CN116138932A

CN116138932A - Femoral stem and hip joint prosthesis with same

Info

Publication number: CN116138932A
Application number: CN202310430800.6A
Authority: CN
Inventors: 徐学方; 许书富; 丁玉宝; 陈丽菀; 王晓红; 段红平
Original assignee: Beijing Naton Medical Technology Holdings Co Ltd
Current assignee: Beijing Naton Medical Technology Holdings Co Ltd
Priority date: 2023-04-21
Filing date: 2023-04-21
Publication date: 2023-05-23
Anticipated expiration: 2043-04-21
Also published as: CN116138932B

Abstract

The invention relates to a femoral stem and a hip joint prosthesis with the femoral stem, wherein the femoral stem comprises: the novel femoral neck and femoral neck handle comprises a conical head, a femoral neck and a handle body which are sequentially connected, wherein the handle body is provided with a front side face, a rear side face and an inner side face and an outer side face, the front side face and the rear side face are oppositely arranged along the front and rear directions of the handle body, the distance between the front side face and the rear side face is gradually reduced along the directions from the outer side face to the inner side face, an included angle alpha between the front side face and the rear side face is more than or equal to 4 degrees and less than or equal to 12 degrees, a chamfering part is arranged between at least one of the front side face and the rear side face and the outer side face, the surface of the chamfering part is an arc-shaped surface, and the surface of the chamfering part faces to the inner side of the handle body. The femoral stem has strong anti-rotation performance and good implantation effect.

Description

Femoral stem and hip joint prosthesis with same

Technical Field

The invention relates to the technical field of artificial prostheses, in particular to a femoral stem and a hip joint prosthesis with the femoral stem.

Background

The femoral stem is used as an implant in the current orthopedic hip joint replacement operation, is suitable for repairing and reconstructing human hip joint diseases, and usually forms a complete hip joint prosthesis together with the acetabular liner and the acetabular outer cup after being implanted with the femoral head prosthesis. However, the shape design of the femoral stem has an important impact on the stability of the femoral stem, the stress shielding of the femoral stem, and the ease of installation of the femoral stem.

In the related art, for example, a cylindrical design is adopted at the distal end of the conical round handle, the rotation resistance of the prosthesis is weaker due to the cylindrical design, and in order to increase the matching performance of the prosthesis with bone during implantation, a reamer is needed to be used for reaming, so that the blood supply of a medullary cavity can be influenced, and the effect after implantation is poor.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the related art to some extent.

Therefore, the embodiment of the invention provides the femoral stem with strong anti-rotation performance and good implantation effect.

Embodiments of the present invention also provide a hip joint prosthesis.

The femoral stem of an embodiment of the present invention comprises: the novel femoral neck and femoral neck handle comprises a conical head, a femoral neck and a handle body which are sequentially connected, wherein the handle body is provided with a front side face, a rear side face and an inner side face and an outer side face, the front side face and the rear side face are oppositely arranged along the front and rear directions of the handle body, the distance between the front side face and the rear side face is gradually reduced along the directions from the outer side face to the inner side face, an included angle alpha between the front side face and the rear side face is more than or equal to 4 degrees and less than or equal to 12 degrees, a chamfering part is arranged between at least one of the front side face and the rear side face and the outer side face, the surface of the chamfering part is an arc-shaped surface, and the surface of the chamfering part faces to the inner side of the handle body.

According to the femoral stem of the embodiment of the invention, the distance between the front side surface and the rear side surface is gradually reduced along the direction from the outer side surface to the inner side surface, so that the cross section of the stem body is in a shape with small inner side and large outer side, and the anti-rotation performance of the femoral stem is improved. And because the included angle alpha between the front side surface and the rear side surface is more than or equal to 4 degrees and less than or equal to 12 degrees, the filling rate of the handle body in the marrow cavity can be improved, the anti-rotation performance of the handle body is stronger, and the implantation effect of the femoral stem is improved. In addition, because be equipped with chamfer portion on the handle body, and the surface of chamfer portion is sunken towards the inboard of the handle body, can avoid the closed angle of femoral stem to cause the problem that the femoral stem caused the femur split easily when driving into, improve the fixed effect of the handle body and femoral medullary cavity, anti-rotation effect is better.

