GB2304582A - Improved condylar platen and pad construction - Google Patents

Abstract

The construction, which may be used with most types of orthopaedic and orthotic hinge, integrates by moulding a hinge backplate 16 with a joint pad platen 14 and shimming means 18. The platen has a flexible marginal portion 56 disposed about an extension 54 moulded peripherally to the enclosed hinge backplate, which portion may be contoured for conformability to a joint. The extension creates a recess between the flexible margin and the backplate. A joint pad is air- and foam-filled and a central portion thereof fits within said recess while a peripheral portion locates on the flexible margin. The condylar pad is covered overall by a bonnet. The construction eliminates drag between a platen and hinge arms and facilitates manufacture by reducing and combining parts.

Description

AN IMPROVED CONSTRUCTION FOR ORTHOPAEDIC HINGES REQUIRING CONDYLAR OR OTHER JOINT PADS ABSTRACT An improved condylar platen and pad construction for use with most types of hinge used in orthopaedic and orthotic appliances integrates, by moulding, a hinge back plate with a joint pad platen and shimming means. The platen has a flexible margin portion disposed about an extension moulded peripheral to the enclosed hinge back plate. The flexible margin may be contoured for conformability to a joint. The extension creates a recess between the flexible margin and the hinge back plate. A joint pad is air and foam filled and a central portion of it fits within the recess of the platen and a peripheral portion locates on the flexible margin. The condylar pad is covered overall by a bonnet.

The improved condylar platen construction eliminates drag between a platen and hinge arms and accelerates and eases manufacture by reducing and combining parts. The instant pod is more versatile and functionally effective than prior art pads.

FIELD OF THE INVENTION The invention relates to hinges which are used in orthopaedic and orthotic practice to make braces and other appliances for use at human joints.

BACKGROUND OF THE INVENTION AND THE PRIOR ART The are manly hinge designs used in orthopaedic and onhotic braces and splints.

in a first type widely used at the knee, hip and @lbow, there are two hinge arms joined at and flexing about a single pivot. This type is generally referred to by those skilled in the art as the uni-axial, unipivotal or monocentric type.

The present author was the first inventor of a single flexion axis hip hinge described in GB 2 163 352.

Other single pivot hinges described in the partent literature include US 4 370 977 to Mauldin & Driver, US 4 489 718 to Martin and US 4 620 532 to Housewerth.

In a second type. perhaps even more widely used, particularly at the knee, there are two hinge arms, each having its own pivot and also each having a set of gear teeth about the periphery of the part which extends between the pivots. The arms are so sized and arranged that the gear teeth mesh between the pivot points, thereby integrating the arm movements. Thus if one arm moves. the other must move as well. This type is generally referred to by those skilled in the art as the geared bi-axial, geared duocentric or geared polycentric type. The latter term is perhaps the most widely recognised.

Some examples of geared polycentric two pivot hinges include US 4 337 764 to Lerman, US 4 697 583 to Mason et al and US 4 732 143 to Kausek A third type also has two hinge arms, each having its own pivot but in this design there are no gear teeth. Thus, the arm movements are not integrated and each arm can always move independently without effecting the other. This type of hinge is generally referred to by those skilled in the art as the true bi-axial, true bi-prvotal or simply just bi-plvotal type.

The present author has been the first inventor of a number of orthopaedic hinges with tv,o independent pivots. Some examples include patents GB 2,182.714 and US and EOP counterparts 4 915 098 and 327286 respectively; GB 2 208 065 and US counterpart 4 881 299; US 5 000 170 and Canadian counterpart 1 299 455; US 5 038 765 and US 5 039 247.

Other patents disclosing hinges with two independently pivoting arms include US 4 249 524 to Anderson. US 4 520 802 to Mercer and Aaserude and UK 499 208 to Griffiths (not orthopaedic).

Both bi-pivotal hinges and geared polycentric hinges are, in mechanical terms, three bar linkages.

However, the integration of the hinge arms in the geared polycentric type causes the loss of one degree of freedom.

