DE10051445A1 - Knee joint endoprosthesis with thigh and shin bone component uses congruent ceramics slide surfaces diametered appropriate to femur condyles and tibia plateau. - Google Patents

Abstract

The component (4) anchored at the distal end of the thigh bone (2,3) has a sliding surface (9) as part of the prosthesis itself which defines a single ball surface. This surface is congruent to the hollow ball slide surface (12) of a component anchored at the proximal end (13) of the shin bone (14). The diameter of surface (9) matches the total anatomical dimensions of the distal femur condyles (7,8) and the diameter of the slide surface (12) of the shin component (11) matches the total anatomical dimensions of the proximal tibia plateau (15). The radius of the slide surfaces (9 and 12) ranges from 20-55 mm and the axis (18) of the ball-shaped component (4) of the thigh bone for both flexural and tensile movements of the lower leg (14) stands normal to the mechanical leg axis (17) i.e. the bearing line through the knee joint. The center point (5) of the shin bone component (11) lies on the bearing axis (17) with the result that this point (5) coincides with the intercept (5) of axis (18) and the leg axis (17) when the joint is under load. The two points (5) are spaced by the natural joint space (20) between surfaces (9 and 12) when the joint is out of load.

Description

The invention relates to a knee joint endoprosthesis according to the preamble of the first claim.

Because the natural movements of a knee joint are not easy Folding movement of the lower leg against the thigh by a rigid Axis restricted is the design of a full or partial prosthesis of the knee joint difficult. In the previous design of the knee joints, an attempt was made to imitate natural movement as much as possible. The result was that in Usually, when the lower leg is flexed, a rolling movement of the Femoral prosthesis component was made on the tibial partner and approximately in the Range of the last possible angular degrees of the flexion movement a sliding movement.

In the technical paper "The design of guide surfaces for fixed-bearing and mobile- bearing knee replacements "by Peter S. Walker, Shivani Sathasivam in Journal of Biomechanics, 32, 1999, pages 27 to 34, the mechanical processes at the movement described in a knee joint and in mathematical formulas composed.

According to the previous view, the knee joint kinematics is a rolling Underlying sliding movement. This view is in need of revision. It is true that the bony structures of the knee are polycentric. But that affects not the part of the knee that is static when bending and stretching transfers, namely the dorsal portion of the femoral condyles and thus articulating structures of the tibia head. The Menisci form as an articulation surface Cup-shaped structures, the associated monoradiaries medially and laterally Guide the femoral condyle parts in a stable manner. The menisci are capsular / periostal at their base grown together with the tibia. It only consists of the tissue's own elasticity Possibility of a relative movement around the condyles in a dorsomedial  Sliding of about 2 mm to guide elastic. This possibility of movement is reduced zero when the elasticity of the menisci, such as in the elderly, is reduced. If there is no stabilization by the Menisci on the Tibia Plateau, the holding function is maintained only by the tape apparatus, from which sliding movements of up to 2 cm can then occur. This Possibility of movement does not correspond to a movement in an anatomical healthy knees.

It is therefore the object of the present invention to develop a knee joint To present endoprosthesis, by designing the non-physiological Burdens are reduced to a minimum.

The task is solved with the help of the characteristic features of the first Claim. Advantageous embodiments of the invention are in the Claimed claims.

For the part of the main joint that transmits the static load According to the invention, a sliding surface is selected which is formed by a single spherical surface is defined. The component anchored to the distal end of the femur has a sliding surface that applies to both partial and full dentures, such as a single spherical surface is defined. The at the proximal end of the The tibial anchored component also has a sliding surface that acts as Inner surface of a hollow sphere congruent with the sliding surface of the femoral component is. Both sliding surfaces lie on top of each other. The knee joint Endoprosthesis enables a physiological movement and Self-centering and stabilization with fully preserved ligament apparatus and with still functional lateral ligaments. In addition, the dot and dash contact of the prosthetic components avoided.