In some embodiments, the inner side surface is an arcuate surface protruding away from the outer side surface, the arcuate surface extending in an up-down direction of the handle body throughout the handle body.

In some embodiments, the medial side is tangential to the anterior side and the posterior side; and/or the radius of the arc of the inner side surface near the distal end of the handle body is larger than the radius of the arc of the inner side surface near the proximal end of the handle body.

In some embodiments, the front side is an arcuate surface protruding in a direction away from the rear side, the rear side is an arcuate surface protruding in a direction away from the front side, and a tangent to the front side and a tangent to the rear side define the included angle α; and/or, the front side surface and the rear side surface are plane.

In some embodiments, the number of chamfer portions is two, both chamfer portions extend along the length direction of the handle body, one chamfer portion is disposed between the front side surface and the outer side surface, and the other chamfer portion is disposed between the rear side surface and the outer side surface.

In some embodiments, the handle body includes a shoulder portion, a main body portion, and a distal end portion connected in this order, the chamfer portion on the shoulder portion is arranged along an extending direction of the shoulder portion, the chamfer portion on the main body portion is arranged along an axial direction of the main body portion, and the chamfer portion on the distal end portion gradually extends obliquely toward an inner side of the distal end portion in a direction in which an end of the distal end portion adjacent to the main body portion faces away from the end of the main body portion.

In some embodiments, a side of the chamfer adjacent the inner side surface is a perpendicular distance D from the crown surface of the shank, and a side of the chamfer adjacent the outer side surface is a perpendicular distance C from the crown surface of the shank, wherein C/D is 0.4 or more and 0.6 or less; and/or, an included angle beta between the surface of the chamfer part and the sagittal plane of the handle body is more than or equal to 40 degrees and less than or equal to 60 degrees.

In some embodiments, the handle body is provided with a plurality of vertical ribs, the vertical ribs extend along the length direction of the handle body, and the vertical ribs are arranged at intervals along the inner and outer directions of the handle body.

In some embodiments, the height of the upstanding ridge decreases gradually in the direction from the outside to the inside of the handle body, and the maximum height of the upstanding ridge near the outer side surface is 2.2mm or less; and/or the height of the vertical ridge is gradually reduced along the direction from top to bottom of the handle body; and/or, the distance E between the adjacent vertical ridges is more than or equal to 4mm and less than or equal to 6mm; and/or the ratio of the extension length H1 of the vertical ridge to the total length H2 of the handle body is H1/H2, wherein the H1/H2 is more than or equal to 0.5 and less than or equal to 0.6; and/or one end of the vertical ridge, which is away from the handle body, is provided with a rounded corner.

A hip joint prosthesis according to another embodiment of the present invention comprises: a femoral stem, the femoral stem being a femoral stem according to any one of the embodiments of the present invention; the ball head is arranged on the cone head; an acetabular cup, the acetabular cup being pivotably engaged with the ball head.

According to the hip joint prosthesis provided by the embodiment of the invention, the distance between the front side surface and the rear side surface is gradually reduced along the direction from the outer side surface to the inner side surface, so that the cross section of the handle body is in a shape with small inner side and large outer side, and the anti-rotation performance of the femoral stem is improved. And because the included angle alpha between the front side surface and the rear side surface is more than or equal to 4 degrees and less than or equal to 12 degrees, the filling rate of the handle body in the marrow cavity can be improved, the anti-rotation performance of the handle body is stronger, and the implantation effect of the femoral stem is improved. In addition, because be equipped with chamfer portion on the handle body, and the surface of chamfer portion is sunken towards the inboard of the handle body, can avoid the closed angle of femoral stem to cause the problem that the femoral stem caused the femur split easily when driving into, improve the fixed effect of the handle body and femoral medullary cavity, anti-rotation effect is better.

