A general-purpose powerful femoral stem extractor

Abstract

The present invention discloses a general-purpose powerful femoral stem extractor, comprising: a first rod member, the first end of the first rod member being a free end; and a second rod member, the first end of the second rod member serving as a free end, the second end of the second rod member being hinged to the middle part of the first rod member; and a third rod member, the first end of the third rod member being hinged to the third end of the second rod member, the second end of the third rod member being a free end; and a fourth rod member, the first end of the fourth rod member being hinged to the third end of the third rod member, the second end of the fourth rod member being hinged to the second end of the first rod member; and a fifth rod member, the first end of the fifth rod member being connected to the second end of the first rod member; and a locking member, the locking member being disposed at the connection between the first rod member and the fourth rod member for locking the connection state between the first rod member and the fourth rod member. The present invention has the effects of being able to ensure reliable clamping of the femoral stem, shortening the extraction time of the femoral stem, and avoiding phenomena such as periprosthetic fractures and prosthesis fractures.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a universal high-strength femoral stem extractor. Background Art

[0002] Total hip arthroplasty has become a well-established and reliable treatment method after 30 years of clinical practice verification. However, with the development of society, the indications for total hip arthroplasty have been expanded to elderly and young patients, and the subsequent postoperative revision needs have become increasingly acute. Compared with primary hip arthroplasty, hip revision surgery is more difficult, especially regarding how to efficiently and securely remove the femoral stem, which has always been a difficult and painful point in the medical field.

[0003] Based on this background, several femoral stem prosthesis-assisted removal tools have emerged on the market. For example:

[0004] A Chinese patent discloses a femoral stem extraction instrument (CN202022439526.3), which has many defects: ① It takes a long time to clamp the femoral stem by rotating the tail handle multiple times; ② The extraction direction is not coaxial with the implantation direction of the femoral stem prosthesis, and during the extraction process, the prosthesis is prone to breakage and periprosthetic fractures.

[0005] A Chinese patent discloses a bite-type femoral stem extraction instrument assembly (CN201620243007.0), which also has many defects: ① It takes a long time to clamp the femoral stem by rotating the rotation adjustment head multiple times; ② The bite position is the conical part of the femoral stem prosthesis, and the clamping rod is long and thin. For prostheses with a particularly tight fit and smaller models, insufficient clamping force will occur during the extraction process, resulting in the femoral stem falling off.

[0006] Generally speaking, the femoral stem prosthesis-assisted removal tools in the prior art have some defects: These tools usually use a screwing method to complete the clamping of the stem body, resulting in a long time consumption; and the force application direction of these tools is different from the extraction direction of the femoral stem prosthesis, which not only makes the operation complex, but also easily causes prosthesis breakage and periprosthetic fractures, bringing secondary injuries to patients; moreover, the clamping force of these tools is limited, which may cause the femoral stem to fall off during the clamping process.

[0007] Based on the above, the present invention designs a convenient and reliable universal high-strength femoral stem extractor for hip revision surgery, so as to shorten the time of revision surgery and avoid secondary injuries to the proximal joint when removing the femoral stem prosthesis. Summary of the Invention

[0008] The purpose of the present invention is to provide a universal high-strength femoral stem extractor to solve the problems raised in the above background art.

[0009] To solve the above technical problems, the present invention provides the following technical solution: a general-purpose powerful femoral stem extractor, comprising: a first rod, the first end of the first rod being a free end; and a second rod, the first end of the second rod being a free end, the second end of the second rod being hinged to the middle of the first rod; and a third rod, the first end of the third rod being hinged to the third end of the second rod, the second end of the third rod being a free end; and a fourth rod, the first end of the fourth rod being hinged to the third end of the third rod, the second end of the fourth rod being hinged to the second end of the first rod; and a fifth rod, the first end of the fifth rod being connected to the second end of the first rod; and a locking member, the locking member being disposed at the connection between the first rod and the fourth rod for locking the connection state between the first rod and the fourth rod.