In a further embodiment of the invention, the diameter of the sliding surface corresponds the femoral prosthetic component essentially the anatomical  Overall dimensions of the distal femoral condyles and the diameter of the The sliding surface of the tibial prosthesis component corresponds essentially to that Overall anatomical dimensions of the proximal tibial plateau. Through the Attention to the anatomical conditions is avoided that the Prosthesis changed the joint geometry and one compared to the movement a distorted movement occurs in a healthy knee. In addition, the loss of the Bone tissue limited to the bare minimum.

The diameter of the femoral and distal sliding surfaces can advantageously be based on the Stature and age of the patient are matched and are in a range of about 40 mm to about 100 mm.

In the case of stress, that is, in a patient standing with the leg extended, the axis around which the flexion and extension of the lower leg takes place in the essentially perpendicular to the mechanical leg axis, the supporting line, through which Stand knee joint. The axis goes through the center of the femoral spherical prosthetic component. If the axis of rotation is also through the Center of the congruent gliding surface, the gliding surface of the on the tibia bone anchored prosthesis component, the two sliding surfaces lie completely on each other and an even surface pressure is guaranteed. in the Relieved state of the joint, the two sliding surfaces should at most around the natural joint gap between the two sliding surfaces distance. This makes it possible for body fluid to get between the two Sliding surfaces occurs that can perform a lubrication function.

In particular with a joint whose ligaments are only partially functional are or can no longer perform a holding function during one In a further development of the invention, load can stabilize the movement the sliding surfaces of those anchored on the tibia bone and on the femur bone Prosthesis components the movement of the components against each other  Stabilizing, interlocking geometric shapes can be arranged. Thereby lateral bending of the lower leg is advantageously prevented.

Based on the natural contours of the bones, it can be used as a sphere trained prosthetic component, which is anchored to the femur, a the mechanical leg axis has a recess intersecting in the dorsal direction, whose cross-section is the cross-section of an elevation on the surface of the tibia Prosthesis is adapted.

If the patella is still preserved and is still being guided by ligaments, the in of the spherical femoral component of the prosthesis simultaneously serve as a guide and sliding surface for the dorsal patella contour. This However, the depression can also be shaped so that it is one on the dorsal patella Contour arranged artificial guide serves as a guide and sliding surface.

The femoral prosthesis component has an uninterrupted sliding surface Spherical surface, can be used to stabilize the axis for flexion and extension each in the planes through the ends of the axis of rotation parallel to the mechanical Leg axis run, on the femoral and on the tibial prosthesis component Contours can be arranged in the bending, stretching and rotational movement of the Lower leg perform a support and guiding function. These contours can for example made of biocompatible metals.

The contour relating to the femoral prosthesis component runs in each case in the Planes that are parallel to the mechanical leg axis through the ends of the axis.

In a further embodiment of the invention, both the movement of the Interlocking, interlocking geometric components Shapes with the contours in the planes through the ends of the axis be supplemented. Such a combination can be advantageous, for example,  when the ligament is no longer or only insufficient to stabilize the Joint can contribute.

To the movement of the prosthetic components the natural To adapt the movement sequence, it is necessary that the flexion, extension and Rotational movements through stops to limit the flexion, extension and Rotational movement of the lower leg are equipped. This will make one over the Natural position of the lower leg extending extension, especially in stressed condition, avoided.

In a further embodiment of the invention, the prosthesis components in turn each be composed of function-related components. So can for example, the one anchored to the proximal end of the tibia bone Component have a sliding surface made of a different material than that Part anchoring the sliding surface on the tibia plateau. The sliding surface can for example from a polyethylene plastic or from a ceramic material consist, while the anchoring component consists of a biocompatible metal. Likewise, with the femoral prosthesis component, the sliding surface can be made from one different material than the material of the component with which they are on the Thigh is anchored.

