Anchoring unit for a knee prosthesis component, prosthesis kit, method for preparing an anchoring unit for implantation

Abstract

The invention relates to an anchoring unit (10) for anchoring a knee prosthesis component (100) to a leg bone, the anchoring unit comprising: an anchoring sleeve (12) having a sleeve wall (14) defining a through-opening (16) which is designed to receive a prosthesis shaft (102), wherein at least a portion of the sleeve wall is made of a thermoplastic material. The invention also relates to a prosthesis kit and to a method for preparing an anchoring unit (10) for implantation.

Description

[0001] Applicant:

[0002] Aesculap AG

[0003] At Aesculap Square

[0004] 78532 Tuttlingen

[0005] General Power of Attorney: 752190.9

[0006] 0392003 OWO 12.03.2026

[0007] BUR / KUN

[0008] Title: Anchoring unit for a knee prosthesis component,

[0009] Prosthesis kit, procedure for preparing an anchoring unit for implantation

[0010] Description

[0011] The present invention relates to the field of implant technology. In particular, the present invention relates to an anchoring unit for anchoring a knee prosthesis component to a patient's leg bone. The present invention also relates to a prosthesis kit with such an anchoring unit. Furthermore, the present invention relates to a method for preparing an anchoring unit for implantation.

[0012] A knee prosthesis (also called a knee replacement) is a prosthesis that replaces the knee joint completely or partially. Typically, a knee prosthesis has two components: a femoral component and a tibial component. The femoral component is implanted into the femur (thigh bone), and the tibial component is implanted into the tibia (shin bone). These knee prosthesis components typically include a stem that supports the actual joint replacement portion of the prosthesis.

[0013] In cases of existing bone defects, a sleeve-shaped anchoring unit is often used in addition to the actual knee prosthesis component. This unit serves to anchor the knee prosthesis component to the affected leg bone. Such a sleeve-shaped anchoring unit is also called a "cone." A cone is usually placed in the metaphyseal region of the leg bone. For this reason, the outer contour of a cone often mirrors the metaphyseal region of the tibia or femur, thus achieving a good fit. A cone typically has a through-opening designed to accommodate a prosthetic stem of the knee prosthesis component. The knee prosthesis component, positioned in this way, can then be attached to the cone using bone cement. The cone facilitates bone ingrowth (osteointegration), thereby anchoring the knee prosthesis component to the leg bone.

[0014] Known cones are typically manufactured monolithically from a metallic material. Such a cone is described in the patent applications WO 2024 / 047127 Al and EP 4 197496 Al.

[0015] The invention addresses the problem of providing an anchoring unit for anchoring a knee prosthesis component that enables bone-sparing implantation.

[0016] The first aspect of the description concerns an anchoring unit for securing a knee prosthesis component to a patient's leg bone. The anchoring unit includes an anchoring sleeve. Specifically, the anchoring unit is formed by the anchoring sleeve, giving it a sleeve-like shape. However, the anchoring unit may also include one or more additional sections besides the anchoring sleeve.

[0017] The anchoring sleeve has a sleeve wall that defines a through-opening. Specifically, the sleeve wall is closed in the circumferential direction, so that the sleeve wall completely encloses the through-opening. However, the sleeve wall may also be interrupted in the circumferential direction. The through-opening is designed to receive a prosthetic stem of a knee prosthesis component.

[0018] At least one section of the sleeve wall is made of a thermoplastic material. Specifically, only one section of the sleeve wall is made of the thermoplastic material. However, several discrete sections of the sleeve wall can also be made of the thermoplastic material.

[0019] The inventors recognized that the underlying problem is solved by an anchoring unit designed as described above. The at least locally limited fabrication of the sleeve wall from the thermoplastic material allows for extensive adaptation of the sleeve wall's geometry to the bone defect in the leg bone. For this purpose, the thermoplastic material can be heated to a temperature exceeding its glass transition temperature before implantation. The sleeve wall can then be adapted to the bone defect by deformation of the thermoplastic material, particularly plastic deformation. Consequently, little or no bone substance needs to be removed to achieve a good fit of the cone within the bone defect. Furthermore, the plastic deformation of the thermoplastic material prevents the generation of restoring forces that could otherwise stress the bone.

