DE3008292A1 - MEDIUM-HANDED FINGERBONE JOINT PROSTHESIS - Google Patents

Description

The invention relates to gel prostheses, to be precise finger joint prostheses, in particular to prostheses for the metacarpal-finger-bone joint. Various prostheses are known for use in the surgical repair of diseased or damaged finger joints. One known device (see, for example, US Patents 3,662,765 and 3,593.3 ^ 2) consists of a one-piece flexible rubber body with plugs for attachment in the intramedullary canal of the two bones forming the joint. Although in widespread use, this type of prosthesis has certain disadvantages. For example, rubber with adequate flexibility does not have the required mechanical strength and some mechanical deterioration and even breakage of this type of prosthesis has been clinically observed under the conditions encountered in actual use. In addition, these prostheses can cause an extremely unnatural feeling in the body because they do not always bend at the desired point or do not adequately control rotational movements between ulna and radius, and because they give the extensor tendon insufficient momentary arm to overcome the extensor inertia,

A second type of known finger joint prosthesis (see, e.g., U.S. Patents 3,506,982, 4,011,603, and 4,059,854) includes two Components, the protruding head portion of the one Component snaps into the plastic housing of the other component and is retained therein. This type of prosthesis generally creates a more accurate representation of the movement

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of the natural finger joints as the one-piece rubber implants, however, it is basically a tethered device nonetheless and thus can exaggerate an uncomfortable feeling Cause constriction in a patient's body. The forces inherent in the mechanical compulsion of this type of prosthesis are transferred to the plastic housing, which can fail due to creeping or breaking.

A potential problem with the use of joint prostheses is generally always that the attachment between an intramedullary rod of the prosthesis and the! found of the intramedullary Canal of the guest bone under the influence of those occurring in use at the bone-prosthesis attachment interface Can relieve tension. This problem can occur regardless of whether the fixation is cement or bone tissue ingrowth or alternatively possible procedures. Torsional, shear, tensile and fracture forces acting on the prosthesis become general transferred to the bone-prosthesis attachment interface, which is then caused by the constantly recurring effect of these forces can be weakened *

It would therefore be of great use to the technology, some kind of joint prosthesis to create in which the transfer to the Forces acting on the prosthesis on the bone-prosthesis attachment interfaces reduced to a minimum and thus the integrity of the after implantation and, for example, tissue ingrowth achieved Fastening ensured and also the risk of a subsequent loosening of the fastening during use of the Prosthesis is diminished. It would be at the metacarpal joint also extremely beneficial, with a new prosthesis, the movement

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The movements and degrees of freedom of movement of the natural joint without, of course, the mechanical strength of the Affect the device.

A novel prosthesis door a joint of a first bone with a second bone has now been invented, consisting of a first component, a second component in pivot bearing relationship with the first component, wherein the first component operatively connected to the first bone, the second component operatively connected to the second bone and the connection of at least one of these components to its bone is such that relative longitudinal movement therebetween the component and its bone is intended. Although there is particular interest in a finger joint prosthesis, in particular a metacarpal finger bone joint prosthesis, the new prosthesis can be adapted for use in other joints, for example the elbow or knee joint will.

Of particular interest is a novel prosthesis for a joint consisting of a first bone with a second bone from a first intramedullary plug which is adapted to be attached to the wall of the intramedullary canal three first bone and is provided with a longitudinal bore formed therein, a second intramedullary plug which is suitable to be attached to the ¥ and of the intramedullary canal of the second bone, and with a longitudinal bore formed therein is provided, a first constituent part with a bearing portion and a rod extending therefrom and a second component having a bearing portion and an itself

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rod extending therefrom, said rod of the first and second components being slidably received longitudinally in the bores in the first and second intramedullary plugs, respectively, and with the bearing portions of the first and second components in mutual gelenice engagement with one another. Since the rods of the first and second components can slide freely in the longitudinal direction in their receiving bores, the transmission of tensile forces exerted on the prosthesis to the plug-bone fastening interfaces is virtually impossible. The transmission of compressive forces can also be used as
Shear force on the plug-bone attachment interfaces
can be greatly reduced.