Especially with regard to the optimal sliding pairing of the materials of the sliding surfaces it can be advantageous if the sliding surfaces of the femoral and tibial Denture components are made of ceramic. Ceramic sliding surfaces have become already proven in total hip prostheses. When pairing Ceramics on ceramics, especially for ceramic materials made of aluminum oxide, Zirconium oxide or mixed oxide ceramics as well as silicon nitride are the resultant Abrasion particles are biologically harmless and, in contrast to the abrasion of the ultra high molecular weight polyethylene materials (UHMW-PE) to no osteolysis causing abrasion particles.  

The knee joint endoprosthesis according to the invention is not only suitable as Total prosthesis, but can also be provided as a unicondylar prosthesis. there are the prosthesis components for use either on the medial or on the to form the lateral side. The same applies to unicondylar prostheses Sliding surfaces of the femoral prosthetic component designed so that they are part of a both distal femoral condyles are spherical surface.

The use of a unicondylar prosthesis enables the replacement of a partial area of the knee joint while largely preserving the remaining joint area and the Possibility of a total prosthesis if the joint continues to degenerate to provide. A unicondylar prosthesis can also be implanted minimally invasively which allows the patient to be released from the clinic earlier.

The knee joint endoprosthesis according to the invention is also particularly suitable as Interim prosthesis with the function of a spacer between the thigh and Lower leg bone during surgery that is due to infection or Inflammation of the joint area requires immediate implantation of a joint prosthesis not possible. For such an application, with a transition prosthesis, need the interlocking geometric interlocking movements Forms on the sliding surfaces or those that have a supporting and guiding function Contours are not provided.

The following figures show exemplary embodiments of the invention Knee joint endoprosthesis, on which the invention is explained in more detail.

Show it:

Fig. 1 is a side view of a knee-joint endoprosthesis,

Fig. 2 is a view of the knee joint endoprosthesis according to Fig. 1, from the side of the patella is not shown here,

Fig. 3 is a knee-joint endoprosthesis with the movement of the components against each other stabilizing interlocking geometric forms, in a side view;

Fig. 4 here a knee-joint endoprosthesis according to FIG. 3, a plan view of the patella slideway

Fig. 5 a perspective view of the tibial prosthesis component with a movement stabilizing elevation on the sliding surface of the tibial prosthesis component,

Fig. 6 shows an embodiment for a knee-joint endoprosthesis, which is provided for stabilizing the axis of rotation for flexion and tension with the supporting and guiding function performing contours, in a side view;

Fig. 7 shows the embodiment of FIG. 6 as a front view according to the section in FIG. 6 registered sectional profile,

Fig. 8 shows a saddle-shaped insert into the femoral prosthetic component with the supporting and guiding function performing contours,

Fig an exemplary embodiment of a unicondylar prosthesis on the lateral side of the knee of the left leg, partly in section. 9 in the tibial region,

Fig. 10 the femoral prosthesis component and

Fig. 11, the tibial prosthesis component.

In Fig. 1, 1 denotes a knee joint endoprosthesis according to the invention. It consists of a component 4 anchored to the distal end 2 of the femur bone 3 , which in the present exemplary embodiment consists of a ceramic ball, for example made of aluminum oxide. The ball has a cutout 6 extending beyond its center point 5 , into which the femoral condyles 7 and 8 ( FIG. 2), shortened by their sliding surfaces, are inserted and connected to the prosthesis component 4 by gluing, cementing in or by a fit (cementless).

The sliding surface 9 of the femoral prosthesis component 4 is defined by a single spherical surface. The radii 10 of the spherical sliding surface 9 are selected such that the dimensions of the ball 4 essentially correspond to the overall anatomical dimensions of the distal femoral condyles 7 and 8 .

The tibial prosthesis component 11 is cup-shaped and its sliding surface 12 is the inner surface of a hollow sphere which is congruent with the sliding surface 9 of the femoral prosthesis component 4 . The tibial prosthesis component 11 is anchored on the proximal end 13 of the tibia bone 14 on the tibia plateau 15 prepared for this.