There is a small number of other types of hinge used in onhopaic and orthotic appliances back, for instance. on sliding pivots and four bar mechanisms but these are not widely employed in commertially avaitable devices.

The present invention is applicable to most uni-axial, geared polycentric and true bi-pivotal hinges as well as to some of the less widely used types.

Of concern to these who make and design braces is the total number of parts to be handed during manufacture, since the greater the number and complexity of parts, the greater the skill needed and the more time taken in assembly. This ultimately reflects in increased cost to the end user.

In recent years, a great deal of attention has been paid by those skilled in the art to the deign of functional knee braces which are intended to provide stabillty for unstable kness. Current op@@ion favour. design in which hinges are disposed in close approximation to the knee, have minimal thickness profiles and are provided with pint pads called condylar pads Several types of condylar pad have been used and the earliest examples were simple applique pads with no special platen structure.These pads were genrally foamed plastics, usually but not always a closed cell type, such as expanded polyethylene or expanded polyvinyl alcohol, attached to the inside of each hinge back plate using adhesives.

The present author has designed braces employing this type of condylar pad including two products called MasterbraceTM and MasterbraceTM II. These are made by Messrs Protectair Lim@ted of Abingdon, UK and are currently sold by Messrs Johnson and Johnson Professional of Bracknell, UK and Raynham, Massachusetts, USA in a number of c-tries including the UK and the USA.

Where platens have been employed d they live usually been a shaped die-cut. vacuum fumed or moulded entity used as a mount for a condylar pad. The aim in shaping a platen is to present the pad in a more anatom@cal manner to a curved surface about a condyls of a joint. If a continuous condylar pad is used with such a platen, extending over the entire surface, the assembly will have the advantage of being more comfortable. This is because the pad will be compressed more or less evenly over a large contact area.This contrasts with the flat applique pad which depends upon compression forces delivered via the brace straps to force a first entity into conformity with a curved body surface.

In 1984 the present author designed a moulded dished platen which used a continuous condylar pad.

This was and still is employed as an optional 'kne cage' in two products called 'Rehabilitative Knee Brace' and 'AdjustabraceTM' both made and sold by the commercial companies referenced above.

This entity is mounted upon and spaced apart from the inner surface of a hinge back plate on one or more hexagonal-bodied spacer bolt pans. Each has a female threaded recces in the head end and a male thread on the shank. These have the disadvantage in r normal knee that even deploying one such spacer tends to space the platen off the bsek of the hinge, towards the knee joint. rather more than is desirable.Thus, nowadays. thelr use IS mainly confined to special applications involving deformed joints.

From inspection of products in the market place and from manufacturers' literatttre the author has found two basic constructions for condylar pad platens; no specific platen constructions were discovered in the patent literature scrutinised.

A non-exclusive example of the fnst type is used on a functional be brace poduct called 'LegendTM,' made by Messrs Don Joy Inc of Cartsbed, Califorma, USA. where a shaped, moulded.

flexible condylar pad platen is made from plastics and is secured against an inner hinge cover. also made from plastics. Both elements are secured together against a hinge back plate with nvet securing means which also provide pivot means. The pivot rivet secunng means pass through hinge arms and a hinge front plate to Which they are clenched to complete the basic hinge assembly.

A non-exclusive example of the second type is used on another functional knee brace product called 'EdgeTM', made by Messrs innovation Sports of Irvine. Califomia, USA, where a metal hinge back plate is secured over part of a small, shaped, condylar pad platen, moulded in a rubber material, by screw means which engage with pivot boss means provided by and arising front plate.

Thee constructions suffer from a common disadventage due to the condylar platen being anchored against the beck of the hinge plate or mechanism. This is that the platen and condylar pad assembly.

being so closely coupled to the back of the hinge, can impinge during use, on the inner surfaces of the hinge arms, causing drag. Only if the platen and pad were to be made so small as to be of doubtful support value would the risk of impingement in this type of design be completely avoided Additionally. in the riveted type, especially where, as in the example quoted, the rivets must pass through more than one layer of plastic, the recognised phenomenon of creep is aggravated by cyclic flexing of the platen during use. These factors will work agamst the rivets and are bound to cause looco-ing +nd general deterionation of or the brace hinge overtime.

