Short femoral stem prosthesis for hip joint revision and replacement surgery

Abstract

The utility model relates to the technical field of artificial hip joint prostheses, in particular to a short femoral stem prosthesis for hip joint revision and replacement surgery. Comprising a femoral head cone (1), a femoral neck (2) and a stem body (3) which are sequentially connected. The femoral head cone (1) is used for installing a femoral head prosthesis, and the coronal plane of the femoral neck (2) is gradually increased in the direction from the femoral head cone (1) to the handle body (3); the stem body (3) is configured to be implanted into a femoral medullary cavity and used for replacing an originally implanted ineffective primary replacement femoral stem prosthesis, the stem body (3) comprises a near-end stem body (31) and a far-end stem body (32) which are sequentially connected, the near-end stem body (31) is composed of a porous structure (303) and a stem body base body (315) below the porous structure (303), and the near-end stem body (31) starts from an osteotomy line (307) and ends at a far-end terminating line (308) of the porous structure (303).

Description

Technical Field

[0001] The utility model relates to the technical field of artificial hip joint prostheses, in particular to a short femoral stem prosthesis used for hip joint revision and replacement surgery. Background Art

[0002] After necrosis of the hip joint, prosthesis replacement surgery can restore normal movement. Specifically, a femoral stem prosthesis is implanted into the femoral medullary cavity, and a ball head is placed at the femoral head cone of the femoral stem prosthesis. This ball head engages the acetabulum and rotates with it to restore normal joint movement. However, if the initial implanted hip prosthesis becomes ineffective due to various reasons, a revision surgery is required to replace it with a modified hip prosthesis.

[0003] Currently available revision femoral stem prostheses are typically extended, with a CT value of no less than 200 mm, intended to achieve distal fixation, thereby stabilizing and securing the revision femoral stem. Since revision surgery requires removal of the original failed femoral stem prosthesis, significant proximal trabecular bone loss occurs, reducing the likelihood of achieving proximal fixation. Prior art revision femoral stem prostheses are categorized into biocompatible and cemented types.

[0004] The existing technology has the following defects:

[0005] 1. Further bone loss during distal reaming and reaming, especially in young patients, is not sufficient for end-of-life use. Therefore, the first revision should not destroy too much bone.

[0006] 2. Over-reliance on distal fixation leads to proximal stress shielding and accelerated bone resorption;

[0007] 3. It is necessary to remove the distal bone and cement base of the medullary cavity, which is cumbersome and sometimes requires femoral

[0008] Distal fenestration treatment carries a high risk of intraoperative fracture.

[0009] Therefore, there is an urgent need for a short femoral stem prosthesis for hip revision replacement surgery and a manufacturing method thereof to solve the above problems. Utility Model Content

[0010] One purpose of the present invention is to provide a short femoral stem prosthesis for hip revision replacement surgery in order to address the above-mentioned deficiencies. The invention is a short-stem femoral stem prosthesis with a porous structure of high porosity at the proximal end that is conducive to bone ingrowth and a biologically fixed revision femoral stem prosthesis. The prerequisite for the biologically fixed femoral stem prosthesis to achieve the expected bone ingrowth and proximal fixation is that the proximal stem body (31) can be press-fitted with the proximal trabeculae after the primary replacement or revision prosthesis is removed. Under the premise of meeting the strength requirements, the matching degree between the prosthesis and the proximal trabeculae and the distal cortical bone is improved to achieve press-fit and reduce stress shielding.

[0011] To achieve the above objectives, the short femoral stem prosthesis for hip revision replacement surgery of the present invention adopts the following technical solutions:

[0012] A short femoral stem prosthesis for hip revision replacement surgery comprises a femoral head cone (1), a femoral neck (2), and a stem body (3) connected in sequence; the femoral head cone (1) is used to install the femoral head prosthesis, the coronal plane of the femoral neck (2) is a plane formed by the femoral neck axis (101) of the femoral head cone (1) and the femoral neck (2) and the stem body axis (310), and the coronal plane of the femoral neck (2) gradually increases in the direction from the femoral head cone (1) to the stem body (3);

[0013] The handle (3) is configured to be implanted in the femoral medullary cavity to replace the originally implanted failed primary replacement femoral stem prosthesis, and the handle (3) comprises a proximal handle (31) and a distal handle (32) connected in sequence, wherein the proximal handle (31) is composed of a porous structure (303) and a handle base (315) thereunder, and the proximal handle (31) starts at an osteotomy line (307) and ends at a porous structure cut-off line (308) at the distal end of the porous structure (303); the handle (3) is composed of the proximal handle (31) and the distal handle (32). The stem body (31) gradually decreases to the distal stem body (33) to adapt to the shape of the proximal femoral medullary wall; the CT of the femoral stem prosthesis is the maximum distance from the center point (102) of the femoral head installed on the femoral head cone (1) to the most distal arc (309) of the distal stem body (32), the CT of the femoral stem prosthesis is 115 to 145 mm, and the length L of the stem body (3) is 93 to 135 mm. CT and L increase as the specifications of the femoral stem prosthesis increase, and it is a short stem among the existing femoral stem prosthesis design types;

