FR2590794A1 - Joint prosthesis, in particular for a finger joint - Google Patents

Abstract

The device relates to a joint prostheses of the type including two pins 11, 12 intended each respectively to be engaged in the two bones to be connected, and, positioned between the said pins, jointed surfaces. According to the invention, these jointed surfaces include, for the pin 11, two spherical caps 15A, 15B directed in opposite directions, and, for the pin 12, two spherical caps 16A, 16B which, complimentary to the preceding ones, fit into them, interacting with restraining means capable of allowing only a relative pivoting, around a transverse axis T, of the said spherical caps 16A, 16B with respect to the said spherical caps 15A, 15B. Application in particular to joint prostheses for the fingers.

Description

"Joint prosthesis, in particular for
finger joint "
The present invention relates generally to joint prostheses, and it relates more particularly to those according to which only a joint around an axis must be authorized.

 This is the case, for example #, of the joints intervening between the successive phalanges of a finger, which, as we know, constitute trochlear diarthroses, that is to say joint joints in which a bone rolls on another thanks to a groove, forming a pulley, which this one presents for this purpose.

 The prostheses currently offered as a replacement for such a joint in the event of trauma are not entirely satisfactory.

 First of all, there are prostheses made of flexible material, natural or synthetic rubber for example, the mechanical strength of which is sometimes insufficient.

 Then there are mechanical prostheses comprising, for example, two pins, intended to be engaged, each respectively, in the two bones to be connected, and, intervening between said pins, a simple yoke, integral with one of these ci, and an axis, integral with the other.

 Such mechanical prostheses have a double disadvantage.

 First of all, they do not lend themselves, without break or complication of unacceptable structure, to any possibility of dislocation, or in other words of dislocation, even though on the contrary such a possibility must physiologically be sought.

 In addition, the articular surfaces which they bring into play being open surfaces, that is to say surfaces opening laterally in several places, since they are successive cylindrical surfaces, they can, by bone invasion, be progressively seized.

 The present invention generally relates to a joint prosthesis which does not have these drawbacks and which is likely to give satisfaction.

 This articulation prosthesis, which is of the type comprising two pins, intended to be each engaged respectively in the two bones to be connected, and, intervening between said pins, articular surfaces suitable for allowing only a relative pivoting of these- ci around a transverse axis, is generally characterized in that said articular surfaces -comport, for one of the spindles, said here by simple convenience spindle carrier, two spherical caps, which, centered one and the other on an axis perpendicular to said carrier pin being oriented in opposite directions relative to each other, are carried by said carrier pin, and, for the other of said pins, said here for convenience pin carried , two other spherical caps, which, each complementary respectively to the previous ones, and thus able to be taken with them, are carried by said worn pin, in cooperation with means, said here for simple convenience ity restriction means, capable of authorizing only a relative pivoting, along said axis, of the spherical caps of the pin carried relative to the spherical caps of the carrier pin.

 According to a first embodiment envisaged, the carrying spindle is integral with a crosspiece, which can optionally be reduced to a simple flange, and at the end of which are each respectively arranged, back to back, its spherical caps, and, these Ci thus thus belonging to distinct spherical surfaces, said cross member constitutes by itself the associated restriction means, since it opposes the rotation around itself of the spindle carried.

 As a variant, the spherical caps of the carrying spindle are convex and belong to the same spherical surface, for example a ball, and, for constituting the associated restriction means, there are provided, integral with said carrying spindle, two bearing surfaces planes, which, parallel to each other, are perpendicular to the desired axis of articulation, and, integral with the spindle carried, two plane abutment surfaces, each capable of coming to bear respectively on said surfaces of support of the spindle.

 In any case, since the spherical caps of the carried pin can play relative to the spherical caps of the carrier pin with which they are engaged, it exists, advantageously and in a very simple and safe manner, without risk of breakage, a possibility of dislocation.