The intramedullary plugs are preferably made of plastic, while the slidable rods of the two components are preferably made of metal or a metal alloy, thereby reducing wear and friction between the plugs and rods. The bearing portion of one of the components (the distal component in the case of a metacarpal-finger bone joint prosthesis) provides
preferably ^ the other component is a convex metal or metal alloy bearing surface, and the bearing portion of the
Another component preferably includes a removable plastic bearing insert which provides the convex bearing surface with a concave bearing surface and contacts it in use. The use of such a removable plastic bearing insert, of course, significantly increases the wear and tear and friction between the bearing portions of the two components

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In a preferred embodiment, the medial handbone finger-bone joint prosthesis is the prosthesis with devices to prevent either rotational movement of the proximal Constituent relative to the proximal intramedullary plug about the longitudinal axis of the metacarpal or a rotational movement the distal component relative to the distal intramedullary plug about the longitudinal axis of the proximal finger bone, however, not both provided. As a result of this feature, which can of course also be realized just as well in prostheses for other joints, so is the transmission of most of them torsional forces exerted on the prosthesis as a shear effect on the plug-bone attachment interfaces are virtually eliminated or significantly reduced without the inherent mechanical stability of the prosthesis to do demolition.

Another feature of the new metacarpal-finger-bone joint pro the se according to the invention relates to the construction and mutual action of the bearing sections of the two Components in the prosthesis that provide a movement and degree of freedom similar to those of the natural metacarpal-finger joint make possible.

The invention will now be described in detail with reference to a preferred embodiment which is in a metacarpal-finger bone gel prosthesis consists. Reference to this embodiment does not limit the scope of the invention, which is limited only by the scope of the claims is fixed. Show it:

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Fig. 1 is an exploded perspective view a metacarpal finger bone joint prosthesis according to the invention,

1A shows an enlarged illustration of a section of the intramedullary finger bone stop of the prosthesis Fig. 1, with representation of the bone tissue ingrowth surface in greater detail,

FIG. 2 shows a plan view from above of the components of the prosthesis according to FIG. 1 in mutual engagement during extension,

. Fig. 3 is a side view of the components of the prosthesis according to Fig. 1 in mutual engagement when stretching and when showing the components when bending (indicated outer line) and the direction of articulation of the prosthesis,

Figure 4 is a bottom plan view of the components the prostheses according to FIG. 1 in mutual engagement when stretched and when showing the axial rotary movement of the rod of the finger component within the longitudinal bore of the intramedullary Finger plugs,

FIG. 5 is a view similar to FIG. 2 when showing FIG Pivoting movement of the finger component between ulna and radius with respect to the median and part of the hand bone when stretching,

6 shows a view from below of the components of the prosthesis according to FIG. 1 in mutual engagement during extension and if the finger component is significantly twisted with respect to the metacarpal component via a pivoting movement between ulna and radius, with the palm half cut away of the shell section of the metacarpal components and representation of the one for the collateral ligament for restoration

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the moment arm available to the prosthesis,

FIG. 7 is a side view of the prosthesis shown in FIG. 1 when it is secured in the intramedullary canals of the metacarpal bone the proximal finger bone with almost full "flexion and with cut away parts of the intramedullary plug,

8 shows a perspective illustration of the left hand of a person with the thumb pressed against the tip of the index finger, in a kind of pinching effect, compared to that shown in FIG The prosthesis is stable,

9 is a front view of a modified embodiment of the plastic bearing insert of the metacarpal component of the prosthesis according to FIG. 1.

In Figures 1 to 7, a preferred embodiment is the Invention, i.e. a metacarpal-finger bone joint prosthesis 1 is shown. The prosthesis 1 consists of an intramedullary metacarpal bone plug 3 made of plastic, a metacarpal component 5 »consisting of a metal housing body 6 and a Plastic bearing insert 7j from a finger bone component 9 Metal and an intramedullary finger bone plug 11 made of plastic. The metacarpal bone and the proximal finger bone of the surgically restored metacarpal-finger bone joint are shown in FIG. The different Ligaments and tendons that participate in the natural joint, such as the collateral ligaments, are shown in FIG. 7 not shown but are generally viable and left in place.

