Endoprosthesis

Abstract

The subject of the invention is an endoprosthesis for implantation in bone surgery, in particular hip surgery, without the use of surgical cement. A hip endoprosthesis for implantation in bone surgery of a ball and socket joint, in particular a hip joint, characterized in that it comprises: a mobile connection provided by the contact surfaces (10) of the two modules, the endoprosthesis femoral head (9) and the endoprosthesis acetabulum (1), whose surfaces in contact with the bone near the joint have a shape similar to a sphere, on which a needle (2) is placed, the needle having an axis substantially parallel to the longitudinal axis of the endoprosthesis; and at least two cutting blades (3) having an arcuate cross-sectional profile, producing a recess (5) for the removal of the cutting products.

Description

Technical Field

[0001] The subject of the invention is an endoprosthesis for implantation in bone surgery, in particular hip surgery, without the use of surgical cement. Background Art

[0002] Patent PL174976 shows an endoprosthesis composed of an acetabulum and a femoral head for implantation in bone joint surgery, the endoprosthesis having sharp protrusions on the limiting surfaces, while the limiting surfaces of the acetabulum and the femoral head have the form of spherical crowns, and the sharp protrusions having axes parallel to each other correspondingly have the form of symmetrically placed polygonal needles with varying lengths, wherein each needle contacts the adjacent edge needles at its base, and the outer polygonal needle protrusions placed near the supporting edge and the supporting surface, respectively, have the shortest length, and the total area of ​​the polygonal protrusions and the central polygonal needle is advantageously seven times the area of ​​the sphere on which they are placed.

[0003] German patent description DE 3443109 Al also shows a solution in which the endoprosthesis is more securely fastened by using a conical irregular portion protruding from the limiting surface of the endoprosthesis and pointing to the connecting surface of the bone. The conical irregular portion is a separate unit having a conical portion and a cylindrical portion arranged in the matrix of the acetabulum and in the matrix of the femoral head. For this purpose, holes are made in the flat surface of the femoral head and on the annular offset of the outer spherical surface of the acetabulum. These holes weaken both the acetabulum and the femoral head of the endoprosthesis in the lateral section, and at the same time, the conical irregular portion arranged in them is at risk of loosening, which leads to unstable embedding of the endoprosthesis in the bone. In the known solution DE 3443109 Al, the conical irregular portion is completely pressed into the cancellous bone, which increases the contact area, which is conducive to the embedding of the endoprosthesis in the bone material. A drawback of this solution is that the best possible bone-endoprosthesis contact area is not used, due to the fact that the conical irregular parts are placed at regular intervals on the flat surface of the femoral head and on the annular offset of the external spherical surface of the acetabulum, and that the flat contact surfaces, by directly contacting the bone at the moment of implantation, prevent the subsequent ingrowth of cancellous bone in a natural-like form, which would ensure good shock absorption of the loads on the joint.

[0004] The invention of CN105125324 shows an improved metal acetabular cup with a rough thin layer for an artificial hip joint. The improved metal acetabular cup is characterized in that the cup is made by casting or forging, and a rough medical metal thin layer is formed on the corresponding surface of the acetabular cup in contact with the patient's bone by additive manufacturing.

[0005] The invention of AU2015286971 relates to an acetabulum for a hip prosthesis, comprising an inner cavity and a posterior outer surface facing the bone. In order to enable implantation of the acetabulum without the use of cement, at least some areas of the outer surface are porous and osseointegrative, and the acetabulum is made entirely of ceramic material.

[0006] In the invention of US20130190889, an artificial hip joint composed of a multi-layer shell-core composite structural component is proposed, and the artificial hip joint includes an artificial acetabulum and an artificial femoral head that match each other. The artificial acetabulum has a multi-layer shell-core composite structure, and is composed of a ceramic acetabulum liner, a transition layer, and an acetabulum shell made of porous metal or porous alloy or porous toughened ceramic. The artificial femoral head has a multi-layer shell-core composite structure, and is composed of a ceramic spherical shell layer, a transition layer and a toughened ceramic inner core. The artificial acetabulum liner and the artificial femoral head spherical shell layer of the hip joint have high rigidity, corrosion resistance and wear resistance, and the artificial layer of the acetabulum shell of the endoprosthesis and the inner layer of the core of the femoral head of the endoprosthesis have high strength and impact resistance, so as to improve adhesion and stability. It is a solution for producing micropores.