[0020] Within the scope of this disclosure, the term "thermoplastic material" refers to a material that becomes plastically deformable at elevated temperature and solidifies again upon cooling. Preferably, the thermoplastic material comprises at least one thermoplastic component. Preferably, the thermoplastic material is not physiologically degradable. Within the scope of this disclosure, a "non-physiologically degradable material" is a material that, after implantation into a leg bone, is not degraded or is degraded at most so slowly that the structural integrity of a part made of a non-physiologically degradable material is permanently maintained following implantation.

[0021] Preferably, the anchoring sleeve is tapered. The cross-section of the anchoring sleeve thus decreases from a first longitudinal end of the anchoring sleeve to a second longitudinal end. An anchoring sleeve shaped in this way is particularly suitable for placement in the metaphyseal region of a leg bone. The tapered anchoring sleeve can optionally be symmetrical or asymmetrical. In a further preferred embodiment, the anchoring sleeve is cylindrical. The anchoring sleeve can also have a tapered first longitudinal section and a cylindrical second longitudinal section.

[0022] Preferably, the sleeve wall has a structured surface on at least some of its outer surface. This promotes the ingrowth of the leg bone to the anchoring unit. The structured surface can, for example, have teeth, grooves, and / or a grid structure. A suitable grid structure is known as a "structan surface".

[0023] Preferably, the section of the sleeve wall made from the thermoplastic material is a wall segment of the sleeve wall. A wall segment is a section of a wall that extends over the entire thickness of the wall (i.e., the complete wall thickness).

[0024] In some preferred embodiments, the thermoplastic material has a gas transition temperature (TG) of at least 50 °C. A glass transition temperature of at least 50 °C ensures the structural integrity of the anchoring unit following implantation. Preferably, the glass transition temperature is at least 100 °C, more preferably at least 50 °C and at most 200 °C, and particularly preferably at least 100 °C and at most 200 °C.

[0025] In some preferred embodiments, the thermoplastic material comprises at least one thermoplastic selected from the group consisting of: polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polylactic acid (PLA). These thermoplastics have proven particularly advantageous with regard to their material properties and biocompatibility. Preferably, the mass fraction of thermoplastic in the thermoplastic material is at least 75% by weight, and particularly preferably at least 90% by weight. The thermoplastic material can consist of one or more thermoplastics.

[0026] In some preferred embodiments, the thermoplastic material comprises at least one non-thermoplastic additive. Such an additive allows for the targeted modification of the thermoplastic material's properties. For example, an additive can be used that promotes bone ingrowth to the thermoplastic material. Calcium phosphate is a particularly preferred additive. The additive can be in the form of particles uniformly distributed throughout the thermoplastic material.

[0027] Preferably, the mass fraction of additive in the thermoplastic material is at least 1 wt.%, preferably at least 2 wt.%, and particularly preferably at least 5 wt.%. Limiting the mass fraction of additive is also advantageous in order not to impair the desired deformability of the thermoplastic material. Preferably, the mass fraction of additive in the thermoplastic material is at most 20 wt.%, preferably at most 15 wt.%, and particularly preferably at most 10 wt.%.

[0028] In some preferred embodiments, the sleeve wall is monolithically manufactured from the thermoplastic material. The sleeve wall thus consists entirely of the thermoplastic material. These embodiments have the advantage of offering a wide range of possibilities for deforming the sleeve wall.

[0029] Furthermore, a monolithic sleeve wall is easy to manufacture, which reduces production costs. For example, the monolithically manufactured sleeve wall can be produced by injection molding. In embodiments where the sleeve wall is monolithically made of the thermoplastic material, the thermoplastic material preferably contains at least one additive that promotes bone ingrowth to the sleeve wall. Calcium phosphate is particularly preferably included as an additive in the thermoplastic material.

[0030] In some preferred embodiments, the monolithically manufactured sleeve wall has at least one structural section and at least one deformation section, wherein the material thickness of the deformation section is less than the material thickness of the structural section. This design of the sleeve wall allows for the targeted creation of areas where deformation preferentially occurs, namely the deformation section(s). The additional structural sections increase the mechanical robustness of the sleeve wall. Preferably, the sleeve wall has several structural sections and several deformation sections. Preferably, the sleeve wall has at least 3 and at most 8 structural sections. Preferably, the sleeve wall has at least 3 and at most 8 deformation sections.The structural sections and the deformation sections can alternate along the circumference of the sleeve wall. This means that a deformation section is always arranged between two successive structural sections. Similarly, a structural section is always arranged between two successive deformation sections. Preferably, the structural sections and / or the deformation sections extend over the entire length of the anchoring sleeve.