Drawings

Fig. 1 is a front view of a femoral stem of an embodiment of the present invention.

Fig. 2 is a cross-sectional view of a femoral stem of a first embodiment of the present invention.

Fig. 3 is a cross-sectional view of a femoral stem of a second embodiment of the present invention.

Fig. 4 is a cross-sectional view of a femoral stem of a third embodiment of the present invention.

Fig. 5 is a cross-sectional view of a femoral stem of a fourth embodiment of the present invention.

Fig. 6 is a cross-sectional view of a femoral stem of a fifth embodiment of the present invention.

Fig. 7 is a cross-sectional view of a femoral stem of a sixth embodiment of the present invention.

Fig. 8 is a side view of a femoral stem of an embodiment of the present invention.

Fig. 9A is a front view of sample 1 of a femoral stem of an embodiment of the present invention.

Fig. 9B is a cross-sectional view of sample 1 of a femoral stem of an embodiment of the present invention.

Fig. 10A is a front view of sample 2 of a femoral stem of an embodiment of the present invention.

Fig. 10B is a cross-sectional view of sample 2 of a femoral stem in an embodiment of the present invention.

Fig. 11A is a front view of sample 3 of a femoral stem of an embodiment of the present invention.

Fig. 11B is a cross-sectional view of sample 3 of a femoral stem in an embodiment of the present invention.

Fig. 12A is a front view of sample 4 of a femoral stem of an embodiment of the present invention.

Fig. 12B is a cross-sectional view of sample 4 of a femoral stem in an embodiment of the present invention.

Fig. 13A is a front view of sample 5 of a femoral stem of an embodiment of the present invention.

Fig. 13B is a cross-sectional view of sample 5 of a femoral stem in an embodiment of the present invention.

Reference numerals:

100. a handle body;

110. a shoulder; 120. a main body portion; 130. a distal end portion;

101. a front side; 102. a rear side; 103. an inner side surface; 104. an outer side surface; 105. a chamfering part; 1051. a concave arc; 106. vertical ridges;

200. a conical head;

300. a femoral neck.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

In order to better explain and illustrate the technical scheme of the invention, the direction and the like related to the invention are explained and illustrated in combination with the conventional description method in the field.

In the field of anatomies and medical devices, the directions and planes of the medial, lateral, anterior, posterior, distal, proximal, sagittal, coronal, cross-sectional, etc. have specific meanings and are well known to those skilled in the art, and unless otherwise indicated, these terms refer to the meanings recognized by those skilled in the art.

Generally, when describing a human body, joint or prosthesis, three types of cuts are generally referred to as follows: sagittal, coronal, and transverse planes. The sagittal plane refers to a longitudinal section dividing a human body or a joint into a left part and a right part from the front-back direction, wherein the sagittal plane passing through the center of the human body is the median sagittal plane, and the sagittal plane divides the human body into two parts which are equal from left to right. The coronal plane refers to a longitudinal plane that divides the body or joint into anterior and posterior parts from the left-right direction, and is perpendicular to the sagittal plane. The cross section is a plane parallel to the ground plane and dividing the human body or joint into an upper part and a lower part, and the cross section is mutually perpendicular to the coronal plane and the sagittal plane.

A femoral stem and a hip joint prosthesis having the same according to an embodiment of the present invention are described below with reference to fig. 1 to 8.

As shown in fig. 1 to 3, a femoral stem according to an embodiment of the present invention includes: the taper 200, the femoral neck 300 and the stem 100 are connected in sequence. The shank 100 has a front side 101 and a rear side 102 arranged opposite each other in the front-rear direction thereof, and an inner side 103 and an outer side 104 arranged opposite each other in the inside-outside direction thereof. The distance between the front side 101 and the rear side 102 gradually decreases in the direction from the outer side 104 to the inner side 103, and an angle α between the front side 101 and the rear side 102 is 4 ° or more and 12 ° or less.

