CA2288400C - Anatomical orthopaedic crutch - Google Patents

Abstract

An unique orthopaedic crutch designed to fit the anatomy of the user and thereby avoid causing harm to the user. The crutch handle is inclined at the average angle of the human wrist to forearm of 14 degrees to the horizontal plus or minus a few degrees. This is unlike all crutches identified to date which generally require the patient's anatomy to fit to the crutches' design, exemplified by handle angles of zero degrees, or 90 degrees to the vertical. The upper part of the crutch is offset from the lower part by the angled handle takes into account all the major anatomical requirements of the human arm by fitting the natural carrying angle of the human arm in respect of the shoulder elbow wrist and hand. The device has an upper arm-support ring, a comfort-designed anatomically accommodating handle, and a shock-absorber in the lower part. The crutch is adjustable with particular ease and speed using an engraved red line for lining up the adjustment mechanisms

Description

Title: Anatomical Orthopaedic Crutch Field of Invention:
This invention relates to walking aids in the form of a crutch designed to assist old, infirm, injured and handicapped individuals gain mobility. More specifically this invention is a crutch designed to accommodate the anatomy of the human arm for comfort and stability but also to minimize or prevent harmful damage to parts of the arms when in use.

1 Background to the invention While there is a great deal of prior art pertaining to crutches that represent many variations of their designs such as axillary or underarm support by Chen, US Pat No 4,865,065, forearm support to Ewing US Pat No 4,869,280, elbow support and wrist supports, there are embodiments that allow for folding up, sprung arm supports by Herr 5,458,143, conversion into canes as by Kelly, US Pat No 5,482,070, Coogan WO 89/00039 and many other variations. There are no instances identified where the structural anatomy of the arm has been properly taken into account. The normal carrying angle of the arm when in the resting position, reveals that the hand to wrist angle is at an angle of approximately 14 degrees and the elbow is not straight such that the hand is positioned anterior to, or in front of, the shoulder and upper arm.
The fundamental problem with current forearm or 'Canadian' crutches means that the weight of the body has to be borne through the wrist and hand at a unnatural angle and this has been recognised to cause inflammation of the wrist joint restricting the ability to walk comfortably and safely using the crutches which may lead to consequent arthritic changes or carpal tunnel syndrome. Similarly pressure on the elbow joint held straight or fully extended frequently leads to inflammation and pathological joint changes. To a lesser degree pressure on the arms with the use of forearm crutches has been shown to cause occasional stress fractures in the ulnar bone, and crutch use has been implicated in skin inflammation, blood vessel thrombosis and aneurysms. Furthermore the use of currently designed forearm or 'Canadian' crutches leads to physical fatigue and a nerve dmamge syndrome causing numbness in the hands as a result of nerve and circulatory problems.
Even prior art that uses angles in crutch design does not address the anatomical considerations or the spectrum of anatomical problems incurred by the user, nor does it approximate the design of this invention in reducing these conditions. For example Forearm crutch patents by Stockwell, US
Patent No 5,555,904 and Hagberg, US Pat No 5,671,765 show angles to the elbow. However in the former the angle invoked is merely for support of the elbow-forearm rest and has no relationship to anatomical structures of wrist or shoulder, and in the latter the angle of elbow-forearm rest is pointed downwards to a vertical handgrip rest which does not address the correct anatomical angle of the elbow or wrist. A patent converting a crutch to a walking stick by Coogan et al, PCT WO 89/00039 does not describe or claim an angle as such and this crutch will not function anatomically as the wrist is unnaturally bent, and as with the other patents cited there is no upper arm support. A Ski-pole type crutch by Owen, US Pat No 4,196,742 while describing a wrist angle for the handle, but it is rearwards of the upright pole at a steep angle of between 40 and 55 degrees and requires the wrist flexing in use for forward propulsion. In the Owen ski-pole embodiment there is no offset anteriorly of the wrist to shoulder requiring the excessive flexion of the shoulder in use.
The novelty of the current application is in the adherence to the normal structure, angles and functions of the human arm to provide comfort, stability and thereby minimising the risk of damage to the users arm when the device is being used.