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The intramedullary plugs 3 and 11 are preferably made of Ultra high molecular weight polyethylene. They can be provided in different sizes, like that that their dimensions can be adapted to the size of the recipient's bones. The metacarpal plug 3 is generally larger than finger bone plug 11. Both plugs are tapered, with decreasing cross-sectional area towards the ends of the prosthesis. Before inserting an intramedullary plug, the intramedullary canal is opened to a diameter slightly less (by about 0.02 inches) than the diameter of the plug so that the plug can be introduced in a snug fit against the wall of the channel. The outsides of the plugs 3 and 11 are marked with (see Fig. 1 A) laterally running ridges, e.g. 13 »which form laterally running grooves between them, e.g. 15». The Yände the ridges that point away from the contact surface of the two components, for example the ¥ and 17, are inclined to the! resistance to the use of the plug in the intra- ' Reduce medullary canals to a minimum. However, it is very difficult to pull out the inserted plugs by strengthening the bite of the flat tips, for example, of the ridges against the walls of the canals. A permanent one Fastening is achieved by bone tissue ingrowth in the space of the grooves, for example 15. Permanent fastening can of course be achieved by other methods, such as by using orthopedic Cement.

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Each of the intramedullary plugs 3 and 11 is provided with one Longitudinal bore 21 and 23 provided in the central axis of the Stopper is aligned and open at both ends of the stopper. Each of the plugs 3 and 11 ends at his the contact surface of the two components facing end with a circular flange 25 and 27, the Backs 29 and 3I against the resected ends, respectively metacarpal and proximal pinger bone sit up. ¥ ie from Fig. 7 is for the surgical Use of the intramedullary plugs 3 and 11 only requires a very small resection of the natural bone.

The finger component 9 can be a surgical implant in the form of one cast from an alloy in one piece Be the subject. An extremely suitable alloy is Vitallium (Howraedica Inc .; New York, New York). The part 9 consists of a rod 33 »a flange 35 on the proximal end of rod 33, a neck portion 37 extending from proximal flange side 35, and a protruding head portion 39, which is also here as Bearing portion is referred to, carried by the neck portion 37. The rod 33 becomes slidable and rotatable in the longitudinal bore 23 in the intramedullary plug 11 of the finger recorded. A limit to the extent of insertion is reached when the distal side 41 of the flange 35 against the Front side 43 of flange 27 is seated on plug 11. The flange 35 is shaped as a circle when removed from

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two identical and opposite lateral circular segments (see Fig. 1) to a significant pivoting movement of when stretched. Cannot prevent ulna and radius.

The metacarpal component 5 consists of a metal housing body 6 and a plastic bearing insert 7. The housing body 6 can be a surgical implant in the form of an object cast in one piece from an alloy, preferably made of Vitallium (Howmedica Inc.j New York, New York). The housing body 6 consists of a lower head section 45 and a rod 47 which extends from it in the proximal direction. The head section 45 and the plastic bearing insert 7 together form the bearing section, also referred to in this description as the shell section of the metacarpal component 5. The removable plastic bearing insert 7 is retained in the head portion 45 by a friction fit. In the unusual case that considerable wear occurs in an insert 7 during use of the prosthesis, the insert can be surgically removed and replaced with a new one, with the slightest disruption of the remaining part of the surgically restored metacarpal-finger-bone joint. The insert 7 is preferably made from an ultra high molecular weight polyethylene.

The rod 47 is slidable in the longitudinal bore 21 of the intramedullary Middle hand bone plug 3 added. A limitation of the extent of the onset is reached when the

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The rear side 49 of the head section 45 is seated against the front side 5t of the flange 25 on the plug 3. One or more longitudinal ribs (a pair of such ribs, for example 53, is shown in the drawings) protruding from the outside of the rod 47 are received in corresponding longitudinal slots, for example 55 "in the wall of the bore 21, thereby creating a Rotational movement of the component 5 relative to the intramedullary plug 3 about the longitudinal axis of the metacarpal bone is prevented.

Since an axial rotary movement of only one of the two components of the prosthesis I is allowed with respect to the plug receiving it, the situation can never arise in which both components 5 and 9 rotate with respect to the two bones forming the joint while they are remain fixed relative to each other.

Devices other than those shown in the drawings can be used to prevent rotational movement of the metacarpal component 5 with respect to the plug 3 about the longitudinal axis of the metacarpal bone. For example, the front 5I cl ^there flange 25 may have a concave cylindrical surface, which fully or partially works in the form of corresponding convex cylindrical surface of the rear side 49 of the head portion 45 to the stopper 3 and the part 5 against relative rotational movement with a stabilize. The arrival

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wendtmg this optional device for prevention a rotary movement eliminates the need for the ribs indicated in the drawings, for example 53 »and the slots, for example 55 »off.