As the sectional view of the tibia bone 14 and the prosthesis component 11 shows, the diameter of the sliding surface 12 of the tibial prosthesis component 11 essentially corresponds to the overall anatomical dimensions of the proximal tibia plateau 15 . The tibial prosthesis component 11 is anchored in the present exemplary embodiment by a mandrel 16 which extends into the tibia bone and which can be made of the same material as the sliding surface 12 . It is also possible, for example, to anchor it in the tibia bone 14 by means of a screw or a mandrel made of another material, it also being conceivable for the slide surface to be used. The sliding surface 11 can also be mounted in a bowl with a mandrel made of another material, which rests on the tibia plateau 15 , for example polyethylene in a bowl made of a biocompatible metal. An exemplary embodiment is shown in FIG. 7.

In the present exemplary embodiment, the center 5 of the femoral prosthesis component 4 lies on the mechanical leg axis 17 , the supporting line, through the knee joint. For optimal introduction of the load into the tibia bone 14 , the anchoring mandrel 16 also runs in the direction of the mechanical leg axis 17 . The axis 18 , about which the flexion and extension of the lower leg, the tibia bone 14 , takes place, as indicated by the double arrow 19 , is substantially perpendicular to the mechanical leg axis 17 ( FIG. 2).

Fig. 2 shows the front view of the inventive knee-joint endoprosthesis 1, wherein the patella was omitted. As can be seen from FIG. 2, the two sliding surfaces predetermined by the two femoral condyles 7 and 8 in the natural state are replaced by a single sliding surface 9 of the femoral prosthesis component 4 . On the opposite side, the sliding surfaces on the two menisci are replaced by the sliding surface 12 of the tibial prosthesis component 11 .

In Figs. 1 and 2, the knee-joint endoprosthesis is 1 shown in the loaded condition. This means that the sliding surface 9 of the femoral prosthesis component 4 rests on the sliding surface 12 of the tibial prosthesis component 11 . In the unloaded state, the two sliding surfaces 9 and 12 can be spaced apart from one another by the natural joint gap 20 , so that body fluid can penetrate between the two sliding surfaces, the sliding surface 9 and the sliding surface of the tibial prosthesis component 11 located at the position 12 ' . The body fluid can act as a lubricant. In the relieved state, the center points 5 of the sliding surface 9 of the femoral prosthesis component 4 and of the sliding surface 12 of the tibial prosthesis component 11 no longer coincide but, as indicated in position 5 ', are essentially spaced apart from one another by the size of the natural joint gap 20 .

The exemplary embodiment according to FIGS. 3 and 4 differs from the previous exemplary embodiment in that the movement of the components against one another, interlocking geometric shapes, are arranged on the sliding surfaces of the prosthetic components anchored on the tibia bone and on the femoral bone. The features which correspond to the previous exemplary embodiment are designated by the same reference numerals.

As shown in FIG. 1, a side view of the Fig. 3 shows a further embodiment of the knee-joint endoprosthesis according to the invention 1. In contrast to the previous exemplary embodiment, the femoral prosthesis component 104 has a depression 21 which intersects the mechanical leg axis 17 in the dorsal direction. The depression corresponds to an equatorial groove in the sliding surface 9 of the femoral prosthesis component 104 . The groove 21 in the surface 9 of the femoral prosthesis component 104 can also serve to guide the dorsal patella contour.

A bead-shaped elevation 22 engages in the groove 21 on the sliding surface 12 of the tibial prosthesis component 111 . It also extends dorsally, intersecting the mechanical leg axis 17 . The contour 22 engaging in the recess 21 stabilizes in particular the flexion and extension of the lower leg in accordance with the double arrow 19 and prevents the lower leg from buckling under static and dynamic loads.

In Fig. 5 a perspective view of the tibial prosthesis component 111 is depicted. The sliding surface 12 can be seen with the bead-shaped elevation 22 running dorsally therein.