According to the femoral stem of the embodiment of the present invention, since the distance between the front side 101 and the rear side 102 gradually decreases in the direction from the outer side 104 to the inner side 103, the cross section of the stem body 100 is made into a shape with a small inner side and a large outer side, so as to improve the anti-rotation performance of the femoral stem. And because the included angle alpha between the front side surface 101 and the rear side surface 102 is more than or equal to 4 degrees and less than or equal to 12 degrees, the filling rate of the handle body 100 in the marrow cavity can be improved, the anti-rotation performance of the handle body 100 is stronger, and the implantation effect of the femoral stem is improved.

As shown in fig. 7, a chamfer 105 is provided between at least one of the front side 101 and the rear side 102 and the outer side 104, the surface of the chamfer 105 is an arc surface, and the surface of the chamfer 105 is recessed toward the inner side of the handle body 100. It will be appreciated that the peripheral profile of the chamfer 105 is concave arc 1051 in cross-section along the length of the shank 100. Because the handle body 100 is provided with the chamfer portion 105, and the surface of the chamfer portion 105 is sunken towards the inner side of the handle body 100, the problem that the femoral stem is split when being driven into due to sharp angles of the femoral stem can be avoided, the fixing effect of the handle body 100 and the femoral marrow cavity is improved, and the anti-rotation effect is good.

For example, a chamfer 105 is provided between the front surface 101 and the outer surface 104. For another example, a chamfer 105 is provided between the rear surface 102 and the outer surface 104. For another example, chamfer portions 105 are provided between the front side surface 101 and the outer side surface 104 and between the rear side surface 102 and the outer side surface 104.

In the embodiment of the present invention, as shown in fig. 2 to 7, two chamfer portions 105 are provided on the shank 100, and both chamfer portions 105 extend along the length direction of the shank 100, wherein one chamfer portion 105 is provided between the front side surface 101 and the outer side surface 104, and the other chamfer portion 105 is provided between the rear side surface 102 and the outer side surface 104. It will be appreciated that the sharp corners at the junction of the outer side 104 and the front and rear sides are removed by the chamfer 105.

Because the sharp corners of the femoral stem will contact the cortical bone when the femoral stem is implanted. When the situation that only the sharp angle of the femoral stem is contacted with the cortical bone occurs, the model selection of the femoral stem is small, a large amount of gaps are generated between the femoral stem and the medullary cavity, the filling rate is reduced, and the long-term anti-rotation performance of the femoral stem is affected.

When the femoral stem is removed at an angle and with a sharp angle to the outside of the handle body 100, two additional facets are created on the outside. At the moment, the filling rate of the femoral stem in the intramedullary cavity can be increased, and the contact fixing point position of the femoral stem and the intramedullary cavity can be increased, so that the anti-rotation performance of the femoral stem can be increased. In addition, the sharp angle of the femoral stem is easy to cause the problem of femoral fracture when the femoral stem is driven in. Therefore, the femoral stem of the embodiment of the present invention can improve the anti-rotation performance of the femoral stem by providing the chamfer 105, and make the stability after implantation higher.

Alternatively, as shown in fig. 2, the angle α between the front side 101 and the rear side 102 may be 4 °, 7 °, 9 °, or 12 °. The inventor of the present application found through experimental study that when the included angle α between the front side 101 and the rear side 102 is the above value, the anti-rotation performance of the handle body 100 can be stronger, and the implantation effect is better.

The front side 101 and the rear side 102 may be curved or planar. The front side 101 and the rear side 102 shown by the broken lines in fig. 4 are planar, and the front side 101 and the rear side 102 shown by the solid lines are arcuate surfaces.

For example, as shown in fig. 4, the front side 101 is an arc surface protruding toward a direction away from the rear side 102, the rear side 102 is an arc surface protruding toward a direction away from the front side 101, and an included angle α is defined by a tangent line of the front side 101 and a tangent line of the rear side 102. It can be appreciated that the cross section of the femoral medullary cavity is generally elliptical, and the front side 101 and the rear side 102 are both generally arc-shaped, so that the fitting degree of the handle body 100 and the femoral medullary cavity is higher, the filling effect is better, and the anti-rotation capability of the femoral handle is further improved.