[0014] The outer wall of the proximal handle (31) is embedded with a porous structure (303), and the porous structure (303) is configured to contact the trabeculae of the femur. The porous structure (303) covers the proximal handle (31), and the length H of the porous structure (303) is 1 / 3-1 / 2 of the length L of the handle (3), which is conducive to the ingrowth of the trabeculae.

[0015] The femoral head cone (1), the femoral neck (2), the handle (3) and the porous structure (303) are integrally formed.

[0016] The sagittal plane of the distal stem body (32) of the stem body (3) includes an angle α between the front and back sides of 1° to 3°, and gradually becomes thicker from the distal end to the proximal end, while the angle β between the front and back sides of the proximal stem body (31) is 3° to 5°, and the β of the femoral stem prosthesis of the same specification is greater than α by at least 1°.

[0017] The distal end of the distal handle body (32) is provided with a distal arc (309), and the distal arc (309) is tangentially connected to the front and rear sides through the front and rear arcs (311), so as to avoid stress concentration on the front and rear sides of the distal handle body (32) and the femoral cortical bone that may be in contact with it.

[0018] The angle θ between the outer and inner sides of the proximal handle body (31) of the coronal plane of the handle body (3) is 5° to 6°, and the outer side extends to the porous structure (303) area of the proximal handle body (31). In order to retain the trabecular bone volume of the proximal femur, the proximal handle body (31) is shouldered, and the proximal outer shoulder surface (304) has an angle γ of 12° to 15°. The inner side of the proximal handle body (31) is the femoral arc (306), whose radius is 110 mm to 125 mm, and extends to the inner side of the distal handle body (32) and is tangent to the inner side of the distal handle body.

[0019] The distal end of the distal handle (32) is the distal arc (309), which is tangent to the inner side and is tangently connected to the outer side through the distal outer arc (305) to avoid stress concentration on the femoral cortical bone with which the outer distal handle contacts.

[0020] In the short femoral stem prosthesis for hip joint revision replacement surgery, the angle ε between the porous structure cutoff line (308) of the proximal stem body (31) and the stem body axis (310) is 45° to 90°.

[0021] In the short femoral stem prosthesis for hip joint revision and replacement surgery, the radius of the inner arc (312) of the cross section AA and the cross section BB of the stem body (3) gradually decreases from the proximal end to the distal end.

[0022] The short femoral stem prosthesis for hip revision replacement surgery has a cross-section of the distal stem body (32) that is formed by the cross-section line of the anterior and posterior side surfaces (313) tangent to the inner arc (312), the cross-section line of the distal outer anterior and posterior inclined surface (302), and the cross-section line of the distal outer side surface (314), wherein the distal outer anterior and posterior inclined surface (302) extends to the proximal stem body (31).

[0023] The cross section of the proximal handle body (31) is formed by the cross-sectional lines of the front and rear side surfaces (313) tangent to the circular arc (312), the cross-sectional lines of the proximal outer front and rear inclined surfaces (301), and the cross-sectional lines of the proximal outer shoulder surface (304); the proximal handle body (31) is formed by the curved surface formed by the inner circular arc (312) and the handle body base (315) and the porous structure (303) formed by the straight surface formed by the front and rear side surfaces (313), the proximal outer front and rear inclined surfaces (301), the proximal outer shoulder surface (304), part of the distal outer side surface (314) and part of the distal outer front and rear inclined surfaces (302).

[0024] The short femoral stem prosthesis used for hip revision replacement surgery has a proximal stem body (31) with an increased lateral anterior-posterior slope (301) and a portion of the distal lateral anterior-posterior slope (302) and a porous structure (303) compared to the traditional circular or rectangular designs, which increases the contact area with the proximal femoral trabeculae, resulting in increased stability after bone ingrowth and increased torsional resistance. The proximal thickness A of the cross section CC of the proximal stem body (31) is greater than the distal thickness B, and the proximal stem body (31) gradually increases from the proximal end to the distal end in order to increase the compressive stress after implantation and promote bone ingrowth.

[0025] The short femoral stem prosthesis for hip joint revision replacement surgery has a porous structure (303) that is an irregular three-dimensional grid structure, and a thickness of the porous structure (303) is 0.7 to 3 mm.