FIGS. 6 to 8 show another embodiment of a knee-joint endoprosthesis according to the invention. In order to stabilize the axis of rotation 18 for the flexion and extension of the lower leg, in the planes 23 and 24 , which run through the ends of the axis of rotation 18 parallel to the mechanical leg axis 17 , contours 25 and 25 on the femoral prosthesis component 204 and on the tibial prosthesis component 211 respectively 26 , which perform a supporting and guiding function during the bending, stretching and rotating movement of the lower leg. Features which correspond to the preceding exemplary embodiments are designated by the same reference numerals.

The embodiment with respect to the femoral prosthesis component 204 corresponds to the embodiment according to FIGS. 1 and 2 with the difference that between the femur bones 3 and the femoral prosthesis component 204 a saddle-shaped insert 27 is inserted in the cutout 6 , which has contours 25 stabilizing the axis of rotation 18 . Because of the shape of the femoral prosthesis component 4 , in particular with the cutout 6 , this insert 27 offers itself as an aid which can be predetermined in the area of the movements. It can be made of metal or plastic, whereby a suitable material combination of the contours 25 and 26 must be observed in order to prevent premature wear of one of the two components. The saddle-shaped insert 27 can be easily inserted into the cutout 6 of the femoral prosthesis component 204 . It has a loop 28 which wraps around the ball 204 and thus gives the insert 27 additional positional stability. At the attachment of the loop 28 stops 29 are arranged to limit the bending, stretching and rotating movements of the lower leg. As is not shown here, the saddle surface can have aids, for example spikes, for anchoring in the bone tissue.

The tibial prosthesis component 211 differs from the exemplary embodiment according to FIG. 1 in that the component 30 comprising the sliding surface 12 is inserted in a cup 31 . This is shown in Fig. 7, which shows a section through the knee joint according to the course AA shown in Fig. 6, seen in the dorsal direction. The bowl 31 in the present exemplary embodiment consists of a biocompatible metal and has a mandrel 32 with which it is anchored in the tibia bone 14 . It sits completely on the tibial plateau 15 and, as can be seen from FIG. 6, is designed in such a way that an undisturbed flexion, extension and rotation movement of the lower leg can take place. The bowl prevents that when the contour 26 is loaded by the contours 25 of the insert 27, the material of the insert 30 flakes off due to an excessive load on the edge region.

Both the femoral prosthesis component 204 and the material of the sliding surface 12 of the tibial prosthesis component 211 are made of a ceramic material, for example of aluminum oxide, in the present exemplary embodiment. In the present exemplary embodiment, the contour 25 of the saddle-shaped insert 27 is based on the contour 26 of the ceramic insert 30 in the cup 31 . The bowl 31 also has stops 33 with which the movement of the lower leg is limited in interaction with the stops 29 of the saddle-shaped insert 27 .

It is also possible, as is not shown here, that the contour 25 of the insert 27 is supported on a contour which is not formed by the surface of the insert 30 in the cup 31 , but by the wall of the cup 31 itself. It is also possible that with a corresponding material pairing of the two prosthesis components, the cup and the contours are in one piece and consist entirely of a biocompatible metal.

In FIG. 9, an exemplary embodiment of a unicondylar prosthesis on the lateral side of the knee of the left leg is shown in dorsal view. Features which correspond to those of FIGS. 1 and 2 are designated with the same reference numerals for better understanding. The lateral femoral condyle 7 of the femoral bone 3 in the present exemplary embodiment has been shortened by its sliding surface and has been replaced by a prosthesis component 304 . The medial femoral condyle 8, however, is still in its natural state and is supported on the meniscus 34 , which in turn lies on the natural tibial plateau 315 of the tibia bone 14 .

In the present exemplary embodiment, the prosthesis component 304 has the shape of a hemisphere with a cut off spherical cap and can consist, for example, of biocompatible ceramic materials or metals. The prosthesis component 304 is anchored to the lateral femoral condyle 7 , which is inserted into a recess 35 . The anchorage as such is not shown here. It can be done by the known methods, for example by screwing, cementing or by a snug fit. The sliding surface 9 of the unicondylar femoral prosthesis component 304 is defined by a spherical surface, the radii 10 of which are selected such that the dimensions of an imaginary solid sphere, indicated by the dashed line 36 , essentially correspond to the overall anatomical dimensions of the femoral condyles 7 and 8 .