[0007] In the invention of EP1308141, a hip endoprosthesis is proposed, which is provided with a plurality of meridional incisions, which are defined as a number of segments that are elastically bendable in the radial direction. The inner surface of the socket is provided with one or more grooves parallel to the proximal edge, wherein these grooves receive corresponding protrusions of the joint insert. The socket further comprises one or more frustoconical portions, which form the bearing surface for the corresponding frustoconical portions of the joint insert. The inner surface of the socket defines a polygonal seat, which is suitable for engaging with the polygonal portion of the joint insert by means of form fit.

[0008] In EP2338443 patent, a fastening shell and a milling tool for forming the shape of a tooth flank are proposed, the fastening shell having a tooth structure arranged on the outside of a half shell. The equatorial oriented flank of each tooth forms an angle of less than 90 degrees with the component axis, so that a barbed hook effect is produced at the equator. The path of the tool is curved for forming a tooth gap, and is formed so that the teeth of a tooth row are continuously arranged in the tooth gap, and the cutting edges of the teeth do not overlap or have a gap of about 2 mm from the equator toward the pole.

[0009] RU2467724 patent discusses an endoprosthesis comprising a cup-shaped prosthesis and a proximal femoral prosthesis connected in a pivotal manner, the proximal femoral prosthesis having a rod for intraosseous introduction, a neck and a spherical head. On the outer surface of the head, there is a cylindrical section in the form of a plane. The endoprosthesis has a generally spherical inner cavity with a depth exceeding the half-radius of the head, and its input hole is smaller than the diameter of the head and equal to its diameter in the cylindrical section to lock and key the head in the cup-shaped endoprosthesis. The cylindrical section faces the junction of the head and the neck, at an angle of approximately 33°-61° to its axis. The diameter of the head is 22-38 mm, while the diameter of the neck is 13-14 mm. The present invention can provide higher reliability and durability of the function of the endoprosthesis after implantation. Summary of the invention

[0010] The essence of the present invention is a hip joint endoprosthesis for implantation in bone surgery of a ball and socket joint (especially a hip joint), characterized in that the endoprosthesis comprises: a mobile connection provided by the contact surfaces of two modules, the endoprosthesis femoral head and the endoprosthesis acetabulum, whose surfaces in contact with the bones near the joint have a shape similar to a sphere, on which a needle is placed, the needle having an axis substantially parallel to the longitudinal axis of the endoprosthesis; and at least two cutting blades having an arcuate cross-sectional profile, producing a groove for removing the cutting product.

[0011] This is advantageous if the sphere is a convex shell on which the needle is located, which forms the endoprosthetic acetabulum, or if the shell is a concave shell on which the needle is located, which forms the endoprosthetic femoral head.

[0012] It is also advantageous if the endoprosthesis has on its outer surface in the region of the longitudinal axis a porous support surface which is advantageously rounded.

[0013] It is also advantageous if the needle is placed outside the support surface 6 in the region forming the limiting surface and if the needle is placed on a spherical surface forming the limiting surface.

[0014] Furthermore, it is advantageous when the needle-shaped cutting blade has an applied angle β in the range of 5° to 15° (advantageously 10°), an attack angle α of 35° to 45° (advantageously 40°), and the wall thickness H of the wall of the cutting blade 3 reaches 0.25 to 1 mm, advantageously 0.5 mm, and the height H1 of the needle-shaped cutting blade is 2 to 3 times the height H2 of the opposite wall 4 of the groove 5.

[0015] In particular, it is advantageous if the bearing surface has a diameter D2 which is ½ to ⅓ of the diameter D1 of the femoral head.

[0016] This is advantageous if the femoral head endoprosthesis has a cylindrical extension with an angle λ in the range of 30 to 50 degrees relative to the center point and the ends of the grooves are located in the region of the technical clamping device and the distance z between the bases of adjacent needles 2 is at least 100 microns.

[0017] It is also advantageous if the needle has the shape of a cone or an inverted cone or a truncated cone or a regular polyhedron.

