CN116327451B

CN116327451B - Femoral stem prosthesis

Info

Publication number: CN116327451B
Application number: CN202310605629.8A
Authority: CN
Inventors: 徐学方; 许书富; 丁玉宝; 张家英; 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: 2023-05-26
Filing date: 2023-05-26
Publication date: 2023-08-04
Anticipated expiration: 2043-05-26
Also published as: CN116327451A

Abstract

The invention relates to the technical field of medical appliances and discloses a femoral stem prosthesis. The femoral stem prosthesis comprises a stem body, a femoral neck and a neck collar. The stem having a stem shaft and a desired osteotomy face at a proximal end of the stem, the femoral neck being attached to the desired osteotomy face of the stem; the neck collar is arranged on the edge of the femur neck near the proximal end of the handle body, the neck collar extends towards the inner side along the inner and outer directions of a human body, the length of the neck collar is A, the distance between the innermost end point of the expected osteotomy face and the axis of the handle body is MX, A and MX are in linear positive correlation, A=KMX+/-b, K is 0.2-0.3, and b is 0.1-0.5. Therefore, the femoral stem prosthesis of the embodiment of the invention has the advantages of good initial stability and less stimulation to surrounding soft tissues, and also has the advantage of optimizing the stress of the neck collar of the femoral stem prosthesis on the femur osteotomy surface.

Description

Femoral stem prosthesis

Technical Field

The invention relates to the technical field of medical appliances, in particular to a femoral stem prosthesis.

Background

Total hip arthroplasty is the most effective method for treating hip joint disease, and can effectively relieve hip joint pain and improve joint function and quality of life of patients with end-stage hip joint disease. In the related art, a corresponding neck collar structure is provided on the femoral stem prosthesis, and the neck collar structure can reduce early sinking in the operation and increase initial stability, in particular anti-rotation stability. However, in the use process, the problem of overhang occurs when the neck collar is too large, so that the stimulation can be generated to peripheral soft tissues, and the problem of poor initial stability is caused by the too small neck collar.

Disclosure of Invention

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems: the size of the neck collar is related to the size of the handle body, so that the stability of the implanted femoral stem prosthesis can be improved, the stimulation to peripheral soft tissues is reduced, and the stress of the neck collar of the femoral stem prosthesis on the femur osteotomy surface is optimized.

The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, the invention proposes a femoral stem prosthesis. The femoral stem prosthesis has the advantages of good initial stability and less stimulation to surrounding soft tissues, and also has the advantage of optimizing the stress of the neck collar of the femoral stem prosthesis on the femur osteotomy face.

The femoral stem prosthesis of the present invention comprises a stem body, a femoral neck and a neck collar.

The stem having a stem shaft and a desired osteotomy face at a proximal end of the stem (the proximal end of the stem having a desired osteotomy face thereon for mating with the femoral neck) to which the femoral neck is attached; the neck collar is arranged on the edge of the femur neck near the proximal end of the handle body, the neck collar extends towards the direction near the inner side along the inner and outer directions of the human body, the length of the neck collar (specifically, the proximal end of the handle body is provided with an expected bone cutting surface, the neck collar exceeds the length of the handle body along the extending direction of the expected bone cutting surface) is A, the distance between the innermost end point of the expected bone cutting surface and the shaft of the handle body is MX, A and MX are in linear positive correlation, A=KMX+/-b, K is 0.2-0.3, and b is 0.1-0.5. As the dimensions of the shank will change the corresponding dimensions of the implant shank.

Alternatively, a=0.27 MX-0.5.

Optionally, the length A of the neck collar is 5mm-7.5mm.

Optionally, the handle body has a median plane extending along the inside and outside of the human body, the neck collar is symmetrically disposed on the edge of the femoral neck along the median plane of the handle body, and the neck collar has a width greater than that of the femoral neck in the anterior-posterior direction of the human body.

Optionally, the femur neck is close to the bone neck cambered surface of human inboard one side of evagination, the neck includes indent cambered surface and epi, indent cambered surface enclose on the bone neck cambered surface, epi with indent cambered surface intersects in order to form the neck periphery profile.