In the present exemplary embodiment, the femoral prosthesis component 304 has an anterior contour 37 which is matched to the natural contour 38 for guiding the dorsal patella contour on which the medial femoral condyle 8 is obtained.

In the present exemplary embodiment, the tibial prosthesis component 311 consists of a cup 39 which carries an insert 40 with the sliding surface 12 . The sliding surface 12 has the shape of a hemispherical shell and is congruent with the sliding surface 9 of the femoral prosthesis component 304 . In order to match the contour of the bowl 39 to the natural contour 42 of the bone in the area of the menisci - of which the medial 315 is still present - the wall of the bowl in this area has a slight, wall-shaped elevation 43 . In the present exemplary embodiment, the cup 39 is anchored in the tibia bone 14 with a mandrel 41 on the lateral side of the prepared tibia plateau. The anchoring can also be done by any other known measure, for example screwing or gluing.

The combination cup 39 with an insert 40 carrying the sliding surface 12 is advantageous, for example, when the prosthesis component 304 is made of ceramic or metal and the sliding surface 12 of the tibial prosthesis component 311 is also made of ceramic or a plastic. The insert 40 is then easier and easier to manufacture and anchor on the tibia plateau. A complete implant 311 made of ceramic or metal is also possible.

FIG. 10 is a distal plan view of the femoral prosthesis component 304th The bone tissue of the lateral femoral condyle 7 is omitted, so that the surface structure of the prosthesis component is visible in the region of the anchorage with the bone. The adjacent bone of the medial femoral condyle 8 is shown in section.

In FIG. 11, the tibial prosthetic component 311 is shown in detail. The top view in the distal direction shows the hollow spherical sliding surface 12 of the insert 40 .

Claims (15)