As another example, as shown in fig. 2 and 3, the anterior side 101 and the posterior side 102 are each planar, thereby facilitating the manufacturing of the femoral stem. For example, in the cross section along the length direction of the stem 100, the outer peripheral contour of the front side 101 and the outer peripheral contour of the rear side 102 are both straight lines, and the included angle α of the two straight lines is 7 °, so that the rotation resistance of the femoral stem is strong.

In some embodiments, as shown in fig. 2-7, the inner side 103 is a rounded surface that protrudes toward the outer side 104, the rounded surface extending in an up-down direction of the handle 100 throughout the handle 100. The inventor of the present application found through experimental study that after the femoral stem is implanted, the inner side 103 receives a larger force, and the inner side 103 of the stem body 100 of the femoral stem according to the embodiment of the present invention is configured as an arc surface, so that the contact area between the inner side 103 and the femoral medullary cavity can be increased, thereby reducing the stress of the femoral stem on the inner side of the femur to a certain extent and improving the stability of the femoral stem after implantation.

Alternatively, as shown in fig. 3, the medial side 103 is tangential to the anterior side 101 and the posterior side 102. It can be appreciated that, in the cross section along the length direction of the shank 100, the outer peripheral outline of the inner side 103 is tangential to the outer peripheral outline of the front side 101 and the outer peripheral outline of the rear side 102, so that the outer peripheral surface of the shank 100 can be smoothly transited, the problem of splitting the femur when the femur is driven is avoided, the stress of the femur on the inner side of the femur can be reduced to a certain extent, and the implantation effect of the femur is better.

Alternatively, as shown in FIG. 5, the radius of the arc of the inner side 103 near the distal end of the handle 100 is greater than the radius of the arc of the inner side 103 near the proximal end of the handle 100. The dashed line in fig. 5 is the arcuate configuration of the proximal inner side 103 of the handle 100, and the solid line is the arcuate configuration of the distal inner side 103 of the handle 100. It will be appreciated that the medial surface 103 of the distal middle portion of the handle body 100 is of a large arc configuration, thereby improving the anti-rotation capability of the distal middle portion of the handle body 100.

In some embodiments, as shown in FIG. 6, the side of the chamfer 105 adjacent the medial side 103 is a perpendicular distance D from the coronal plane of the shank 100, and the side of the chamfer 105 adjacent the lateral side 104 is a perpendicular distance C from the coronal plane of the shank 100, wherein C/D is greater than or equal to 0.4 and less than or equal to 0.6. For example, the C/D may be 0.4, 0.5 or 0.6.

Alternatively, as shown in fig. 6, the angle β between the surface of the chamfer 105 and the sagittal plane of the shank 100 is greater than or equal to 40 ° and less than or equal to 60 °. For example, the angle β may be 50 °, 55 °, or 60 °. Through experimental study, the inventor of the application finds that when the C/D value and the included angle beta meet the above values, the pressure to the medullary cavity in the femoral stem inserting process can be further reduced, the fixing effect of the contact between the outer side surface 104 and the medullary cavity is enhanced, and the anti-rotation capability of the femoral stem is improved.

Alternatively, the chamfer 105 may take on different configurations at different locations on the front (back) side. The chamfer 105 on the femoral stem of an embodiment of the present invention continues from the uppermost end of the stem 100 to the most distal end. The handle 100 includes a shoulder 110, a main body portion 120, and a distal end portion 130. The chamfer 105 on the shoulder 110 is arranged in the extending direction of the shoulder 110, the chamfer 105 on the body 120 is arranged in the axial direction of the body 120, and the chamfer 105 on the distal end 130 gradually extends obliquely toward the inside of the distal end 130 in the direction (from top to bottom in fig. 1) in which the end of the distal end 130 adjacent to the body 120 faces the end of the distal end 130 away from the body 120. In other words, in the top-down direction, at the shoulder 110 position, the chamfer 105 removal proceeds along the angle of the shoulder; in the main body portion 120 position, in order to facilitate insertion of the femoral stem, removal of the chamfer portion 105 is performed in the vertical direction; at the distal end 130, the chamfer 105 is removed along a certain arc.