 In addition, the articular surfaces which these spherical caps constitute being surfaces which, with the exception of their peripheral edge, are geometrically closed on themselves, the risk that they are inadvertently the object of any bone invasion is advantageously limited.

 Furthermore, and according to a development of the invention, at least one of the pins, and preferably each of these, is associated with a sheath, in which such a pin is engaged, and with respect to which it can play longitudinally.

 It is then this sheath which is sealed in the corresponding bone cavity.

 However, the possible play with respect to it of the corresponding pin advantageously favors a possibility of dislocation at this level.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which
Figure 1 is an axial sectional view of a joint prosthesis according to the invention, in place between the two phalanges of a finger
Figure 2 is, on a larger scale, an axial sectional view of this single articulation prosthesis, shown in isolation, before its installation
Figure 3 is an axial sectional view similar to that of Figure 2 and relates to an alternative embodiment;
Figure 4 is also an axial sectional view similar to that of Figure 2 and relates to another alternative embodiment
Figure 5 is also another view in axial section similar to that of Figure 2, and it also relates to another alternative embodiment
Figure 6 shows, on a larger scale, the detail of Figure 5 identified by a VI insert thereon
Figure 7 is a side view of this alternative embodiment, according to arrow VII of Figure 5
Figure 8 is a cross-sectional view along the line Vili-Vîli of Figure 7;
Figures 9A, 9B are views in axial section which, similar to that of Figure 5, illustrate two successive phases of implementation of the prosthesis according to the invention;
Figure 10 is an elevational view of the sheath which may include such a joint prosthesis
FIG. 11 is a plan view of this sheath, along arrow XI of FIG. 10.

 As illustrated in these figures, the articulation prosthesis according to the invention is of the type comprising two pins 11, 12, intended to be engaged, each respectively, in the two bones 13, 14 to be connected, in this case two any phalanges of any finger, and, intervening between said pins 11, 12, articular surfaces, detailed below, adapted to allow only a relative pivoting of these pins 11, 12 about a transverse axis T , that is to say around an axis substantially perpendicular to their own direction of elongation.

 This transverse axis T has been shown in broken lines in Figures 1 to 5; it has been shown diagrammatically by its trace in Figure 7.

 According to the invention, the articular surfaces used between the pins 11, 12 comprise, for one of these pins, namely, in this case, the pin 11, said here for simple convenience carrying pin, two spherical caps 15A, 15B, which, both centered on an axis perpendicular to said carrier pin 11, in this case the transverse axis of articulation T sought, being oriented in opposite directions relative to the other, are carried by said carrier pin 11, and, for the other of said pins, in this case pin 12, said here by simple convenience pin carried, two other spherical caps 16A, 16B, which, each complementary respectively of the preceding ones, and thus capable of being engaged therewith, as shown, are carried by said carried pin 12, in cooperation with means, here called for simple convenience means of restriction, detailed below, specific to n '' allow a relative pivoting, along said transverse axis l of articulation T, spherical caps 16A, 16B of the carried pin 12 relative to the spherical caps 15A, 15B of the carrying pin 11.

 In the embodiment more particularly shown in FIGS. 1, 2, the carrying pin 11 is integral with a cross member 18 at the ends of which are each respectively arranged, transversely, and back to back, its spherical caps 15A, 15B, and , these thus belonging to distinct spherical surfaces, said crosspiece 18 constitutes by itself the associated restriction means.

 In practice, in the embodiment shown, the spherical caps 15A, 15B of the carrier pin 11 are concave.

 They extend for example over a solid angle close to 180-, as shown.

 It goes without saying that this solid angle can be less than 180-.

 It can also, if desired, be slightly greater than 180-, on the one hand to ensure auditory control, by emission of a characteristic sound "click", of the effective engagement of the spherical caps 16A, 16B in the spherical caps 15A, 15B, and on the other hand to ensure, with all the possibility of dislocation, a relative retention of these spherical caps 16A, 16B by these spherical caps 15A, 15B.