As a result of these shapes of the plugs, rods and flanges shown in the drawings, the transmission of forces exerted on the prosthesis to the bone-plug attachment interfaces is greatly reduced. The transmission of tensile forces to the fastening interfaces is eliminated since the rods kj and 33 are free to slide longitudinally in the bores 21 and 23 in the plugs 3 and 11. Compressive forces are transmitted from head portion 45 and flange 35 to plug flanges 25 and 27 and then distributed primarily as pressure on the resected cortical margins against which the plug flanges are seated and along the substantial surface area of the beveled walls of the intramedullary canals. Thus, the transmission of compressive stresses as shear forces to the fastening interfaces is effectively reduced. The transmission of rotary spar tongues of a type for generating torque about the longitudinal axis of the proximal finger bone is also practically eliminated because of the freedom of the rod 33 to rotate in the bore 23 in the plug 11. The proportion of torsional stresses of some kind to produce a torque around the longitudinal axis of the metacarpal bone that acts as a shear force on the metacarpal plug attachment interface.

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INSPECTED

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is approximately through the sine of the angle of diffraction (or hyper-extension) given. The components 5 and 9 of the prosthesis 1 acting shear forces exert small bending moments on the plug 3 and 11, which over the Lengths of these plugs are distributed. The stresses on the attachment interfaces created by these small bending moments are distributed more evenly due to the softness of the plastic stoppers and have little effect on the integrity of the attachment. Thus, accordingly the risk of movement of the plugs with respect to the intramedullary canal edges during the tissue ingrowth period and the risk of loosening the fastenings during the subsequent Use of the prosthesis is both significantly reduced.

In a modified form of the invention, not shown in the drawings, longitudinal ribs such as ribs 53 are provided on the rods of both components of the prosthesis and longitudinal slots such as slots 55 are provided in the walls of the bores in both intramedullary plugs . Each rod is slidably received longitudinally in one of the intramedullary plugs. By making the ribs considerably thinner than the slots for receiving them, limited freedom of movement for relative rotational movement ( -15 ° to 20 °) is introduced between at least one, and preferably each, of the two rods and the intramedullary plug receiving them. This modification of the invention makes the prosthesis for the metacarpal finger joint, for example, an excellent equal-

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weight between freedom of movement and mechanical constraint granted.

The head portion 39 of the finger component 9 is cylindrical with rounded ends 57 and 59 · Preferably the ends 57 VLOd 59 are semicircular as shown in the drawings. The longitudinal axis of the cylindrical head portion 39 is perpendicular to the articulation plane of the prosthesis (see Pig. 3). The inner walls of the plastic bearing insert 7 define a shell cavity 6t through which the cylindrical head portion 39 is slidably received when the components 5 and 9 are mutually engaged. The concave proximal inner wall 63 of the plastic bearing insert 7 serves as the bearing surface of the metacarpal component 5. The surface 63 is semi-cylindrical in shape with rounded ends and corresponds in shape exactly to the cylindrical head section 39, so that the bearing surface 63 and the head section 39 fit closely fit together when the prosthesis 1 is under pressure. The shell cavity 61 extends distally from the bearing surface 63 to the opening 65 in the discrete end of the insert 7. The opening 65 has approximately the same dimensions as a cross section taken through the longitudinal axis of the head section 39. Therefore, the head portion 39 can freely slide through the opening 65 to enter the shell cavity 61. In the palm wall of the insert 7, a slot 67 extends distally from the bearing surface 63 until it comes into contact with the opening 65. As well as the prosthesis 1 is flexed

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(See FIG. 3), the neck portion 37 of the finger bone component 9 passes through the palm slot 67 in the insert 7 and an aligned slot in the head portion 45. Sufficient clearance is provided so that the neck portion 37 does not contact the side walls delimiting one of the slots 67 and 69. The joint movement is limited by the stop of the head portion 37 of the finger bone component 9 against the surface 71 of the plastic bearing insert 7 and the surface 63 of the metal housing body 6. A joint movement range of about 20 hyper-extension to about 90 ° flexion is permitted.

