Femoral stem
By arranging the first protrusion and the second protrusion on the femoral stem, the anti-rotation and anti-sinking stability of the femoral stem are enhanced, the problem of insufficient stability in the prior art is solved, the service life of the prosthesis is extended and the risk of reoperation is reduced.
Patent Information
- Application Number
- CN202422302332.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-09-20
AI Technical Summary
After being implanted into the human femoral medullary cavity, the existing femoral stem has problems with insufficient anti-rotational stability and anti-sinking properties, which leads to prosthesis failure and increased risk of reoperation.
A femoral stem is designed, on which a first protrusion and a second protrusion are evenly arranged. The first protrusion penetrates into the cortical bone of the medullary cavity, and the second protrusion presses against the cortical bone of the medullary cavity. A variety of cross-sectional shapes are combined to adapt to different medullary cavity shapes, thereby enhancing stability and adaptability.
It improves the anti-rotational stability and anti-subsidence of the femoral stem, extends the service life of the prosthesis, and reduces the burden on patients and the risk of reoperation.
Smart Images
Figure CN223380670U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of passive medical equipment, in particular to a femoral stem. Background Art
[0002] During the artificial hip replacement surgery, it is necessary to implant an artificial hip stem into the human femoral medullary cavity to reconstruct the hip joint structure and restore the function of the hip joint. Among the most existing artificial hip stem failure cases, a considerable number of cases are due to the loosening of the femoral stem, which in turn leads to prosthesis failure. The cross-sectional shapes of the existing femoral stems are mostly rectangular, simple cylindrical or conical, etc. The femoral stem with a rectangular cross-sectional shape can effectively improve the anti-rotational stability of the femoral stem through the four corners of the rectangle. However, the human femoral medullary cavity is mostly a long tubular structure. Therefore, the rectangular cross-section has a poor filling effect on the medullary cavity, that is, the contact area between the bone and the final prosthesis is small, which may affect the later bone regeneration and cannot achieve a long-term fixation effect. At the same time, the control requirements of the position and angle of the femoral stem during implantation are higher than those of the circular cross-section. Although the femoral stem with a circular cross-section fills the medullary cavity well, the cylindrical or conical shape has poor anti-rotation stability because there is no difference in the long and short axes in the circular cross-section and there are no ridges deeply embedded in the cortical bone. The initial stability of the femoral stem mainly depends on its anti-rotation and anti-sinking stability. If it is unstable in the early stage, the femoral stem is prone to sinking, twisting or swinging under load, causing micro-motion, and then a gap appears with the medullary bone, which greatly affects the later integration of the bone and the femoral stem, and then causes other corresponding complications, increasing the risk of reoperation. Utility Model Content
[0003] In order to solve the technical problems existing in the prior art, the present invention provides a femoral stem. The technical solution is as follows:
[0004] A femoral stem comprises a femoral stem taper, a femoral stem neck, a femoral stem shoulder, and a stem body; one end of the femoral stem neck is connected to the stem body via the femoral stem shoulder, and the other end of the femoral stem neck is connected to the femoral stem taper;
[0005] At least two first protrusions are evenly arranged on the handle and around the circumference of the handle. The length of the first protrusion is equal to the length of the handle. At least one second protrusion is arranged between two adjacent first protrusions.
[0006] Optionally, a protruding height of the second protrusion is smaller than a protruding height of the first protrusion.
[0007] Optionally, on the cross section of the handle body, a line connecting the protruding vertices of each first protrusion obtains an outer contour, and a line connecting the protruding vertices of each second protrusion obtains an inner contour, the inner contour is inside the outer contour and the inner contour is concentrically arranged with the outer contour, and the outer contour is circular, elliptical or polygonal.
[0008] Optionally, the inner contour is circular, elliptical or polygonal.
[0009] Optionally, when the inner contour is an ellipse, the ratio of the major axis of the inner contour to the minor axis of the inner contour is in the range of 1-10; when the outer contour is an ellipse, the ratio of the major axis of the outer contour to the minor axis of the outer contour is in the range of 1-10.
[0010] Optionally, the stem body includes a first end and a second end, the first end is connected to the femoral stem shoulder, the diameter of the first end is larger than the diameter of the second end; the taper of the stem body ranges from 2° to 20°.