In some embodiments, as shown in fig. 2, 4 and 8, the handle body 100 is provided with a plurality of vertical ribs 106, the plurality of vertical ribs 106 extend along the length direction of the handle body 100, and the plurality of vertical ribs 106 are spaced along the inner and outer directions of the handle body 100. In an embodiment of the invention, the femoral stem enhances the anti-rotation performance of the stem 100 by adding a upstanding ridge 106.

Optionally, the end of the upstanding ridge 106 facing away from the shank 100 has rounded corners. It will be appreciated that the cross section of the upstanding ridge 106 is generally triangular, and this configuration facilitates insertion of the shank 100 into the cancellous bone of the medullary cavity, and that the rounded corners provided at the ends of the upstanding ridge 106 prevent the problem of femoral fracture due to sharp edges.

It will be appreciated that the number of upstanding ribs 106 may be adjusted according to the size of the femoral stem. For example, the number of upstanding ribs 106 of a small sized femoral stem is small and the number of upstanding ribs 106 of a large sized femoral stem is large. The vertical ribs 106 may be 1, 3 or 5.

Alternatively, as shown in fig. 4, the distance E between adjacent vertical ridges 106 is 4mm or more and 6mm or less. For example, the distance E between adjacent vertical ridges 106 is 5mm, which can make the implantation of the femoral stem more stable and save the cost of manufacturing.

Optionally, the height of the vertical ridge 106 gradually decreases along the direction from outside to inside of the stem body 100, and the maximum height of the vertical ridge 106 near the outer side surface 104 is less than or equal to 2.2mm, so that the influence of the setting of the vertical ridge 106 on the implantation of the femoral stem can be avoided, and the stability of the femoral stem after implantation is improved.

Alternatively, as shown in fig. 1 and 8, the ratio of the extension length H1 of the vertical rib 106 to the total length H2 of the shank 100 is H1/H2, where H1/H2 is 0.5 or more and 0.6 or less. For example, the maximum length H1 of the vertical ridge 106 is 50%, 55%, or 60% of the maximum shank length H2. For example, in the embodiments of the present application, the maximum length H1 of the vertical ridge 106 is 55% of the maximum shank length H2.

Alternatively, as shown in fig. 8, the height of the upstanding ridge 106 decreases progressively in the direction from top to bottom of the shank 100. Specifically, the included angle J of the upstanding ridge 106 is greater than the included angle between the front side 101 and the rear side 102 of the handle body 100. Therefore, the height of the vertical ridge 106 at the top is highest, and the height of the vertical ridge 106 is lower to 0 as going down, so that the anti-rotation effect of the femoral stem can be improved.

It will be appreciated that the shape of the shank 100 and the vertical ridge 106 of the femoral stem are important factors affecting the anti-rotation performance of the femoral stem, in order to verify the effect of features such as the chamfer 105 of the outer side 104 of the femoral stem being cut off, the concave arc 1051 being arranged at the cut-off of the chamfer 105, the vertical ridge 106, and the like on the anti-rotation performance, the femoral stem with different features is embedded into bone cement, the same rotation torque is applied on the femoral stem, and the effect of different features in the femoral stem on the anti-rotation performance is compared by comparing the torsion angles of the femoral stem with different features.

Specifically, the inventors of the present application conducted comparative experiments on femoral stems as follows.

1. Test sample:

2.1 tools

Instrument/device/software	Use of the same
		Abaqus(2017, SIMULIA, USA)	Finite element analysis

2.2 Material Properties

The femur stem is made of cobalt-chromium-molybdenum alloy

2.3 grid cells

The unit type C3D10 is characterized in that the size of the femoral stem grid is 2mm, the size of bone cement is 5mm, and the grid of the contact part of the bone cement and the femoral stem is thinned to be 1.5mm.