The prosthesis 1 precisely reproduces the areas of movement and the degree of freedom of movement of the natural metacarpal-finger bone joint and therefore has a natural and realistic "feel" after implantation in the body of a patient. Since the head portion 39 can slide within the shell cavity 6i , the components 5 and 9 of the prosthesis 1 are considerably less restricted and have greater freedom of movement for relative play than the components of the connected prostheses according to the prior art. The freedom of movement of the head portion 39 within the shell cavity 61 provides additional means of preventing the transmission of tensile stresses exerted on the prosthesis to the bone-plug attachment interfaces. The mechanical stability of the prosthesis 1 is supported by the self-stabilizing effects of the various

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natural ligaments and tendons, such as the collateral ligaments and the extensor and flexor muscle tendons. the The extensor tendon is flexed in the 75 in the dorsal side of the head portion 45 held. The track 75 has a distovolar curve. As shown in Fig. 3, the axis of articulation of the prosthesis 1, i.e. the Longitudinal axis of the head section 39 »volar from that through the Longitudinal axis of rods 33 and 47 offset when extending the delimited line by that for the weaker extensor tendon available moment arm and at the same time an appropriate moment arm for the stronger flexor muscle tendon to provide

The natural midbone-finger-bone joint has considerable freedom to move sideways when it is stretched directed swinging motion of the proximal finger bone with respect to the metacarpal bone, but is with flexion highly resistant to this type of relative pivoting movement, in which the proximal finger bone around the Longitudinal axis of the metacarpal bone would be rotated. Thus, for example, is the naturally flexed metacarpal-finger-bone joint highly stable to the type of pinching activity shown in FIG. The prosthesis 1 reproduces these two abilities of the natural metacarpal-finger-bone joint. When stretched (see FIGS. 5 and 6) the component 9 is mechanically free, with reference to FIG to pivot the component 5 sideways to a significant extent (about 25 ° on either side of the center line). One

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mechanical hindrance of the pivoting movement during extension is finally achieved by the impact of the component 9 against the insert 7. However, the natural collateral ligaments stabilize the joint prosthesis by themselves during use. It should be noted that a lateral pivoting displacement of 25 when the proximal pinger bone is extended with respect to the metacarpal bone requires an extremely large stretch (about 4 to 5 wm) of the collateral ligament that opposes such a displacement. The shapes of the head section 39 void of the bearing surface 63 of the two components also give the collateral ligament or the inner muscles the greatest possible moment arm (given anatomical dimensions), which acts in the sense of producing the prosthesis. The moment arm available for such restoration is shown in Fig. 6 as approximately the length L "drawn from the center of rotation of the prosthesis. The forces exerted on component 9 by the collateral ligaments in inducing a spoke Elle pivoting movement during extension and restoration of the prosthesis after such a pivoting movement is transmitted as a compressive force3 to component 5 and then to flange 25, exerting shear forces on component 5 and thus transmitting bending moments to rods 33 and.

Upon flexion, forces acting on the prosthesis which would tend to cause a rotational movement of the component 9 around to cause the longitudinal axis of the metacarpal (see

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for example Fig. 8), opposed resistance due to the contact of the head portion 39 with the dorsal and volar walls 77 and 79 of the plastic bearing insert 7 and the interaction of the ribs, for example 53, with slots, for example 55. In addition, many are already indicated, torsional stresses acting on the prosthesis of such a nature that they tend to rotate the cylindrical head portion 39 about the longitudinal axis of the proximal finger bone, in fact ineffective to cause such rotation due to the freedom of the rod 33 »To rotate within the longitudinal bore 23 of the intramedullary plug 11.

In a modified form of the metacarpal component 5 shown in FIG. 9 and within the scope of the present invention, lips 101 are provided at the distal end of the plastic bearing insert 107 to reduce the size of the opening 165. The purpose of the lips 101 is to prevent displacements due to extreme relative displacement of the components under tension or extreme relative spinal-ulnar pivotal movement of the components (greater than about 30 ° to either side of the center point). The head portion 39 is held in engagement with a press fit within the shell cavity Ιοί. A relative pivoting movement of the radius and ulna during extension and relative separation of the components in the longitudinal direction of the metacarpal bone component are mechanically unhindered in normal use , ie they are not subject to extreme conditions

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merely by, the natural anatomical means, i.e. ligaments and seeing controlled and limited. Since the lips 101 of the head portion 39 in use only in an unusual extreme situation would be touched, the head portion 39 of these lips is not in the same ¥ ice in the shell cavity retained or tightly held by the lips, as in the head sections of those in US patents 3i506,982, 4,011,603 and 4,059,854 described embodiments of the case £