[0010] A first interference surface is provided on one side of the third rod close to the fourth rod; a second interference surface is provided on one side of the fourth rod close to the third rod; when the first rod and the second rod are closed, a pre-tightening force is generated between the first interference surface and the second interference surface.

[0011] The locking member is a sleeve, the sleeve is sleeved on the connection between the first rod and the fourth rod, and the sleeve includes: a first inner wall, an internal thread is provided on the first inner wall, and the internal thread is screwed with an external thread provided on the first rod or the fifth rod; and a second inner wall, the pre-tightening force generated by the second inner wall on the first rod and the fourth rod can lock the connection state between the first rod and the fourth rod.

[0012] The first rod includes a first clamping section and a first connecting rod section, the first clamping section being close to the free end of the first rod; the second rod includes a second clamping section and a second connecting rod section, the second clamping section being close to the free end of the second rod; the first clamping section and the second clamping section together form a clamping pliers handle, and the first connecting rod section and the second connecting rod section together form a connecting rod handle, and an obtuse angle is formed between the axis where the clamping pliers handle is located and the axis where the connecting rod handle is located.

[0013] The included angle between the axis where the clamping pliers handle is located and the axis where the connecting rod handle is located is 130° to 145°.

[0014] A first groove is provided on one side of the first clamping section close to the second clamping section; a second groove is provided on one side of the second clamping section close to the first clamping section; the first groove and the second groove correspond exactly.

[0015] Anti-slip patterns are provided on the walls of the first groove and the first groove.

[0016] The first rod member includes a first receiving groove which is located on one side of the first rod member close to the second rod member. The second end of the second rod member extends into the first receiving groove, and the second end of the second rod member is connected to the first receiving groove by a first pin. The second end of the fourth rod member also extends into the first receiving groove, and the second end of the fourth rod member is connected to the first receiving groove by a second pin. The third rod member includes a second receiving groove which is located on one side of the third rod member close to the fourth rod member. The third end of the second rod member extends into the second receiving groove, and the third end of the second rod member is connected to the second receiving groove by a third pin. The first end of the fourth rod member also extends into the second receiving groove, and the first end of the fourth rod member is connected to the second receiving groove by a fourth pin.

[0017] A general-purpose powerful femoral stem extractor further includes a slide hammer which is located at one end of the fifth rod member away from the first rod member, and the slide hammer is connected to the second end of the fifth rod member.

[0018] A general-purpose powerful femoral stem extractor further includes a weight-reducing hole, and the weight-reducing hole includes one or more.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0020] 1. A general-purpose powerful femoral stem extractor disclosed by the present invention designs a four-bar linkage structure. Combining with the function of the fourth rod member, the lever principle is applied twice, so that the clamping end can obtain a greater clamping force under the same force, which can ensure reliable and stable clamping of the femoral stem, and is simple and easy to operate. It can greatly shorten the extraction time of the femoral stem and ensure the efficient progress of the operation.

[0021] 2. A general-purpose powerful femoral stem extractor disclosed by the present invention is provided with a first interference surface and a second interference surface on the basis of powerful clamping. After the clamping pliers handle completes the clamping action, the first interference surface and the second interference surface can automatically lock the clamping action. At the same time, in cooperation with the structure of the locking sleeve, by tightening the locking sleeve, it can further ensure that the clamping action is locked, that is, sufficient pre-tightening force can be provided to ensure that the femoral stem does not slip off, providing a secondary insurance for the successful extraction of the femoral stem.