[0018] It is also advantageous if the needle has smooth side surfaces or shaped side surfaces.

[0019] It is also advantageous when the height of the needles on the surface of the acetabular shell of the endoprosthesis decreases from the edge to the support surface, the height of the needles on the surface of the convex femoral head shell of the endoprosthesis decreases from the central axis of the endoprosthesis to the external direction, and the height of the highest needle is approximately twice the height of the lowest needle.

[0020] This is particularly advantageous when the apex of the needle produces a surface with a contour similar to the surface of a sphere on which the needle is placed.

[0021] Furthermore, it is advantageous if the needle is placed on the outer surface of the acetabulum and on the inner surface of the femoral head.

[0022] It is advantageous if the insert is introduced onto the inner spherical surface of the acetabular endoprosthesis.

[0023] The use of the solution proposed in this invention is expected to provide the following technical and practical effects:

[0024] Minimized micro-movement and loosening of the acetabulum and cap due to the density of the pins with maximized attachment surface in the bone-implant relationship,

[0025] Eliminates the use of glue / cement, which can cause stem endoprostheses to loosen after a period of time,

[0026] · Adequate distribution of forces between bone and endoprosthesis, as well as a much less invasive implantation procedure and the possibility of use in a wider age range of patients,

[0027] · Growth on the side (adhesive) surface is more favorable due to the use of multiple needle areas,

[0028] The endoprosthesis can be used longer,

[0029] Relatively easy to replace in case of need for repeated implantation,

[0030] Make the shape of the endoprosthesis closer to the biological model,

[0031] Endoprostheses can be implanted in patients with advanced osteoporosis without the use of surgical cement.

[0032] The minimally invasive implantation procedure minimizes the degree of trauma to bone tissue, and the design of the endoprosthesis cap protects the blood vessels that supply the proximal femur. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In exemplary embodiments, the subject matter of the invention is illustrated in the drawings, wherein Figure 1 A view of the acetabulum showing one side of the supporting surface. Figure 2 Show Figure 1 details. Figure 3 is the cross section of the cutting insert, and Figure 4 It is a cross section of the acetabulum. Figure 5 A view showing the acetabulum. Figure 6 Shown from Figure 5 Detail of the acetabulum. Figure 7 A view of the acetabulum showing the support surface side. Figure 8 Show from Figure 7 Detail of the acetabulum. Fig. 9 A cross section of a cutting insert is shown. Fig.10 A view showing the acetabulum. Fig.11 Shown from Fig.10 Detail of the acetabulum. Fig.12 A view showing the femoral head. Fig.13 Shown from Fig.12 Detail of the view. Fig.14 Shows a cross section of the femoral head. Fig.15 A view of the femoral head on one side of the restraining surface is shown. Fig.16 Shown from Fig.15 Detail of the view. Fig.17 A view showing the femoral head, and Fig.18 Shown from Fig.17 Detail view of the femoral head. Fig.19 A view of the femoral head on one side of the restraining surface is shown. Fig. 20 Is from Fig.19 Detail of the femoral head. Fig.21 shows a cross section of a needle, and Fig. 22 A fragment showing a cross section of a femoral head. Figure 23 is a cross section of a needle. Fig.23a The needle is shown in the form of a cone. Figure 23b It is a needle-like object in the form of an inverted cone. Fig.23c It is a needle-like object in the form of a pyramid. Fig.23d It is a needle-shaped object in the form of a rectangular parallelepiped. Fig.24 A fragment of a cross section of the acetabulum is shown. Fig.25 An isometric view of the acetabulum is shown on the contact side of the friction pair. Fig.26 A cross section showing the endoprosthetic acetabulum and femoral head system embedded in a bone surface. Fig. 27 shows a cross section of the friction pair, and Fig.28 A cross section of a femoral head endoprosthesis is shown with the elongation angle of the cylindrical surface illustrated. Fig.29 The introduction of an insert 14 onto the inner spherical surface of the endoprosthetic acetabulum 1 is shown. DETAILED DESCRIPTION