1. Knee joint endoprosthesis, consisting of a component anchored to the distal end of the femur with a sliding surface that allows the flexion, extension and rotation movement of the lower leg and a component anchored to the proximal end of the tibia bone with a sliding surface that is on the sliding surface of the Femoral component rests, characterized in that the component ( 4 , 104 , 204 , 304 ) anchored to the distal end ( 2 ) of the femur bone ( 3 ) has a sliding surface ( 9 ) which applies to both partial and full dentures , is defined by a single spherical surface and that the component ( 11 , 111 , 211 , 311 ) anchored to the proximal end ( 13 ) of the tibia bone ( 14 ) has a uniform surface ( 12 ), which is the inner surface of a hollow sphere with the sliding surface ( 9 ) of the femoral component ( 4 , 104 , 204 , 304 ) is congruent. 2. Knee joint endoprosthesis according to claim 1, characterized in that the diameter of the sliding surface ( 9 ) of the femoral prosthesis component ( 4 , 104 , 204 , 304 ) essentially corresponds to the overall anatomical dimensions of the distal femoral condyles ( 7 , 8 ) and that the diameter the sliding surface ( 12 ) of the tibial prosthesis component ( 11 , 111 , 211 , 311 ) essentially corresponds to the overall anatomical dimensions of the proximal tibia plateau ( 15 ; 315 ). 3. knee joint endoprosthesis according to claim 2, characterized in that the radius ( 10 ) of the femoral ( 9 ) and the distal ( 12 ) sliding surfaces from about 20 mm to about 50 mm. 4. Knee joint endoprosthesis according to one of claims 1 to 3, characterized in that the axis ( 18 ) of the femoral bone ( 3 ) anchored spherical prosthesis component ( 4 , 104 , 204 , 304 ) around the flexion and extension of the lower leg ( 14 ) takes place, essentially perpendicular to the mechanical leg axis ( 17 ), the supporting line through which the knee joint stands and that the center ( 5 ) of the congruent sliding surface ( 12 ) on the prosthesis component ( 11 , 111 , anchored to the tibia bone ( 14 ) 211 , 311 ) lies on the mechanical leg axis ( 17 ) and that this center point ( 5 ) and the intersection ( 5 ) of the axis ( 18 ) with the mechanical leg axis ( 17 ) coincide in the loaded state of the joint and at most in the relieved state of the joint around the natural joint gap ( 20 ) between the two sliding surfaces ( 9 , 12 ). 5. Knee joint endoprosthesis according to one of claims 1 to 4, characterized in that on the sliding surfaces ( 9 , 12 ) of the prosthesis components ( 104 ) anchored on the femur bone ( 3 ) and on the tibia bone ( 14 ) anchored prosthesis components ( 111 ) the movement of the components mutually stabilizing, interlocking geometric shapes ( 21 , 22 ) are arranged. 6. knee joint endoprosthesis according to claim 5, characterized in that the anchored on the femur bone ( 3 ) prosthesis component ( 104 ), which is designed as a ball, has a mechanical leg axis ( 17 ) in the dorsal direction intersecting recess ( 21 ), the Cross-section is adapted to the cross-section of an elevation ( 22 ) on the surface ( 12 ) of the tibial prosthesis component ( 111 ). 7. knee joint endoprosthesis according to claim 6, characterized in that the recess ( 21 ) in the spherical femoral prosthesis component ( 104 ) serves simultaneously as a guide and sliding surface of the dorsal patella contour. 8. Knee-joint endoprosthesis according to one of claims 1 to 4, characterized in that for stabilizing the axis ( 18 ) for flexion and extension around the spherical prosthetic component ( 204 ) anchored on the femur bone ( 3 ) in each case in the planes ( 23 , 24 ), which run through the ends of the axis ( 18 ) parallel to the mechanical leg axis ( 17 ), contours ( 25 , 26 ) are arranged on the femoral ( 204 ) and on the tibial ( 211 ) prosthesis component. Stretching and rotating movement of the lower leg ( 14 ) perform a support and guiding function. 9. knee joint endoprosthesis according to one of claims 5 to 7 in conjunction with claim 8, characterized in that the prosthesis components ( 104 , 204 ; 111 , 211 ) in the bending, stretching and rotating movement a guide both by means of the geometric shapes ( 21 , 22 ) on the sliding surfaces ( 9 , 12 ) of the prosthesis components as well as through the contours ( 25 , 26 ) on the prosthesis components. 10. knee joint endoprosthesis according to one of claims 5 to 9, characterized in that the bending, stretching and rotating movements stabilizing guides ( 25 , 26 ) of the prosthesis components ( 204 , 211 ) stops ( 29 , 33 ) for limiting the bend -, Stretch and rotational movements of the lower leg ( 14 ). 11. Knee joint endoprosthesis according to one of claims 1 to 10, characterized in that the prosthesis components ( 204 ; 211 ) are each composed of function-related components ( 4 , 27 ; 30 , 31 ). 12. Knee joint endoprosthesis according to claim 11, characterized in that the sliding surfaces ( 12 ) of the prosthesis components ( 211 ) consist of a different material ( 30 ) than the components ( 31 ) on which they are arranged. 13. Knee joint endoprosthesis according to one of claims 1 to 12, characterized in that the sliding surfaces ( 9 , 12 ) consist of ceramic. 14. Knee joint endoprosthesis according to one of claims 1 to 13, characterized in that the prosthesis ( 1 ) is provided as a unicondylar prosthesis and that the prosthesis components ( 304 , 311 ) are designed for use on the medial or on the lateral side in the knee joint . 15. Knee joint endoprosthesis according to one of claims 1 to 10, characterized in that the knee joint endoprosthesis ( 1 ) can be used in an operation for substitution of a prosthesis as an interim prosthesis with the intended function of a spacer between the thigh and lower leg bones.