Apart from appliqué and continuous platen mounted pads, another obvious but not very satisfactory solution has been adopted by several manufacturers in recent years. This has been to adapt me doughnut-shaped air tilled pads from ear defenders as condylar pads. Those skilled in the art will be aware that joint condyies present hard @minences with limited soft tissue covering and this is one moon why condylar pads are favoured.However, when a brace with a simple doughnut pad is applied to a joint the flexible platen is bent outwards and the empty centre Cf the doughnut allows the hud or minimally lined platen and hinge bock plate to be pressed against the condylar eminence causing discomfort and sometimes, pain.

Furthermore, tests on several manufacturer's braces carried out early in 1995. st Leighton Hospital, Crewe, UK kd the author to observe that dependent braces. such as knee braces, feted with air filled cottar pads suffer 'peristaltic' effects. As the knee flexes and extends. such pOs are locally and differentially compressed, leading to the transfer of air between the proximal ard distal poroons of the pad on a cyclic basis.When the air in such a pad is compressed above a bony emnence, the pad effectively pushes the brace distally. worsening a common problem encountered with knee-braces known as 'ride-down'. This term is used by those skilled in the art to describe slippage of a brace down the leg. The human leg. in any case, has a natural, more or less conical, proximal to distal profile and it will be appreciated that a relatively small distal displacement of a brace will result in loss of contact and further. more profound. slippage.

Doughnut-shaped air filled condylar pads are less effective than appliqué or continuous pads because not only do they worsen ride-down and ftil to provide useful pad thickness over the ostre of the hinge back plate, they also become completely ineffective it punctured.

SUMMARY OF THE INVENTION The present invention provides a condylar platen construct and condylar pad for improved construction of virtually any design of orthopaedic hinge which can accommodate two hinge arms, pivotally mwntd on one or more pivots, a hinge back plate and pivotal securing means for securing the hinge arms to the back plate and which in addition usss pivot washers or shimming means (or which would benefit therefrom) between the hinge arms and hinge back plate. The Instant construction is employed when it is desired to provide a condylar or other joint pad for a joint such as the knee or elbow.

According to a first aspect of the invention, a condylar paten construct is moulded in suitable plastics over an insert hinge back plate, preferably made in metals or alternatively in hard structural composites and having one or more through holes adapted to recirive pivot securing means. The condylar platen construct additionally provides integral pknar shimming means over one entire face of the hinge back plate which. by virtue of selecting materials having very low friction charactenstis, are effectively self-lubricating for the anticipated life of the hinge.

According to a second aspect of the invention, the condylar pad platen moulding has an extension, paripheral to the incorporated hinge back plate and directed towards the joint,.

Aceordine to 1 third aspect of the invention, the condylar pad platen of the construct l,ies a substantial flexible margin, disposed about the peripheral extension, which is optionally asymmetrical and which may, additionally. be contoured in a manner generally similar to the pen of the body over which it is to be positioned.

Provision of the extension peripheral to the hinge back plate crates a recess between this and the flexible margin. The extension spaces the flexible margin away from the hinge ems and prevents impingement, thereon, during use. In addition. the extension isolates the flexing portion of the condylar pad platen from the overmoulded hinge back plate.

According to a fourth aspect of the invention, a compressible condylar pad is pnavided which has a central portion, so sized and shaped thet It forms a downstand, which engages with the reon, in the condylar pad platen. It also has a peripheral portion, which is similar in plan view to and slightly larger in area than the flexible man of the condylar pad platen upon which it is located.

According to a fifth aspect of the invention, the compressible con-ar pad has a first, flexible and preferably sealed enclosing struchm. having a partial filling of air and a second, filling element comprising cushions made in resilient foamed piastic OBJECTS OF THE INVENTION It is, Xrefore, the principal object of this invention to provide a novel condylar pad platen, integrated with a hinge back plate and shimming means into one component, for an orthopaedic hinge having at least one pivot It Is another important oloct of this invention to provide a novel compressible condylar pad, for use with the irritant condytar pad platen, which has r downstanding central portion and a peripheral portion, botch portions being filled with a combination of air and resilient foamed plastics.