 While the carrying pin 11 can for example be made of metal, with a relatively tapered end preferably provided, from place to place, with barbs 19 adapted to facilitate anchoring in the bone in which it must be engaged, the crosspiece 18 is preferably made of synthetic material biologically compatible with bone tissue, such as high density polyethylene or polytetrafluoroethylene for example.

 Anyway, the assembly generally has a T shape, the support pin 11 being engaged by a cylindrical head 20 in a bore 21 affecting in its median zone the crosspiece 18, with, for its blocking thereon , a pin 22 extending transversely, along the transverse axis of articulation T, from one of the spherical caps 15A, 15B to the other, in the median zone thereof.

 Anyway, also, it is on the transverse end edge of the cross member 18 that these spherical caps 15A, 15B are shaped, with subsistence, around them, of a rim 23A, 23B of sufficient thickness to present an acceptable mechanical resistance.

 In the embodiment shown, the spherical caps 16A, 16B of the carried pin 12 are convex and they each belong respectively to separate balls 25A, 25B, said carried pin 12 comprising two arms 26A, 26B at the ends of which are each respectively reported said balls 25A, 25B.

 In practice, opposite the spherical cap 16A, 16B which it forms, each of the balls 25A, 25B is truncated, for example along a plane PA, PB substantially perpendicular to the transverse axis of articulation T, such that shown, with subsistence, in the central region of the part thus truncated of such a ball 25A, 25B, of a lug 28A, 28E, by which the latter is secured to the arm 26A, 26B relates to the spindle carried 12 .

 For example, a washer 29A, 29B, which is integral with the associated arm 26A, 26B, but which can also form a separate part thereof by being suitably attached to it by welding or the like, is engaged in this effect on the pin 28A, 28B of the ball 25A, 25B concerned.

 The beads 25A, 25B thus used can for example be made of alumina, sapphire in particular, or any other equivalent mineral or synthetic material, such as ceramics.

 Jointly, the washers 29A, 29B used for their fixing can be metallic, and they are then advantageously secured to their lug 28A, 28B by shrinking on it.

 In the embodiment shown, the spindle 12 is split into two half-spindles 12A, 12B, on either side of a median plane M perpendicular to the transverse axis of articulation T, and it is of these half-spindles which are each respectively secured to the associated spherical caps 16A, 16B.

 Each half-spindle 12A, 12B is in one piece with the arm 26A, 26B carrying the corresponding ball 25A, 25B, the assembly being for example made of metal.

 Preferably, there is provided, between these half-pins 12A, 12S, as shown, for their attachment to one another, latching means.

 It is, for example, according to an embodiment of the press-button type, of a spherical cavity 30A, of solid angle greater than 180., shaped on the internal face of the half-spindle 12A, in the vicinity of its connection to the corresponding arm 26A, and of a lug 30B, which, of spherical configuration complementary to that of said cavity 30A, extends in correspondence projecting on the internal face of the half-spindle 12B, in the vicinity of its connection with the associated arm 26B.

 Anyway, these two half-pins 12A, 12B are in practice tapered, the assembly having for example the appearance of a point, with or without barb.

 When, at rest, the balls 25A, 25B forming the spherical caps 16A, 16B of the carried pin 12 are engaged in the spherical caps 15A, 15B of the carrier pin 11, the half-pins. 12A, 12B constituting said carried pin 12 progressively move away from each other from their end, as shown in solid lines in FIG. 2.

 As shown schematically in broken lines in this FIG. 2, it is therefore necessary to constrain them elastically so that, joining one another, they jointly form the associated spindle 12, with snap-fastening of the lug 30B in the corresponding cavity 30A .

 This advantageously results in an elastic pressure effect between the spherical caps 16A, 16B and the spherical caps 15A, 15B, favorable for keeping them properly in engagement.

 It also follows from the above that, in practice, the spherical caps 16A, 16B of the spindle carried 12 are both centered on the same axis, which is the transverse axis of articulation T on which are themselves centered on the spherical caps 15A, 15B of the support pin 11.