Optionally, in the internal and external directions of the human body, along the extending direction of the expected osteotomy face, the superposition length of the concave cambered surface and the femoral neck is B, the length of the innermost side of the expected osteotomy face from the outermost side of the expected osteotomy face is C, and B and C are in positive correlation.

Alternatively, the ratio of B/C is 0.25-0.35.

Optionally, the extension surface is an arc surface protruding towards the inner side of the human body.

Optionally, the extension surface is connected with two sides of the femoral neck along the anterior-posterior direction of the human body so as to form a first connecting point and a second connecting point, and an included angle between tangents of the extension surface at the first connecting point and the second connecting point is D, and D is 5-25 degrees.

Optionally, the cross-sectional size of the stem decreases from proximal to distal to the femur.

Optionally, the femoral stem prosthesis is a titanium alloy prosthesis.

The femoral stem prosthesis has the technical effects that: the femoral stem prosthesis of the present invention is formed by establishing a linear relationship between the length a of the neck collar and the distance MX between the innermost end of the intended osteotomy face and the stem axis, and defining a as a linear positive correlation with MX, a = kmx±b, where K is 0.2-0.3 and b is 0.1-0.5. Thereby meeting the suitability between the neck collar and the femur in the femoral stem prosthesis, and further meeting the requirement that different patients adapt to neck collars of different sizes so as to improve the recovery and use effects of the patients after the prosthesis is implanted. The problem that the neck collar protrudes out of the femoral distance to be overhanging after the femoral stem prosthesis is implanted when the neck collar is oversized is avoided, the problem that peripheral soft tissues are stimulated in the long-term use process is avoided, and the problem that the neck collar cannot well cover the osteotomy face due to the fact that the neck collar is too small is avoided, so that the neck collar cannot well exert the function of increasing initial stability is avoided.

In addition, after the handle body is implanted into a human body, if excessive stress is transmitted to the far end of the femur through the handle body, stress shielding can be caused to the near end of the femur, so that the near-end femur can generate symptoms such as bone resorption, osteoporosis and the like, the neck collar of the collar femoral handle is contacted with the near-end osteotomy surface, partial stress can be applied to the near end of the femur through the neck collar, and the transmission of force is optimized. However, if the contact area between the neck and the osteotomy surface is too small, the neck may be overstressed, resulting in bone damage to the osteotomy surface in contact with the neck. The femur stem prosthesis of the invention can well cover the osteotomy surface of the neck collar under different specifications by establishing the association between A and MX, thereby adjusting the stress between the neck collar and the osteotomy surface. Thereby, the position and magnitude of the femoral stem prosthesis to the femoral conducted forces is optimized.

The femoral stem prosthesis has the advantages of good initial stability and less stimulation to surrounding soft tissues, and in addition, the stress of the neck collar of the femoral stem prosthesis on the femur osteotomy surface is optimized.

Further, a=0.27 MX-0.5. This allows the neck collar to better cover the medial osteotomy (femoral distance) and maximize load transfer to the region near the lesser trochanter. Further improving the effect of femoral stem prosthesis implantation.

Further, by setting the length A of the neck collar to 5mm-7.5mm. Therefore, the method has the advantage of good applicability.

Further, by providing the shank with a median surface extending along the inside and outside of the human body, the neck collar is symmetrically disposed on the edge of the femoral neck along the median surface of the shank, and the neck collar has a width greater than that of the femoral neck in the front-rear direction of the human body. Therefore, the stress of the femoral stem prosthesis on the osteotomy face of the femur is further optimized, and the stability of the femoral stem prosthesis after implantation is further improved.

Further, by limiting the relationship between the coincidence length B of the concave cambered surface and the femur neck and the length C of the innermost side of the expected osteotomy surface from the outermost side of the expected osteotomy surface, the influence of the neck collar on the mobility of the hip joint system is reduced as much as possible, the contact and coverage of the neck collar on the femur distance on the inner side of the femur can be ensured, and the conduction of force is optimized.