[0026] The short femoral stem prosthesis for hip joint revision replacement surgery has a distal stem body (32) with a rough surface having a surface roughness of Ra2-20 by adjusting the additive manufacturing process parameters, thereby increasing the roughness of the stem body and preventing the prosthesis from sinking in the long term.

[0027] The short femoral stem prosthesis used for hip joint revision replacement surgery is made of titanium alloy material.

[0028] The method for manufacturing a short femoral stem prosthesis for revision hip replacement surgery comprises the following steps:

[0029] S1. Designing the size and shape of the short femoral stem prosthesis for hip revision replacement surgery and establishing a mechanical model;

[0030] S2. Finding stress concentration locations and dangerous sections of the mechanical model, and optimizing the stress concentration locations and dangerous sections;

[0031] The fatigue strength of the dangerous section and neck of the distal end of the femoral stem was investigated under the action of concentrated load. The stress condition can be simplified into an eccentric compression model. By simplifying the force system, the eccentric compression model can be simplified into a compression-bending combined deformation, where

[0032] in, When investigating the fatigue strength of the dangerous section at the distal end of the femoral stem, the concentrated force of the test load is used. , when investigating the fatigue strength of the femoral neck, ; is the area of the dangerous section; is the horizontal distance from the danger point to the loading point; is the bending section coefficient of the dangerous section, which is related to the shape and cross-section of the section; The allowable fatigue strength of the femoral stem manufacturing material.

[0033] S3, processing and forming the short femoral stem prosthesis blank for hip joint revision replacement surgery;

[0034] Titanium alloy powder is used as raw material, of which aluminum Al accounts for 5.5%-6.75%, vanadium V accounts for 3.5%-4.5%, and the rest is titanium Ti (weight percentage). Laser additive manufacturing technology is used to form femoral stem prosthesis blanks. The head cone and neck of the femoral stem prosthesis blank are left with processing allowances. Dry ice is used to remove the residual powder in the porous structure of the proximal end of the femoral stem prosthesis blank. The blank is then placed in a vacuum sintering equipment for vacuum sintering. The vacuum sintering temperature is 750-850°C and the vacuum degree is 10 -2 Pa, the vacuum sintering time is 30-60 minutes, and the femoral stem prosthesis blank is sintered.

[0035] S4. The short femoral stem prosthesis blank for hip joint revision and replacement surgery is subjected to precision machining after forming, and the head cone and other parts are machined. Then, the neck is polished, the product is cleaned, and it is packaged and sterilized to produce a finished short femoral stem prosthesis for hip joint revision and replacement surgery.

[0036] The method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery is characterized in that:

[0037] In step S1 , the shape and size of the proximal handle can be changed according to preoperative planning.

[0038] In the method for manufacturing a short femoral stem prosthesis for hip revision and replacement surgery, in step S3, the short femoral stem prosthesis for hip revision and replacement surgery is integrally printed using additive manufacturing equipment (3D printer).

[0039] The handle (3) is generally multi-conical, and compared with the existing cylindrical, conical or bi-conical designs, it increases the possibility of producing a press fit with the trabeculae after proximal bone loss after revision.

[0040] The cross section of the distal handle (32) is polygonal, which increases the contact area of trabeculae, the possibility of bone ingrowth and the anti-rotation performance of the implant compared to existing circular and rectangular designs.

[0041] The femoral head cone (1), the femoral neck (2), the handle (3), the reinforcement structure, the support structure, and the porous structure (303) are integrally formed. The porous structure is an irregular three-dimensional grid-like structure.

[0042] The short femoral stem prosthesis for hip revision replacement surgery is manufactured using additive manufacturing. The digitalization and flexibility of its product manufacturing can achieve full matching with the postoperative trabeculae through preoperative planning and adjustment of the design of the proximal stem body (31) to achieve proximal fixation.

[0043] The beneficial effects of the short femoral stem prosthesis used in hip joint revision replacement surgery of the utility model are as follows:

[0044] 1. Bone preservation: The short femoral stem prosthesis of this utility model for hip revision surgery only requires reaming the proximal end of the femoral medullary cavity, which can maximize bone preservation. In the past, the commonly used revision extended femoral stem would further lose bone during the distal medullary expansion and reaming process, resulting in iatrogenic bone destruction.

[0045] 2. Reduce proximal femoral stress shielding and promote proximal bone remodeling. The short femoral stem prosthesis of this invention, used in hip revision surgery, is completely press-fitted proximally, subjecting the proximal femur to compressive stress. With the dual assistance of the 3D-printed trabecular structure and HA coating, it induces bone ingrowth and stimulates bone remodeling. This avoids the proximal femoral stress shielding and proximal bone resorption caused by the over-reliance on distal fixation in previous revision long-stems.