 In practice, in the embodiment shown, these spherical caps 15A, 15B, 16A, 16S all have the same radius.

 The implementation of the articulation prosthesis 10 according to the invention is done as follows.

 Firstly, and after suitable phasing of the phalanx 13 to be fitted, the carrier pin 11 is driven axially into this phalanx 13, until the cross member 18 which it carries is in contact with its end.

 In a second step, and after also suitable leveling off of the phalanx 14 to which the previous one must be connected, the balls 25A, 25B constituting the spherical caps 16A, 16B of the spindle 12 are engaged in the spherical caps 15A, 15B of the load-bearing spindle 11, preferably with sound control of this engagement, as mentioned above, and, the half-spindles 12A, 12B carrying these balls 25A, 25B being resiliently brought together until they click into place one on the other and thus reconstitution of the carrier spindle 12, the latter is in turn engaged axially in said phalanx 14.

 In the alternative embodiment illustrated in FIG. 3, the spherical caps ISA, 15B of the support pin 11 are convex and belong to the same spherical surface, and, for the constitution of the associated restriction means, it is provided, integral with said pin carrier 11, two flat bearing surfaces 32A, 32B, which, parallel to one another, are perpendicular to the transverse axis of articulation T sought, and, integral with the spindle carried 12, two abutment surfaces planes 33A, 33B, each capable of coming to bear respectively on said bearing surfaces 32A, 32B of the carrier spindle 11.

 In practice, in the embodiment shown, the support pin 11 is integral, no longer with a cylindrical head, as previously, but with a flange 34, the two faces of which each respectively form the bearing surfaces 32A, 32B associated, and in the middle zone of which is located, embedded by projecting laterally on either side of said bearing surfaces 32A, 32B, a ball 35 which forms the spherical surface to which the spherical caps 15A, 15B concerned also belong .

 Jointly, the spherical caps 16A, 16B of the carried pin 12 are then concave spherical caps, and they are each respectively formed at the end of end caps 35A, 35B, which, by their end surface, form, around said spherical caps 16A, 16B, the associated abutment surfaces 33A, 33B.

 These end pieces 35A, 35B, which, like the preceding cover 18, can for example be made of synthetic material such as high density polyethylene or polytetrafluoroethylene, are in the form of generally cylindrical elements, which are arranged in alignment one from the other, on either side of the flange 34 of the support pin 11, and the ends of which opposite said flange are preferably rounded, as shown.

 The arms 26A, 26B of the spindle carried 12 are for example simply fitted there, as shown.

 For the rest, the carried spindle 12 has a structure similar to that described above, and the same is true for the carrying spindle 11.

 As will be understood, the splitting into two half-spindles of the carried spindle 12 can facilitate, to a certain extent, the implementation of the assembly.

 It also promotes obtaining an elastic pressure effect between the spherical caps in play, and therefore a return effect in the event of dislocation.

 However, as will appear below, this splitting is not imperative.

 If, for example, it is still found in the alternative embodiment illustrated in FIG. 4, the corresponding half-pins 12A, 12B are then rigidly secured to one another, for example using 'a rivet 36, as shown.

 Furthermore, in this variant, and as for the embodiments illustrated in FIGS. 1, 2, the spherical caps 156A, 15B of the spindle 11 belong to different spherical surfaces and they are both jointly carried by a cross member 18.

 However, in this variant embodiment, these are convex spherical caps, and, in practice, they each belong respectively to separate balls 38A, 38B each chained to the corresponding ends of the crosspiece 18 respectively.

 This cross member 18, which, as previously, is preferably made of synthetic material biologically compatible with bone tissue, is, in practice, molded onto a flange 34 forming the corresponding end of the support pin 11, said flange 34 being for this purpose traversed right through by an opening 38, and, for its transverse locking in position on this flange 11, it projects laterally, at each of its ends, of said opening 38. around the latter.

 Jointly, the balls 38A, 38B are, as before, made of alumina, sapphire, or ceramic.