It should be noted that the feature of the invention which has been described here and relates to the shapes of the Bearing sections of the metacarpal finger bone joint prosthesis relates in detail, even without the use of the other Feature that can be practiced, which involves the movement of the rods of the components within the intramedullary plug. Thus, for example, the rods of the components of the metacarpal-finger-bone joint prosthesis directly to the walls of the intramedullary canals by tissue ingrowth, cement, or other fasteners be attached. The other can do in a similar way Feature of the invention which relates to the movement of the rods of the components within the intramedullary plug can be practiced using the bearing section designs disclosed in U.S. patents 3,506,982, 4,011,603 and 4,059,854 are described, in contrast of the ones described here. As already stated, the other feature of the invention does not apply to metacarpal

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Finger-bone joint prosthesis is limited but has general applicability to other types of joint prostheses as well. It however, it is preferred to use both features of the invention together to produce the optimal metacarpal-finger joint prosthesis to achieve.

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Claims (1)

Expectations : 1. Prosthesis for a joint of a first bone with a second bone, characterized by a first component, a second component in pivot bearing relationship with the first component, the first component being operatively connected to the first bone, the second component being operatively connected to the second bone is connected t and the compound of at least one of the components with their bone is such that a relative movement between the component and its bone of the bone is provided in the longitudinal direction. 030037 / 0-614 ~ ^{/ ζ} ZrOELASSEXE VEMTnETKlI HEIM EUROPAISCIIEX PATENT OFFICE PROFESSIONAL UEI'RESHXT.VTIVES HEFOItE THE EfUOPEAX PATENT OFFICE -Z- 008292 2. Prosthesis according to claim 1, characterized in that the clone t Connections of the first and second components to the first and second bones, respectively, is such that there is relative movement between each of the components and their bone is provided in the longitudinal direction of the bone » 3 finger joint prosthesis according to claim 2. k. Prosthesis according to Claim 3 »characterized in that the finger joint is the metacarpal-pinger joint. 5. Prosthesis according to claim 4, characterized in that the Connection of the first component with the first bone is such that a relative rotational movement between the first component and the first bone is provided around the longitudinal axis of the first bone, and the connection of the second component with the second bone is such that a relative rotational movement between the second component and the second bone is prevented around the longitudinal axis of the second bone, 6. Prosthesis me claims 5 »characterized in that the first bone is the proximal finger bone. 7 «Prosthesis for a joint of a first bone with a second bone, characterized by a first component, a second component in pivot bearing relationship with the first component, the first component being operative with 0 3 0 in 7 / ii 8 1 4 / o ORtGINAL INSPECTED the first bone, the second component is operatively connected to the second bone and the connection of the first component with the first bone dex ^ art is that a relative rotational movement between the first component and the second component is provided about the longitudinal axis of the first bone. 8. Prosthesis according to claim 7 »characterized in that the connection of the second component with the second bone is such that there is relative rotational movement between the second component and the second bone about the longitudinal axis of the second bone is prevented. 9. Finger joint prosthesis according to claim 8. 10. Prosthesis according to claim 9 »characterized in that the finger joint is the metacarpal finger joint. 11. Prosthesis according to claim 10, characterized in that the first bone is the proximal finger bone. 12. Prosthesis according to claim 10 or 11, characterized in that the connections of the first and second components with the first and second bones, respectively, is such that relative movement between each of the components and their bone is provided in the longitudinal direction of the bone. 030037 / QSU ~ - ^{/ k} 13 · Prosthesis for a joint of a first bone with a second bone, characterized by a first intramedullary plug suitable to be fixed to the wall of the intramedullary canal of the first bone and provided with a longitudinal bore, a second intramedullary plug which is suitable for attachment to the intramedullary canal of the second bone and is provided with a longitudinal bore, a first component with a bearing section and a rod extending from it, and a second component with a bearing section and a rod extending from it, wherein the rods of the first and second components are longitudinally slidably received in the bores of the first and second intramedullary plugs, respectively, and the bearing portions of the first and second components are mutually articulated with one another. 