the angled bar 50 in a variety of ways with a variety of materials that are within the scope of this invention. For example, hinges could be used where the two bars 40, 50 rotatably couple. As another example, instead of hollow tubing, solid bars could be used and then the angled bar 50 could sit beside the mounting bar 40, and appropriate offsets in the seat 12, receptacle 28, or bars 40, 50 would provide for the comfort of the patient.
While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art, including substitution of materials, shapes, and attachment options. Some other options contemplated but not shown are to build the device into a chair or similar seating arrangement, and/or to provide a backrest. Also, although the mounting bar 40 and angle bar 50 are shown in their shortest versions possible with the bars only long enough to position the end holes 42, 52, 64, and 68 where they are required, the bars could also be longer than shown. The invention in its broader aspects is not limited to specific details, representative apparatus, and method and illustrative examples shown and described. Various features described herein may be used alone or in any combination. Accordingly, departures may be made from such details without changing the general inventive concept.

Claims

1. A device for manipulating the knee comprising:

a seating portion;

a mounting bar coupled to said seating portion to extend between the legs of a person on said seating portion, said mounting bar extending forward from said seating portion and having a pivot axis, said mounting bar adjustably attached to said seating portion such that said pivot axis can be approximately aligned with the user's knee;

an angled bar rotatably coupled to said mounting bar at said pivot axis, said angled bar having an upper component above said pivot axis and a lower component below said pivot axis;

a handle attached to said upper component of said angled bar; and

a leg engaging pad attached to said lower component of said angled bar;

wherein said device extends the knee of the user to a substantially straight orientation when the user sits on said seating portion and pulls on said handle.

2. The device of claim 1, wherein said angled bar presents an angle between said upper component and said lower component in the range of approximately 120 degrees to approximately 150 degrees.

3. The device of claim 2 further comprising:

a receiver on said seating portion, said receiver having a plurality of holes;

at least one aperture in said mounting bar;

a pin sized to be received by a selected one of said plurality of holes and a selected one of said apertures in said mounting bar to adjustably attach said mounting bar to said seating portion.

4. The device of claim 2 further comprising:

a receiver on said seating portion, said receiver having at least one hole;

a plurality of apertures in said mounting bar;

a pin sized to be received by a selected one of said plurality of apertures in said mounting bar, and a selected one of said holes in said receiver, to adjustably attach said mounting bar to said seating portion.

5. The device of claim 1 wherein said angled bar presents an angle between said upper component and said lower component of about 135 degrees.

6. The device of claim 1, wherein said leg engaging pad is adjustable to be located on one of oppositely facing sides of said lower component for engaging either leg of the user.

7. The device of claim 1, wherein said leg engaging pad is adjustable along said lower component of said angled bar to conform to a length of the user's leg.

8. The device of claim 1, wherein said leg engaging pad comprises an axle and a foam pad overlying said axle, said foam pad rotatably coupled to said axle.

9. The device of claim 1, further comprising a strap coupled to said seating portion for securing at least one of said user's legs to said seating portion.

10. The device of claim 1, wherein said handle is attached proximate an end of said upper component of said angled bar.

11. The device of claim 1, wherein said pivot axis is proximate an end of said mounting bar.

12. The device of claim 1, further comprising at least one pinch guard proximate said pivot axis.

13. A device for manipulating the knee comprising:

a seating portion having a centerline, a forward edge, a receiver on top of said centerline proximate said forward edge, said receiver having at least one receiver hole;

a first pin sized to be received into said receiver hole;

a mounting bar having a first end with at least one first hole, and a second end, said mounting bar slidable in said receiver such that said first hole in said first end can be aligned with said receiver hole in said receiver and said first pin can be inserted through a selected receiver hole in the receiver and a selected first hole, said mounting bar extending forward from said seating portion so that said second end is exterior to said receiver;

an angled bar rotatably coupled to said second end of said mounting bar, said angled bar having an upper component and a lower component disposed at an angle of approximately 120 degrees to approximately 150 degrees to said upper component, and further comprising a handle on said upper component, and a leg engaging pad on said lower component;

whereby a user's knee is manipulated by the user when said handle is pushed or pulled when the user's leg is in contact with said leg engaging pad.

14. The device of claim 13, wherein said angle is about 135 degrees.

15. The device of claim 13, further comprising a second pin, a hole in said second end of said mounting bar sized to receive said second pin, and a hole in said angled bar adapted to rotate around said second pin to rotatably couple said angled bar to said mounting bar.

16. The device of claim 13, wherein said mounting bar has a non-circular cross section.

17. The device of claim 16, wherein said cross section of said mounting bar is rectangular.

18. The device of claim 13, wherein said mounting bar comprises a hollow tube of rectangular cross section, said mounting bar further comprising a top notch and a bottom notch proximate said second end to allow said upper component of said angled bar and said lower component of said angled bar to rotate about said pivot axis within said hollow tube.

19. The device of claim 13, wherein said leg engaging pad is adjustable along said lower component of said angled bar.

20. The device of claim 19, wherein said lower component of said angled bar further comprises a plurality of holes, and said leg engaging pad further comprises a retained pin sized to engage said plurality of holes, and a spring biased to engage said retained pin in said plurality of holes.