GB2201353A - Exercising apparatus - Google Patents

Abstract

Apparatus for flexing a joint of a patient comprises a frame; an electric motor 17 mounted in the frame and having a crank to which is connected a cord 27 which hangs from the free end of the arm 15 and carries a sting 31 through which a patient can pass a limb. Control of the operation of the apparatus is provided by a speed controller which allows adjustment of the flexing cycle. Preferably, the frame includes a base 10, a column 14 and a laterally-projecting arm 15. The location at which the cord depends from the arm may be varied, as may the range of movement of the sling. <IMAGE>

Description

SURGICAL APPARATUS This invention relates to apparatus adapted to cause flexing of a joint of a human patient, for example following surgery or damage to the joint.

Traditionally, when a joint between two limbs has suffered trauma, such as may occur during surgery involving the joint or through accident damage, it-has been the practice to immobilise the joint whilst the healing process takes place. In recent years, however, it has been established that in many cases the healing process may be promoted if the joint is constantly moved in a cyclic fashion through a limited angle and at a relatively slow rate, but at the same time taking care so as not to cause the patient undue discomfort.

As a result of recent studies on the rate of healing of joints when subjected to such cyclic movement, there have been designed various apparati adapted specifically to impart a controlled movement to a joint previously subjected to trauma. Typically, such apparati have two portions adapted to be connected with the limbs or other body-parts to each side of the joint to be flexed and a system of links and levers interconnected to a drive mechanism so that the two portions are moved relatively, so leading to controlled flexing of the joint. For example, one particular design of apparatus adapted to flex the knee joint of a patient has a first portion-for receiving the patient's thigh and a second portion for receiving the patient's lower calf and foot, the two parts being mounted on a frame with the second portion being slidable relative to the first.A motor-driven screwed rod has a nut connected to the second portion whereby rotation of the screwed rod in one sense causes the angle between the two portions (and hence of the patient's knee joint) to increase, and in the other sense, to decrease. The rate of rotation of the screwed rod governs the rate of angular movement of the knee joint and the period of rotation of the rod in each sense controls the range of angular movement of the joint. Other similarly complex apparati have been designed for causing controlled flexing movement of other joints, including hip joints and the fingers.

The just-described apparatus has been shown to give good results from the patient's point of view, in that healing of a joint is much promoted by the use of the apparatus, and in general recovery of joint movement and strength may be more complete. The apparatus is however complex and so both costly to manufacture and less than wholly reliable in operation, so requiring frequent maintenance. Moreover, since the frame and the several moving parts have to be placed on the bed occupied by the patient, it is possible for the bed clothes to become entangled in the moving parts, so jamming the machine operation.

A further characteristic of known joint-flexing apparatus such as has been described above is that the joint is forcibly flexed according to a predetermined regime. Should a patient find that the movement generated by the machine is uncomfortable, he must take positive action to turn off the machine; once done, he still cannot move his limbs to a more comfortable position until released from the machine, typically by undoing retaining straps.

It is a general object of this invention to provide apparatus able to cause flexing of a patient's joints, but which largely reduces the disadvantages of known such apparatus, as discussed above. An aim of the invention is therefore to provide relatively simple apparatus, both in its construction and operation, and which does not forcibly flex a joint even against a patient's wishes, until switched off.

Accordingly, this invention provides apparatus for flexing the joint of a patient, which apparatus comprises a frame adapted to extend above the joint to be flexed, a sling for cradling a limb or joint region of the patient which sling is suspended by a flexible tension member from the frame, drive means for cyclically raising and lowering the sling by alternately and repeatedly pulling and releasing said tension -member, and control means to permit adjustment of both the cycle time and the range of movement of the sling.

The apparatus of this invention particularly lends itself to the flexing of a major joint of a human body that is, one of the shoulder or elbow joints, or one of the hip or knee joints. To use the apparatus, it is positioned so that the frame extends over the patient above the region from where the joint is to be flexed ana then the sling is passed round a limb or joint, as appropriate to cause flexing movement of the required joint, on raising and lowering of the sling. For example, in the case where a knee joint is to be flexed, the sling may be passed immediately around the knee joint; if it is the hip joint which must be flexed, then the sling may be passed either under the knee joint, or adjacent the ankle.Then, when the machine is set in operation, the raising of the sling by the drive arrangement pulling on the flexible tension member causes angular movement of the joint, but releasing the tension member permits the return movement of the joint under gravitational forces. Thus, the patient may easily prevent flexing movement if he wishes - in the case where the sling is positioned around the knee joint, all the patient has to do is resist the downward movement of his knee joint, for example by resisting the sliding movement of his foot on the bed, so keeping the knee joint in a raised position.A patient may similarly maintain any other limb being treated in its lifted position - for example by temporarily resting the limb on a raised support which may be provided for that purpose - so easily over-riding the flexing movement of the apparatus, without having to inhibit the operation of the apparatus itself.