[0031] In some preferred embodiments, the ratio of the maximum material thickness of the structural section to the minimum material thickness of the deformation section is at least 2:1. The maximum material thickness of the structural section, i.e., the material thickness at the point in the structural section where the material thickness is maximum, is therefore at least twice as large as the minimum material thickness of the deformation section, i.e., the material thickness at the point in the deformation section where the material thickness is minimum. Preferably, the ratio is at least 3:1, and particularly preferably between 3:1 and 10:1.

[0032] In some embodiments, the maximum material thickness of the structural section is between 2 mm and 10 mm. Such a material thickness results in advantageous stiffness of the structural components.

[0033] In some embodiments, the minimum material thickness of the deformation section is between 0.5 mm and 2 mm. Such a material thickness results in advantageous deformability of the heated deformation section.

[0034] In some preferred embodiments, the sleeve wall comprises at least one deformation section made of the thermoplastic material and at least one structural section connected to the deformation section. The structural section may be made of a non-thermoplastic material. Thus, the sleeve wall is partially made of the thermoplastic material and partially of the non-thermoplastic material. Alternatively, the structural section may be made of a thermoplastic material with a glass transition temperature higher than that of the thermoplastic material of the deformation section. In this case, the deformation section and the structural section are made of different thermoplastic materials. In particular, the glass transition temperature of the thermoplastic material of the structural section is at least 50 °C higher, preferably at least 100 °C higher.The desired deformability of the sleeve wall can be achieved by including at least one deformation element. Providing at least one structural element allows for the optimization of other aspects of the anchoring unit. For example, a material can be chosen for the structural element to which the leg bone more readily adheres than to the thermoplastic material of the deformation element.

[0035] In some preferred embodiments, the non-thermoplastic material is a metallic material. Preferably, the metallic material comprises titanium. The metallic material can consist entirely of titanium. Alternatively, the metallic material can be a titanium alloy. Titanium is particularly preferred due to its high stiffness and good biocompatibility. Preferably, the mass fraction of titanium in the metallic material is at least 50 wt.%, more preferably at least 75 wt.%.

[0036] In some preferred embodiments, the structural part and the deformation part are wall segments of the sleeve wall arranged offset from one another. In particular, the wall segments are arranged offset from one another in the circumferential direction of the anchoring sleeve or in the longitudinal extent of the anchoring sleeve.

[0037] In some embodiments, at least one structural component is designed in a plate-like shape. In a plate-like element, the length and width of the element are significantly greater than its thickness. A plate-like element is therefore essentially two-dimensional. The plate-like design of the structural component ensures effective anchoring of the knee prosthesis component to the leg bone. The plate-like structural component is preferably curved. An anchoring sleeve with curved structural components can be more easily fitted into the metaphyseal region of a leg bone.

[0038] In some embodiments, at least one deformation element is designed to be rod-shaped. In a rod-shaped element, the element's length is significantly greater than its width and height. A rod-shaped element is therefore essentially one-dimensional.

[0039] In some embodiments, the sleeve wall has several separately formed structural parts and / or several separately formed deformation parts.

[0040] Preferably, the structural elements and the deformation elements together form a circumferentially closed sleeve wall, wherein the structural elements are arranged one behind the other in the circumferential direction of the sleeve wall, and wherein at least one deformation element is always arranged between two adjacent structural elements, coupling the two structural elements together. Preferably, the structural elements extend in the circumferential direction of the sleeve wall along a circumferential angle interval of at least 30° (plate-shaped structural elements). The deformation elements preferably extend in the circumferential direction of the sleeve wall along a circumferential angle interval of at most 10° (rod-shaped deformation elements).

[0041] In some preferred embodiments, the structural part is connected to the deformation part by a positive-locking connection. This allows for a particularly robust mechanical connection between the structural part and the deformation part.