[0046] 3. Reduce thigh pain. The short femoral stem prosthesis of this utility model for hip revision replacement surgery concentrates stress on the proximal femur, completely avoiding irritation to the distal femur and reducing the risk of thigh pain in patients;

[0047] 4. Reduce the risk of distal isthmus fractures. This short femoral stem prosthesis for revision hip replacement surgery does not require grinding and filing of the distal femur. In patients with osteoporosis, obstruction of the femoral isthmus, and abnormal anterior femoral arch, distal fixation revision surgery with a long stem often results in drill bit penetration and isthmus fractures due to distal femoral medullary expansion. This short femoral stem prosthesis for revision hip replacement surgery can completely avoid these problems.

[0048] 5. The operation is simple and is exactly the same as the first hip stem replacement, with almost no learning curve. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a coronal view of a femoral stem prosthesis provided by a specific embodiment of the short femoral stem prosthesis of the present invention for hip joint revision replacement surgery.

[0050] Figure 2 This is a sagittal view of a femoral stem prosthesis provided by a specific embodiment of the short femoral stem prosthesis of the present invention for hip joint revision replacement surgery.

[0051] Figure 3 yes Figure 1 AA cross-sectional view of the short femoral stem prosthesis of the present invention for hip revision replacement surgery.

[0052] Figure 4 yes Figure 1 BB cross-sectional view of the short femoral stem prosthesis of the present invention for hip revision replacement surgery.

[0053] Figure 5 yes Figure 1 A CC cross-sectional view of the short femoral stem prosthesis of the present invention for hip revision replacement surgery.

[0054] Figure 6 The utility model is a flowchart of a method for manufacturing a femoral stem prosthesis provided in accordance with a specific embodiment of the short femoral stem prosthesis for hip joint revision replacement surgery.

[0055] In the picture:

[0056] 1. Femoral head cone; 2. Femoral neck; 3. Stem;

[0057] 31. Proximal handle; 32. Distal handle;

[0058] 101. Femoral head cone axis or femoral neck axis; 102. Femoral head center;

[0059] 301. Proximal lateral anterior-posterior inclined surface; 302. Distal lateral anterior-posterior inclined surface; 303. Porous structure; 304. Proximal lateral shoulder surface; 305. Distal lateral arc; 306. Femoral calcar arc; 307. Osteotomy line; 308. Cut-off line of porous structure; 309. Distalmost arc; 310. Handle body axis; 311. Anterior and posterior arcs; 312. Medial arc; 313. Anterior and posterior side surfaces; 314. Distal lateral side cross-section line; 315. Handle body base. DETAILED DESCRIPTION

[0060] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0061] In the description of this utility model, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0062] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0063] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0064] Refer to the attached Figure 1-6 A short femoral stem prosthesis for hip revision replacement surgery comprises a femoral head cone (1), a femoral neck (2) and a stem body (3) connected in sequence; the femoral head cone (1) is used to install the femoral head prosthesis, the coronal plane of the femoral neck (2) is a plane formed by the axis (101) of the femoral head cone (1) and the femoral neck (2) and the axis (310) of the stem body, and the coronal plane of the femoral neck (2) gradually increases in the direction from the femoral head cone (1) to the stem body (3);

[0065] The handle (3) is configured to be implanted in the femoral medullary cavity to replace the originally implanted failed primary replacement femoral stem prosthesis, and the handle (3) comprises a proximal handle (31) and a distal handle (32) connected in sequence, wherein the proximal handle (31) is composed of a porous structure (303) and a handle base (315) thereunder, and the proximal handle (31) starts at an osteotomy line (307) and ends at a porous structure cut-off line (308) at the distal end of the porous structure (303); the handle (3) is composed of the proximal handle (31) and the distal handle (32). The stem body (31) gradually decreases to the distal stem body (33) to adapt to the shape of the proximal femoral medullary wall; the CT of the femoral stem prosthesis is the maximum distance from the center point (102) of the femoral head installed on the femoral head cone (1) to the most distal arc (309) of the distal stem body (32), the CT of the femoral stem prosthesis is 115 to 145 mm, and the length L of the stem body (3) is 93 to 135 mm. CT and L increase as the specifications of the femoral stem prosthesis increase, and it is a short stem among the existing femoral stem prosthesis design types;

[0066] The outer wall of the proximal handle (31) is embedded with a porous structure (303), and the porous structure (303) is configured to contact the trabeculae of the femur. The porous structure (303) covers the proximal end (31), and the length of the porous structure (303) is 1 / 3-1 / 2 of the length H of the handle (3), which is conducive to the ingrowth of the trabeculae.

