A modular femoral stem prosthesis

Abstract

The present invention provides a femoral stem prosthesis, comprising a first handle body vertically provided with a first through hole, and two pulleys are arranged inside the first through hole; the second handle body is a cylindrical body with a tapered bottom, and the second handle body is vertically provided with a second through hole, and the second through hole is provided with a thread, and the outer surface of the second handle body is provided with a spiral slide rail, the second handle body is fixed through the first through hole of the first handle body, and the slide rail is slidably connected to the above-mentioned two pulleys; the driving device comprises: a ratchet is a gear with multiple helical teeth evenly distributed, and the pawl is composed of a single helical tooth, which is swingably fixed on an elastic shaft, and the elastic shaft is fixedly arranged on the first handle body; a screw rod is fixedly connected to the ratchet, and a thread is arranged on the outer surface of the screw rod, and the thread is meshed with the thread in the second through hole. The technical solution of the present application effectively solves the technical problems of poor implantation stability and large bone removal of femoral stem prosthesis in the related art.

Description

Technical Field

[0001] The invention relates to the field of medical instruments, and in particular to a femoral stem prosthesis. Background Art

[0002] Hip replacement is a surgical procedure for severe hip damage or degenerative lesions (such as femoral head necrosis, hip arthritis, and acetabular dysplasia). In this operation, the damaged hip joint is replaced by an artificial joint to restore the patient's joint function and relieve pain. Since the birth of modern hip replacement surgery in the early 1960s, the technology has continued to mature and become the standard surgery for treating hip joint diseases in the field of orthopedics. The femoral stem prosthesis is a key component used to replace the femoral head and femoral neck in hip replacement surgery. Early prosthesis materials were mostly stainless steel or other metals. With the advancement of materials science, lightweight and high-strength materials such as titanium alloys and cobalt-chromium alloys have begun to be widely used. The original prosthesis design was relatively simple. With the progress of biomechanical research, the shape design of modern femoral stem prostheses is more in line with the anatomical structure, and a variety of surface treatment technologies (such as porous coatings and hydroxyapatite coatings) are used to promote the growth and integration of bone tissue and ensure the long-term stability of the prosthesis.

[0003] The design of femoral stem prosthesis must meet specific biomechanical requirements to ensure that it can withstand the stress and load during human movement. Modern prostheses are usually anatomically designed to ensure that they can mimic normal joint movement and reduce stress shielding, which can lead to bone loss in the proximal femur. In addition, the length, diameter, curvature and surface roughness of the prosthesis are personalized according to the patient's bone conditions to improve the fit and durability of the prosthesis. Its fixation method has undergone a transition from "cement fixation" to "cementless fixation". Early prostheses were mostly fixed in the femur by bone cement (bone glue), but with the development of cementless prosthesis technology, more and more prostheses use rough surfaces or coatings to promote bone ingrowth and achieve biological fixation. The advantage of this fixation method is that it is more durable and reduces the risk of cement aging or falling off.

[0004] With the development of 3D printing technology, customized design of femoral stem prosthesis has become possible. Doctors can use 3D modeling and printing technology to create personalized prostheses based on the patient's specific anatomical structure, which not only improves the matching degree between the prosthesis and the bone, but also reduces the operation time and improves the postoperative rehabilitation effect.

[0005] Although the application of femoral stem prosthesis in hip replacement has achieved remarkable success, most of the current femoral stem implants use intramedullary reamer to preset the femoral stem groove and then implant the femoral stem. This implantation method has poor fixation and requires a large amount of bone, which increases the burden on patients. Summary of the invention

[0006] The purpose of the present invention is to provide a modular femoral stem prosthesis to solve the technical problems of poor implant stability of the femoral stem prosthesis and large amount of bone required.

[0007] In order to solve the above problems, the present invention provides a modular femoral stem prosthesis, which specifically includes: a first handle body, a first through hole is vertically provided on the first handle body, and two pulleys are arranged inside the first through hole; a second handle body, which is a cylindrical body with a tapered bottom, a second through hole is vertically provided on the second handle body, and a thread is arranged inside the second through hole, and a spiral slide rail is arranged on the outer surface of the second handle body, and the second handle body is fixed through the first through hole of the first handle body, and the slide rail is slidably connected to the above-mentioned two pulleys; a driving device, the driving device includes: a ratchet, which is a gear with multiple helical teeth evenly distributed; a pawl, which is composed of a single helical tooth and is swingably fixed on an elastic shaft, and the elastic shaft is fixedly arranged on the first handle body; a screw rod, a spring is arranged between the pawl and the elastic shaft, the screw rod is fixedly connected to the ratchet, and a thread is arranged on the outer surface of the screw rod, and the thread is meshed with the thread in the second through hole.

[0008] Furthermore, the outer surface of the first handle body is provided with a blade groove and a plurality of anti-slip protrusions.

[0009] Furthermore, the plurality of anti-slip protrusions are trapezoidal bodies or rough surfaces composed of a plurality of spheres.

[0010] Furthermore, a positioning ball is arranged at the bottom of the first handle body.

