Knee joint endoprosthesis with luxation stop
Patent Information
- Application Number
- PCT/EP2026/054370
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-18
- Filing Date
- 2026-02-18
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026054370_27082026_PF_FP_ABST
Abstract
Description
[0001] Applicant:
[0002] Aesculap AG
[0003] At Aesculap Square
[0004] 78532 Tuttlingen
[0005] General Power of Attorney: Ref. 752190.9
[0006] 03920023WO 17.02.2026
[0007] BUR / MAY
[0008] Title: Knee joint endoprosthesis with dislocation stop
[0009] Description
[0010] The present invention relates to a knee endoprosthesis comprising a tibial component, a femoral component, and a connecting device for articulatedly connecting the tibial component to the femoral component, wherein the femoral component and the tibial component are mounted to rotate relative to each other about an axis of rotation. In particular, a meniscal component is arranged non-rotatably on the tibial component. The femoral component has at least one femoral condyle with a femoral condylar surface, and the meniscal component has at least one upper surface facing the femoral component with at least one meniscal articular surface which contacts the femoral condylar surface of the at least one femoral condyle.
[0011] The connection device comprises a pivotable mounting of the tibial and femoral components relative to each other around a hinge axis. This hinge axis allows, particularly in a simple manner, a flexion movement between the tibial and femoral components, so that the knee endoprosthesis as a whole can replicate an almost natural flexion movement of the knee.
[0012] Furthermore, the connection device includes a rotatable mounting of the tibial and femoral components relative to each other around an axis of rotation. For example, the axis of rotation can essentially correspond to a longitudinal axis of the patient's tibia. Thus, particularly during knee flexion, a more or less pronounced rotation around a longitudinal axis of the patient's leg can also occur.
[0013] Knee joint endoprostheses of the type described above are known, for example, from DE 10 2014 106012. This is a constrained knee prosthesis that allows flexion and relative rotation between the femoral and tibial components.
[0014] The present invention is based on the objective of improving the coupling of a knee endoprosthesis of the type mentioned above in such a way that handling during implantation of the knee endoprosthesis, in particular during coupling of the tibial part and femoral part, can be improved.
[0015] This problem is solved according to the invention in a knee joint endoprosthesis of the type described above by the fact that the connecting device comprises a rotary bearing element consisting of at least two or more parts, wherein the rotary bearing element comprises an outer rotary bearing element, an inner rotary bearing element arranged in the outer rotary bearing element, and at least one locking element for providing axial locking of the rotary bearing element, wherein the axial locking can be activated by actuating the inner rotary bearing element, in particular relative to the outer rotary bearing element, wherein the locking element is movable radially outwards such that it projects beyond an outer circumference of the outer rotary bearing element.so that, with the axial locking mechanism activated, the locking element limits proximal movement of the femoral component and distal movement of the tibial component relative to each other parallel to the axis of rotation by means of stops on a stop element, thus providing axial locking of the rotary bearing element to the tibial component. The multi-part rotary bearing element basically serves to provide a rotatable support for the tibial component and femoral component relative to each other around the axis of rotation.
[0016] The described design allows, on the one hand, a certain degree of relative movement between the femoral and tibial components when the axial locking mechanism is activated. This movement takes the form of a sliding bearing, i.e., a limited proximal posterior stroke parallel to the axis of rotation, mimicking the natural flexibility of a knee joint. Simultaneously, the axial locking mechanism provides a dislocation stop, which can be activated in a relatively simple manner.
[0017] The multi-part rotary bearing element is coupled to the tibial part or to parts connected or connectable to it via suitable means, for example a thread. The stop element is implemented, for example, by the tibial part itself or by a bearing bushing arranged in the tibial part for supporting the multi-part rotary bearing element.
[0018] The outer pivot bearing element forms a receptacle for the inner pivot bearing element and essentially comprises, for example, a sleeve-like or tube-like circumferential wall. The inner pivot bearing element is received within the outer pivot bearing element and essentially comprises, for example, a pin- or rod-like shape.
[0019] Actuating the inner rotary bearing element, particularly relative to the outer rotary bearing element, causes the locking element to move radially outward, such that it projects beyond the outer circumference of the outer rotary bearing element, thereby enabling the locking element to abut against a stop element. In principle, when the axial locking mechanism is activated, the effective outer circumference of the multi-part rotary bearing element is increased in the area of the locking element. The inner rotary bearing element includes, particularly at a proximal end, a corresponding tool receptacle for attaching a suitable tool to actuate the inner rotary bearing element. The outer rotary bearing element can also include, particularly at a proximal end, a corresponding tool receptacle for attaching a suitable tool to engage or disengage the multi-part rotary bearing element with or from the outer part.with parts connected or connectable to it.