Summary of the Invention In its broadest independent aspect, the invention provides a walking aid comprising a leg with a handle located part way up the leg; the leg having a region below the handle which in use may engage the ground as a user leans onto the walking aid; and a region above said handle for supporting the arm of the user; characterised by any one or more of the following features:

a) the handle is an inclined elongate handle at approximately 14 degrees to the horizontal, located between the leg's upper and lower regions; the leg's handle, upper and lower regions having a common supporting bar; an arm being located across and beneath the handle between said upper and lower regions. The handle thus has an ovoid space between the upper and lower parts of the handle to allow for storing small personal items or hanging things on.

b) the upper region is offset to the handle c) said region for supporting the upper arm incorporates a cuff d) a shock absorber is provided in the lower region integral in the cap at the ground contact point f) A red line is provided on the telescopic, adjustable upper and lower regions for rapid and accurate location of the sprung-pin locking mechanism of the adjustable parts by simply lining up the red lines.
An anatomical handgrip is provided with a hand grip stop that anatomically matches the space between the thumb and first finger.

f) Furthermore the hand-grip stop is domed to match the palm of the hand. The handgrip is also may have a thick neoprene handle attached by Velcro TM or similar mechanism, for comfort and may be a disposable-replaceable type for hygiene.

Aspect a) is particularly advantageous because the handle is at the natural carrying angle of the wrist and hand, user comfort is paramount, it prevents the anatomically related problems from arising as no distortion or flexion of joints is required, as well as reducing pressure problem on skin, nerves and blood vessels. Aspect a) allows the walking aid to rely on the supporting strength of a common supporting bar. Therefore, in use, the walking aid is less likely to break at joints which would have been the case in a prior art crutch with several supporting bars. This configuration also allows an improved construction of the handle region as compared to the prior art system. It also reduces the number of components necessary thus rendering the crutch more straightforward to manufacture at a lower cost.

Aspect b) is particularly advantageous because it allows the normal anatomical orientation of shoulder to elbow, and elbow to wrist and hand.
Furthermore it is normal for some flexion of the elbow to occur when suing crutches and it allows the elbow region and/or forearm region of a user to be less constrained by the upper portion of the crutch in a non-ergononiic manner.

Aspect c) is particularly advantageous because it allows crutches to provide good stability and less lateral arm wobble over those with forearm support only and avoids the brachial plexus nerve damage on underarm or axillary forms.

Aspect d) has the advantage of softening the ground contact shock which when unabsorbed is a cause of fatigue in users of walking aids.
Aspect e) is also particularly advantageous because it reduces the difficulty and stress in adjusting the crutch length as required by one user, or for use by different users.

1 Aspect f) is particularly advantageous and provides for hand comfort against fatigue, a hand stop to prevent the hand moving too far down the handle, a palmar support for resting the hand on, and a removable washable neoprene cover for additional comfort, safety and hygiene. The reduction in pressure related problems of the hand is also minimised In a subsidiary aspect in accordance with the invention's broadest independent aspect, at least one of the two handle parts is of plastics material with webbing reinforcements. This allows the walking aid to be of minimal weight but of sufficient strength to withstand the periodic pressure exerted during a user's walk. The plastic injection moulding may be mass produced and made in two sections that will clamp over and be attached over the 'S' shape of the tubular aluminium leg of the crutch with fasteners eg nuts and bolts. This will allow for ease of manufacture and strength to the crutch.

Brief Description of the Figures Figures 1 and 2 show the right and left-handed elevations of the crutch respectively.

Figure 3 shows the right-hand elevation demonstrating the hinged cuff at the top of the upper region.

Figure 4 shows the front elevation Figure 5 shows the rear elevation Figure 6 shows a partly exploded rear elevation Figure 7 shows a plan view of the top of the crutch Figure 8 shows a view from below looking upwards Figure 9 Shows a detailed right-hand elevation of the handle showing the parts for assembly to the inner tube seen externally as the upper and lower aluminium crutch body tubes.

Figure 10 shows a section through the lower end of the crutch near the ground contact point showing the end cap with shock absorber Figure 11 shows a section through the lower end of the crutch near the ground contact point showing the end cap with air bubble shock absorber Figure 12 shows the shape of the neoprene saddle with flaps for attaching around the handle using Velcro TM.