Most preferably, the frame of the apparatus includes a wheeled base from which upstands a column having a laterally-projecting arm disposed at a height considerably greater than that at which the patient will lie on a bed. For stability purposes, it is preferred for the column to upstand from a side region of the base and for the arm then to project in a direction which overlies the base, so that the base may be wheeled to be disposed largely under the patient's bed but with the column upstanding beside the bed edge. The arm then will extend over a patient lying in the bed, so permitting the location of a joint or limb in the sling.

Advantageously, the drive means includes an electric motor disposed within a suitable housing on the base of the apparatus, the flexible tension member passing over rollers or pulleys provided in both the arm and the column as appropriate for connection with the drive means. Conveniently, the electric motor is drivingly coupled to a variable-throw crank mounted with its axis horizontal, the flexible tension member being connected to that crank and being arranged so that upon operation of the motor, the sling will cyclically be raised and lowered.The throw of the crank may be altered by adjusting the point at which the tension member is connected to the crank, for example by providing a plurality of threaded holes extending through the crank, a hole at an appropriate radius being selected to receive a bolt to which the tension member is coupled having regard to the required range of movement of the sling. In this way, for a constant crank rotational movement speed, the speed of movement of the sling may be varied along with the range of movement thereof.

The control means should include at least a speed controller for the drive means so permitting ready adjustment of the cycle time for raising and lowering the sling. Advantageously, a constant current speed controller is used, so that the drive means may operate with a substantially constant power output though at a variable speed. Preferably the control means also includes an overload trip, so as to ensure the drive means will be shut down if undue resistance to operation is encountered. Moreover, a more sophisticated control means may include a timer, permitting for example periods of operation alternating with periods of rest and in such a case, the duration of both periods should separately be selectable, so as to enable the optimum conditions to be obtained for any given joint being treated.Also, a remote on/off control may be provided for the patient, to allow him to stop operation of the apparatus should he so desire.

By way of example only, one specific embodiment of joint flexing apparatus constructed in accordance with this invention will now be described in detail, reference being made the accompanying drawings, in which: Figure 1 is a general isometric view of the embodiment of joint-flexing apparatus; Figure 2 is a detailed sectional view of the drive unit employed in the apparatus of Figure 1; Figure 3 is a vertical sectional view through the apparatus of Figure 1; Figure 4 is a partial view showing the use and operation of the apparatus; Figure 5 is a detailed view of a first modification to the arm of the apparatus of Figure 1; and Figure 6 is a detailed view of a second, alternative modification to the arm.

Referring initially to Figures 1 to 3, the apparatus for flexing a joint of a patient and constructed in accordance with this invention comprises a base plate 10 provided with wheels 11, the pair of which nearer front edge 12 of the base plate are arranged to have a castering action and also are provided with releasable locks able to prevent the rotation thereof. Mounted on the base plate 10 adjacent the rear edge 13 thereof is a hollow column 14, upstanding generally vertically and provided at its upper end with a hollow arm 15 projecting forwardly over the base plate 12. The column 14 has such a height that the arm 15 will be typically 1 m. above a patient lying on a bed, when the base plate 10 has been wheeled to a position under the bed and with the column 14 adjacent the bed edge.

Mounted on the base plate 10 adjacent the column 14is a housing 16, within which is disposed an electric motor 17 together with an integral reduction gear unit and having an output shaft 18. Keyed to the shaft is a crank 19, the crank having five threaded holes 20 into any one of which may be screwed a bolt 21 having a stirrup 22 journalled thereon. A shaft 23 is carried by the stirrup 22 and has a pulley 24 rotatably mounted thereon.