[0020] Furthermore, it is provided that the axial locking mechanism can be released by actuating the inner pivot element, particularly relative to the outer pivot element, by allowing the locking element to be moved radially inwards such that it does not protrude, or only minimally protrudes, beyond the outer circumference of the outer pivot element. Consequently, when the axial locking mechanism is not activated, proximal movement of the femoral component and distal movement of the tibial component relative to each other parallel to the axis of rotation are no longer restricted, as the locking element no longer abuts the stop element. Therefore, the axial locking mechanism and the dislocation stop can be released. This can be particularly advantageous during revision surgery for checking and / or replacing, especially parts of, the knee endoprosthesis.
[0021] In one embodiment, actuating the inner pivot element relative to the outer pivot element comprises an axial relative movement along the axis of rotation, wherein, in particular, the inner pivot element is moved distally or proximally relative to the outer pivot element, and / or wherein actuating the inner pivot element relative to the outer pivot element comprises a rotational movement about the axis of rotation, wherein, in particular, the inner pivot element is moved relative to the outer pivot element. The relative movement of the inner pivot element relative to the outer pivot element can be a pure translational movement, for example, a displacement, along the axis of rotation distally or proximally. The relative movement of the inner pivot element relative to the outer pivot element can be a pure rotational movement.The relative movement of the inner pivot element relative to the outer pivot element can include translational and rotational movement. For example, the inner pivot element can have an external thread that engages with an internal thread of the outer pivot element. To release the axial locking mechanism, the inner pivot element can be moved relative to the outer pivot element in the opposite direction.
[0022] According to one embodiment, locking means can be provided on the inner and outer rotary bearing elements, which lock together when the locking mechanism is activated.
[0023] For example, one of several radially outward-pointing locking cams can be provided on the inner rotary bearing element, which engage in corresponding recesses inside the circumferential wall of the outer rotary bearing element, in particular by springing into them. The locking mechanism can be released by disengaging it.
[0024] In one embodiment, a locking device is provided that prevents unintentional release of the axial locking mechanism, i.e., relative movement of the inner rotary bearing element relative to the outer rotary bearing element that would release the axial locking mechanism. The locking device can be located on the inner and / or the outer rotary bearing element. The locking device can also be a separate component. In particular, the locking device can engage in a tool element receptacle of the outer rotary bearing element and / or in a tool element receptacle of the inner rotary bearing element, thus clamping the outer and inner rotary bearing elements against each other.
[0025] According to one embodiment, when the axial locking mechanism is activated, the locking element projects radially outward through an opening in the outer slewing bearing element or at a distal end of the outer slewing bearing element, extending beyond the outer circumference of the outer slewing bearing element. Thus, when the axial locking mechanism is activated, the effective outer circumference of the multi-part slewing bearing element is increased by the locking element in the region of the opening in the outer slewing bearing element or at its distal end. The opening is, for example, a through-hole in the circumferential wall of the outer slewing bearing element. The opening extends, for example, radially perpendicular to the axis of rotation through the circumferential wall. The opening can also extend radially obliquely to the axis of rotation through the circumferential wall. To activate orDeactivating the axial locking mechanism moves the locking element radially outward or radially inward within the opening. The orientation of the opening can define the movement path of the locking element. If the opening extends radially perpendicular to the axis of rotation, the locking element also moves perpendicular to the axis of rotation. If the opening extends radially obliquely to the axis of rotation, the locking element also moves obliquely to the axis of rotation. The shape of the opening can be adapted to the shape of the locking element. If multiple locking elements are present, multiple openings are provided accordingly.
[0026] In one embodiment, the outer and inner rotary bearing elements provide a receptacle for the locking element, and the locking element is received in the inner and outer rotary bearing elements when the axial locking mechanism is deactivated. For example, when the axial locking mechanism is deactivated, the locking element is completely contained within or between the inner and outer rotary bearing elements and does not project beyond the outer rotary bearing element. In particular, the locking element is loosely and freely movable within the receptacle between the inner and outer rotary bearing elements.In this example, the receptacle for the locking element is provided by a cylindrical section of the inner slewing bearing element in conjunction with a corresponding sleeve section of the outer slewing bearing element, wherein the inner circumference of the sleeve section of the outer slewing bearing element is such that an inner circumference of the cylindrical section of the inner slewing bearing element is formed, creating a receiving space for the locking element. A receiving space can also be formed by corresponding recesses in the outer and / or inner slewing bearing element.
[0027] According to one embodiment, the inner rotary bearing element comprises at least one actuating section, such that by actuating the inner rotary bearing element to activate the axial locking mechanism, the locking element can be moved radially outwards by means of the actuating section. The actuating section is, for example, a section formed on the inner rotary bearing element with an outer circumference that increases or decreases in a direction along the axis of rotation. The actuating section can also be formed by a section of the inner rotary bearing element with a diameter that increases or decreases in the direction around the axis of rotation.