[0067] The femoral head cone (1), the femoral neck (2), the handle (3) and the porous structure (303) are integrally formed. The porous structure is an irregular three-dimensional grid structure.

[0068] The sagittal plane of the distal stem body (32) of the stem body (3) includes an angle α between the front and back sides of 1° to 3°, and gradually becomes thicker from the distal end to the proximal end, while the angle β between the front and back sides of the proximal stem body (31) is 3° to 5°, and the β of the femoral stem prosthesis of the same specification is greater than α by at least 1°.

[0069] The distal end of the distal handle body (32) is provided with a distal arc (309), and the distal arc (309) is tangentially connected to the front and rear sides through the front and rear arcs (311), so as to avoid stress concentration on the front and rear sides of the distal handle body (32) and the femoral cortical bone that may be in contact with it.

[0070] The angle θ between the outer and inner sides of the proximal handle body (31) of the coronal plane of the handle body (3) is 5° to 6°, and the outer side extends to the porous structure (303) area of the proximal handle body (31). In order to retain the trabecular bone volume of the proximal femur, the proximal handle body (31) is shouldered, and the proximal outer shoulder surface (304) has an angle γ of 12° to 15°. The inner side of the proximal handle body (31) is the femoral arc (306), whose radius is 110 mm to 125 mm, and extends to the inner side of the distal handle body (32) and is tangent to the inner side of the distal handle body.

[0071] The distal end of the distal handle (32) is the distal arc (309), which is tangent to the inner side and is tangently connected to the outer side through the distal outer arc (305) to avoid stress concentration on the femoral cortical bone with which the outer distal handle contacts.

[0072] In the short femoral stem prosthesis for hip joint revision replacement surgery, the angle ε between the porous structure cutoff line (308) of the proximal stem body (31) and the stem body axis (310) is 45° to 90°.

[0073] In the short femoral stem prosthesis for hip joint revision and replacement surgery, the radius of the inner arc (312) of the cross section AA and the cross section BB of the stem body (3) gradually decreases from the proximal end to the distal end.

[0074] The short femoral stem prosthesis for hip revision replacement surgery has a cross-section of the distal stem body (32) that is formed by the cross-section line of the anterior and posterior side surfaces (313) tangent to the inner arc (312), the cross-section line of the distal outer anterior and posterior inclined surface (302), and the cross-section line of the distal outer side surface (314), wherein the distal outer anterior and posterior inclined surface (302) extends to the proximal stem body (31).

[0075] The cross section of the proximal handle body (31) is formed by the front and rear side section lines (313) tangent to the circular arc (312), the section lines of the proximal outer front and rear inclined surfaces (301) and the section lines of the proximal outer shoulder surface (304); the proximal handle body (31) is formed by the curved surface formed by the inner circular arc (312) and the handle body base (315) and the porous structure (303) formed by the straight surface formed by the front and rear side surfaces (313), the proximal outer front and rear inclined surfaces (301), the proximal outer shoulder surface (304), part of the distal outer side surface (314) and part of the distal outer front and rear inclined surfaces (302).

[0076] The short femoral stem prosthesis used for hip revision replacement surgery has a proximal stem body (31) with an increased lateral anterior-posterior slope (301) and a portion of the distal lateral anterior-posterior slope (302) and a porous structure (303) compared to the traditional circular or rectangular designs, which increases the contact area with the proximal femoral trabeculae, resulting in increased stability after bone ingrowth and increased torsional resistance. The proximal thickness A of the cross section CC of the proximal stem body (31) is greater than the distal thickness B, and the proximal stem body (31) gradually increases from the proximal end to the distal end in order to increase the compressive stress after implantation and promote bone ingrowth.

[0077] The short femoral stem prosthesis for hip joint revision replacement surgery has a porous structure (303) that is an irregular three-dimensional grid structure, and a thickness of the porous structure (303) is 0.7 to 3 mm.

[0078] The short femoral stem prosthesis for hip joint revision replacement surgery has a distal stem body (32) with a rough surface having a surface roughness of Ra2-20 by adjusting the additive manufacturing process parameters, thereby increasing the roughness of the stem body and preventing the prosthesis from sinking in the long term.

[0079] The short femoral stem prosthesis used for hip joint revision replacement surgery is made of titanium alloy material.