It is another imporhnt c-ct of this invention to provide resilient foamed plastics cushions for the instant con-r pad where the cushion provided for the central portion and that provided for the peripheral portion of the pad may be similar or they may differ and in either case may be made of more than one type of rellient foamed plastics. By these means. a condylar pad, according to the instant invention, may be made more or kss compressible according to therapeutic need.

BRIEF DESCRIPTION OF THE DRAWEIGS Other object and advantages will become clear as the present invention is described in greater detail. by way of example only. with reference to the accompanying drwnngs.

In general. a convention has been adopted of describing the position of structural elements in drawings in relation to their anatomical disposition, using such terms as 'anterior' and 'posterior' to describe fore and rear with react to a human body upon which a device. incorporating the present invention, would be used.

in the drawings: FIG. 1. is an inner, joint side, plan vim of a condylar platen construct comprising a condylar pad platen, a hinge back plate and a shim, according to the present invention. for use with an orthopaedic or orthotic hinge.

FIG. 2, is an outer, hinge side, underpin view at the condylar platen construct of Fig 1.

FIG.3. is a posterior side view of the condylar platen construct of Fig 1.

FIG 4, is a sectional posterior side view, at enlarged scale, of the condylar platen construct along a Line r a', in Fig 1. showing the hinge plate incorporated therein.

FIG. 6, is a sectional distal end vicw, at eniarged scale, of the condylar platen construct along a line b - b', in Fig 1. showing preferred asymmetry of the flexible margin of the condylar pad platen moulding.

FIG 6, is an inner, joint side, plan view of a compressible condylar pad, according to the present invention, for use with the condylar platen construct of Fig 1.

FIG 7, is an outer, platen side, underplan view of the compressible condylar pad of Fig 6.

FIG 8, is a side view of the compressible condylar pad of Fig 6.

FIG , is a sectional distal end view of the compressible condytar pad along a line c - c5, in Fig 6, showing cushions incorporated therein and preferred anterior asymmetry.

FIG 10, b a distal end view of the compressible condylar pad of Fig 6, positioned adjacent to the condylar platen construct of Fig 1, indicating functional relationship.

FIG 11. is an anterior front view of an orthopaedic hinge. hiving tao pivots and incorproating a condylar platen construct comprising a condlar pad platen, hinge back plate and shim, other with a compressible condylar pad and bonnet, according to the present invention.

FIG. 12, is an exploded front view of the hinge of Fig 11, showing the relationship of the condylar platen construct and compressible condylar pad. to other sallent structures thereof.

DESCRIPTION OF THE INVENTION With general referance to FIGS 1 - 12, a condylar platen construct and a compressible condylar pad for an orthopaedic hinge, according to a moat preferred embodiment of the Present invention, have the general designations 10 and 12, respectively. It is to be understood that 10. 12 will be used together as a combined entity and generally but not always, in a paired configuration, with one such entity being disposed as pat of a hinge on one side of a joint and another such entity being disposed as part of a hinge on the other side of the same joint.

Condylar platen construct 10 comprises a novel condylar pad platen 14 and a substantially flat hinge back plate 15 preferably made in metals such as aluminium, stainless steel or titanium but alternatively made in hard strutural composite materials. Hinge back plate 16 is incorporated into condylar platen construct 10 by inserting it into an Injection mould and moLaicling it subt-tially overall. Condylar pod platen 14 is made of suitable plastics, such as a flexible grade of nylon 6.

The overmouliling is effected in such a manner that hinge back plate 16 is provided. with a moulded integral planer shim IS, which by virtue of the bw friction characteristics of the materials selected. is effectively self-lubricating for the anticipated life of the hinge.

hinge back plate 16 is adapted by the provision of through pivot holes 20 and 22 for the receive of pivot rivet securing means 24 and 26 (seen only in FIG 12). On its first, inner or paten face 28 condylar platen construct 10 has hinge back plate 16 exposed in areas 30 and 32 suirounding pivot holes 20 and 22.