Further, by setting the ratio of B/C to 0.25-0.35, the contact and coverage of the neck collar to the femoral distance inside the femur is further improved, and the stress range between the femoral stem prosthesis and the osteotomy surface of the femur is optimized.

Further, by defining the extension surface to be connected to both sides of the femoral neck in the anterior-posterior direction of the human body so as to form a first connection point and a second connection point, the angle between tangents of the extension surface at the first connection point and the second connection point is D, and D is 5-25 °, so that coverage of the medial femoral distance of the neck collar can be increased as much as possible, while also reducing occurrence of overhang, and improving the degree of fit between the femoral stem prosthesis and the femur.

Drawings

Fig. 1 is a schematic view of the structure of a femoral stem prosthesis according to an embodiment of the present invention.

Fig. 2 is a sectional view taken along the line E-E in fig. 1.

Fig. 3 is a left side view of a femoral stem prosthesis according to an embodiment of the present invention.

Fig. 4 is a table showing the comparison of different neck lengths and different specifications of the handle body according to the present invention.

Fig. 5 is a correspondence between different gauges and neck collar lengths a.

Fig. 6 is another correspondence between different gauges and neck collar length a.

Fig. 7 is neck length corresponding to the 2#, 6# and 11# handles for the experimental and control groups.

Fig. 8 is a graph of the effect of coverage of the neck and femur osteotomies corresponding to the handle 2 for the experimental and control groups.

Fig. 9 is a table comparing the maximum stress experienced after assembly of the # 2 stem with the femur for the experimental and control groups.

Fig. 10 is a graph of stress contrast profiles experienced after assembly of the # 2 stem with the femur for the experimental and control groups.

Fig. 11 is a graph showing the effect of covering the neck and the femur osteotomy surface corresponding to the 6# stem for the experimental group and the control group.

Fig. 12 is a table comparing the maximum stress experienced after assembly of the 6# stem with the femur for the experimental and control groups.

Fig. 13 is a graph of stress contrast profiles experienced after assembly of the 6# stem with the femur for the experimental and control groups.

Fig. 14 is a graph showing the effect of covering the neck and the femur osteotomy surface corresponding to the 11# stem for the experimental group and the control group.

Fig. 15 is a table comparing the maximum stress experienced after assembly of the 11# stem with the femur for the experimental and control groups.

Fig. 16 is a graph of stress contrast profiles experienced after assembly of the 11# stem with the femur for the experimental and control groups.

Reference numerals:

femoral stem prosthesis 100;

a handle body 1;

a femoral neck 2; a first connection point 21; a second connection point 22;

neck collar 3; a concave cambered surface 31; an epitaxial surface 32;

the shank shaft 200.

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.

Based on the basic anatomical posture, the human body can be provided with three typical mutually perpendicular axes, wherein the sagittal axis is a horizontal line in the front-back direction; the coronal (frontal) axis is a horizontal line in the left-right direction; the vertical axis is a vertical line perpendicular to the horizontal line in the vertical direction. The human body or the organ can be cut into different sections according to the axis, the sagittal plane is a vertical section along the sagittal axis direction, and the sagittal plane is a longitudinal section dividing the human body into a left part and a right part; the coronal plane is a vertical section along the coronal axis direction, which is a longitudinal section dividing the human body into a front part and a rear part; the horizontal plane or cross section is a horizontal cross section made along a horizontal line, which divides the human body into an upper part and a lower part, and is perpendicular to the two longitudinal sections.

The femoral distance (calcar femoral) is a compact bone plate located in the medial-posterior aspect of the lesser trochanter deep femoral neck, body connection, and is the extension of the posterior medial cortex of the femoral body into the cancellous bone. Small rotor: located posteriorly and posteriorly in the proximal femur is the bone bulge at the medial end of the intertrochanteric crest continuing from the greater trochanter.

A femoral stem prosthesis 100 according to an embodiment of the present invention is described below with reference to fig. 1-16.

The femoral stem prosthesis 100 of the embodiment of the present invention includes a stem body 1, a femoral neck 2, and a neck collar 3.