[0080] A method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery is characterized in that the method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery comprises the following steps:

[0081] S1. Designing the size and shape of the short femoral stem prosthesis for hip revision replacement surgery and establishing a mechanical model;

[0082] S2. Finding stress concentration locations and dangerous sections of the mechanical model, and optimizing the stress concentration locations and dangerous sections;

[0083] The fatigue strength of the dangerous section and neck of the distal end of the femoral stem is investigated under the action of concentrated load. The stress condition can be simplified into an eccentric compression model. By simplifying the force system, the eccentric compression model can be simplified into a compression-bending combined deformation, where

[0084]

[0085] in, When investigating the fatigue strength of the dangerous section at the distal end of the femoral stem, the concentrated force of the test load is used. , when investigating the fatigue strength of the femoral neck, ; is the area of the dangerous section; is the horizontal distance from the danger point to the loading point; is the bending section coefficient of the dangerous section, which is related to the shape and cross-section of the section; The allowable fatigue strength of the femoral stem manufacturing material.

[0086] S3, processing and forming the short femoral stem prosthesis blank for hip joint revision replacement surgery;

[0087] Titanium alloy powder is used as raw material, of which aluminum Al accounts for 5.5%-6.75%, vanadium V accounts for 3.5%-4.5%, and the rest is titanium Ti (weight percentage). Laser additive manufacturing technology is used to form femoral stem prosthesis blanks. The head cone and neck of the femoral stem prosthesis blank are left with processing allowances. Dry ice is used to remove residual powder in the porous structure of the proximal end of the femoral stem prosthesis blank. The blank is then placed in a vacuum sintering equipment for vacuum sintering. The vacuum sintering temperature is 800-850°C and the vacuum degree is 10 -2 Pa below, vacuum sintering time is 30-60 minutes (at vacuum degree 10 -2 Pa below and kept at 800-850°C for 30-60 minutes) to sinter the femoral stem prosthesis blank.

[0088] S4. The short femoral stem prosthesis blank for hip joint revision replacement surgery is subjected to precision machining, including lathing of the head cone and other parts, and then polishing the neck, cleaning the product, and packaging and sterilizing to manufacture a finished femoral stem prosthesis.

[0089] The method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery is characterized in that:

[0090] In step S2, the method for optimizing the stress concentration position and the dangerous section includes: changing the shape of the reinforcing structure; increasing the number and / or distribution, and / or position, and / or direction of the reinforcing structure; changing the closure or openness of the reinforcing structure and the cavity inside the handle; and increasing the radius of the connection between the reinforcing structure.

[0091] In the method for manufacturing a short femoral stem prosthesis for hip revision replacement surgery, in step S3, the femoral stem prosthesis is integrally printed using additive manufacturing equipment (3D printer). Example

[0092] like Figure 1As shown, this embodiment provides a short femoral stem prosthesis for hip joint revision replacement surgery, comprising a femoral head cone (1), a femoral neck (2) and a stem body (3) connected in sequence. The femoral head cone (1) is configured to connect a ball head, which can rotate with the ball head groove in the acetabulum to form a hip joint. The coronal surface of the femoral neck (2) gradually increases from the femoral head cone (1) to the stem body (3) to transition to the position of the stem body (3), and the outer wall of the femoral neck (2) is arc-shaped, which can achieve an arc transition connection and avoid stress concentration. The stem body 3 is configured to be implanted in the femoral medullary cavity, and the stem body (3) includes a proximal stem body (31) and a distal stem body (32) connected in sequence, and the coronal surface of the stem body (3) gradually decreases from the proximal stem body (31) to the distal stem body (32) to form a taper.

[0093] It should be noted that the above-mentioned coronal plane refers to the front-back section of the human body. The left-right section of the human body is called the sagittal plane.

[0094] In addition, by providing a porous structure (303) at the position where the proximal end of the stem body (31) contacts the trabeculae, on the one hand, the roughness of the surface of the femoral stem prosthesis can be increased, so that the static friction between the prosthesis and the trabeculae is increased, thereby preventing the prosthesis from sinking; on the other hand, the provision of the porous structure (303) is conducive to the growth of human bone tissue, so that the prosthesis and the bone tissue are well adapted; in addition, the porous structure (303) is integrally formed with the entire prosthesis, which can avoid the coating from falling off and improve the service life of the prosthesis compared to the existing sandblasting and spraying processes.

[0095] The changes in the prosthesis's elastic modulus and plasticity in this embodiment effectively reduce the effects of stress shielding, ensuring that bone tissue receives sufficient stress stimulation after implantation. Furthermore, the increased plasticity of the prosthesis creates a greater interference fit between the prosthesis and the femur, significantly increasing stress on the lateral surface of the femur and effectively reducing the risk of osteoporosis on the lateral surface of the femur.

[0096] The short femoral stem prosthesis used in this embodiment for revision hip replacement surgery is made of titanium alloy. Titanium alloy has the advantages of light weight, high strength, and high corrosion resistance, ensuring the high quality of the finished prosthesis. Specifically, the femoral stem prosthesis is printed using titanium alloy powder (Ti6Al4V powder) using additive manufacturing equipment.