 As for the spherical caps 16A, 16B of the carried pin 12, which are concave, they belong to spherical segments 40A, 40B, which, also made of synthetic material biologically compatible with bone tissue, are overmolded, according to the provisions of type of the preceding ones, on the corresponding arms 26A, 26B of this spindle carried 12, and, therefore, as before, they are carried by the latter.

 In the embodiment shown, a clearance is left between the facing faces of the cross member 18 and these spherical segments 40A, 40B.

 But these faces, which are planar, extending substantially perpendicular to the transverse axis of articulation T, can, as a variant, be contiguous.

 In the alternative embodiment shown in Figures 5 to 9, the pins 11, 12 are moon and the other massive.

 As in the embodiment illustrated in FIGS. 1, 2, the spherical caps 15A, 15B of the support pin 11 are concave spherical caps, and they are, each respectively, arranged back to back, at the ends of a crosspiece .

 However, in the embodiment shown in FIGS. 5 to 9, this crosspiece is reduced in practice to a flange 34 forming the corresponding end of the carrying pin 11.

 In the embodiment shown, the lateral surfaces 32A, 32B of this flange 34, which are planar, and which extend generally parallel to one another, substantially perpendicular to the transerval axis of articulation T, are slightly set back from the current part of the support pin 11.

 In practice, and for reasons which will appear below, the shoulders 41 which therefore has the support pin 11 at the root of its flange 34 have, in plan, a circular outline.

 The flange 34 has, itself, in plan, a circular outline and, in the manner of a ring, it is largely hollowed out of an opening 42 in which is disposed a plate 43 having, back to back, the spherical caps 15A, 15B corresponding.

 In practice, the lateral faces of this plate 43 are each respectively level with those corresponding to the flange 34 which it equips.

 As before, the plate 43 is preferably made of synthetic material biologically compatible with bone tissues.

 Anyway, and as before, it is therefore at the ends of the crosspiece formed by the flange 34, in this case the lateral faces of the plate 43 thereof, that the caps are arranged back to back spherical 15A, 15B of the support pin 11.

 Furthermore, in the embodiment shown, the spherical caps 16A, 16B of the pin carried 12 each belong respectively to two pins 44A, 44B which are mounted movable transversely relative to pins 11, 12, along the transverse axis of articulation T, said spindle carried 12 comprising two arms 26A, 26B each having, respectively, in alignment with one another, two housings 45A, 45B in which each of said pins 44A, 44B are each slidably engaged.

 Like the plate 43, these pins 44A, 44B can for example be made of synthetic material biologically compatible with bone tissue.

 They can also be pawns of alumina, sapphire or ceramic.

 Anyway, they are generally cylindrical, having for example, and as shown, a circular transverse contour, and the spherical caps 16A, 16B form the ends.

 In the embodiment shown, the housings 45A, 45B in which these pins 44A, 44B are arranged, pass right through the arms 26A, 26B concerned of the pin carried 12, and they therefore open to the outside.

 Preferably, and as shown, between these pins 44A, 44B and the arms 26A, 26B which carry them are provided latching means suitable for blocking in the disengageable position of said pins 44A, 44B in their respective housings 45A, 45B.

 For example, and as shown, there is provided, for each of them, between leather and flesh, an elastically deformable ring 46A, 46B which, disposed in a groove 47A, 47B of the arm 26A, 26B concerned capable of absorbing it completely, FIGS. 9A, 9B, is able to cooperate, jointly, with a corresponding groove 48A, 48B of the pin 44A, 44B corresponding to it, allowing only a partial engagement, FIGS. 5, 6.

 Furthermore, in the embodiment shown, the arms 26A, 26B of the carried pin 12 form a yoke, which, complementary to the flange 34 forming the end of the carrying pin 11, is capable of enclosing the latter, the surfaces internal of these arms 26A, 26B, which are planar, and which extend substantially parallel to one another, perpendicular to the transverse axis of articulation T, being established at a distance from each other substantially equal to the thickness of said flange 34 while being slightly greater than the latter.