The handle body 1 has a handle body axis 200 and an intended osteotomy face at a proximal end of the handle body, the femoral neck 2 is attached to the intended osteotomy face of the handle body 1, the neck collar 3 is provided on an edge of the femoral neck 2 near the proximal end of the handle body 1, the neck collar 3 extends in an inward-outward direction toward an inward direction of a human body, a length of the neck collar 3 (specifically, a length of the neck collar 3 beyond the handle body 1 in an extending direction of the intended osteotomy face) is a, a distance between an innermost end point of the intended osteotomy face and the handle body axis (a midline between the inside and outside of the handle body) 200 is MX, a is linearly positively correlated with MX, a=kmx±b, wherein the adjustment coefficient K is 0.2 to 0.3, and b is 0.1 to 0.5. As the shape and size of the femur will affect the corresponding size of the implant stem 1.

The femoral stem prosthesis 100 of the present embodiment establishes a linear relationship between the length a of the neck collar 3 and the distance MX between the innermost end point of the intended osteotomy plane and the stem axis (midline between the inside and outside of the stem) 200 and defines a linear positive correlation with MX, a = kmx±b, where K is 0.2-0.3 and b is 0.1-0.5. Thereby satisfying the suitability between the neck collar 3 and the femur in the femoral stem prosthesis 100, and further satisfying the suitability of different patients to the neck collar 3 of different sizes, so as to promote the recovery and use effect of the patients after the implantation of the prosthesis. The problem that the neck collar 3 protrudes out of the femoral distance to be overhanging after the femoral stem prosthesis 100 is implanted when the neck collar 3 is oversized is avoided, the problem that the peripheral soft tissues are stimulated in the long-term use process is avoided, and the problem that the neck collar 3 cannot well cover the osteotomy face due to the fact that the neck collar 3 is too small is avoided, so that the neck collar 3 cannot well exert the function of increasing the initial stability.

In addition, after the handle body is implanted into a human body, if excessive stress is transmitted to the far end of the femur through the handle body, stress shielding can be caused to the near end of the femur, so that the near-end femur can generate symptoms such as bone resorption, osteoporosis and the like, the neck collar of the collar femoral handle is contacted with the near-end osteotomy surface, partial stress can be applied to the near end of the femur through the neck collar, and the transmission of force is optimized. However, if the contact area between the neck and the osteotomy face is too small, the neck may be overstressed, resulting in bone damage to the osteotomy face in contact with the neck. The femoral stem prosthesis provided by the embodiment of the invention can well cover the osteotomy face of the neck collar under different specifications by establishing the association between A and MX, so that the stress between the neck collar and the osteotomy face is adjusted. Thereby, the position and magnitude of the femoral stem prosthesis to the femoral conducted forces is optimized. See fig. 8-16 for specific effects.

The femoral stem prosthesis 100 of the embodiment of the present invention has the advantages of good initial stability and less irritation to surrounding soft tissues, and in addition, has the advantage of optimizing the stress caused by the neck collar of the femoral stem prosthesis on the osteotomy surface of the femur.

Specifically, the dimensions of the shank 1 are matched according to the distance MX between the innermost end of the intended osteotomy plane and the shank axis.

Alternatively, a=0.27 MX-0.5. This allows the neck collar 3 to better cover the medial osteotomy plane (femoral distance) and to transfer the load to the region near the lesser trochanter to the greatest extent. Further enhancing the effect of implantation of the femoral stem prosthesis 100.

Further, the length A of the neck collar 3 is 5mm-7.5mm. Therefore, the method has the advantage of good applicability.

As shown in fig. 1 to 3, the shank 1 has a median surface extending along the inside and outside of the human body, and the neck collar 3 is symmetrically disposed on the edge of the femoral neck 2 along the median surface of the shank 1, and the width of the neck collar 3 is greater than the width of the femoral neck 2 in the anterior-posterior direction of the human body.

According to the femoral stem prosthesis 100 provided by the embodiment of the invention, the contact area between the neck collar 3 and the femur can be increased by the fact that the width of the neck collar 3 is larger than that of the femur neck 2. Thus, the stress generated by the femoral stem prosthesis 100 on the osteotomy face of the femur is further optimized, and the stability of the femoral stem prosthesis 100 after implantation is further improved.