[0034] The hip joint endoprosthesis for implantation in bone surgery of a ball-and-socket joint, in particular a hip joint, comprises a mobile connection provided by the contact surfaces 10 of the two modules of the endoprosthesis femoral head 9 and the acetabulum 1. The surfaces of the endoprosthesis femoral head 9 and the acetabulum 1 that are in contact with the bone near the joint have a shape similar to a sphere, on which a needle 2 is placed. The needle 2 has an axis substantially parallel to the longitudinal axis of the endoprosthesis, and at least two cutting blades 3 with an arcuate cross-sectional profile are formed, producing a groove 5 for removing the cutting product. In the endoprosthesis, the sphere is a convex shell on which the needle 2 is located, which forms the endoprosthesis acetabulum 1. The sphere is a concave shell on which the needle 2 is located, which forms the endoprosthesis femoral head 9. The endoprosthesis has a porous support surface 6 that is advantageously rounded on its outer surface, in the region of the longitudinal axis. The needle 2 is placed in the region of the formation of the limiting surface 11 outside the support surface 6, and is placed on the spherical surface forming the limiting surface 11. In the endoprosthesis, the cutting blade 3 has an applied angle β in the range of 5° to 15° (advantageously 10°), an attack angle α of 35° to 45° (advantageously 40°), and the wall thickness H of the wall of the cutting blade 3 reaches 0.25 to 1 mm, advantageously 0.5 mm, and the H1 height of the cutting blade 3 is 2 to 3 times the H2 height of the opposite wall 4 of the groove 5. The support surface 6 has a D2 diameter, which is 1 / 2 to 1 / 3 of the D1 diameter of the femoral head 1. The femoral head endoprosthesis has a cylindrical extension with an angle λ in the range of 30 to 50 degrees relative to the center point. In the endoprosthesis, the end of the groove 5 is located in the area of ​​the technical clamping device 8. The distance between the bases of adjacent needles 2 is at least 100 microns. The needle 2 has the shape of a cone or an inverted cone or a truncated cone or a regular polyhedron. In addition, the needle 2 has a smooth side surface or a shaped side surface. The height of the needle 2 decreases from the edge to the support surface and from the central axis of the endoprosthesis to the external direction. The height of the highest needle 2 is about twice the height of the lowest needle 2. The apex of the needle 2 creates a surface with a contour similar to the surface of a sphere (on which the needle is placed). The needle 2 is placed on the outer surface of the acetabulum 1 and on the inner surface of the femoral head 9. In addition, an insert 14 is introduced or not introduced on the inner spherical surface of the endoprosthesis acetabulum 1.

[0035] The endoprosthesis is composed of an acetabulum 1 and a femoral head 9, which have polygonal needle protrusions in the form of needles 2 on their limiting surfaces in the form of spherical shells for achieving the growth of trabeculae, wherein the needles 2 have parallel axes and varying lengths, and their total area is a multiple of the joint area, and the minimum distance "z" between the bases of the needles 2 is 100 microns. The bases of the needles 2 are not tangential. The axes of the needles 2 are perpendicular to the planes of the supporting surfaces of the femoral head and the supporting surfaces of the acetabulum 1, respectively. In addition, in order to reduce the wear of the friction pair of the acetabulum 1 and the femoral head 9 of the hip joint endoprosthesis, an insert 14 is introduced or not introduced on the inner spherical surface of the endoprosthesis acetabulum 1 made of non-metallic material.

[0036] A prerequisite for the operation of the system is to adapt the shape and size of the endoprosthetic femoral head 9 to the size and shape of the endoprosthetic acetabulum 1 in order to ensure the correct operation of the friction pair.