[0022] 3. A general-purpose powerful femoral stem extractor disclosed by the present invention designs that the clamping pliers handle and the connecting rod handle form an obtuse angle, ensuring that the force direction of the femoral stem prosthesis during extraction is the same as the implantation direction, that is, coaxial, which can effectively avoid the occurrence of fractures around the femoral stem prosthesis and breakage of the femoral stem prosthesis caused by uneven force around during the extraction of the femoral stem. Description of the Drawings

[0023] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0024] Figure 1 is a perspective view of a universal high - force femoral stem extractor in an embodiment of the present invention;

[0025] Figure 2 is an exploded view of a universal high - force femoral stem extractor in an embodiment of the present invention;

[0026] Figure 3 is a cross - sectional view of the locking member in an embodiment of the present invention;

[0027] Figure 4 is a front view of a universal high - force femoral stem extractor in an embodiment of the present invention;

[0028] Figure 5 is a schematic orientation diagram among the clamping pliers handle, the connecting rod handle and the femoral stem in an embodiment of the present invention;

[0029] In the figure:

[0030] The first rod 1, the first clamping section 1 - 1, the first groove 1 - 2, the first connecting rod section 1 - 3, the first receiving groove 1 - 4;

[0031] The second rod 2, the second clamping section 2 - 1, the second groove 2 - 2, the second connecting rod section 2 - 3;

[0032] The third rod 3, the first interference surface 3 - 1, the second receiving groove 3 - 2;

[0033] The fourth rod 4, the second interference surface 4 - 1;

[0034] The fifth rod 5;

[0035] The locking member 6, the sleeve 6 - 1, the first inner wall 6 - 2, the second inner wall 6 - 3;

[0036] The first pin 7;

[0037] The second pin 8;

[0038] The third pin 9;

[0039] The fourth pin 10;

[0040] The slide hammer 11;

[0041] The weight - reducing hole 12;

[0042] The proximal femur 13;

[0043] The femoral stem 14. Detailed implementation manners

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Compared with the primary hip replacement surgery, the hip revision surgery has less autologous bone available and also requires the removal of the previously implanted prosthesis, resulting in a sharp increase in the surgical difficulty. In particular, how to efficiently and securely remove the femoral stem previously implanted in the body has always been a difficult and painful point in the medical field. Based on this, some femoral stem extractors have emerged on the market to assist in the removal of the femoral stem. However, the existing femoral stem extractors all have some defects. For example, the existing femoral stem extractors are not easy to use, causing a long time consumption. Moreover, some extractors have limited clamping force, resulting in looseness between the extractor and the femoral stem during the removal process, which may cause damage to the autologous bone. In addition, for the existing extractors, the force application direction is not coaxial with the removal direction of the femoral stem prosthesis, and during the removal process, situations such as prosthesis fracture and periprosthetic fracture are likely to occur.

[0046] Based on the above, the present invention provides embodiments to solve the defects existing in the prior art, specifically a universal high-strength femoral stem extractor.

[0047] Specifically, as Figures 1-2 , this femoral stem extractor includes a first rod 1, and the first end of the first rod 1 is a free end; it also includes a second rod 2, and the first end of the second rod 2 is used as a free end, and the second end of the second rod 2 is hinged to the middle of the first rod 1. In this way, the opening and closing actions of the first rod 1 and the second rod 2 can complete the clamping function; it further includes a third rod 3, the first end of the third rod 3 is hinged to the third end of the second rod 2, and the second end of the third rod 3 is a free end. Applying a force to the free end of the third rod 3 can cause a displacement of the third end of the second rod 2, and further cause an angular displacement of the second end of the second rod 2, so that the first rod 1 and the second rod 2 complete the opening and closing actions.

[0048] Furthermore, on the basis of having a clamping effect, in order to obtain a greater clamping force, as Figures 1-2, this femoral stem extractor further includes a fourth rod member 4. The first end of the fourth rod member 4 is hinged to the third end of the third rod member 3, and the second end of the fourth rod member 4 is hinged to the second end of the first rod member 1. Thus, when a force is applied to the free end of the third rod member 3, the third rod member 3 and the fourth rod member 4 perform an opening and closing action, and at the same time drive the third end of the second rod member 2 to displace. This is equivalent to adding a lever effect on the basis of the third rod member 3, enabling the free ends of the second rod member 2 and the first rod member 1 to obtain a greater clamping force. That is, compared with an ordinary clamping pliers, this femoral stem extractor applies the lever principle twice and can obtain a greater clamping force under the same force.