[0042] In some preferred embodiments, the structural part has a recess, and the deformation element projects into the recess to form the positive-locking connection. The recess can be formed on a lateral side of the structural part facing the circumferential direction of the anchoring sleeve. Preferably, the recess is filled by the deformation element. Preferably, the recess is elongated, for example, as a groove, channel, or furrow.

[0043] In some embodiments, the recess has an undercut, and the deformation element engages behind the undercut to form the positive-locking connection. Such a positive-locking connection is particularly robust mechanically. Preferably, the deformation element has a dovetail-shaped projection that extends into the recess and engages behind the undercut.

[0044] In some embodiments, the structural component is manufactured using an additive manufacturing process. This allows even complex geometries, such as the aforementioned structured surface, to be precisely realized. Preferably, the structural component is manufactured by selective laser melting, particularly preferably from a titanium-containing metal material. In some embodiments, the deformation element is injection-molded onto the structural component. An injection molding process combines high precision and cost-efficiency with the ability to produce complex, functionally integrated components in large quantities.

[0045] In some embodiments, the deformation part is attached to the structural part by a plug connection, in particular a detachable one.

[0046] A second aspect of the description concerns a prosthesis kit. The prosthesis kit includes an anchoring unit designed as described above, as outlined in the first aspect. The prosthesis kit also includes a knee prosthesis component, which has a prosthesis stem that can be positioned in the opening of the sleeve wall. The prosthesis stem supports the actual joint replacement portion of the knee prosthesis component.

[0047] Regarding the advantages achievable with the prosthesis kit, please refer to the relevant explanations concerning the anchoring unit. The features described in connection with the anchoring unit can be used for further development of the prosthesis kit.

[0048] In some embodiments, the prosthesis kit includes bone cement for attaching the knee prosthesis component to the anchoring unit.

[0049] A third aspect of the description concerns a procedure for preparing an anchoring unit for implantation into a patient's leg bone.

[0050] The procedure initially involves providing an anchoring unit in accordance with the first aspect.

[0051] The method also includes heating the sleeve wall of the anchoring unit, whereby the thermoplastic material is heated, at least in certain areas, to a temperature higher than its glass transition temperature. In the heated area, the thermoplastic material can then be deformed, particularly plastically. The method further includes changing the geometry of the sleeve wall by deforming the heated thermoplastic material, particularly plastically. The sleeve wall thus initially has a base geometry. The sleeve wall is provided and heated in this base geometry. By deforming the heated material, the sleeve wall is transformed from its base geometry to a target geometry. For example, the material can be deformed in such a way that the cross-sectional shape of the sleeve wall is changed.In particular, the sleeve wall can have a circular cross-section in its initial geometry and a cross-section that deviates from a circular shape in its target geometry. Preferably, the thermoplastic material is deformed according to the patient's leg bone defect in such a way that the contact area between the sleeve wall and the leg bone is increased when the anchoring unit is implanted.

[0052] In some preferred embodiments, the sleeve wall is heated by applying an electrical voltage to the sleeve wall, by storing the sleeve wall in a heating chamber, or by a heating tool. For this purpose, a rod-shaped heating tool can be used, for example, which can be arranged in the through-opening of the anchoring sleeve. In particular, the sleeve wall is heated uniformly. Alternatively, the sleeve wall can also be heated only in a spatially limited area.

[0053] At least one area of ​​the sleeve wall is therefore not heated to a temperature higher than the glass transition temperature of the thermoplastic material. For example, the sleeve wall is heated locally only in the areas that are to be deformed.

[0054] The invention will be explained in more detail below with reference to the drawings. These show:

[0055] Figure 1 shows a perspective view of an anchoring unit according to a first embodiment;

[0056] Figure 2 shows a sectional view of the anchoring unit from Figure 1 with a knee prosthesis component arranged therein; Figure 3 shows a detail view of a sleeve wall of the anchoring unit from Figure 1;

[0057] Figure 4 shows a method for preparing the anchoring unit from Figure 1 for implantation into a leg bone; and

[0058] Figure 5 shows a sectional view of an anchoring unit according to a second embodiment.

[0059] Figure 1 shows a perspective view of an anchoring unit 10. Figure 2 shows a sectional view of the anchoring unit 10, with the section plane perpendicular to the longitudinal center axis of the anchoring unit 10. Figure 3 is a detail view of a section of Figure 2.