2.4 contact arrangement

The femoral stem is in surface contact with the bone cement setting surface, the friction coefficient is 0.4, and the center of the end face of the neck of the femoral stem is provided with a reference point and the rigid body of the femoral stem is restrained.

2.5 boundary conditions and loadings

A y-direction torque of 4Nm was applied at the reference point, placing a fully fixed constraint on the cement side.

2.6 submitting the calculation

And (5) submitting the model to a solver for calculation, and extracting the torsion angle of the model for comparison and analysis.

3. Results and analysis

The twist angle of each sample femoral stem when the same rotational torque was applied is shown in the table. Wherein the twist angle of sample 1 is minimal.

As shown in fig. 9A, 9B, 10A and 10B, by comparing the sample 1 and the sample 2, the differences between the sample 1 and the sample 2 are: the chamfer portion 105 of the sample 1 has a concave arc 1051, and the chamfer portion 105 of the sample 2 has no concave arc 1051, and the torsion angle of the sample 1 is smaller than that of the sample 2 through finite element analysis. Thus, it can be seen that the concave arc 1051 of the chamfer 105 is beneficial to increase the anti-rotation performance of the femoral stem.

As shown in fig. 9A, 9B, 11A and 11B, by comparing sample 1 and sample 3, the differences between sample 1 and sample 3 are: the outer side of the sample 1 is provided with a chamfer 105, the outer side of the sample 2 is not provided with the chamfer 105, and the torsion angle of the sample 1 is smaller than that of the sample 3 through finite element analysis, so that the chamfer 105 arranged on the outer side is beneficial to increasing the anti-rotation performance of the femoral stem.

As shown in fig. 9A, 9B, 12A and 12B, by comparing sample 1 and sample 4, the differences between sample 1 and sample 4 are: sample 1 has a vertical ridge 106, sample 2 has no vertical ridge 106, and the torsion angle of sample 1 is smaller than the torsion angle of sample 4 through finite element analysis, so that it can be known that the vertical ridge 106 is beneficial to increasing the anti-rotation performance of the femoral stem.

As shown in fig. 9A, 9B, 13A and 13B, by comparing the sample 1 and the sample 5, the torsion angle of the sample 1 is smaller than that of the sample 5 through finite element analysis, compared with the sample 1, the sample 5 has no chamfer portion 105 and no vertical ridge 106, so that the joint action of the outer chamfer and the vertical ridge 106 is beneficial to increasing the anti-rotation performance of the femoral stem.

As can be seen from comparing samples 1, 2, 3 and 5, the anti-rotation performance of the analysis sample gradually becomes worse as the characteristics of the anti-rotation design of the sample decrease, so that the anti-rotation performance of the femoral stem can be optimized when the characteristics of the outer side of the femoral stem, such as the chamfer 105, the concave arc 1051 at the chamfer 105, the vertical ridge 106 on the stem body 100, and the like are independently or jointly acted, and the degree of optimization can be overlapped.

4. Conclusion(s)

In summary, the provision of the chamfer portion 105 on the outer side of the femoral stem, the concave arc 1051 at the chamfer portion 105, the vertical ridge 106 on the stem body 100, and other features are beneficial to optimizing the anti-rotation performance of the femoral stem when acting alone or together, and the degree of optimization can be overlapped.

A hip joint prosthesis according to another embodiment of the present invention comprises: femoral stem, ball head and acetabular cup. The femoral stem is the femoral stem of the present invention, the ball head is mounted on the awl 200, and the acetabular cup is pivotally mated with the ball head.

According to the hip joint prosthesis of the embodiment of the present invention, since the distance between the front side 101 and the rear side 102 is gradually reduced in the direction from the outer side 104 to the inner side 103, the cross section of the stem body 100 is in a shape of small inner side and large outer side, so as to improve the anti-rotation performance of the femoral stem. And because the included angle alpha between the front side surface 101 and the rear side surface 102 is more than or equal to 4 degrees and less than or equal to 12 degrees, the filling rate of the handle body 100 in the marrow cavity can be improved, the anti-rotation performance of the handle body 100 is stronger, and the implantation effect of the femoral stem is improved.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While the above embodiments have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those of ordinary skill in the art without departing from the scope of the invention.