[0011] Optionally, at least one binding and fixing hole is provided on the side surface of the femoral stem shoulder, and a punching hole is provided on the top surface of the femoral stem shoulder.
[0012] Optionally, the upper and lower side surfaces of the femoral stem neck are arcuate structures, and the other two side surfaces of the femoral stem neck are planar structures, and the roughness Ra of the planar structures is in the range of 0.01-0.8.
[0013] Optionally, the width of the planar structure ranges from 1 mm to 10 mm.
[0014] Optionally, the surface roughness Rz of the femoral stem taper is in the range of 3.2-50, the femoral stem taper is a frustum structure, the bottom surface with a large diameter of the femoral stem taper is connected to the femoral stem neck, and the taper range of the femoral stem taper is between 1°-10°.
[0015] The beneficial effects of the technical solution provided by the embodiment of the utility model include at least:
[0016] The first protrusion of this invention is designed to embed deeply into the cortical bone of the femoral medullary cavity during implantation, ensuring excellent anti-rotational stability. The second protrusion is designed to directly contact the cortical bone of the medullary cavity, achieving excellent anti-sinking effect. The design of the first and second protrusions can extend the service life of the prosthesis in the patient's body and reduce the burden on the patient. The cross-section of the handle of this invention can be polygonal, elliptical, or circular, which can match a variety of femoral medullary cavities of different shapes and sizes, adapting to different shapes and sizes of medullary cavities and better adapting to the patient's medullary cortical bone and femoral anatomical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0018] Figure 1 A schematic diagram of the planar structure of a femoral stem provided by the utility model;
[0019] Figure 2 A schematic diagram of the three-dimensional structure of a femoral stem provided by the utility model;
[0020] Figure 3 A top view of a femoral stem provided by the utility model;
[0021] Figure 4 This is a schematic diagram of a cross section of a femoral stem provided by the present invention, wherein both the inner and outer contours are circular;
[0022] Figure 5 This is a schematic diagram of a cross section of a femoral stem provided by the present invention, wherein the inner contour is an ellipse;
[0023] Figure 6 This is a schematic diagram of a cross section of a femoral stem provided by the present invention, wherein the inner contour thereof is a polygon;
[0024] Figure 7 This is a schematic diagram of a cross section of a femoral stem provided by the present invention, wherein the outer contour thereof is an ellipse;
[0025] Figure 8 This is a schematic diagram of a cross section of a femoral stem provided by the present invention, with a polygonal outer contour.
[0026] Reference numerals:
[0027] 1. Cross section of the stem; 1-1. First protrusion; 1-2. Second protrusion; 2. Stem; 3. Femoral stem shoulder; 4. Planar structure surface; 5. Femoral stem taper; 6. Femoral stem neck; 6-1. Arc surface structure; 6-2. Planar structure; 7. Binding and fixing hole; 8. Punch hole; 9. Inner contour; 10. Outer contour. DETAILED DESCRIPTION
[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0029] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the usual meanings understood by persons of ordinary skill in the field to which this utility model belongs. The words "first", "second" and similar terms used in this utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
[0030] It should be noted that the terms "up", "down", "left", "right", "front" and "back" used in the present invention are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.
[0031] like Figures 1-8 As shown, this embodiment provides a femoral stem; comprising a femoral stem taper 5, a femoral stem neck 6, a femoral stem shoulder 3 and a stem body 2, one end of the femoral stem neck 6 is connected to the stem body 2 via the femoral stem shoulder 3, and a preset angle is provided between the central axis of the stem body 2 and the central axis of the femoral stem neck 6. The other end of the femoral stem neck 6 is connected to the femoral stem taper 5. At least two first protrusions 1-1 are evenly arranged on the stem body 2 and around the circumference of the stem body 2, and the extension direction of the first protrusion 1-1 is the same as the extension direction of the stem body 2, that is, the length of the first protrusion 1-1 is equal to the length of the stem body 2, and the length of the first protrusion 1-1 refers to the length of the longest side of the first protrusion 1-1; at least one second protrusion 1-2 is provided between two adjacent first protrusions 1-1, and preferably, the protruding height of the second protrusion 1-2 is less than the protruding height of the first protrusion 1-1. The second protrusions 1-2 extend in the same direction as the handle 2, i.e., the length of the second protrusions 1-2 is equal to the length of the handle 2. The length of the second protrusions 1-2 refers to the length of the longest side of the second protrusions 1-2. The number of first protrusions 1-1 and the number of second protrusions 1-2 are preferably even.