[0028] The locking element can itself comprise any geometric shape, in particular a freeform shape. According to one embodiment, the locking element comprises at least a partial spherical shape and / or an oval or elliptical shape and / or a cylindrical shape and / or a shape with at least one flat surface and at least one, in particular two, inclined flank surfaces. The shape of an opening in the outer rotary bearing element can be complementary to the geometry of the locking element. The diameter of the opening can be chosen to be smaller than the locking element, so that a captive locking mechanism can be provided. In an embodiment with at least two locking elements, the two locking elements can be complementary to each other and combine to form a type of cylinder, in particular a circular cylinder or a cylinder with an oval or elliptical base.The shape, comprising at least one flat surface and at least one, in particular two, inclined flank surfaces, can advantageously be provided at an outer end of the locking element and, in particular, be designed to run against a stop element.
[0029] In one embodiment, the locking element is a spring element and / or comprises a spring element, and the spring element applies a spring force to the locking element in a radially outward or radially inward direction. For example, the locking element is pre-tensioned radially inward and, to activate the axial locking mechanism, is moved radially outward against the spring force.
[0030] In one embodiment, the locking element comprises a spherical shape, and the inner pivot element includes an actuating section with an outer circumference that increases or decreases in one direction along the axis of rotation. The outer pivot element includes an opening extending radially through a circumferential wall of the outer pivot element. To activate the axial locking mechanism, the inner pivot element is moved along the axis of rotation relative to the outer pivot element, and the locking element is moved radially outward through the opening of the outer pivot element by the actuating section of the inner pivot element. The actuating section of the inner pivot element includes, for example, an outer circumference that increases distally along the axis of rotation and decreases proximally along the axis of rotation.The opening through the circumferential wall of the outer pivot element extends, for example, radially outwards and obliquely radially outwards from the axis of rotation in a proximal direction. The inner pivot element is, for example, screwed into, or can be screwed into, an internal thread of the outer pivot element. To activate the axial locking mechanism, the inner pivot element is moved proximal along the axis of rotation relative to the outer pivot element by screwing it into the internal thread of the outer pivot element. This moves the actuating section proximally, so that the increasing outer circumference of the actuating section acts on the locking element, pushing the locking element radially outwards through the opening of the outer pivot element. The locking mechanism is released by actuating the inner pivot element in the opposite direction.
[0031] According to one embodiment, two locking elements are provided, and the two locking elements have a complementary shape and combine to form a cylindrical shape, and the inner rotary bearing element has an actuating section with a diameter that increases in one direction around the axis of rotation.comprising a decreasing diameter, and the actuating section is arranged between the two locking elements, and the outer rotary bearing element comprises two openings opposite each other with respect to the axis of rotation and extending radially through a circumferential wall of the outer rotary bearing element, wherein, to activate the axial locking, the inner rotary bearing element is moved in a rotational movement about the axis of rotation relative to the outer rotary bearing element, and thereby the locking elements are moved radially outwards through a respective opening of the outer rotary bearing element by the actuating section of the inner rotary bearing element.
[0032] The actuation section of the inner rotary bearing element comprises, for example, in a section perpendicular to the axis of rotation, a cross-section that deviates from a circular shape, in particular an at least approximately oval or elliptical cross-section.
[0033] Accordingly, the actuating section comprises a first diameter and a second diameter, which is perpendicular to the first, where the first diameter is smaller than the second. The cross-sectional diameter of the actuating section can increase by approximately one-quarter of its cross-section from the smaller diameter to the larger diameter, and vice versa. To activate the axial locking mechanism, the inner pivot element is rotated, for example, 90° around the axis of rotation relative to the outer pivot element. This causes the increasing diameter of the actuating section to act on the two locking elements, pushing them radially outward through the opposing openings of the outer pivot element. The locking mechanism is released by actuating the inner pivot element in the opposite direction.In further development, it can be provided that the inner rotary bearing element comprises two expandable detent sections separated from each other by a longitudinal slot along the axis of rotation, which can be expanded when the axial locking is activated by a locking device engaging in the longitudinal slot, so that detent means provided on the detent sections engage in a recess on the outer rotary bearing element.
[0034] According to one embodiment, the knee endoprosthesis includes a receptacle for the pivot bearing element provided on the tibial component, wherein the stop element is provided by a corresponding geometry, in particular a recess, for example a circumferential groove, in the receptacle. The tibial component itself can provide the receptacle. The receptacle is, for example, a blind hole concentric to the axis of rotation. The stop element is provided, for example, by an inner circumferential groove in the blind hole, wherein, when the locking mechanism is activated, the locking element projecting beyond the outer circumference of the outer pivot bearing element engages at least partially in the inner circumferential groove. A proximal stop element can be formed by an annular recess inside the bearing sleeve or the blind hole. In the area of the recess, the inner diameter of the bearing sleeve or blind hole is reduced.The diameter of the blind hole decreases from a first diameter to a second diameter in the proximal direction. A distal stop element can also be formed by an annular recess inside the bearing sleeve or the blind hole. In the area of the recess, the inner diameter of the bearing sleeve or the blind hole decreases from a first diameter to a second diameter in the distal direction.