As shown in fig. 1 to 3, the femoral neck 2 is provided with an outer convex bone neck cambered surface on one side close to the inner side of a human body, the neck collar 3 comprises an inner concave cambered surface 31 and an outer extending surface 32, the inner concave cambered surface 31 is enclosed on the bone neck cambered surface, and the outer extending surface 32 is intersected with the inner concave cambered surface 31 to form the peripheral outline of the neck collar 3.

The femoral stem prosthesis 100 of the embodiment of the invention is enclosed on the convex bone neck cambered surface of the femur neck 2 through the concave cambered surface 31 of the neck collar 3. Thus, the connection area of the two is improved. Therefore, the connecting device has the advantage of good connecting stability.

Alternatively, the neck collar 3 may be detachably provided on the femoral neck 2. The femoral stem prosthesis 100 of the present embodiment is not limited thereto and in some embodiments, the neck collar 3 may be integrally formed on the femoral neck 2.

In the medial-lateral direction of the human body, along the extending direction of the expected osteotomy face (e.g., the section of E-E in fig. 1), the overlapping length of the concave cambered surface and the femoral neck is B, the length of the innermost side of the expected osteotomy face from the outermost side of the expected osteotomy face is C, and B and C are positively correlated.

According to the femoral stem prosthesis 100 of the embodiment of the invention, by limiting the length B of the connection between the neck collar 3 and the stem body 1, the length C of the innermost side of the expected osteotomy surface from the outermost side of the expected osteotomy surface, the neck collar 3 is contacted with only the inner femoral distance of the femur as much as possible, so that the influence of the neck collar 3 on the mobility of the hip joint system is reduced as much as possible, the contact and coverage of the neck collar 3 to the inner femoral distance of the femur can be ensured, and the transmission of force is optimized.

Alternatively, the ratio of B/C is 0.25-0.35. Thereby, the contact and coverage of the neck collar 3 to the femoral distance inside the femur is further improved, optimizing the stress range between the femoral stem prosthesis 100 and the osteotomy face of the femur.

Further, B/C was 0.3. It can be ensured that the neck collar 3 is located only on the inner side of the stem body, further reducing the influence of the neck collar 3 on the mobility of the hip joint system, and further optimizing the stress matching degree between the femoral stem prosthesis 100 and the osteotomy face of the femur. The advantage of the neck collar 3 on the effect of the mobility of the hip joint system on optimizing the conduction effect of the force is further improved.

As shown in fig. 1 to 3, the extension surface 32 is an arc surface protruding toward the inside of the human body, and the extension surface 32 is connected to both sides of the femoral neck 2 in the front-rear direction of the human body so that the neck collar 3 has a crescent-shaped structure. The structure is of a round shape which is more in line with the shape of the osteotomy face of a human body, and can avoid the problem that the sharp part formed on the extension face 32 stimulates surrounding soft tissues. Thereby, the comfort of the patient after implantation of the femoral stem prosthesis 100 is further enhanced.

As shown in fig. 2, the extension surface 32 is connected to both sides of the femoral neck 2 in the anterior-posterior direction of the human body so as to form the first connection point 21 and the second connection point 22, and the angle D between the tangents of the extension surface 32 at the first connection point 21 and the second connection point 22 is 5-25 °. Therefore, the coverage of the neck collar 3 on the medial femoral distance can be increased as much as possible, while also reducing the occurrence of overhang, and improving the fit between the femoral stem prosthesis 100 and the femur.

Alternatively, D is 20 °. Thereby, the degree of fit with the femur is further improved.

As shown in fig. 1 to 3, the cross-sectional size of the stem 1 decreases from the proximal to distal direction near the femur.

Alternatively, the cross section of the columnar shank 1 may be an irregular polygon.

And (3) effect verification: the effect of the length of the neck collar on osteotomy face coverage and on the stress at the osteotomy face of the femur was verified.