In this embodiment. other areas of hinge back plate IS are exposed on second. outer or hinge face 34 of condylar platen construct 10 at 36 and 38. These are provided to allow hinge bushings 40 ans 42 (also seen only in FIG 12) to be secured against hinge back plate 16, providing metal to metal contact. This is preferable engineering practice to allowing bushings 40 and 42 to be compressed the plastic of integral planar shbn IS, which extends substantially over second, outer or hinge face 34.

Hinge back plate 10 is also adapted by the provision of through clearance hobs 44 and 46, for the receival of screws (not illustrated) concemed in the assembly of an orthopacdic hinge 48. The heads of these screws locate in receases formed between the plastic first, inner or platen face 28 of condylar platen construct 10 and exposed metal areas 50 and 52 of hinge back plate 16.

As mey be sesn by brief reference so FIGS 2 and 5, there are no exposed areas of hinge plate 16 corresponding to 50 and 62 on second, outer or hinge face 34 because there are no structures operating against either 16 or integral planar shim 18 at those positions.

That part of the condylar pad platen moulding 14 immediately poripheral to hinge back plate 16 is formed into an extension 54 towards the joint. The purpose of extension 54 is to ensure that when a flexible margin 56 of condylar pad platen 14 and a compressible condylar pad 12 located thereupon are compressed against a joint, flexible margin 56 may conform thereto but is effectively prevented from impinging upon hinge arms 58 and 60 of an orthopaedic hinge into which it is incorporated.

By this novel means, drag on hinge arms 58 and 60 is avoided.

Flexible margin 56 of condylar pad plan U extends about extension 54 of hinge back plate 16 to provide a substantial platform for compressible condylar pad 12. In this ambodiment, which is for a knee hinge. flexible margin S. is asymmetrical, resembling a modified ellipee or modified rectangle and being larger anteriorly than posteriorty, Flexible margin 56 has a guttered or open ended trough profile.

The provision of extension 54, creates a shallow recess 62, similar in shape to and slightly larger in area than, hinge back plate 16.

A novel compressible condylar pad 12 has a ceirtial porbon 61. so sized and shaped that it form, a downstand which substantially engages with recess 62 in condylar pad platen 14. Compressible condylar pad 12 also has a peripheral portion S., which is similar in Illan view to and slightly larger than, flexible margin 56 of condylar ped platen 14, upon which it rest.

As seen in FIG 9. compressible condylar pad 12 has a first element in the form of a flexible enclosing structure 68. 68 is formed. preferably. from a plurality of layers of textiles reinforced film plastics, sealed by high frequency welding in a suitable vacuum forming and die-cutting tool. This produces a narrow linear sealing zone 70 disposed between central portion 64 and penpheral portion 66.

Flaxible enclosing structure 68 has a partial filling of air indicated at 72 but additional and novel elements are in the form of cushions 74 and 70 provided within central portion 64 and peripheral portion 66. respectively. Cushins 74 and 76 are preferably mad in resilient foamed plastics, which may be of open cell or closed cell type or 9 combination of both types. If only cEd ceH foam is used it preferably has an uncompressed volume about 20% less than the tobl volume of flexible enclosing structure 68.It is not necessary to form compressible condylar pad 12 to the gutter profile of flexible margin 56 of condylar pad platen 14 since the inherent flexibility and resilience of the materials from which 12 is made is sufficient to accommodate such contouring as is likely to be required.

Tests have shown that an important advantage of compressible condybr pads using resilient foamed plastics cushions in a flexible enrig structure is that they are much less prone to peristaltic effects. Thus, during cyclic flexion and extension of the limb segments about the joint, any tendency of an appliance, so provided, to ride down a limb is much reduced in comparison to that encountered when pnor art condylar pads, filled with air alone, are used.