Detailed Description of the Figures Figures 1 and 2 shows the crutch comprising an aluminium pivot 1 and 1 plastic or nylon, upper arm cuff 2 fitted into an upper region 3 made of an aluminium tube which in turn fits into the aluminium-tube upper adjustable region 12 showing adjustment holes 7. At collar 8 this engages the upper handle part 11 containing the palm knob 10 which is for comfort and to prevent slippage from the handle 11 during use, and the lower part 9 which provides bracing support for the handle 11, all these parts are made from plastic or nylon or similar light weight non-metallic material and may be attached to the aluminium tubular upper body of the crutch 12 and lower body 17 with a nut and bolt arrangement.
A lower collar 181ocates the connection body 17 to handle 11. The whole assembly is shown having an optimal angle of 14 degrees indicated by the dotted line 13. The handle assembly engages the aluminium lower adjustable region 17 and lower adjustment holes 19, this engages the aluminium lower part 14 over which fits the rubber or other non-slip material, end cap 15. The spring pin mechanisms upper 6 and lower 20 are represented by the holes on the adjustment parts and the sprung pin operates to adjust the length of the crutch portion upper or lower, to fit the size of the user and operate by locking into a hole in the adjustable parts 12 and 17. Lower body 17 locates into lower region part 14 at collar 21.
The diagrams also show on the upper crutch part 3 and lower crutch part 14 the Red Line 4 called the Steve Line which is used to facilitate the engagement of the adjusting mechanisms 7 and 19 with pins 6 and 20 respectively. Velcro TM straps are shown R which engage the saddle for the handle (Figure 12) to hold he saddle in place, and friction grip washer/collars 5 upper and 21 lower ensure a tight fit of the adjustment mechanism parts 3 and 12, and 17 and 14 respectively. The ovoid hole 16 between the lower handle part 9 and upper handle part 10 is used for hanging storage items.

Figure 3 shows the upper arm cuff 2 hinged upwards on the hinge 1 to allow for ease of arm entry.

1 Figures 4 and 5 show rear and front views that show more clearly the spring clip operating pin 6 upper and 201ower.

Figure 6 shows an exploded view of the upper part 3 with hinge 1 and cuff 2 separated from upper adjustable part 12 and similarly lower adjustable part 17 separated from lower part 14.

Figure 7 shows the view from above the hinge 1 and cuff 2 looking down on the palm knob 10 of the upper handle part 11.

Figure 8 shows the bottom end of the crutch with the foot 15 fitting onto lower part 14 and adjustable part 17.

Figure 9 shows the parts of the handle, the lower part 9 and upper part that attach round the central tubular body 12. The preferred average angle of fourteen (14) degrees is shown with the dotted line 13. The ovoid hole 16, is for storing or hanging items within the lower handle part 9.
Figure 10 shows the lower part of the leg 14 containing an end plug A
fitted into the end cap 15 containing shock absorber spring B and two thrust washers C.

Figure 11 is the same as for Figure 10 without the shock absorber spring and thrust washers, and instead showing the edge Q of the end plug A and a pre-cast air-pocket bubble D which acts as the shock absorber.

Figure 12 shows the actual size and shape of the neoprene saddle for fitting over the handle showing the part R which fits on the grip stop and palm dome 10 (Figure 1) of the handle upper part 11, (Figure 1).

Claims (6)

1. A walking aid in the form of a crutch comprising a leg with a handle located part way up the leg; the leg having a region below the handle which in use may engage the ground as a user leans onto the walking aid; and a region above said handle for supporting the arm of the user, characterised as follows:

a) the handle with an angle of between 0 and 89 degrees being preferably 14 degrees below the horizontal, located between the leg's upper and lower regions, the leg's handle, upper and lower regions have a common supporting bar; an arm being located across and beneath the handle between said upper and lower regions for strength and support, and the handle has thus an ovoid space between the upper and lower parts of the handle;

b) the leg's upper region is offset from the leg's lower region by the handle located between them to accommodate normal human arm anatomy while allowing space for elbow flexion;

C) the upper region above the handle for supporting the arm incorporates a circular cuff for supporting the upper arm and is hinged onto the top of the leg's upper region;

d) a shock absorber is provided at the bottom of the leg at the ground contact point where the leg has a ribbed rubber insert or stopper inserted onto it and the leg then inserted into a hollow rubber end cap containing two washers welded to a spring.

2. A walking aid according to Claim 1, wherein the handle has an anatomical hand stop and palm-fitting dome and for use when user is stationary.

3. A walking aid according to Claim 1 wherein the handle has a neoprene saddle as a handgrip, the saddle being held on by Velcro TM straps and therefore replaceable as required.

4. A walking aid according to any of the preceding claims 1-3 wherein the upper and lower regions of said leg are telescopic.

5. A walking aid according to claim four (4) where the telescopic regions are adjustable using a resilient pin-into-hole locking mechanism, a scribed line being provided on the upper and lower telescopic regions for aligning of said mechanism.

6. A walking aid according to Claim 1, wherein the shock absorber is a pre-cast air bubble at the end of the leg at ground contact point to provide the shock absorption.