 The arrangements are such that, when the flange 34 of the carrying pin 11 is engaged in this yoke, and the pins 44A, 44B of the carried pin 12 are engaged, by their spherical caps 16A, 16B, with the spherical caps 15A , 15B of said flange 34, FIG. 5, said pins 44A, 44B are flush with the outer surface of the arms 26A, 26B constituting said yoke.

 Preferably, and as shown, to present an appearance similar to that of the joint to be replaced externally, these arms 26A, 26B have, transversely, a rounded external profile, and it is the same, in continuity with them, for the corresponding end of the pins 44A, 44B.

 In plan, they have a circular contour complementary to that of the shoulders 41 of the support pin 11, for cooperation with these, FIG. 7.

 Finally, in the embodiment shown in FIGS. 5 to 9, it is associated, with at least one of the pins 11, 12, and, in practice, with both of them, a sheath 51, 52, in which such a pin 11, 12 is engaged, and with respect to which it can play longitudinally.

 Preferably, and as shown, the pins 11, 12 have, on the outside, a pyramidal outline, being very slightly tapered in the direction of their end opposite to the transverse axis of articulation T, and, as a corollary, the sleeves 51, 52 have, internally, a pyramidal contour complementary to the previous one.

 The corresponding shanks are therefore pyramid shanks.

 In the embodiment shown, the cross section of the pyramidal contours concerned is quadrangular.

 It might as well be triangular.

 More generally, it is preferably polygonal to normally prevent any rotation of the spindles. 11, 12 in their sheaths 51, 52.

 In the embodiment shown, the sleeves 51, 52 thus used also have a pyramidal outer contour, like their inner contour.

 Furthermore, over at least a portion of their length, they have notches 53 transversely.

 These sleeves 51, 52 are intended to be forcibly engaged in the knuckles to abut, previously excavated for this purpose, their notches 53 then allowing them to anchor there.

 they can also be made integral with these phalanges by any other appropriate means, and for example by sealing or screwing.

Anyway, once in place these sheaths 51, 2, the implementation of the prosthesis according to the invention, in its embodiment shown in Figures 5 to 9, is done as follows
The pins 44A, 442 of the spindle carried 12 being in the projecting position relative to its arms 2SS, 26B, with the corresponding elastically deformable rings 46A, 46B elastically driven back into the grooves 47A, 47B thereof, FIG. 9A, it suffices to engage, by its flange 34, the support pin 11 in the yoke formed by these arms 26Â, 26B, since in contact with the cylindrical shoulders 41 of this support pin 11 with the cylindrical lateral paroli of the latter, FIG. 9B, then , to push back, in their housings 45A, 45B, the pins 44A, 44B, until their spherical caps 16 #, ~ 16B coming into engagement with those 15A, 15B of the plate 43 clamped by the flange 34, their outer ends are again in continuity with the corresponding rounded surface of said arms 26A, 26B, FIG. 5.

 At the end of this operation, the elastically deformable rings 46A, 46B engage elastically in the grooves 48A, 48B of the pins 44A, 44B, which advantageously results, as previously, in a sound "click" materializing the correct execution of the assembly. to ensure.

 Of course, these operations are carried out before or after the engagement of the pins 11, 12 in their respective sleeves 51, 52.

 In this embodiment, and unlike the previous provisions, a dislocation, if it occurs, occurs preferentially, not at the level of the spherical caps in engagement with each other, but between at least one of the pins 11 , 12 and the corresponding sleeve 51, 52.

 As indicated above, since the fitting of such a pin 11, 12 with its sheath 51, 52 is advantageously pyramidal, there is normally no possibility of rotation between it and this sheath.

 However, in the event of dislocation, on the contrary advantageously such a possibility of rotation develops, a clearance then appearing between the spindle 11, 12 concerned and its sheath 51, 52, due to its longitudinal displacement relative to the latter.