Disposed within the arm 15 and adjacent the free end thereof is a pulley 25, and a further, similar pulley 26 is mounted within the column 14 adjacent its junction with the arm 15. A cord 27 passes over pulley 25, pulley 26 and then around pulley 24 carried by the stirrup 22; from there, the cord passes round a further pulley 28 also mounted within the column14, and the end of the cord 27 is then made fast to the stirrup 22, as best seen in Figure 2. The end of the cord 27 hanging down from pulley 25 is made fast to a ring 30, a sling 31 comprising a loop of broad soft fabric having at its ends releasably connected to a ring 30.

A hinged flap 32 is mounted on a side face of the column 1 4 so as to permit access to the crank 1 9 and the bolt 21, and the top face of the housing 16 is provided with an on/off switch 33 and a speed control knob 34, for the motor 17.

Figure 4 shows the apparatus in use, with a patient 35 sitting on a bed 36 and with the sling 31 passing under the left knee joint of the patient.

Operation ratio of the motor 17 then will cause the sling cyclically to be raised and lowered, as shown by arrow 'A'. During this, the patient's knee and hip joints will be flexed, the patient's heel sliding along the bed 36, during such flexing motion. A sock of soft fleecy material may be provided on the patient's foot and a smooth board on the bed, to minimise friction between the patient's heel and the bed; in addition a smooth board may be placed on the bed further to reduce the friction, if required.

It will be appreciated that though the knee joint is raised as the sling is lifted by the force of the motor, descent of the joint is under gravity and such descent easily may be resisted by the patient at any time, merely by preventing his heel sliding along the bed 36. Thus, without the patient having to operate any motor controls, the patient may inhibit flexing of his joints by the apparatus, or he may limit the range of movement of the joint. The gravitational effect may be increased by adding weights to the sling, in the case of a patient having a particularly stiff joint.

Figure 5 shows a modified form of arm to replace arm 15 shown in Figures 1 to 4. Arm 40 illustrated in Figure 5 has a first part 41 rigidly connected to the column 14 and a second part 42 telescopically arranged with respect to the first part 41. A thumb-screw 43 permits locking of the two parts at a desired relative setting. It will be appreciated that this modification assists in the positioning of the sling directly over a patient's limb to be moved, whilst still enabling the base 10 to be largely located beneath a bed.

Figure 6 shows another alternative form of arm, where the whole of the arm 45 is fixed, but the shaft 46 on which is journalled pulley 25 may be moved to any one of three pre-set positions, defined by cut-out portions 47 in the arm. Again, this assists the positioning of the sling, as has just been described above.

Claims (12)

1. Apparatus for flexing the joint of a patient, which apparatus comprises a frame adapted to extend above the joint to be flexed, a sling for cradling a limb or joint region of the patient which sling is suspended by a flexible tension member from the frame, drive means for cyclically raising and lowering the sling by alternately and repeatedly pulling and releasing said tension member, and control means to permit adjustment of both the cycle time and the range of movement of the sling.

2. Apparatus according to claim 1, wherein the frame of the apparatus includes a wheeled base from which upstands a column having a laterally-projecting arm disposed at a height considerably greater than that at which the patient will lie on abed.

3. Apparatus according to claim 2, wherein the column upstands from a side region of the base, the arm projecting in a direction which overlies the base.

4. Apparatus'according to any of the preceding claims, wherein the drive means includes an electric motor disposed within a suitable housing on the base of the apparatus, the flexible tension member passing over rollers or pulleys provided in both the arm and the column as appropriate for connection with the drive means.

5. Apparatus according to claim 4, wherein the electric motor is drivingly coupled to a variable-throw crank, the flexible tension member being connected to that crank and being arranged so that upon operation of the motor, the sling will cyclically be raised and lowered.

6. Apparatus according to claim 5, wherein the throw of the crank is adjustable by varying the point at which the tension member is connected to the crank.

7. Apparatus according to any of the preceding claims, wherein the control means includes a speed controller for the drive means so permitting ready adjustment of the cycle time for raising and lowering the sling.

8. Apparatus according to claim 7, wherein a speed controller is used which allows the drive means to operate with a substantially constant power output though at a variable speed.

9. Apparatus according to claim 7 or claim 8, wherein the control means includes an overload trip, arranged to cause the drive means to shut down if undue resistance to operation is encountered.

10. Apparatus according to any of the preceding claims, wherein the control means includes a timer arranged to permit periods of operation alternating with periods of rest.

11. Apparatus according to any of the preceding claims, wherein there is provided a remote on/off control for use by the patient.

12. Apparatus for flexing the joint of a patient, according to claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.