1 purpose: by adopting the femoral stem prosthesis provided by the embodiment of the invention, neck collars with different sizes are designed for the stem bodies with the same specification, different rules are set for the neck collars along with the change of the specification, and the design of the neck collar size is verified by comparing the influence of the neck collar sizes on the coverage of the osteotomy face and the influence on the stress at the femoral osteotomy face.

2. Sample and sample selection principle

The specification range of the handle body is 1# -12# and three specifications of small size, middle size and large size are selected to represent in order to verify the change of the neck collar along with the specification. This time, handle 2#, handle 6# and handle 11# were selected as validation samples.

The neck collar sizes of the handle bodies of the experimental groups (three groups are respectively an experimental group 1, an experimental group 2 and an experimental group 3) are all in the scope of the patent protection, the neck collar length is set to be increased along with the specification, the 2# handle body is adopted by the experimental group 1 through calculation, and the length A of the corresponding neck collar is 5mm; the experimental group 2 adopts a 6# handle body, the length A of the corresponding neck collar is 6mm, the experimental group 3 adopts a 11# handle body, and the length A of the corresponding neck collar is 7mm.

The neck collar of the handle in control group 1 (three groups, control group 11, control group 12 and control group 13 respectively) was unchanged with the specification and was constant at 7mm.

The neck collar of the control group 2 (three groups are respectively a control group 21, a control group 22 and a control group 23) handle body is also set to be larger along with the specification, but the length of the neck collar is smaller as a whole, the control group 21 adopts a 2# handle body, the length A of the neck collar is 3mm, the control group 22 adopts a 6# handle body, the length A of the neck collar is 3.5mm, the control group 23 adopts an 11# handle body, and the length A of the neck collar is 5mm.

The neck collar of the control group 3 (three groups are control group 31, control group 32 and control group 33 respectively) is also set to be larger along with the specification, but the length of the neck collar is larger as a whole, the control group 31 adopts a 2# handle, the length A of the neck collar is 7.5mm, the control group 32 adopts a 6# handle, the length A of the neck collar is 8.5mm, the control group 33 adopts an 11# handle, and the length A of the neck collar is 9.5mm.

3. The experimental method comprises the following steps:

3.1 the 2# and 6# and 11# shanks were assembled with the appropriate sized femur on the basis of intramedullary canal size matching.

3.2 devices, tools, software: abaqus (2021, dassault, USA), finite element analysis.

3.3 Material Properties: the material properties are shown in the following table, and the handle body material is titanium alloy. Specifically, the Young's modulus of the shank (Ti 6Al 4V) is 110000MPa, and the Poisson's ratio is 0.3; the Young's modulus of cortical bone is 17000MPa, and the Poisson's ratio is 0.3; the Young's modulus of cancellous bone was 840MPa and the Poisson's ratio was 0.2.

3.4 grid cells

Cell type C3D10, stem and femoral mesh size 1mm.

3.5 contact arrangement

Binding cortical bone to cancellous bone; the handle body comprises a neck collar and a bone which are arranged to be rubbed.

3.6 boundary conditions and loads

The ball head position of the handle body is subjected to 2300N load vertically downwards; the distal end is fixed, constraining six degrees of freedom.

3.7 commit calculation

And submitting the calculation of a solver, and extracting stress near the neck of the bone model for comparison analysis.

4 experimental results

When the 2# stem and appropriately sized femur are assembled, the different neck sizes for coverage Kuang Canjian of the femoral resection surface is shown in fig. 8, and the stresses near the neck are shown in fig. 9 and 10.

When the 6# handle body and the femur with proper size are assembled, the coverage condition of different neck sizes on the femur osteotomy face is shown in fig. 11, and the stress near the neck is shown in fig. 12 and 13.

When the 11# handle body and the femur with proper size are assembled, the coverage condition of different neck sizes on the femur osteotomy face is shown in fig. 14, and the stress near the neck is shown in fig. 15 and 16.