[0037] Endoprosthesis femoral head 9 is placed in the clamping part of the external device (not shown in the figure) that provides rotational movement. This device makes the endoprosthesis move around its symmetry angle at a specific speed suitable for the material being machined. The endoprosthesis in the form of femoral head 9 is rotated, so that the cutting blade 3 is used to remove the bone tissue 7, which falls between the wall 4 of the cutting blade 3 and the wall of the groove 5 or between the wall of the cutting blade 3 and the needle 2. The pressure applied by the newly cut bone tissue 7 between the wall of the cutting blade 3 and the wall 4 of the groove 5 or between the wall of the cutting blade 3 and the needle 2 makes the bone tissue 7 move away from the endoprosthesis through the direct surface where the endoprosthesis contacts the bone tissue 7 surface. This process continues until the optimal position of the endoprosthesis is obtained. The endoprosthesis causes the space between the needles 2 to be slightly filled with small bone fragments, which will satisfy the process of bone reconstruction and the stability of the endoprosthesis. After removing the diseased tissue of the joint connection and using the cutting blade 3 to obtain a shape similar to the contour produced by the end of the needle 2, the endoprosthesis is disconnected from the device (not shown) providing rotational movement, and then placed on the surface prepared previously, and gradually inserted into the cancellous bone space under the condition of the axis of symmetry of the femoral head 13 parallel to the joint. The support surface 6 does not contact the periosteum, cortex and cancellous bone, and the needle 2 at a distance longer than the plane of the support surface 6 is inserted therein at the same time. The needle does not completely penetrate the cancellous bone to be able to release excessive intraosseous fluid pressure. The space between the needles 2 that are not filled with bone tissue 7 in this process will be filled with osteoblasts that will grow during the recovery period during the tissue regeneration process.

[0038] The implantation method for the acetabular endoprosthesis is similar to that of the femoral head, and the acetabular endoprosthesis is implanted so that the support surface 6 of the truncated limiting surface is attached to the bone in a plane perpendicular to the axis of the central acetabulum 1 of the bone and is placed in a symmetrical manner with respect to the axis, and the polygonal needle 2 in the region of the ball zone on the limiting surface 11 of the endoprosthesis acetabulum 1 is partially sunken into the spongy structure of the bone. Due to the lack of movement between the endoprosthesis acetabulum and the bone 12, the remaining space between the polygonal needle projections 2 does not sink into the cancellous bone until the limiting surface 11 is filled with osteoblasts growing during the recovery period. The support surface 6 with a slight rounding protects the implantation process from possible vascular trauma present in the immediate vicinity of the cut tissue.

[0039] In addition, in order to reduce the wear of the friction pair between the acetabulum 1 and the femoral head 9 of the hip joint endoprosthesis, an insert 14 may or may not be introduced on the inner spherical surface of the endoprosthesis acetabulum 1 made of non-metallic material.

[0040] A prerequisite for the operation of the system is to adapt the shape and size of the endoprosthetic femoral head 9 to the size and shape of the endoprosthetic acetabulum 1 in order to ensure the correct operation of the friction pair.

[0041] The needles 2 are partially sunken in the bone tissue 7 , advantageously up to half their height, in order to allow osteoblasts to grow on the surface that is not sunken in the bone tissue 7 .

[0042] Reference numerals

[0043] 1—Acetabular

[0044] 2—Needle

[0045] 3—Cutting blades

[0046] 4—Wall

[0047] 5—Groove

[0048] 6—Supporting Surface

[0049] 7—Bone tissue

[0050] 8—Technical clamping device

[0051] 9—Femoral head

[0052] 10—Friction pair contact surface

[0053] 11—Limiting Surfaces

[0054] 12 - Pelvic bones

[0055] 13—Femoral head

[0056] 14—Insert

[0057] H—cutting edge 3 wall thickness

[0058] H1—cutting edge 3 height

[0059] H2—relative height of wall 4

[0060] α—Angle of attack

[0061] β—application angle

[0062] λ—elongation angle of the femoral head 9 endoprosthesis body

[0063] D1—diameter of femoral head 1

[0064] D2—diameter of support surface 6

[0065] z—the distance between needles 2.

Claims

1. An endoprosthesis for implantation in bone surgery of a ball and socket joint, the endoprosthesis comprising: A movable connection, which is provided by a contact surface (10) of each of an endoprosthesis femoral head component (9) and an endoprosthesis acetabular component (1), wherein each of the endoprosthesis femoral head component (9) and the endoprosthesis acetabular component (1) has a bone contact surface having a shape similar to a sphere, on which a needle (2) is placed, each of the needles having an axis substantially parallel to the longitudinal axis of the endoprosthesis, characterized in that each of the bone contact surfaces of the endoprosthesis femoral head component (9) and the endoprosthesis acetabular component (1) has at least two cutting blades (3) having an arcuate cross-sectional profile, wherein each of the cutting blades (3) produces a groove (5) for removing the cutting product.