Another advantage of the Instant compressible condylar pads with combined resilient foamed plastics cushions and air filling is that they retain function if trapped air is lost. Indeed, if a combiration of open and closed cell foams is used. it becomes possible to offer the end user the opbon to puncture one or both of portions 64 and 66 of compressible condylar pad 12 for a firmer but still functional fit.

Furthermore, it is possible to engineer a series of resilient foamed plastics cushions for e number of different purposes, such as providing different levels of compressitility at different stages of treatment. This may be accomplished by. for instance. laminating together layers of resilient foamed plastics of different density or type, such as a combination of open and closed cell types. Subject only to the characteristics of the foamed materials selected, the cushions may be die-cut or may, altermatively. be compression moulded. Of course, the cushion employed in central portion 64 of compressible condylar pad 12 need not have the sane composition or characteristics as that employed in peripheral portion 66.

In FIG 10. compressible condylar pad 22 is shown, unflexed. adjacent to condylar platen construct 10 in approximate functional retationship. When 12 is actually fitted to 10 it will, of course, deform someinhat as it takes up the anterior to posterior curvature of flexible margin 56. As is suggested by FIG 10, central portion 64 of compressible condylar pad 12 is somewhat smaller in area than recess 62 (not annotated in FIG 10) of condylar pad platen 14.Thus, peripheral portion 66 of compressible condylar pod 12 and not sealing zone 70 overlies extension .4. ensuring that a condition of an unpadded edge lying a;nst a bony eminence cannot occur, In any case, it is to be bome in mind that the dimension of 54 will be only so greet as is necessary to ensue that flexible margin 56 will not impinge on the arms of the hinge being designed.Although it is dependent upon the configuration of the hinge arms in any given hinge. the dimension of 54 can generally be kept to 5 to 6 mm and the overall profile of orthopaedic hinges using the condylar platen construct of the present invention may be kept very slim indeed.

Peripheral portion 66 of compressible condylar pad 12 is retained on flexible margin 66 of condylar pad platen 14 by a bonnet n made of suitable fabrics such as a polyester material and which is self- retaining by virtue of having @lastic edging means. Bonnet 78 provides an overall cover for compressible condylar pad 12 and condylar - platen l4.

For security and ease of manufacture, the underside of central portion 64 of compressible condytar pad 12 may be secured within recess 62 using a combination of self adhesive hook and bop materials (not illustrated).

In some circumstances, it may be preferred to use the instant condylar pad platen with a compressible condylar pad other than that immediately hereinbefore described in respect of the first and most preferred embodiment.

In a second and also preferred embodiment, there is no flexible enclosing structure. A cushion is compression moulded in closed cell resilient foamed plastics and is analogous to compressible condylar pad t2 of the first embodiment. It has a central portion which occupies recess 62 and a peripheral portion which locates on flexible margin 56 with a compressed zone betw the two portions which is analogous to sealing zone 70. It has similar dimensions to compressible condylar pad 12.

In another preferred embodiment two separate cushions are deployed. A first cushion occupies recess 62 and a second cushion extends over the entire inner aspect of condylar pad platen 14, including the first cushion. Overall dimensions are similar to those of compressible condylar pad In another preferred embodiment, also involving two cushions, a first cushion occupies recess 62 and extends through a second, ring shaped, cushion which extends over and is located upon flexible margin 56. Once again, overall dimensions are similar to those of compressible condylar pad 12 To conclude this brief review of the versatility of the instant compressible condylar pads. in a variant of the first and most preferred embodiment. central portion 64 of compressible condylar pad 12 additionally extents partially or fully upwards through peripheral portion 66. Flexible enclosing structure 68 and sealing zone 70 are retained.

Bonnet 78 is used in all of these embodiments of a compressible condylar pad and condylar platen construct 10 is unaltered in all cases.

As disclosed, areas of condylar platen construct 10 about pivot holes 20 and 22 for accepting pivot securing means, are relieved, exposing first, inner or platen face 23 of hinge back plate 16 at 30 and 32. Pivctal securing means may be in the form of rivet means or screw means, acting in co-operation with, for instance. bushing means. If rivet means are employed, as in the preferred embodiment, it is d@@@able that exposed areas 30 and 32 about through holes 20 and 22 are large enough to provide access for the arrvil part of a @veting press during @@@@mbly.