Claims

1. A femoral stem comprising: the cone head, the femur neck and the handle body are connected in sequence, the handle body is provided with a front side surface and a rear side surface which are oppositely arranged along the front-back direction of the handle body, an inner side surface and an outer side surface which are oppositely arranged along the inner-outer direction of the handle body,

the distance between the front side surface and the rear side surface gradually decreases along the direction from the outer side surface to the inner side surface, the included angle alpha between the front side surface and the rear side surface is more than or equal to 4 degrees and less than or equal to 12 degrees,

a chamfer part is arranged between at least one of the front side surface and the rear side surface and the outer side surface, the surface of the chamfer part is an arc-shaped surface, and the surface of the chamfer part is sunken towards the inner side of the handle body.

2. The femoral stem of claim 1, wherein the medial side is an arcuate surface projecting away from the lateral side, the arcuate surface extending in a superior-inferior direction of the stem body throughout the stem body.

3. The femoral stem of claim 2, wherein the medial side is tangential to the anterior side and the posterior side;

and/or the radius of the arc of the inner side surface near the distal end of the handle body is larger than the radius of the arc of the inner side surface near the proximal end of the handle body.

4. The femoral stem of claim 1, wherein the anterior side is an arcuate surface that projects in a direction away from the posterior side, the posterior side is an arcuate surface that projects in a direction away from the anterior side, and a tangent to the anterior side and a tangent to the posterior side define the included angle a;

and/or, the front side surface and the rear side surface are plane.

5. The femoral stem of claim 1, wherein there are two chamfer portions, each of the two chamfer portions extending along the length of the stem, one of the chamfer portions being disposed between the anterior side and the lateral side and the other chamfer portion being disposed between the posterior side and the lateral side.

6. The femoral stem of claim 5, wherein the stem body comprises a shoulder, a body portion, and a distal portion connected in sequence, wherein a chamfer on the shoulder is disposed along the extension of the shoulder, wherein a chamfer on the body portion is disposed along the axial direction of the body portion,

the chamfer portion on the distal end portion gradually extends obliquely toward the inside of the distal end portion in a direction in which an end of the distal end portion adjacent to the main body portion faces an end of the distal end portion away from the main body portion.

7. The femoral stem of claim 1, wherein a side of the chamfer adjacent the medial side is a perpendicular distance D from the coronal plane of the stem and a side of the chamfer adjacent the lateral side is a perpendicular distance C from the coronal plane of the stem, wherein C/D is 0.4 or greater and 0.6 or less;

and/or, an included angle beta between the surface of the chamfer part and the sagittal plane of the handle body is more than or equal to 40 degrees and less than or equal to 60 degrees.

8. The femoral stem of claim 1, wherein the stem body is provided with a plurality of vertical ridges, the plurality of vertical ridges each extend along the length direction of the stem body, and the plurality of vertical ridges are spaced apart along the inner and outer directions of the stem body.

9. The femoral stem of claim 8, wherein the height of the upstanding ridge decreases progressively in the direction from the exterior to the interior of the stem body and the maximum height of the upstanding ridge proximate the exterior side is less than or equal to 2.2mm;

and/or the height of the vertical ridge is gradually reduced along the direction from top to bottom of the handle body;

and/or, the distance E between the adjacent vertical ridges is more than or equal to 4mm and less than or equal to 6mm;

and/or the ratio of the extension length H1 of the vertical ridge to the total length H2 of the handle body is H1/H2, wherein the H1/H2 is more than or equal to 0.5 and less than or equal to 0.6;

and/or one end of the vertical ridge, which is away from the handle body, is provided with a rounded corner.

10. A hip joint prosthesis, comprising:

a femoral stem, the femoral stem being as claimed in any one of claims 1 to 9;

the ball head is arranged on the cone head;

an acetabular cup pivotally mated with the ball head.