[0035] According to one embodiment, the knee endoprosthesis comprises a bearing sleeve for mounting the pivot bearing element, the bearing sleeve providing a receptacle for the pivot bearing element. Such a bearing sleeve makes it possible, in particular, to arrange the pivot bearing element in a recess on the tibial component and to mount it slidably, thus allowing movement of the pivot bearing element and the bearing sleeve relative to each other about the axis of rotation and parallel to each other. The bearing sleeve can advantageously be made of plastic, in particular PEEK, and thus prevent metal abrasion from the tibial and femoral components, which are made primarily of metal. The stop element can be provided by a suitable geometry, in particular a recess, for example an inner circumferential groove, in the bearing sleeve, or by a distal end of the bearing sleeve, in particular the end of a sleeve wall.For example, when the locking mechanism is activated, the locking element projecting beyond the outer circumference of the outer pivot bearing element engages at least partially in the inner circumferential groove of the bearing sleeve. Alternatively, when the locking mechanism is activated, the locking element projecting beyond the outer circumference of the outer pivot bearing element can project at least partially beyond the distal end of the bearing sleeve and engage behind the sleeve wall. According to this embodiment, the tibial component has a bearing sleeve receptacle for receiving the bearing sleeve, for example, in the form of a blind hole. The bearing sleeve receptacle makes it possible, in particular, to support the bearing sleeve on the tibial component over a sufficient length parallel to the axis of rotation.
[0036] Further advantages are outlined in the description and the accompanying drawings.
[0037] Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description. In this context, identical reference numerals in different figures denote identical or at least functionally comparable elements. When describing individual figures, reference is also made, where appropriate, to elements from other figures. The figures show, in schematic form: Fig. 1 a schematic perspective exploded view of a knee endoprosthesis;
[0038] Fig. 2 shows a schematic sectional view of a knee joint endoprosthesis according to a first embodiment;
[0039] Fig. 3 shows a perspective view of a pivot bearing element of the knee joint endoprosthesis from Fig. 2;
[0040] Fig. 4 shows a perspective view of part of the rotary bearing element from Fig. 3;
[0041] Fig. 5 shows a detailed view of the knee joint endoprosthesis from Fig. 2 in sectional view with the axial locking mechanism released;
[0042] Fig. 6 shows a detailed view of the knee joint endoprosthesis from Fig. 2 in sectional view with activated axial locking;
[0043] Fig. 7 shows a detailed sectional view of part of the knee joint endoprosthesis from Fig. 2;
[0044] Fig. 8 shows an alternative embodiment of the part from Fig. 7;
[0045] Fig. 9 shows a perspective view of a rotary bearing element of a knee joint endoprosthesis according to a further embodiment;
[0046] Fig. 10 is a perspective view of part of the rotary bearing element from Fig. 9;
[0047] Fig. 11 shows the rotary bearing element from Fig. 9 in sectional view with the axial locking mechanism released and with a bearing sleeve;
[0048] Fig. 12 shows the rotary bearing element with bearing sleeve from Fig. 11 in a sectional view with the axial locking mechanism activated. Fig. 1 shows an exemplary knee endoprosthesis with its individual components, collectively designated by reference numeral 10. It comprises a femoral component 12, which can be fixed to a patient's femur with or without a stem, a tibial component 14, which can be fixed to a patient's tibia, and a meniscal component 16, which is arranged between the femoral component 12 and the tibial component 14 in a manner that prevents rotation on the tibial component 14. Furthermore, the knee endoprosthesis 10 includes a connecting device 18 comprising several parts, with which the femoral component 12 and the tibial component 14 can be connected to each other.
[0049] The femoral segment 12 comprises a medial femoral condyle 20 and a lateral femoral condyle 22. A recess 46, bounded by parallel side walls 42 and 44, is formed between the two femoral condyles 20 and 22. The side walls 42 and 44, together with a cover wall (not shown), form a receptacle for a pivot pin 56. The side walls 42 and 44 each have an opening 58 and 60, respectively, into which a drive shaft 62 is inserted. The pivot pin 56 has a transverse bore 64 extending along a longitudinal axis defined by it, which defines a pivot axis 66 and serves to receive the drive shaft 62. The drive shaft 62 can be provided at one end with a short external thread section 68, which corresponds to an internal thread 70, which is formed in the opening 58 of the side wall 42.Overall, a hinge joint 196 is formed between the fem part 12 and the hinge pin 56. In the manner described, the hinge pin 56 is pivotably mounted in the recess 46 about the hinge axis 66.
[0050] Furthermore, a longitudinal opening 76 is formed on the articulating pin 56, which runs anteriorly to the transverse bore 64. It defines an axis of rotation 78 of the knee endoprosthesis 10. The longitudinal opening 76 corresponds to a proximal section 82 of a multi-part pivot bearing element 84 (not shown in detail), the proximal section 82 engaging in the longitudinal opening 76. The pivot bearing element 84 can be connected to the articulating pin 56 in a manner not shown, for example, via an external thread. A cylindrical section 88 of the pivot bearing element 84 adjoins the proximal section 82.