It is to be understood that, if the hinge has two pivots. there will preferably be provided one relieved area for each pivot rivet or screw, as described, rather than one larger area of exposed metal. This is in order that the strength and integrity of condylar platen construct 10 is not compromised.

FIG 12. shows the principal parts of an orthopaedic hinge employing the instant invention.

Con@@deration of this figure will indicate that, in this hinge, though not all hinges, the element of a front shim @0 is important and the element of a front hinge plate 82 is essential. Front hinge cover 84 is desirable for cosmetic reasons but in a functional knee brace @@ also constitut@@@ a guard against impingement of metal parts upon the brace wearer and other participants in contact sports.

A very important advantage of instant condylar platen construct 10 is that it is extremely strong and completely @@@unates the tendendy of pnor art, separate condylar platens. to work against pivot securing means, particularly pivot rivet means, which inevitably loosen. This is achieved first by isotating flexible margin 56 of condylar pad platen 14 from the pivot securing means by means of extension 54 and second by the provision of exposed metal areas 30 and 32 about pivot rivet secunng means 24 adn 26, allowing metal to metal contact. This elinunates the inevitable creep effects that obtain where metal secunng means are clenched against conventional plastics.

Further advantages of instant condylar pad platen denve from contouring flexible margin 56 which confers better limb conformability and also by positioning it inboard of hinge back plate 16 which eliminates the nsk of impingement on hinge arms and consequent platen drag seen in prior art construchons.

In summary, in contre-distinction to pnor art condylar platens and pads, the instant combination of condylar platen construct 10 and compressible condylar pad 12 offers improved conformability to the limb, improved progressive padding over the entire platen (and therefore the hinge) and longer hinge life at unimp@@@ed performance levels with smoother operation. By combining at least three prior art components into condylar platen construct 10, the instant invention is much essier to use in building up a hinge, saving time and attendant labour costs. Finally, the instant invention provides the opportunityto design condylar pads for use with the instant condylar pad platen 14 which are more vaned, versatile and therepeutically appropnate than those of the prior art.

Whilst the present invention has been descnbed in respect of particular embodiments. further modifications may readily be made by those skilled in the uL It is intended that the ctaims should cover any such modificabons falling within the spirit and scope of the invention.

Claims (1)

1. A condylar platen construct and assembly: for an orthopaedic hinge defined by having two hinge arms pivotalty mounted on one or more pivots, a hinge back plate and at least one setof pivotal securing means for securing the hinge arms to the backplate: comprising: a condylar pad platen formed in suitable flexible plastics by injection moulding and; a hinge back plate, preferably made in metals and having one or more through holes adapted to receive pivot securing means and incorporated into said construct as an inset and substantially moulded overall to form; integral pbnar shimming means for said hinge extending substantially over an entire first ftce;;and said condylar pad platen moulding additionally having an extension, extending in the direction of a joint at which said condylar platen construct is deployed, peripheral to said incorporated binge back plate and away from a second face thereof; and said condylar pod platen moulding further having a substantial flexible margin extending outwds foom said extension to provide 9 platform; said extension creating a recess between said flexible margin and said inoorporated hinge back plate, thereby providing means for preventing impingement of said flexible margin upon said hinge arms of said orthopaedic hinge into which said condylar platen construct is incorporated and further thereby isolating said flexible margin from said incorporated hinge backplate; and a compressible condylar pad 2.The platen constntct of claim 1, wherein said hinge back plate is made in hard structural composite materials.

3. The condylar platen construct of cairn 1, wherein exposed areas of said hinge back plate are provided aground one or more of said through holes on said first face.

4. The condylar platen construct of claum 1. wherein exposed areas of said hinge back plate are provided around one or more of said through holes on said second face.

5. The condylar leaten constct of claim 1, wherein, injection moulding plastics have low friction properties and integral planar shimming means formed therein are thereby effectively self-lubricating.