2. The endoprosthesis according to claim 1, characterized in that The ball and socket joint is a hip joint.

3. The endoprosthesis according to claim 1, characterized in that The sphere is a convex shell which forms the endoprosthesis acetabular component (1) and on which the needle (2) is located.

4. The endoprosthesis according to claim 1, characterized in that The sphere is a concave shell which forms the femoral head component (9) of the endoprosthesis, and the needle (2) is located on the concave shell.

5. The endoprosthesis according to claim 1, characterized in that On the spherical surface, in the region of the longitudinal axis, the endoprosthesis has an advantageously rounded and porous support surface (6).

6. The endoprosthesis according to claim 5, characterized in that The needle (2) is placed outside the support surface (6) in a region forming a limiting surface (11).

7. The endoprosthesis according to claim 6, characterized in that The needle (2) is placed on the spherical surface forming the limiting surface (11).

8. The endoprosthesis according to claim 1, characterized in that The cutting blade (3) of the needle (2) has an application angle β in the range of 5° to 15°, an attack angle α of 35° to 45°, and a wall thickness H of the wall of the cutting blade (3) of the needle (2) reaches 0.25 to 1 mm, and the height H1 of the cutting blade (3) is 2 to 3 times the height H2 of the opposite wall (4) of the groove (5).

9. The endoprosthesis according to claim 8, characterized in that The application angle β is 10°.

10. The endoprosthesis according to claim 8, characterized in that The attack angle α is 40°.

11. The endoprosthesis according to claim 8, characterized in that The wall thickness H of the cutting blade (3) of the needle-shaped object (2) is 0.5 mm.

12. The endoprosthesis according to claim 5, characterized in that The support surface (6) has a diameter D2 of 1 / 2 to 1 / 3 of the diameter D1 of the endoprosthesis femoral head component (9).

13. The endoprosthesis according to claim 1, characterized in that The endoprosthesis femoral head component (9) has a cylindrical elongated portion having an angle λ in the range of 30 to 50 degrees relative to a center point.

14. The endoprosthesis according to claim 1, characterized in that The end of the groove (5) is located in the region of the technical clamping device (8).

15. The endoprosthesis according to claim 1, characterized in that The distance z between the bases of adjacent needles (2) is at least 100 micrometers.

16. The endoprosthesis according to claim 1, characterized in that The needle (2) has a cone shape.

17. The endoprosthesis according to claim 1, characterized in that The needle (2) has the shape of an inverted cone.

18. The endoprosthesis according to claim 1, characterized in that The needle (2) has a frustoconical shape.

19. The endoprosthesis according to claim 1, characterized in that The needle-shaped object (2) has a regular polyhedron shape.

20. The endoprosthesis according to claim 1, characterized in that The needle-shaped object (2) has a smooth side surface.

21. The endoprosthesis according to claim 1, characterized in that The needle (2) has a shaped side surface.

22. The endoprosthesis according to claim 5, characterized in that The height of the needles (2) on the surface of the shell of the endoprosthetic acetabular component (1) decreases from the edge to the support surface (6).

23. The endoprosthesis according to claim 1, characterized in that The height of the needles (2) on the surface of the shell of the convex endoprosthesis femoral head component (9) decreases from the longitudinal axis of the endoprosthesis to the external direction.

24. The endoprosthesis according to claim 1, characterized in that The height of the highest needle (2) is approximately twice the height of the lowest needle (2).

25. The endoprosthesis according to claim 1, characterized in that The apex of the needle (2) creates a surface having a profile similar to the surface of a sphere on which the needle is placed.

26. The endoprosthesis according to claim 1, characterized in that The needle (2) is placed on the outer spherical surface of the endoprosthetic acetabular component (1).

27. The endoprosthesis according to claim 1, characterized in that The needle (2) is placed on the inner spherical surface of the endoprosthesis femoral head component (9).

28. The endoprosthesis according to claim 1, characterized in that An insert (14) is or is not introduced onto the inner spherical surface of the endoprosthetic acetabular component (1).

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