[0032] In this embodiment, the stem 2 is provided with eight first protrusions 1-1 and eight second protrusions 1-2. The eight first protrusions 1-1 and second protrusions 1-2 not only ensure that the first protrusions 1-1 and second protrusions 1-2 are evenly distributed along the cross-sectional circumference of the stem 2, but also ensure that the stem is subjected to uniform force in the front-to-back and left-to-right directions when the femoral stem is driven into the femoral medullary canal. In other words, the axis of the stem is aligned with the axis of the femoral medullary canal during insertion. This design can reduce the risk of varus or valgus in the femoral stem, extend the service life of the stem, and reduce the risk of surgical revisions for patients.
[0033] When implanted into the medullary cavity, the first protrusion 1-1 is deeply embedded in the cortical bone of the femoral medullary cavity, ensuring excellent anti-rotational stability. The second protrusion 1-2 directly contacts the cortical bone of the medullary cavity, achieving excellent anti-sinking effect. To better match the patient's medullary cavity bone conditions and anatomical features, the number of first protrusions 1-1 and second protrusions 1-2 can be adjusted within a range of 2-40, and the first and second protrusions 1-1, 1-2 can be designed and arranged in any size and position.
[0034] The stem body 2 includes a first end and a second end. The first end is connected to the femoral stem shoulder 3. The stem body 2 is a tapered rod. The shape of the femoral stem body is similar to that of the prior art and will not be described in detail here. The diameter of the first end is greater than the diameter of the second end. The taper of the stem body 2 ranges from 2° to 20°, meaning the angle of inclination between the first and second ends is between 2° and 20°. In this embodiment, the stem body 2 adopts a 5° taper to further improve the stability of the femoral stem within the medullary cavity and prevent excessive sinking.
[0035] The side of the femoral stem shoulder 3 away from the femoral stem neck 6 is inclined toward the femoral stem neck 6, and the range of the inclination angle is 0.1°-20°. In this embodiment, the inclination angle is 1°, which can make it more convenient to implant the prosthesis during surgery.
[0036] At least one binding and fixing hole 7 is provided on the side surface of the femoral stem shoulder 3 to facilitate binding of broken and loose bones with steel wire during surgery and to facilitate reconstruction of bone structure. The diameter range of the binding and fixing hole is 1mm-10mm. In this embodiment, two binding and fixing holes 7 are preferably provided, and a punching hole 8 is provided on the top surface of the femoral stem shoulder 3 for connecting and fixing implant devices. This can achieve a firm connection with other implant devices and also restrict the relative axial rotation of the two, facilitating the manipulation of the rotation angle during implantation of the femoral stem.
[0037] The femoral stem neck 6 has a taper ranging from 1° to 10°. The upper and lower sides of the femoral stem neck 6 are curved structures 6-1, while the other two sides are flat structures. The surface of the flat structure 6-2 is polished to a roughness Ra of 0.01-0.8, effectively reducing the risk of tiny particles generated by collision between the neck and the acetabulum liner, which can cause osteolysis. The width of the flat structure 6-2 ranges from 1mm to 10mm, increasing the range of motion of the entire joint prosthesis system while ensuring fatigue strength. Figure 1 W is the width of the planar structure 6-2. The area of the side where the femoral stem neck 6 and the femoral stem shoulder 3 are connected is larger than the area of the side where the femoral stem neck 6 and the femoral stem taper 5 are connected.
[0038] The surface roughness Rz of the femoral stem taper 5 ranges from 3.2 to 50, compatible with the surface requirements of most commercially available metal and ceramic femoral heads, achieving secure taper locking. The femoral stem taper 5 is a frustum, with its larger bottom surface connecting to the femoral stem neck 6. The taper ranges from 1° to 10°.
[0039] On the cross section 1 of the stem, a line connecting the protruding vertices of each first protrusion 1-1 forms an outer contour 10, and a line connecting the protruding vertices of each second protrusion 1-2 forms an inner contour 9. The inner contour 9 is located inside the outer contour 10 and is concentric with the outer contour 10. The inner contour 9 can be circular, elliptical, or polygonal, and the outer contour 10 can be circular, elliptical, or polygonal. This design can better adapt to the cortical bone of the patient's medullary cavity and the anatomical characteristics of the femur.