This possibility of rotation, which remains limited, can advantageously allow the relative torsional force applied to the phalanges concerned to inadvertently lead to loosening of the prosthesis
The recall between the phalanges in question is then done naturally by the tendons usually intervening between them.

 As before, the sheaths 51, 52 thus used are preferably made of synthetic material biologically compatible with bone tissues.

 As indicated above, the notches 53 which they comprise, and which operate in the manner of barbs, may be sufficient for their implantation in the corresponding bone cavities.

 The material of these being in practice a very progressive spongy material, the intervals between these notches 53 are very quickly the object of a significant bone invasion consolidating their fixation in the phalanges concerned.

 In the variant embodiment shown diagrammatically in FIGS. 10, 11 for one of them, in this case the sheath 51, one and / or the other of the sheaths 51, 52 thus used can be attached by screwing in the phalanxes to be fitted, these sheaths then having externally a thread 54, which can either be integral with them, or result from an insert on them.

 The advantage of such an arrangement is that it allows the position of the sleeves 51, 52 to be rectified by rotation in the knuckles to be fitted before the pins 11, 12 are engaged therein.

 Of course, the present invention is not limited to the embodiments described and shown, but encompasses any variant embodiment and / or combination of their various elements.

 In addition, the field of application of the invention is not limited to that of only prostheses for fingers.

 It can extend for example as well to that of prostheses for elbows or knees.

Claims (21)