14. Finger joint prosthesis, characterized by a proximal intramedtxllären plug which is adapted to be secured to the wall of the intr & .: redullären channel of the proximal bone, and is provided with a longitudinal bore, _r a distal intramedullary pegs for attachment to the wall of the intramedullary canal of the distal bone is suitable and provided with a longitudinal bore, a proximal component with a bearing portion and a rod extending from it and a distal component with a bearing portion and 030037/0814 a rod extending therefrom, the rods of the proximal and distal components being longitudinal slidably received in the bores of the proximal and distal intramedullary plugs and the bearing sections of the proximal and distal components are in mutual joint engagement. 15 · Prosthesis according to claim 14, characterized in that the joint is the metacarpal-finger bone joint, the proximal bone is the metacarpal and the distal bone is the proximal finger bone. 16. Prosthesis according to claim 15t, characterized in that they have devices to prevent rotational movement of at least one of the components relative to the intramedullary plug receptacle about the longitudinal axis of the bone contains to which the plug is attached. 17 · Prosthesis according to claim 16, characterized in that the rotational movement of only one of the components relative to the receiving intramedullary plug about the Longitudinal axis of the bone to which the plug is attached is prevented. 18. Prosthesis according to claim 17, characterized in that the means for preventing rotational movement of one or more of the outside of the rod of those Component contains protruding longitudinal ribs, the rotational 030037/0814 _{/ A} • · ./o movement is prevented, and corresponding longitudinal slots for receiving the ribs in the ¥ and the longitudinal bore in the intramedullary plug with which this component is attached works together smoothly. 19. Prosthesis according to claim 17 or 18 _: characterized in that the rotational movement of the proximal component relative to the proximal intramedullary plug about the longitudinal axis of the metacarpal is prevented. 20. Prosthesis according to claim Λ ¹ ^ or I5, characterized in that the proximal and distal intramedullary plugs at their distal and proximal ends both end with bottles which are suitable for sitting against the cortical surfaces of the proximal and distal bones and a · to distribute a considerable part of the compressive forces exerted on the prosthesis during use on these surfaces. . The prosthesis of claim 20, characterized in that each of the intramedullary plugs is beveled so that he a π i '; increasing distance from the one with one Closing the bottle at the end of the stopper, decreasing cross-sectional area Has. 22. Prosthesis according to claim 14, characterized in that the plastic intramedullary plugs and the proximalon and distal components made of metal or a 030037 / 08U Metal alloy are made. A 22m prosthesis according to claim 22, characterized in that the bearing portion of one of the components provides the other component with a convex metal or metal alloy bearing surface and the bearing portion of the other component has a removable plastic bearing insert which provides the convex bearing surface with a concave bearing surface and contacts it in use. 24. Prosthesis according to claim 23 »characterized in that the joint is the metacarpal-finger bone joint, the proximal bone is the metacarpal bone, the distal one Bone is the proximal finger bone and the convex bearing surface of the bearing portion of the distal component is presented. 2 ^. Prosthesis for a joint of a first bone with a second bone, characterized by a first intramedullary plug adapted to be attached to the wall of the to be attached to the intramedullary canal of the first bone, and provided with a longitudinal bore formed therein is a first component with a bearing section and a rod extending from it, which is rotatably received in the longitudinal bore, and a second component with a bearing portion and a rod extending from it for insertion into the intramedullary canal of the second bone, wherein 03OO37 / 08U the bearing portions of the first and second components are articulated with one another. 26. finger joint prosthesis according to claim 25, 27. Prosthesis according to claim 26, characterized in that the finger joint is the metacarpal-finger bone joint is. 28. Prosthesis according to claim 27, characterized in that the first bone is the proximal finger bone. 29. Articulated metacarpal-finger-bone joint prosthesis, characterized by a first component with a Rod for seating in the intramedullary canal of a first bone, a neck portion at one end of the Rod and a protruding head section on the Neck portion, -wherein the head portion is generally cylindrical in shape with rounded ends and when the longitudinal axis of the head section is perpendicular to Level of gel movement of the prosthesis, and a second component with a rod for sitting in the intramedullary Channel of a second bone and a shell section at one end of the rod with walls to define it a shell cavity which is delimited at one end by a concave bearing surface into which the head portion fits tightly into it, with this shell cavity 030037/0814 "' ^{/ 9} extends in the longitudinal direction from the bearing surface to an opening in the end of the shell portion that the second bone is turned away, and wherein the palm wall of the shell portion with a longitudinal slot in communication is provided with the shell cavity and the opening, the head portion of the first component of FIG the cup cavity and is slidably movable therein; and the neck portion of the first component when bending the joint prosthesis lies in the slot of the palm wall of the shell section and the second Component is mechanically restrained from a rotational movement about the longitudinal axis of the second bone, whereby the shape of the shell cavity is such that in normal use it is a mechanically unobstructed relative The two components can be pivoted from spoke to ulna if the joint prosthesis is considerably stretched, and a mechanically unimpeded relative separation of the two components in the longitudinal direction of the second component, and further is such that by the contact of the head portion with the back or palm walls of the shell section a rotational movement of the head section of the first component relative to the shell portion of the second component around the longitudinal axis of the second bone is prevented. 