[0060] The anchoring unit 10 is designed to anchor a knee prosthesis component 100 to a patient's leg bone. Depending on the type of knee prosthesis component 100, the leg bone can be the femur or the tibia.

[0061] The anchoring unit 10 has an anchoring sleeve 12. In this case, the anchoring unit 10 is formed by the anchoring sleeve 12. Alternatively, the anchoring unit 10 can have one or more additional, non-sleeve-shaped sections besides the anchoring sleeve 12.

[0062] The anchoring sleeve 12 has a sleeve wall 14 that defines a through-opening 16. In this case, the sleeve wall 14 is continuous, i.e., closed in the circumferential direction of the anchoring sleeve 12. The through-opening 16 is designed to receive a prosthetic stem 102 of the knee prosthesis component 100. A prosthetic stem 102 arranged in this way is indicated by dashed lines in Figure 1. As can be seen in Figure 1, the prosthetic stem 102 projects axially through the anchoring sleeve 12. The section of the knee prosthesis component 100 that replicates the knee joint is supported by the prosthesis stem 102, but is not shown for the sake of simplicity. During the implantation of the anchoring unit 10 and the knee prosthesis component 100 into a leg bone, the prosthesis stem 102 can be attached to the anchoring sleeve 12 by means of bone cement 104.The bone cement 104 can fill a gap between the prosthesis stem 102 and the sleeve wall 14, as shown in Figure 2.

[0063] The anchoring sleeve 12 is designed with a tapered shape. An anchoring sleeve 12 of this shape is particularly suitable for placement in the metaphyseal region of a leg bone.

[0064] The sleeve wall 14 has several structural parts 18, which are formed separately from one another. The structural parts 18 are made of a non-thermoplastic material. The non-thermoplastic material is preferably a metallic material, in this case a titanium alloy. In the embodiment shown in the figures, exactly four structural parts 18 are present. However, a different number of structural parts 18 may also be present. In the present embodiment, the structural parts 18 are identical with respect to their shape.

[0065] The sleeve wall 14 also has several deformable deformation elements 20 made of a thermoplastic material. The thermoplastic material comprises at least one thermoplastic, for example, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), or polylactic acid (PLA). In this case, the thermoplastic material is polyetheretherketone (PEEK). The separately formed structural parts 18 are coupled to one another by the deformation elements 20. The deformation elements 20 thus hold the structural parts 18 together and thereby give the sleeve wall 14 its structural integrity. In the embodiment shown in Figures 1 to 3, exactly four deformation elements 20 are present. However, a different number of deformation elements 20 may also be present. In the present embodiment, the deformation elements 20 are identical in shape.

[0066] In the embodiment shown in Figures 1 to 3, the structural parts 18 are wall segments of the sleeve wall 14 arranged offset from one another. The structural parts 18 are arranged one behind the other in the circumferential direction of the anchoring sleeve 12 and each extends along the entire length of the anchoring sleeve 12, i.e. from a first longitudinal end 22 of the anchoring sleeve 12 to a second longitudinal end 24 of the anchoring sleeve 12.

[0067] The structural parts 18 are in the present form as plates and each extend along a circumferential angle interval of approximately 80°. Depending on the number of structural parts 18 and the number and dimensions of the deformation parts 20, a different dimensioning of the structural parts 18 may also be provided.

[0068] As can be seen in Figures 1 to 3, the structural parts 18 are spaced apart from one another, so that a gap, in this case slit-shaped, is always formed between two adjacent structural parts 18. In each of these gaps, one of the deformation parts 20 is arranged. The deformation parts 20 are rod-shaped for this purpose.

[0069] In the embodiment shown in Figures 1 to 3, the deformation elements 20 also extend along the entire length of the anchoring sleeve 12. Alternatively, several deformation elements 20 can be arranged in the spaces between, each extending only over a limited section of the length of the anchoring sleeve 12.

[0070] The structural parts 18 are positively connected to the deformation parts 20. The type of positive connection is explained in more detail below with reference to Figure 3. Figure 3 shows an enlarged detail view of a structural part 18 and a deformation part 20.