 1. Joint prosthesis, of the kind comprising two pins (11, 12) intended to be engaged, each respectively, in the two bones to be connected, and, acting between said pins (11, 12), articular surfaces specific to n '' authorize that a relative pivoting thereof around a transverse axis (T), characterized in that said articular surfaces comprise, for one (11) of the pins, said here for simple convenience carrying pin, two caps spherical (15A, 15B) which, centered one and the other on an axis perpendicular to said carrier pin (li) being oriented in opposite directions with respect to each other, are carried by said carrier pin ( 11), and, for the other (12) of said pins, called here by simple convenience pin carried, two other spherical caps (16A, 16B), which, each complementary respectively to the previous ones and thus able to be engaged with these- ci, are carried by said worn pin (12), in cooperation with mo yen, here called for simple convenience, means of restriction, capable of authorizing only a relative pivoting, along said axis (T), of the spherical caps (16A, 16B) of the spindle carried (12) relative to the spherical caps ( 15A, 15B) of the carrier spindle (11).  2. Joint prosthesis according to claim 1, characterized in that the carrying pin (11) is integral with a crosspiece (18, 34) at the ends of which are each respectively arranged, back to back, its spherical caps (15A , 15B), and, these thus belonging to distinct spherical surfaces, said crosspiece (18, 34) constitutes by itself the associated restriction means.  3. Joint prosthesis according to claim 2, characterized in that the spherical caps (15A, 15B) of the carrier pin (11) are concave.  4. Joint prosthesis according to claim 3, characterized in that the spherical caps (15A, 15B) of the carried pin (12) each belong respectively to separate balls (25A, 25B), said carried pin (12) comprising two arms (26A, 26B) at the end of which are each respectively reported said balls (25A, 25B).  5. Joint prosthesis according to claim 4, characterized in that, opposite the spherical cap (16A, 1XB) which it forms, each of said balls (25A, 25B) is truncated, with subsistence, in the middle zone of the thus truncated part of this ball (25A, 25B), of a lug (28A, 28B) by which the latter is secured to the arm (26A, 26B) concerned of the pin carried (12).  6. Joint prosthesis according to claim 3, characterized in that the spherical caps (16A, 16B) of the carried pin (12) each belong respectively to two pins (44A, 44B) which are mounted movable transversely relative to the two pins (11, 12), said carried pin (12) comprising two arms (26S, 26B) each having respectively; in alignment with one another, two housings (45A, 45B) in which said pins (44A, 44B) are slidably engaged.  7. Joint prosthesis according to claim 6, characterized in that said housings (45A, 45B3 open to the outside.  8. Joint prosthesis according to any one of claims 6, 7, characterized in that, between the pins (44A, 44B) and the arms (26A, 26B) which carry them are provided snap-fit means specific to a blocking in the disengageable position of said pins (44A, 44B) in their housings (45A, 45B)  9. Joint prosthesis according to any one of claims 6 to 8, characterized in that the crosspiece (18) of the carrier pin (11) is reduced to a flange (34) and the arms (96h; 26B) of the carried pin (12) form a yoke which encloses said flange (34) of the carrying pin (11).  10. Joint prosthesis according to claim 9, characterized in that the flange (34) of the carrying pin (11) forms a ring in which is disposed a plate (43) having back to back the spherical caps (15A, 15s ) corresponding.  11 Joint prosthesis according to any one of claims 6 to 10, characterized in that the arms (26A, 26B) of the carried pin (12) themselves have a rounded external profile.  12. Joint prosthesis according to claim 2, characterized in that the spherical caps (15A, SA, 15B) of the carrier pin (11) are convex and they each belong respectively to two separate balls (38A, 38B) each encased respectively at the ends of the crosspiece (18), and, jointly, the spherical caps (16A, 16B) of the carried spindle (12), which are concave, are each carried respectively by arms (26A, 26B) which the latter has .  13. A joint prosthesis according to claim 1, characterized in that the spherical caps (15A, 15B) of the carrier pin (11) are convex and belong to the same spherical surface, and, for constituting associated restriction means, two flat bearing surfaces (32A, 32B) which are parallel to each other are perpendicular to the desired articulation axis (T), integral with said carrier spindle (11), and, integral with the carried spindle (12), two planar abutment surfaces (33A, 33B), each capable of coming to bear respectively on said bearing surfaces (32A, 32B) of the carrying spindle (11).  14. Joint prosthesis according to claim 13, characterized in that the carrying pin (11) is integral with a flange (34), the two faces of which each respectively form the associated bearing surfaces (32A, 39B), and in the median zone of which is embedded, projecting laterally on either side of said bearing surfaces (32A, 32B), a ball (35), which forms the spherical surface to which the spherical caps ( 15A, 15B) concerned.  15. Articulation prosthesis according to any one of claims 13, 14, characterized in that the spherical caps (16A, 16B) of the carried pin (12), which are concave, are each respectively formed at the end of tips (35A, 35B), which, by their end surface, form, around said spherical caps (16A, 16B), the associated abutment surfaces (33A, 33B), said carried pin (12) comprising two arms (26A, 26B) at the end of which said tips are each respectively reported (35A, 35B).  16. Joint prosthesis according to any one of claims 1 to 15, characterized in that the spherical caps (16A, 16B) of the carried pin (12) are centered one and the other on the same axis, which is the one on which the spherical caps (15A, 15B) are centered on the carrier pin (11).  17. Joint prosthesis according to any one of claims 1 to 16, characterized in that the carried pin (12) is split into two separate half-pins (12A, 12B) on either side of a plane median (M) perpendicular to the transverse axis of articulation (T), and said half-pins (12A, 12B) each carry the associated spherical caps (16A, 16B) respectively.  18. Joint prosthesis according to claim 17, characterized in that it is provided, between the two half-pins (12A, 12B), for their attachment to one another, latching means.  19. Joint prosthesis according to any one of claims 17, 18, characterized in that, at rest, the two half-pins (12A, 12B) are at least partially spaced from one another, so it is necessary to constrain them elastically so that they jointly form the spindle carried (12).  20. Joint prosthesis according to any one of claims 1 to 19, characterized in that, at least one of the pins (11, 12) is associated with a sheath (51, 52), in which it is engaged and in relation to which it can play longitudinally.  21. joint prosthesis according to claim 20, characterized in that, externally, the spindle (11, 12) concerned has a pyramidal contour, and the sheath (51, 52) corresponding internally to a pyramidal contour complementary to the previous one.