30. Prosthesis according to claim 29, characterized in that the first bone is the proximal finger bone and the second Is the metacarpal bone. 030037/0814 _{>## / i0} 31 »Prosthesis according to claim 29, characterized in that the head portion of the first component is made of metal or a metal alloy and the shell cavity through the walls of one in the shell section of the second Component contained, removable plastic bearing insert is limited. 32. Prosthesis according to claim 31 »characterized in that the first bone the proximal pinger bone and the The second bone is the metacarpal bone. 33. Prosthesis according to claim 30, characterized in that the prosthesis contains a first intramedullary plug, which is suitable to be attached to the ¥ and the intramedullary canal of the proximal finger bone, and is provided with a longitudinal bore formed therein, the rod portion of the first component is rotatably received in the longitudinal bore. 34. Prosthesis according to claim 33, characterized in that the protlie-ie contains a second intramedullary plug, which is suitable to be attached to the ¥ and intramedullary canal of the metacarpal bone and is provided with a longitudinal bore formed therein, the rod portions of the first and second Components both slide lengthways in the holes in the first and second intramedullary plugs be included. 030037 / 08U "* ^{/ 11} 35 * Prosthesis according to claim 2 ° -, characterized in that the head portion of the first component is able to slide freely through the opening to enter the shell cavity. 36. Prosthesis according to claim 31 », characterized in that the plastic bearing insert is provided with lip means at the end of the insert that of the second Bone is turned away, with these lip devices reducing the size of the opening to cause dislocation of the Prosthesis as a result of abnormal relative pivoting movement of the two components between ulna and radius or as a result prevent abnormal relative separation in the longitudinal direction of the two components from one another. 37. Prosthesis for a joint of a first bone with a second bone, characterized by a first intramedullary Plug suitable for being attached to the ¥ and intramedullary canal of the first bone and is provided with a longitudinal bore formed therein. a second intramedullary plug that is adapted to be attached to the ¥ and the intramedullary canal of the second bone, and with one in it formed longitudinal bore is provided, a first component with a bearing portion and one extending therefrom Rod, a second component having a bearing section and one extending therefrom Rod, being the rods and the first and second 030037/0814 ... / 12 Components sliding lengthways in the holes in the first and second intramedullary plugs are received, and the bearing portions of the first and second Components are in mutual articulation, as well as devices that have a limited rotational movement at least one of the components relative to the intramedullary plug receiving it around the longitudinal axis of the bone which the plug is attached to allow. 38. Finger joint prosthesis, characterized by a proximal intramedullary plug, suitable for being attached to the wall of the intramedullary canal of the proximal bone and is provided with a longitudinal bore formed therein, a distal intramedullary plug which is adapted to be attached to the ¥ and the intramedullary canal of the distal bone, and with one in it formed longitudinal bore is provided, a proximal component with a bearing portion and one of rod extending from it, a distal component with a bearing section and a rod extending from it Rod, the rods of the proximal and distal components sliding longitudinally in the bores of the proximal and distal intramedullary plugs, respectively, and the bearing sections of the proximal and distal components are in mutual articulation, as well as devices that a limited rotational movement of at least one of the constituents ... / 13 030037/0814 share id. to the intramedullary receiving him Allow plug around the longitudinal axis of the bone to which the plug is attached. 39 · Prosthesis according to claim 37 or 38, characterized by Means allowing limited rotational movement of each of the components relative to the intramedullary receiving it Allow plug around the longitudinal axis of the bone to which the plug is attached. hO. Prosthesis according to claim 37i 38 or 39 », characterized in that the device for limiting the rotational movement contains one or more longitudinal ribs which protrude from the outside of the rod of the component whose rotation is limited, as well as corresponding longitudinal slots for receiving the ribs in the wall of the Longitudinal bore in the intramedullary plug with which the component is slidingly engaged, the ribs being considerably thinner than the slots. 030037/0814 ... / 14