[0071] As can be seen in Figure 3, the structural part 18 has a recess 26. The recess 26 is formed in a lateral side 28 of the structural part 18 that points in the circumferential direction of the anchoring sleeve 12. In this case, the recess 26 is elongated and extends along the entire length of the lateral side 28. The recess 26 has an undercut 30. The deformation part 20 projects into the recess 26 and thereby forms the positive-locking connection. For this purpose, the deformation part 20 has a dovetail-shaped projection 32 that engages behind the undercut 30. In this case, the projection 32 is elongated and extends along the entire length of the deformation part 20.

[0072] In this case, the structural parts 18 and the deformation parts 20 are connected to each other by plug connections. The projections 32 of the deformation parts 20 are inserted into the recesses 26 of the structural parts 18. Alternatively, the deformation parts 20 can also be injection-molded onto the structural parts 18.

[0073] In Figures 1 to 3, the outer surface 34 of the sleeve wall 14, i.e., the side of the sleeve wall 14 facing away from the through-opening 16, is shown as smooth. In contrast, it is preferred that the outer surface 34 of the sleeve has a structured surface, at least in some areas. This promotes the ingrowth of the leg bone to the anchoring unit 10. The structured surface can, for example, have teeth, grooves, and / or a lattice structure. A suitable lattice structure is known as a "structan surface." Particularly preferably, the structural elements 18 each have the structured surface, at least in some areas. The inner surface 36 of the sleeve wall 14, facing the through-opening 16, is preferably smooth.

[0074] The geometry of the sleeve wall 14 according to Figures 1 to 3 represents a standard geometry of the sleeve wall 14. The anchoring unit 10 can be implanted with the sleeve wall 14 shaped as shown in Figure 2. However, depending on the leg bone or bone defect into which the anchoring unit 10 is to be implanted, it is advantageous to adapt the geometry of the sleeve wall 14 to the bone defect before implantation. This is made possible by the deformation elements 20 made of the thermoplastic material. Figure 4 shows a procedure for preparing the anchoring unit 10 for implantation using a flowchart. The sleeve wall 14 initially has the standard geometry.

[0075] In a first step 201, the sleeve wall 14 is heated, whereby the thermoplastic material is heated at least in certain areas to a temperature greater than its glass transition temperature T.g The thermoplastic material in this case is PEEK, which has a glass transition temperature of 143 °C. Accordingly, the thermoplastic material is heated to a temperature of at least 143 °C, for example, to a temperature of 150 °C. In this case, the sleeve wall 14 is heated by placing the anchoring unit 10 in a heating chamber 106. This ensures that the sleeve wall 14 is heated uniformly.

[0076] In a subsequent second step 103, the geometry of the sleeve wall 14 is modified by deforming the heated thermoplastic material. The shape of the structural components 18 remains unchanged. However, the arrangement of the structural components 18 relative to each other changes. Preferably, the geometry of the sleeve wall 14 is deformed such that the contact area between the sleeve wall 14 and the leg bone is increased when the deformed sleeve wall 14 is implanted into the bone defect. By way of example only, Figure 4 shows that the geometry of the sleeve wall 14 is modified by applying a compressive force to the sleeve wall 14 in accordance with arrows 108.

[0077] Of course, other modifications to the geometry of the sleeve wall 14 are also possible. The possibilities for deforming the sleeve wall 14 can also be increased by using a larger number of structural parts 18 and deformation parts 20.

[0078] Figure 5 shows a second embodiment of the anchoring unit 10. In the embodiment shown in Figure 5, the sleeve wall 14 is monolithically made of a thermoplastic material. The thermoplastic material comprises at least one thermoplastic component, for example, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), or polylactic acid (PLA). In this case, the thermoplastic material comprises polyetheretherketone (PEEK) as the thermoplastic component. In addition to the thermoplastic component, the thermoplastic material preferably comprises at least one additive. In this case, the thermoplastic material comprises calcium phosphate as the additive. Calcium phosphate facilitates the ingrowth of the leg bone to the thermoplastic material.

[0079] The sleeve wall 14 shown in Figure 5 has several structural sections 38 and several deformation sections 40. In the deformation sections 40, the material thickness is reduced compared to the structural sections 38. This results in the deformation of the heated sleeve wall 14 preferentially occurring in the deformation sections 40. The geometry of the structural sections 38 remains essentially unchanged.

[0080] In the embodiment shown in Figure 5, exactly four structural sections 38 are present. However, a different number of structural sections 38 may also be present. In the present embodiment, the structural sections 38 are identical in shape.