6. The condylar pad platen of claim 1, wherein said flexible margin is asymmetrical with respect to said hinge beck 7. The condylar pad platen of claims 1, and 6 wherein said flexible margin has a guttered or open- ended bough pfofik.

8. The condylar pad platen of claims 1, 6 and 7, wherein said flexible margin is contoured with respect to the plane of said hinge back plate.

9. The compressible condylar pad of claim 1, wherein; a first element is in the form of a flexible enclosing structure conveniently made in plastics and confining air and having; a first central potion extending below the general plane of said compressible condylar pad so as to form a downstand. so sized end shaped as to substentially engage said recess in said condylar pad platen; and 9 second peripheral portion extending above the general plane of said compressible condytar pad, so sized and shaped as to locate generally upon said flexible margin portion of said condylar pad platen; and a sealing zone disposed between said first central portion and said second peripheral portion; a second element is in the form of first and second cushions made of resilent foamed plastics; said first cushion being located within said central portion of said enclosed stnlcture; and said second cushion being located within said peripheral portion of said enclosed structure.

10. The compressible condylar pad of claim 9 wherein said enclosed structure is sealed against the and egress of of air.

11. The compressible condylar of claim 9. wherein said enclosed structure has provision for ingress and egress of air.

12. The compressible condylar pad of claim 1, wherein a first cushion element is provided for said recess in said condylar pad pilten and a second cushion element extends over the entire pan area of said flexible margin and said fist pad element 13. The compresible condylar pad of claim 1, wherein a first cushion element 15 provided for said recess in said condylar ped platen which extends through a second cushion eleement having the form of ring and which extends over said flexible margin of said condylar pad platen.

14. The compressible condylar pad of claims 9. 12 and 13, wherein each of said first and second cushions are made from open cell resilient foamed plastics.

15. The compressible condylar pad of claims 9, 12 and 13, wherein each of said first and second cushions is made from closed cell resilient foamed plastics.

16. The compressible condylar pad of claims 9, 12 and 13, wherein each of said first and second cushions is made from a combination of more than one type of resilient foamed plastics.

17. The compressible condylar pad of claims 9, 12, 13, and 16, wherein each of said first and second cushions is made from the same resilient foamed plastics.

18. The compressible condylar pad of claims 9, 12, 13, and 16, wherein each of said first and second cushions is made from different resilent foamed plastics.

19. The compressible condylar pad of claims 9, 12, 13 and 15 to 18, wherein said first and second cushions are made by die-cutting.

20. The compressible condylar pad of claims 9, 12, 13 and 15 to 18, wherein said first and second cushions are made by compression moulding.

21. The compressible condylar pad of chim 9. wherein said first central downstand portion additionally extends upwards through said peripheral portion.

22. The compressible condylar pad of claims 9, 12 and 13, wherein secunng means to said condylar pad platen are in the form of a fabrics bonnet having a self-retaining edge provided by elastic means.

25. The compressible condylar pad of claim 1, wherein; a first central portion extends below the general plane of said compressible condylar pad so as to form a downstand, so sized and shaped as to substantially engage said recess in said condylar pad platen; and a second peripheral portion extends above the general plane of said compressible condylar pad, so sized and shaped as to locate generally upon said flexible margin portion of said condylar pad platen.

said compressible condylar pad being formed in resilient foamed plastics by compression moulding.

26. A condylar platen construct for an orthopaedic hinge comprising: a condylar pad platen; a hinge back plate incorporated in said platen; planar shimming means for said hinge extending substantially over a first face of said back plate; and a compressible condylar pad; said platen having an extension peripheral to said back plate and extending away from a second face of said back plate and said platen having a flexible margin extending outwardly from said extension, said extension creating a recess between said flexible margin and said back plate.

27. A condylar platen construct according to claim 26, wherein said pad comprises a first central portion forming a downstand substantially to engage in said recess, and a second peripheral portion adapted to locate substantially upon said flexible margin.

28. A condylar platen construct substantially as hereinbefore described with reference to the accompanying drawings.