[0097] As attached Figure 6 As shown, this embodiment also provides a method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery, which is used to manufacture the femoral stem prosthesis as described above. The method for manufacturing a short femoral stem prosthesis for hip joint revision replacement surgery includes the following steps:

[0098] S1. Design the size and shape of a short femoral stem prosthesis for hip revision replacement surgery and establish a simulation model;

[0099] S2. Find the stress concentration locations and dangerous sections of the simulation model and optimize them;

[0100] S3, processing and forming femoral stem prosthesis;

[0101] S4, performing surface treatment on the formed femoral stem prosthesis;

[0102] S5. Test to verify whether the femoral stem prosthesis meets the mechanical requirements.

[0103] In step S1, the patient's condition can be medically analyzed through CT, X-rays, etc., and a femoral stem prosthesis simulation model suitable for the patient can be established according to the specific condition.

[0104] In step S3, the femoral stem prosthesis is printed in one piece using additive manufacturing equipment. The one-piece molded femoral stem prosthesis has high strength and does not require welding, turning and other processes.

[0105] In step S4, the surface treatment of the femoral stem prosthesis includes but is not limited to removing surface burrs, improving surface quality, and further processing transition fillets.

[0106] In step S5, the state of the femoral stem prosthesis after implantation into the human body can be simulated, external force can be applied to the femoral stem prosthesis, and whether the prosthesis meets the mechanical requirements can be monitored.

[0107] The present embodiment provides a method for manufacturing a short femoral stem prosthesis for hip revision and replacement surgery. The method sets the size and shape of the short femoral stem prosthesis for hip revision and replacement surgery according to the individual conditions of the patient, and establishes a simulation model for analysis, thereby optimizing the stress concentration position and dangerous section of the prosthesis to ensure that the prosthesis has sufficient strength. After the prosthesis is surface treated, it is necessary to conduct tests to verify whether the molded prosthesis meets the mechanical requirements. The prosthesis can only be implanted in the human body after passing the test. Compared with the standardized femoral stem prosthesis in the prior art, this method can customize the prosthesis according to the differences and personalized needs of patients, so that the prosthesis is more compatible with the patient's bone tissue and speeds up the running-in speed between the patient and the prosthesis.

[0108] The utility model is used for hip joint revision replacement surgery short femoral stem prosthesis and its manufacturing method manufacturing femoral stem prosthesis product test table:

[0109] Molded product performance:

[0110]

[0111] Porous structure performance:

[0112]

[0113] Product pass test:

[0114]

[0115] GB / T recommended national standards

[0116] ASTM American Society for Testing and Materials

[0117] DIN EN ISO are German standards, British standards and international standards.

[0118] YY / T Pharmaceutical Industry Standard

[0119] From the analysis of the mechanical properties and fatigue strength test table of the femoral stem prosthesis product verified by the above test, the test verified that the mechanical technical parameters of the femoral stem prosthesis product meet the requirements of relevant national specifications, German standards, British standards, international standards, American Society for Testing and Materials, and pharmaceutical industry standards, and the fatigue strength meets the YY / T0809.4 and YY / T0809.6 pharmaceutical industry standards.

[0120] The utility model belongs to the technical field of artificial hip joint prostheses and discloses a short femoral stem prosthesis for hip revision and replacement surgery and a method for manufacturing the same. The short femoral stem prosthesis for hip revision and replacement surgery comprises a femoral head cone, a femoral neck, and a stem body connected in sequence. The stem body comprises a proximal end, a mid-section structure, and a distal end connected in sequence. The outer wall of the proximal end is embedded with a porous structure that contacts the trabeculae of the femur. The entire prosthesis is formed in one piece.