[0040] When the inner contour 9 is elliptical, the ratio of the major axis of the inner contour 9 to the minor axis of the inner contour 9 is in the range of 1-10. When the outer contour 10 is elliptical, the ratio of the major axis of the outer contour 10 to the minor axis of the outer contour 10 is in the range of 1-10. When the inner contour 9 is polygonal, the shape and size of each second protrusion 1-2 are different, and the protrusion height is also different. When the outer contour 10 is polygonal, the shape and size of each first protrusion 1-1 are different, and the protrusion height is also different. When both the inner contour 9 and the outer contour 10 are circular, the radius of the inner contour 9 is smaller than the radius of the outer contour 10. The protrusion height is the distance from the protrusion vertex to the surface of the handle body 2.
[0041] The first protrusion in this solution is designed to embed deeply into the cortical bone of the femoral medullary cavity during implantation, ensuring excellent anti-rotational stability. The second protrusion is designed to directly contact the cortical bone of the medullary cavity, achieving excellent anti-sinking effect. The design of the first and second protrusions can extend the service life of the prosthesis in the patient's body and reduce the burden on the patient. The cross-section of the stem in this solution can be polygonal, elliptical, or circular, adapting to various femoral medullary cavity shapes and sizes, and better adapting to the patient's medullary cortical bone and femoral anatomical characteristics.
[0042] The following points need to be explained:
[0043] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention. Other structures may refer to conventional designs.
[0044] (2) For the sake of clarity, the thickness of layers or regions in the drawings used to describe the embodiments of the present invention are exaggerated or reduced, that is, these drawings are not drawn to scale. It is understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or intervening elements may be present.
[0045] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.
[0046] The above are only specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.
Claims
1. A femoral stem, characterized in that: The femoral stem comprises a femoral stem taper, a femoral stem neck, a femoral stem shoulder and a stem body; one end of the femoral stem neck is connected to the stem body through the femoral stem shoulder, and the other end of the femoral stem neck is connected to the femoral stem taper; At least two first protrusions are evenly arranged on the handle and around the circumference of the handle. The length of the first protrusion is equal to the length of the handle. At least one second protrusion is arranged between two adjacent first protrusions.
2. The femoral stem according to claim 1, characterized in that A protruding height of the second protrusion is smaller than a protruding height of the first protrusion.
3. The femoral stem according to claim 1, wherein: On the cross section of the handle body, the line connecting the protruding vertices of each first protrusion obtains an outer contour, and the line connecting the protruding vertices of each second protrusion obtains an inner contour, the inner contour is inside the outer contour and the inner contour is concentrically arranged with the outer contour, and the outer contour is circular, elliptical or polygonal.
4. The femoral stem according to claim 3, characterized in that: The inner contour is circular, elliptical or polygonal.
5. The femoral stem according to claim 4, characterized in that: When the inner contour is an ellipse, the ratio of the major axis of the inner contour to the minor axis of the inner contour is in the range of 1-10; when the outer contour is an ellipse, the ratio of the major axis of the outer contour to the minor axis of the outer contour is in the range of 1-10.
6. The femoral stem according to claim 1, characterized in that The stem body includes a first end and a second end, the first end is connected to the femoral stem shoulder, the diameter of the first end is larger than the diameter of the second end; the taper of the stem body ranges from 2° to 20°.
7. The femoral stem according to claim 1, characterized in that At least one binding and fixing hole is provided on the side surface of the femoral stem shoulder, and a punching hole is provided on the top surface of the femoral stem shoulder.
8. The femoral stem according to claim 1, wherein: The upper and lower side surfaces of the femoral stem neck are arcuate structures, and the other two side surfaces of the femoral stem neck are planar structures. The roughness Ra of the planar structures is in the range of 0.01-0.
8.
9. The femoral stem according to claim 8, characterized in that: The width of the planar structure ranges from 1 mm to 10 mm.
10. The femoral stem according to claim 1, wherein: The surface roughness Rz of the femoral stem taper is in the range of 3.2-50. The femoral stem taper is a frustum structure. The bottom surface with a large diameter of the femoral stem taper is connected to the femoral stem neck. The taper range of the femoral stem taper is between 1°-10°.