[0011] Further, the pulley is made of ceramic material to provide higher wear resistance and stability.

[0012] Furthermore, the ratchet gear has a bevel angle of 10°-15° to optimize torque transmission and control accuracy.

[0013] Furthermore, the surfaces of the first handle body and the second handle body in contact with the autologous bone are provided with a double-layer coating, and the coating close to the prosthesis is a trabecular bone structure sprayed with titanium powder, and an HA coating is sprayed on the trabecular bone coating.

[0014] Furthermore, the thickness of the double-layer titanium powder spray coating is 10-50 microns, and the thickness of the HA coating is 5-15 microns. The thickness of the titanium powder spray coating: 10-50 microns can provide sufficient mechanical support while ensuring bone integration, making the prosthesis more firmly fixed in the body. The thickness of the HA coating: 5-15 microns is sufficient to promote rapid bone integration without affecting the overall structural strength of the prosthesis.

[0015] According to the technical solution of the present invention, a first through hole is vertically provided on the first handle body, and two pulleys are arranged inside the first through hole; the second handle body is a cylindrical body with a tapered bottom, and a second through hole is vertically provided on the second handle body, and a thread is arranged inside the second through hole, and a spiral slide rail is arranged on the outer surface of the second handle body, and the second handle body is fixed through the first through hole of the first handle body, and the slide rail is slidably connected to the two pulleys; the driving device includes: a ratchet is a gear with multiple helical teeth evenly distributed; a pawl, the pawl is composed of a single helical tooth and is swingably fixed on an elastic shaft, and the elastic shaft is fixedly arranged on the first handle body; a screw rod, the screw rod is fixedly connected to the ratchet, and a thread is arranged on the outer surface of the screw rod, and the thread is meshed with the thread in the second through hole. After the first handle is implanted, the second handle is inserted, and then the second handle is rotated. Under the pulley fixation of the first handle, it is slowly moved downward along the slide rail on the surface. In this process, bone debris will remain in the slide rail, which can better fit with the autologous bone. After reaching the fixed depth, the ratchet on the driving device is rotated to further fix the second handle. Under the action of the pawl, the ratchet can only rotate in one direction. In the final stage of fixation, the second handle can continue to move downward under the action of the screw rod until it is adjusted to the preset position to complete the implantation of the femoral stem prosthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 An assembly diagram of a modular femoral stem prosthesis is shown;

[0018] Figure 2 A front view of a modular femoral stem prosthesis is shown;

[0019] Figure 3 The right triaxial view of the modular femoral stem prosthesis is shown;

[0020] Figure 4 A cross-sectional view of a modular femoral stem prosthesis is shown;

[0021] Figure 5 shows a front view of the drive device;

[0022] Among them, the above-mentioned drawings include the following figure marks: 10, first handle body; 101, blade groove; 102, anti-slip protrusion; 103, positioning ball; 104, pulley; 20, second handle body; 201, slide rail; 30, driving device; 301, ratchet; 302, pawl; 303, elastic shaft; 304, screw rod. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0026] like Figure 1-4 As shown: A femoral stem prosthesis, comprising: a first stem body 10, the first stem body 10 is vertically provided with a first through hole, and two pulleys 104 are arranged inside the first through hole; a second stem body 20, the second stem body is a cylindrical body with a conical bottom, the second stem body 20 is vertically provided with a second through hole, and the second through hole is provided with a thread, and the outer surface of the second stem body is provided with a spiral slide rail 201, the second stem body 20 is fixed through the first through hole of the first stem body 10, and the slide rail 201 is slidably connected to the two pulleys 104; the outer surface of the first stem body 10 is provided with a blade groove 101 and a plurality of anti-skid protrusions 102. A positioning ball 103 is arranged at the bottom of the first stem body 10. Among them, the plurality of anti-skid protrusions are trapezoidal bodies or rough surfaces composed of a plurality of spheres. The main function is to prevent the first stem body from loosening after implantation, especially outward movement.

[0027] like Figure 5As shown, the driving device 30 includes: a ratchet 301 which is a gear with multiple helical teeth evenly distributed; a pawl 302, which is composed of a single helical tooth and is swingably fixed on an elastic shaft 303, and the elastic shaft 303 is fixedly set on the first handle body 10; a screw rod 304, which is fixedly connected to the ratchet 301, and the outer surface of the screw rod 304 is provided with a thread, which is meshed with the thread in the second through hole.

[0028] When in use, first, a first handle body groove corresponding to the first handle body is opened in the medullary cavity of the femur, and then the first handle body is implanted. Under the action of the blade groove 101, the first handle body is gradually embedded in the first handle body groove, and then fixed in the first handle body groove under the action of the anti-slip protrusion 102 to prevent it from withdrawing. Then, the second handle body 20 is inserted into the first handle body. Since there is a slide rail 201 on the surface of the second handle body and a pulley 104 is arranged inside the first handle body, the two are slidably connected. At this time, the second handle body is rotated, and the second handle body will move downward along the slide rail. At the same time, excess bone chips will remain in the slide rail, which can produce a better fusion effect with the autologous bone, until the ratchet 301 on the driving device 30 touches the pawl 302, and then the ratchet on the driving device is rotated. Under the action of the screw rod 304, the second handle body will continue to move downward until it reaches the preset position, and then the pawl 302 locks the ratchet 301 to prevent the second handle body 20 from rotating backward.