[0051] The tibial part 14 comprises a plate 94 with an upper surface 96 pointing towards the distal part 12, which defines a flat tibial surface 98. A short shaft stub 102 is formed on a lower surface 100 of the plate 94, which can optionally be extended modularly with a shaft not shown in the figures.
[0052] A short, sleeve-shaped stub 104 extends from the tibial surface 98 towards the tibial part 12. Starting from an end 108 of the stub pointing towards the tibial part 12, a blind hole 110 is formed on the tibial part 14, concentric to the axis of rotation 78. Inside the blind hole 110, a short internal threaded section 114 is formed in the area of the stub 104.
[0053] which corresponds to an external threaded section 116 of a locking sleeve 118. The locking sleeve 118 has an annular flange-shaped end 120, the outer diameter of which is dimensioned such that it forms a stop that abuts the end 108 of the fitting 104 when the locking sleeve 118 is screwed into the fitting 104.
[0054] The external threaded section 116 is followed by a short cylindrical sleeve section 122, the outer diameter of which is adapted to an inner diameter of the blind hole 110 in the area of the nozzle 104.
[0055] To securely connect the femoral part 12 and the tibial part 14, the connecting device 18 further comprises a bearing sleeve 134 designed rotationally symmetrically to the axis of rotation 78. Starting from a proximal end 136 pointing towards the femoral part 12, this sleeve has a first sleeve section 138, to which a short second sleeve section 140 with a larger outer diameter is attached. A third sleeve section 142, extending to the distal end 144 of the bearing sleeve 134, is attached to this second sleeve section 140. The outer diameter of the third sleeve section 142 is, for example, slightly larger than the outer diameter of the first sleeve section 138, but smaller than the outer diameter of the second sleeve section 140.When the locking sleeve 118 is screwed into the blind hole 110, its end 124 pointing away from the remote part 12 extends approximately to the second sleeve section 140 of the bearing sleeve 134, so that the locking sleeve 118 secures the bearing sleeve in the blind hole 110.
[0056] Inside, the bearing sleeve 134 has a rotationally symmetrical longitudinal opening 146, which defines a rotary bearing element receptacle for the rotary bearing element.
[0057] With reference to Figures 2 to 12, the multi-part rotary bearing element 84 in various embodiments will now be described in particular.
[0058] With reference to Figures 3 to 6, the multi-part rotary bearing element 84 of the knee endoprosthesis 10 from Figure 2 is described. The multi-part rotary bearing element 84 comprises an outer rotary bearing element 202. The outer rotary bearing element 202 essentially comprises, for example, a sleeve-like or tube-like circumferential wall 204 and forms a receptacle for an inner rotary bearing element 206. In the proximal section 82, the rotary bearing element 84 includes an external thread 208 formed on the outer rotary bearing element 202 for connecting the rotary bearing element 84 to the articulating pin 56. At a proximal end 210 of the outer rotary bearing element 202, a tool receptacle is provided for attaching a suitable tool for coupling or uncoupling the multi-part rotary bearing element with the articulating pin 56.
[0059] The inner rotary bearing element 206 essentially comprises, for example, a pin- or rod-like shape. Approximately in the middle of the elongated extent of the pin- or rod-like shape, an external thread 214 is provided on the inner rotary bearing element 206, which corresponds to an internal thread 216 of the outer rotary bearing element 202. The inner and outer rotary bearing elements are connected to each other via the threads 214 and 216. Furthermore, by screwing the inner rotary bearing element 206 into the threads 214 and 216, it can be actuated relative to the outer rotary bearing element 202, i.e., moved in a proximal or distal direction along the axis of rotation 78. The inner rotary bearing element 206 includes a tool receptacle 220 at a proximal end 218 for attaching a suitable tool to actuate the inner rotary bearing element 206.
[0060] In this example, the multi-part rotary bearing element 84 includes a locking element 222 for providing axial locking of the rotary bearing element 84. The axial locking can be activated by actuating the inner rotary bearing element 206. In this example, the locking element 222 has a spherical shape.
[0061] The outer and inner rotary bearing elements 202, 206 provide a receptacle for the locking element 222. In this example, the receptacle for the locking element 222 is provided by a cylindrical section 224 of the inner rotary bearing element 206 adjoining the external thread 214, in conjunction with a corresponding sleeve section 226 of the outer rotary bearing element 206 adjoining the internal thread 216. The inner circumference of the sleeve section 226 of the outer rotary bearing element 206 is such that the outer circumference of the cylindrical section 224 of the inner rotary bearing element 206 is larger than that of the cylindrical section 224 of the inner rotary bearing element 206, thus forming a receiving space for the locking element 222.