5 analysis of results:

51 osteotomy face covering

By comparing osteotomy coverage of experimental and control groups:

the experimental group can be found to show good osteotomy coverage when the small-size (2#), medium-size (6#) and large-size (11#) handles are matched with the femur;

the control group 1 shows a certain overhang when being matched with the small-sized and medium-sized handles, and shows good performance when being matched with the large-sized handles with the femur;

control group 2 showed insufficient coverage when the small, medium and large shanks matched the femur;

the control group 3 showed some overhang when the small, medium and large shanks were matched to the femur.

52 neck vicinity stress by comparing neck vicinity stress conditions of the experimental group and the control group:

it was found that the stress near the neck collar was substantially the same as that of control 1 and control 3 when the small, medium and large shanks were matched to the femur. Because the coverage area of control 1 and control 3 was larger (both overhanging), the stress near the neck was slightly less when control 1 and control 3 matched the femur than the experimental.

The experimental group was found to have much less stress near the neck collar than the control group when the small, medium and large shanks were matched to the femur.

6. Conclusion:

from the analysis of the results, it can be seen that:

the controls 1-3 set the neck collar size to be constant, which will exhibit some overhang when matched to the small and medium-sized handles.

The control group 2 and the control group 3 are respectively provided with a neck collar with smaller and larger size, and when the neck collar size is set to be too small, the conditions of insufficient coverage area and increased stress of the neck collar can occur; when the neck collar is too large, the neck collar can be suspended and the soft tissues are stimulated.

The comparison shows that when the neck collar of the handle body is set to be of a regular size in the experimental group 1-3, not only can good osteotomy coverage be ensured, but also excellent stress near the neck collar can be ensured.

As shown in fig. 4 to 6, in the case where the neck length a is defined to be in the range of 5-7.5mm, the neck may be shared by several adjacent handle bodies of different sizes, i.e., the handle bodies are divided into several groups, the neck length a is the same in the same group, and the neck length a is different in different groups.

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 embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A femoral stem prosthesis comprising:

a handle having a handle shaft and an intended osteotomy face at a proximal end of the handle;

a femoral neck connected to the desired osteotomy face of the stem; and

the neck collar is arranged on the edge of the femur neck, which is close to the proximal end of the handle body, the neck collar extends towards the inner side along the inner and outer directions of a human body, the length of the neck collar is A, the distance between the innermost end point of the expected bone cutting surface and the axis of the handle body is MX, A and MX are in linear positive correlation, A=KMX+/-b, K is 0.2-0.3, and b is 0.1-0.5.

2. The femoral stem prosthesis of claim 1, wherein a = 0.27MX-0.5.

3. The femoral stem prosthesis of claim 1, wherein the neck collar has a length a of 5mm to 7.5mm.

4. The femoral stem prosthesis of claim 1, wherein the stem body has a median plane extending along the inside and outside of the human body, the neck collar being symmetrically disposed on the rim of the femoral neck along the median plane of the stem body, the neck collar having a width greater than the width of the femoral neck in the anterior-posterior direction of the human body.

5. The femoral stem prosthesis of claim 4, wherein the femoral neck has a convex femoral neck arcuate surface on a side thereof adjacent the medial side of the body, the neck comprising a concave arcuate surface circumscribing the femoral neck arcuate surface and an outer arcuate surface intersecting the concave arcuate surface to form the neck peripheral contour.

6. The femoral stem prosthesis of claim 5, wherein the length of the concave arc coincident with the femoral neck in the extension of the intended osteotomy face in the medial-lateral direction of the human body is B, and the length of the innermost side of the intended osteotomy face from the outermost side of the intended osteotomy face is C, with B and C being in positive correlation.

7. The femoral stem prosthesis of claim 6, wherein the ratio of B/C is 0.25-0.35.

8. The femoral stem prosthesis of claim 5, wherein the outer extension surface is an arcuate surface that projects toward the inside of the human body.

9. The femoral stem prosthesis of claim 8, wherein the extension surface is connected to both sides of the femoral neck in the anterior-posterior direction of the human body to form a first connection point and a second connection point, wherein the angle between tangents of the extension surface at the first connection point and the second connection point is D, and wherein D is 5-25 °.

10. The femoral stem prosthesis of any of claims 1 to 9, wherein the femoral stem prosthesis is a titanium alloy prosthesis.