[0029] Through the above-mentioned arrangement, during the implantation of the second stem body, bone chips will remain in the slide rail and gradually cover the entire slide rail, which can be better integrated with the autologous bone and improve the stability of the femoral stem prosthesis. On the other hand, the length of the femoral stem can be shortened, because the role of the screw rod is equivalent to a certain contraction effect, which makes the volume of the femoral stem prosthesis smaller, and because the screw rod can extend the second stem body, it can have a good stress conduction effect. Compared with the traditional femoral stem, the femoral stem has less bone resection, better stability and lighter volume.

[0030] In order to further improve the stability and safety performance of the entire femoral stem prosthesis, the pulley is made of ceramic material to prevent metal debris from being left in the prosthesis due to friction between metals. On the one hand, metal debris will have a certain impact on the human body. On the other hand, if there is metal debris, it will further increase the resistance of the screw to rotate the second handle body to the human body. The ratchet gear angle is 10°-15° to optimize torque transmission and control accuracy. Finally, a coating is provided on the surface of the femoral stem prosthesis. HA coating is a ceramic calcium phosphate-based material with good biocompatibility and bone conduction ability. It is usually prepared on a metal substrate by plasma spraying technology, especially on medical materials such as titanium alloys, and has been widely used in clinical medicine. The bonding strength between the HA coating and the titanium alloy substrate is an important factor affecting its long-term application effect. In order to enhance the bonding strength, a study used vacuum plasma spraying technology to prepare tantalum (Ta)-doped HA coatings in order to improve the bonding strength while maintaining good biological properties. In addition, the application of HA coating in orthopedic implants is also very important, and its thickness and porosity need to be carefully adjusted to optimize the balance between biocompatibility and mechanical properties. The bone integration characteristics of HA coating indicate that it can promote the support and connection of bone to the prosthesis, thereby achieving long-term fixation and durability of the prosthesis. ‌HA coating has better biocompatibility, but its surface in contact with metal is easy to fall off. For this reason, the surface of the first handle body and the second handle body in contact with the autologous bone is provided with a double-layer coating. The coating close to the prosthesis is a trabecular structure sprayed with titanium powder, and the HA coating is sprayed on the trabecular coating. This structure improves the biocompatibility of the femoral stem prosthesis on the one hand, and reduces the risk of coating shedding on the other hand. The thickness of the titanium powder spray coating: 10-50 microns can provide sufficient mechanical support while ensuring bone integration, making the prosthesis more firmly fixed in the body. The thickness of the HA coating: 5-15 microns is sufficient to promote rapid bone integration without affecting the overall structural strength of the prosthesis.

[0031] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0032] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein are interpreted accordingly.

[0033] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A femoral stem prosthesis, characterized in that: include: A first handle body, wherein the first handle body is vertically provided with a first through hole, and two pulleys are arranged inside the first through hole; The second handle body is a cylindrical body with a conical bottom, the second handle body is vertically provided with a second through hole, the second through hole is provided with a thread, the outer surface of the second handle body is provided with a spiral slide rail, the second handle body is fixed through the first through hole of the first handle body, and the slide rail is slidably connected to the two pulleys; A driving device, the driving device comprising: A ratchet, wherein the ratchet is a gear having a plurality of evenly distributed helical teeth; A ratchet, the ratchet is composed of a single oblique tooth and is swingably fixed on an elastic shaft, the elastic shaft is fixedly arranged on the first handle body, and a spring is arranged between the ratchet and the elastic shaft; A screw rod is fixedly connected to the ratchet wheel, and a thread is arranged on the outer surface of the screw rod, and the thread is meshed with a thread in the second through hole.

2. The femoral stem prosthesis according to claim 1, characterized in that: The outer surface of the first handle is provided with a blade groove and a plurality of anti-slip protrusions.

3. The femoral stem prosthesis according to claim 2, characterized in that: The plurality of anti-slip protrusions are trapezoidal bodies or rough surfaces composed of a plurality of spheres.

4. The femoral stem prosthesis according to claim 1, characterized in that: A positioning ball is arranged at the bottom of the first handle.

5. The femoral stem prosthesis according to claim 1, characterized in that: The pulley is made of ceramic material.

6. The femoral stem prosthesis according to claim 1, characterized in that: The ratchet gear has a bevel angle of 10°-15°.

7. The femoral stem prosthesis according to claim 1, characterized in that: The surfaces of the first handle body and the second handle body in contact with the autologous bone are provided with a double-layer coating, and the coating close to the prosthesis is a trabecular bone structure sprayed with titanium powder, and an HA coating is sprayed on the trabecular bone coating.

8. The femoral stem prosthesis according to claim 7, characterized in that: The thickness of the titanium powder spray coating of the double-layer coating is 10-50 microns, and the thickness of the HA coating is 5-15 microns.

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