[0062] With the axial locking mechanism deactivated, the locking element 222 is received in the inner and outer rotary bearing elements. For example, with the axial locking mechanism deactivated, the locking element is completely received in or between the inner and outer rotary bearing elements 202, 206 and does not project beyond the outer rotary bearing element 206. The locking element 222 is loosely and movably received in the receptacle between the inner and outer rotary bearing elements 202, 206. Fig. 5 shows the rotary bearing element 84 in the bearing sleeve 134 with the axial locking mechanism released. It is shown that with the axial locking mechanism deactivated, the locking element 222 is completely received in or between the inner and outer rotary bearing elements 202, 206 in the region of the cylinder section 224 of the inner rotary bearing element 206 and in the region of the sleeve section 226 of the outer rotary bearing element 202 and does not project beyond the outer rotary bearing element 206.In this example, the outer rotary bearing element 202 includes an opening 228 that extends radially outward from the axis of rotation 78 through the circumferential wall 204 of the outer rotary bearing element 202. In this example, the opening 228 extends obliquely radially outward in the proximal direction from the axis of rotation 78.
[0063] To activate the axial locking mechanism, the locking element 222 is moved radially outwards in or through the opening 228 by means of a corresponding actuating section 230 of the inner rotary bearing element 206, so that the locking element 222 protrudes beyond an outer circumference of the outer rotary bearing element, see for example Fig. 6.
[0064] In the example, the actuation section 230 of the inner rotary bearing element 206 comprises an outer circumference that increases in the distal direction along the axis of rotation 78 and decreases in the proximal direction along the axis of rotation 78.
[0065] Fig. 6 shows the rotary bearing element 84 in the bearing sleeve 134 with the axial locking mechanism activated. To activate the axial locking mechanism, the inner rotary bearing element 206 is moved proximal along the axis of rotation 78 relative to the outer rotary bearing element 202 by screwing it into the internal thread 216 of the outer rotary bearing element 202. This moves the actuating section 230 proximally, so that the increasing outer circumference of the actuating section 230 acts on the locking element 222, pushing the locking element 222 radially outward through the opening 228 of the outer rotary bearing element 202. The locking mechanism is released by actuating the inner rotary bearing element 206 in the opposite direction.
[0066] When the axial locking mechanism is activated, the locking element 222 limits proximal movement of the femoral part 12 and distal movement along the axis of rotation 78 of the tibial part 14 relative to each other by means of stops against a proximal stop element 232, which in this example is formed on the bearing sleeve 134. This provides axial locking of the rotary bearing element 84 on the tibial part 14. In this example, the proximal stop element 232 is formed by an annular recess 234 inside the bearing sleeve 134. In the region of the recess 234, the inner diameter of the bearing sleeve 134 decreases from a diameter D2 to a diameter D1 in the proximal direction. This is illustrated, for example, in Fig. 7.
[0067] The bearing sleeve also includes a distal stop element 236. The distal stop element 236 limits distal movement of the femoral part 12 and proximal movement along the axis of rotation 78 of the tibial part 14 relative to each other. In this example, the distal stop element 236 is formed by an annular recess 238 inside the bearing sleeve 134. In the region of the recess 238, the inner diameter of the bearing sleeve 134 decreases from a diameter D2 to a diameter D1 in the distal direction.
[0068] Fig. 8 shows an alternative embodiment of the bearing sleeve, wherein only a proximal stop element 232 and no distal stop element 236 is formed. A distal stop element for the rotary bearing element 84 can also be provided by the bottom of the blind hole 110 on the tibial part 14.
[0069] Figures 9 to 12 show detailed views of a knee endoprosthesis 10 according to a further embodiment. With reference to Figures 9 to 12, the multi-part pivot bearing element 84 of the knee endoprosthesis 10 according to the further embodiment is described.
[0070] The multi-part rotary bearing element 84 also includes an outer rotary bearing element 202. The outer rotary bearing element 202 essentially comprises, for example, a sleeve-like or tube-like circumferential wall 204 and forms a receptacle for an inner rotary bearing element 206. In the proximal section 82, the rotary bearing element 84 can also include an external thread (not shown) formed on the outer rotary bearing element 202 for connecting the rotary bearing element 84 to the pivot pin 56. A tool element receptacle 212 for attaching a suitable tool for coupling or uncoupling the multi-part rotary bearing element with the pivot pin 56 is provided at a proximal end 210 of the outer rotary bearing element 202. The inner rotary bearing element 206 essentially comprises, for example, a pin- or rod-like shape and is arranged in the outer rotary bearing element 202.The inner rotary bearing element 206 includes at a proximal end 218 a tool element receptacle 220 for attaching a suitable tool for actuating the inner rotary bearing element 206.
[0071] In this example, the multi-part rotary bearing element 84 comprises two locking elements 222 for providing axial locking of the rotary bearing element 84. The two locking elements 222 have a complementary shape to each other and combine to form a kind of cylindrical shape, see Figs. 11 and 12.
[0072] The outer and inner rotary bearing elements 202, 206 provide a receptacle for the locking element 222. In this example, the receptacle for the locking element is formed by two openings 228 in the outer rotary bearing element 202, which extend radially from the axis of rotation 78 through the circumferential wall 204 of the outer rotary bearing element 202. In this example, the two openings are arranged opposite each other with respect to the axis of rotation 78. Furthermore, the receptacle is provided by the shape of the actuating section 230 of the inner rotary bearing element 206, which will be explained in more detail below.