[0121] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A short femoral stem prosthesis for hip joint revision replacement surgery, characterized in that: The invention comprises a femoral head cone (1), a femoral neck (2) and a handle (3) connected in sequence; the femoral head cone (1) is used for mounting a femoral head prosthesis, the coronal plane of the femoral neck (2) is a plane formed by the femoral neck axis (101) of the femoral head cone (1) and the femoral neck (2) and the handle axis (310), and the coronal plane of the femoral neck (2) gradually increases in the direction from the femoral head cone (1) to the handle (3); The handle body (3) is configured to be implanted in the femoral medullary cavity to replace the originally implanted failed primary replacement femoral stem prosthesis, and the handle body (3) includes a proximal handle body (31) and a distal handle body (32) connected in sequence, wherein the proximal handle body (31) is composed of a porous structure (303) and a handle body base (315) thereunder, and the proximal handle body (31) starts at an osteotomy line (307) and ends at a porous structure cutoff line (308) at the distal end of the porous structure (303); the handle body (3) is composed of the proximal handle The diameter of the femoral stem prosthesis is gradually reduced from the femoral head center point (102) installed on the femoral head cone (1) to the distal stem body (32) to adapt to the shape of the proximal femoral medullary wall; the CT of the femoral stem prosthesis is the maximum distance from the femoral head center point (102) installed on the femoral head cone (1) to the most distal arc (309) of the distal stem body (32), the CT of the femoral stem prosthesis is 115 to 145 mm, and the length L of the stem body (3) is 93 to 135 mm. CT and L increase as the specifications of the femoral stem prosthesis increase, which is a short stem among the existing femoral stem prosthesis design types; The outer wall of the proximal handle (31) is embedded with a porous structure (303), and the porous structure (303) is configured to contact the trabeculae of the femur. The porous structure (303) covers the proximal handle (31), and the length H of the porous structure (303) is 1 / 3-1 / 2 of the length L of the handle (3), which is conducive to the ingrowth of the trabeculae. The femoral head cone (1), the femoral neck (2), the handle (3) and the porous structure (303) are integrally formed.

2. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The sagittal plane of the stem body (3) is a plane perpendicular to the coronal plane, and the angle α between the front and back sides of the distal stem body (32) of the sagittal plane of the stem body (3) is 1° to 3°, gradually becoming thicker from the distal end to the proximal end, and the angle β between the front and back sides of the proximal stem body (31) is 3° to 5°, and β of the femoral stem prosthesis of the same specification is greater than α by at least 1°.

3. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1 or 2, characterized in that: The distal end of the distal handle (32) is provided with a distal arc (309), and the distal arc (309) is tangentially connected to the front and rear sides through the front and rear arcs (311), so as to avoid stress concentration between the front and rear sides of the distal handle (32) and the femoral cortical bone that may be in contact with it.

4. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The angle θ between the outer and inner sides of the distal stem body (32) is 5° to 6°, and the outer side extends to the porous structure (303) area of the proximal stem body (31). In order to retain the trabecular bone volume of the proximal femur, the proximal stem body (31) is shouldered, and the proximal outer shoulder surface (304) has an angle γ of 12° to 15°. The inner side of the proximal stem body (31) is the femoral arc (306), whose radius is 95 mm to 125 mm, and extends to the inner side of the distal stem body (32) and is tangent to the inner side of the distal stem body.

5. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 4, characterized in that: The distal end of the distal handle (32) is the distal arc (309), which is tangent to the inner side and is tangently connected to the outer side through the distal outer arc (305) to avoid stress concentration on the femoral cortical bone with which the distal handle contacts.

6. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The angle ε between the porous structure cutoff line (308) of the proximal handle body (31) and the handle body axis (310) is 45° to 90°.

7. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The radius of the inner circular arc (312) of the cross-sections AA and BB of the handle body (3) gradually decreases from the proximal end to the distal end.

8. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The cross section of the distal handle body (32) is formed by the cross section lines of the front and rear side surfaces (313) tangent to the inner arc (312), the cross section lines of the distal outer front and rear inclined surfaces (302) and the cross section lines of the distal outer side surfaces (314), wherein the distal outer front and rear inclined surfaces (302) extend to the proximal handle body (31).

9. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 1, characterized in that: The cross section of the proximal handle body (31) is formed by the cross-sectional lines of the front and rear side surfaces (313) tangent to the circular arc (312), the cross-sectional lines of the proximal outer front and rear inclined surfaces (301), and the cross-sectional lines of the proximal outer shoulder surface (304); the proximal handle body (31) is formed by the curved surface formed by the inner circular arc (312) and the handle body base (315) and the porous structure (303) formed by the straight surface formed by the front and rear side surfaces (313), the proximal outer front and rear inclined surfaces (301), the proximal outer shoulder surface (304), part of the distal outer side surface (314) and part of the distal outer front and rear inclined surfaces (302).

10. The short femoral stem prosthesis for hip joint revision replacement surgery according to claim 8 or 9, characterized in that: Compared with the traditional circular and rectangular designs, the proximal stem body (31) increases the contact area between the outer front-back bevel (301) and part of the distal outer front-back bevel (302) and the porous structure (303) and the proximal femoral trabeculae, resulting in increased stability after bone ingrowth and increased torsional resistance. The proximal thickness A of the cross section CC of the proximal stem body (31) is greater than the distal thickness B, and the proximal stem body (31) gradually increases from the distal end to the proximal end in order to increase the compressive stress after implantation and promote bone ingrowth; The porous structure (303) is an irregular three-dimensional grid structure, and the thickness δ of the porous structure (303) is 0.7 to 3 mm.

Images