[0081] In the embodiment shown in Figure 5, exactly four deformation sections 40 are present. In the circumferential direction of the sleeve wall 14, a deformation section 40 always follows a structural section 38, and vice versa. However, a different number of deformation sections 40 may also be present. In the present embodiment, the deformation sections 40 are identical in shape.

[0082] The anchoring unit 10 shown in Figure 5 can be heated and then deformed as previously explained in connection with Figure 4 in order to prepare the anchoring unit 10 for implantation.

Claims

Patent claims 1. Anchoring unit (10) for anchoring a knee prosthesis component (100) to a leg bone, in particular femur or tibia, of a patient, the anchoring unit (10) comprising: an anchoring sleeve (12) having a sleeve wall (14), wherein the sleeve wall (14) defines a through-opening (16) designed to receive a prosthetic stem (102) of a knee prosthesis component (100), and wherein at least one section of the sleeve wall (14) is made of a thermoplastic material.

2. Anchoring unit (10) according to claim 1, characterized in that the thermoplastic material has a glass transition temperature (T g ) of at least 50 °C, preferably at least 100 °C, preferably at least 50 °C and at most 200 °C, preferably at least 100 °C and at most 200 °C.

3. Anchoring unit (10) according to one of the preceding claims, characterized in that the thermoplastic material comprises at least one thermoplastic selected from the group consisting of: polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and polylactide (PLA).

4. Anchoring unit (10) according to one of the preceding claims, characterized in that the thermoplastic material comprises at least one non-thermoplastic additive, in particular calcium phosphate.

5. Anchoring unit (10) according to one of the preceding claims, characterized in that the sleeve wall (14) is monolithically made of the thermoplastic material.

6. Anchoring unit (10) according to the preceding claim, characterized in that the sleeve wall (14) has at least one structural section (38) and at least one deformation section (40), wherein the material thickness of the deformation section (40) is less than the material thickness of the structural section (38).

7. Anchoring unit (10) according to the preceding claim, characterized in that the ratio of the maximum material thickness of the structural section (38) to the minimum material thickness of the deformation section (40) is at least 2:1, preferably at least 3:

1.

8. Anchoring unit (10) according to one of claims 1 to 4, characterized in that the sleeve wall (14) has at least one deformation part (20) made of the thermoplastic material and at least one structural part (18) connected to the deformation part (20), wherein the structural part (18) is made of a non-thermoplastic material, or wherein the structural part (18) is made of a thermoplastic material which has a glass transition temperature (T g ) exhibits a temperature greater than the glass transition temperature (T g ) of the thermoplastic material of the deformation part (20).

9. Anchoring unit (10) according to the preceding claim, characterized in that the non-thermoplastic material is a metallic material, in particular a titanium material 10. Anchoring unit (10) according to one of claims 8 and 9, characterized in that the deformation part (20) and the structural part (18) are wall segments of the sleeve wall (14) arranged offset from each other.

11. Anchoring unit (10) according to one of claims 8 to 10, characterized in that the structural part (18) is connected to the deformation part (20) by a positive locking connection.

12. Anchoring unit (10) according to the preceding claim, characterized in that the structural part (18) has a, in particular elongated, recess (26), and that the deformation part (20) projects into the recess (26) to form the positive locking connection.

13. Comprehensive prosthesis kit: an anchoring unit (10) according to one of the preceding claims; and a knee prosthesis component (100), in particular a femur prosthesis component or a tibial prosthesis component, which has a prosthesis stem (102) that can be arranged in the through-opening (16) of the anchoring unit (10).

14. Method for preparing an anchoring unit (10) for implantation into a patient's leg bone, the method comprising: Providing an anchoring unit (10) according to any one of claims 1 to 12; - Heating the sleeve wall (14), wherein the thermoplastic material is heated at least in certain areas to a temperature greater than the glass transition temperature (Tg). g ) of the thermoplastic material; and - changing the geometry of the sleeve wall (14) by deforming the heated thermoplastic material.

15. Method according to the preceding claim, characterized in that the sleeve wall (14) is heated by applying an electrical voltage to the sleeve wall (14), by storing the sleeve wall (14) in a heating chamber (106) or by a heating tool, in particular a rod-shaped one.

Images