[0073] With the axial locking mechanism deactivated, the two locking elements 222 are completely enclosed in or between the inner and outer rotary bearing elements 202, 206 and do not protrude beyond the outer rotary bearing element 206. Fig. 5 shows the rotary bearing element 84 in the bearing sleeve 134 with the axial locking mechanism released.
[0074] The actuating section 230 of the inner rotary bearing element 206 is arranged between the two locking elements 222 and is enclosed by them in this example. The actuating section 230 of the inner rotary bearing element 206 comprises, for example, a section perpendicular to the axis of rotation 78 that deviates from a circular shape, in particular an at least approximately oval or elliptical section, see also Fig. 10. Accordingly, the actuating section comprises a first diameter D3 and a second diameter D4, see Figs. 11 and 12, where the diameter D3 is smaller than the diameter D4. In Fig. 10, the area with the smaller diameter D3 is designated by reference numeral 240 and the area with the larger diameter D4 by reference numeral 242.With the axial locking mechanism deactivated, the actuating section 230 of the inner rotary bearing element 206 is arranged such that the area 240 with the smaller diameter D3 is aligned between the openings 228.
[0075] To activate the axial locking mechanism, the inner rotary bearing element 206 is moved, for example, 90° around the axis of rotation 78 relative to the outer rotary bearing element 202. This causes the larger diameter D4 of the actuating section 230 to act on the two locking elements 222, pushing them radially outward through the opposing openings 228 of the outer rotary bearing element 202. Fig. 6 shows the rotary bearing element 84 in the bearing sleeve 134 with the axial locking mechanism activated. Accordingly, the actuating section 230 of the inner rotary bearing element 206 is arranged such that the area 242 with the larger diameter D4 is aligned between the openings 228 and acts on the two locking elements 222, causing them to protrude through the openings 228. The axial locking mechanism is released by actuating the inner rotary bearing element in the opposite direction.
[0076] According to the example, the inner rotary bearing element 206 comprises two expandable detent sections 246, 248 separated from each other by a longitudinal slot 244 along the axis of rotation 78. When the axial locking mechanism is activated, the detent sections 246, 248 can be expanded by a locking device 250 engaging in the longitudinal slot 244. As they expand, locking elements 252, for example, locking cams, provided on the detent sections 246, 248, engage in a respective recess 250 inside the outer rotary bearing element 202. In the example, the locking device 250 engages in the tool element receptacle 212 of the outer rotary bearing element 202 and in a tool element receptacle 220 or in the longitudinal slot 244 of the inner rotary bearing element 206, so that the outer rotary bearing element 202 and the inner rotary bearing element 206 are preloaded against each other.The locking elements 222, shown in Figures 9, 11 and 12, comprise at their radially outwardly projecting end a form with a flat surface 256 and two inclined flank surfaces 258. This form can advantageously abut against the proximal or distal stop element 232, 236. Reference numeral list.
[0077] Knee joint endoprosthesis
[0078] Foreign ruling
[0079] tibial part
[0080] Meniscus part
[0081] Connection device
[0082] medial femoral condyle
[0083] lateral femoral condyle
[0084] side wall
[0085] side wall
[0086] recess
[0087] Breakthrough
[0088] Breakthrough
[0089] driveshaft
[0090] Transverse drilling
[0091] hinge axis
[0092] External thread section
[0093] internal thread
[0094] longitudinal penetration
[0095] axis of rotation
[0096] proximal section
[0097] Rotary bearing em ent
[0098] Cylinder section
[0099] plate
[0100] Top
[0101] tibial surface
[0102] bottom
[0103] Stocks
[0104] Support
[0105] End
[0106] Blind hole, internal thread section, external thread section, locking sleeve
[0107] End
[0108] cylindrical sleeve section end
[0109] Bearing sleeve
[0110] proximal end
[0111] first sleeve section, second sleeve section, third sleeve section, distal end, longitudinal opening, hinge joint
[0112] outer pivot bearing element circumferential wall
[0113] inner rotary bearing element external thread
[0114] proximal end tool element holder external thread internal thread
[0115] proximal end tool element holder locking element cylinder section sleeve section
[0116] Opening of the actuating section, proximal stop element, ring. Retraction.
[0117] Dist. Stop element 238 Ring. Recess 240 Small diameter 242 Large diameter 244 Longitudinal slot
[0118] 246 Rest area
[0119] 248 Rest area
[0120] 250 blocking protection 252 locking means
[0121] 254 recess
[0122] 256 flat surface
[0123] 258 flank area
Claims
24 Patent claims 1. Knee joint endoprosthesis (10) comprising a tibial part (14), a femoral part (12), and a connecting device (18) for articulated connection of the tibial part (14) to the femoral part (12), wherein the femoral part (12) and the tibial part (14) are rotatably mounted relative to each other about an axis of rotation (78), characterized in that the connecting device (18) comprises a rotary bearing element (84) comprising at least two or more parts, wherein the rotary bearing element (84) comprising at least two or more parts comprises an outer rotary bearing element (202), an inner rotary bearing element (206) arranged in the outer rotary bearing element (202), and at least one locking element (222) for providing axial locking of the rotary bearing element (84), wherein the axial locking can be activated by actuating the inner rotary bearing element (206), in particular relative to the outer rotary bearing element (202), wherein the locking element (222) is movable radially outwards in this manner,that it projects beyond an outer circumference of the outer pivot bearing element (202), so that, when axial locking is activated, the locking element (222) limits a proximal movement of the femoral part (12) and a distal movement of the tibial part (14) relative to each other parallel to the axis of rotation (78) by means of stops on a stop element (232), and thus axial locking of the pivot bearing element (84) on the tibial part (14) is provided.
2. Knee joint endoprosthesis (10) according to claim 1, wherein the axial locking can be released by actuating the inner rotary bearing element (206), in particular relative to the outer rotary bearing element (202), in such a way that the locking element (222) can be moved radially inwards in such a way that the locking element (222) does not project beyond the outer circumference of the outer rotary bearing element (202).
3. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein actuating the inner pivoting bearing element (206) relative to the outer pivoting bearing element (202) comprises an axial relative movement along the axis of rotation (78), wherein in particular the inner pivoting bearing element (206) is moved distally or proximally relative to the outer pivoting bearing element (202) and / or wherein actuating the inner pivoting bearing element (206) relative to the outer pivoting bearing element (202) comprises a rotational movement about the axis of rotation (78), wherein in particular the inner pivoting bearing element (260) is moved relative to the outer pivoting bearing element (202).
4. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the locking element (222) projects radially outwards beyond the outer circumference of the outer pivoting element (202) through an opening (228) in the outer pivoting bearing element (202) or at a distal end of the outer pivoting bearing element (202) when the axial locking is activated.
5. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the outer and inner pivot bearing element (202, 206) provide a receptacle for the locking element (222), and the locking element (222) is received in the inner and outer pivot bearing element (202, 206) when the axial locking is deactivated.
6. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the inner pivot bearing element (206) comprises an actuating section (230) such that by actuating the inner pivot bearing element (206) to activate the axial locking, the locking element (222) can be moved radially outwards by means of the actuating section (230).
7. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the locking element (22) comprises at least partially a spherical shape and / or an oval or elliptical shape and / or a cylindrical shape and / or a shape with at least one flat surface (256) and at least one, in particular two, inclined flank surfaces (258).
8. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the locking element (222) is a spring element and / or comprises a spring element, and the spring element applies a spring force to the locking element (222) in a radially outward or radially inward direction.
9. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the locking element (222) comprises a spherical shape, and the inner pivot bearing element (206) comprises an actuating section (230) with an increasing diameter in one direction along the axis of rotation (78).comprising a decreasing outer circumference, and the outer rotary bearing element (202) comprising an opening (228) extending radially through a circumferential wall (204) of the outer rotary bearing element (202), wherein, to activate the axial locking, the inner rotary bearing element (206) is moved along the axis of rotation (78) relative to the outer rotary bearing element (202), and the locking element (222) is moved radially outwards through the opening (228) of the outer rotary bearing element (202) by the actuating section (230) of the inner rotary bearing element (206).
10. Knee joint endoprosthesis (10) according to one of the preceding claims 1 to 8, wherein at least two locking elements (222) are provided, and the two locking elements (222) comprise a complementary shape and complement each other to form a cylindrical shape, and the inner pivot bearing element (206) has an actuating section (230) with a diameter that increases in one direction around the axis of rotation (78).comprising a decreasing diameter, and the actuating section (230) is arranged between the two locking elements (222), and the outer rotary bearing element (202) comprises two openings (228) opposite each other with respect to the axis of rotation (78) and extending radially through a circumferential wall (204) of the outer rotary bearing element (202), wherein, to activate the axial locking, the inner rotary bearing element (206) is moved in a rotational movement about the axis of rotation (78) relative to the outer rotary bearing element (202), and thereby the locking elements (222) are moved radially outwards through a respective opening (228) of the outer rotary bearing element (202) by the actuating section (230) of the inner rotary bearing element (206).
11. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the knee joint endoprosthesis (10) comprises a pivot bearing element receptacle provided on the tibial part (14) for the pivot bearing element (84), wherein the 27 The stop element (232) is provided by a corresponding geometry, in particular a recess, for example a circumferential groove, in the rotary bearing element receptacle.
12. Knee joint endoprosthesis (10) according to one of the preceding claims, wherein the knee joint endoprosthesis (10) comprises a bearing sleeve (134) for supporting the rotary bearing element (84), wherein the bearing sleeve (134) provides a rotary bearing element receptacle, wherein the stop element (232) is provided by a corresponding geometry, in particular a recess, for example a circumferential groove, in the rotary bearing element receptacle.