[0049] Furthermore, after the clamping action of the femoral stem is completed, a force needs to be applied to remove the femoral stem. Therefore, relevant connecting parts are also required. Based on this, as Figures 1-2 , this femoral stem extractor further includes a fifth rod member 5. The first end of the fifth rod member 5 is fixedly connected to the second end of the first rod member 1 through a pin as a connecting rod member. In other embodiments, the fifth rod member 5 can also be integrally formed with the first rod member 1.

[0050] Furthermore, as Figures 1-2 , when the first rod member 1 and the second rod member 2 complete the clamping action, the action of removing the femoral stem needs to be started. Therefore, it is necessary to lock the clamping state of the first rod member 1 and the second rod member 2 to free the hands for other surgical steps. Based on this, a first interference surface 3-1 is provided on one side of the third rod member 3 close to the fourth rod member 4; a second interference surface 4-1 is provided on one side of the fourth rod member 4 close to the third rod member 3; when the first rod member 1 and the second rod member 2 are closed, a pre-tightening force is generated between the first interference surface 3-1 and the second interference surface 4-1; in this embodiment, the first interference surface 3-1 is preferably a smooth convex surface relative to the second interference surface 4-1, and the second interference surface 4-1 is preferably a smooth convex surface relative to the first interference surface 3-1.

[0051] Furthermore, as Figures 1-3 , considering that there is a risk of slippage in the pre-tightening effect generated by the above-mentioned first interference surface 3-1 and the second interference surface 4-1, based on this, this femoral stem extractor further includes a locking member 6. The locking member 6 is placed at the connection between the first rod member 1 and the fourth rod member 4 for locking the connection state of the first rod member 1 and the fourth rod member 4.

[0052] Furthermore, for the convenience of operation, as Figure 3, the locking member 6 is a sleeve 6-1. The sleeve 6-1 is sleeved on the connection part of the first rod 1 and the fourth rod 4. The sleeve 6-1 specifically includes a first inner wall 6-2, and an internal thread is provided on the first inner wall 6-2. The internal thread is screwed with the external thread provided on the first rod 1 or the fifth rod 5; it also includes a second inner wall 6-3. The pre-tightening force generated by the second inner wall 6-3 on the first rod 1 and the fourth rod 4 can lock the connection state of the first rod 1 and the fourth rod 4; that is, when it is necessary to lock the clamping state of the first rod 1 and the second rod 2, a spiral action is performed on the sleeve 6-1 to displace the sleeve 6-1 in the direction of the first rod 1 and the fourth rod 4, generating an interference effect on the first rod 1 and the fourth rod 4, so as to lock the state of the first rod 1 and the fourth rod 4 under the locking action of the thread, and further lock the clamping state of the first rod 1 and the second rod 2.

[0053] Furthermore, in order to avoid the prosthesis being broken and the fracture around the prosthesis during the removal process, it is considered to make the force application direction of the femoral stem holder as coaxial as possible with the removal direction of the femoral stem prosthesis. Based on this, as Figures 1-2 , the first rod 1 includes a first clamping section 1-1 and a first connecting rod section 1-3. The first clamping section 1-1 is close to the free end of the first rod 1; the second rod 2 includes a second clamping section 2-1 and a second connecting rod section 2-3. The second clamping section 2-1 is close to the free end of the second rod 2; wherein the first clamping section 1-1 and the second clamping section 2-1 jointly form a clamping pliers handle, and the first connecting rod section 1-3 and the second connecting rod section 2-3 jointly form a connecting rod handle. An obtuse angle is formed between the axis where the clamping pliers handle is located and the axis where the connecting rod handle is located. Thus, as Figure 5 , when an extraction force is applied to the femoral stem holder, a 90° angle is formed between the axis where the clamping pliers handle is located and the head of the femoral stem, and the connecting rod handle and the main body of the femoral stem always remain coaxial to ensure that the force applied to the femoral stem holder is transmitted to the main body of the femoral stem as much as possible, thereby avoiding the situation of the femoral stem being broken or the fracture around the prosthesis.

[0054] Furthermore, according to relevant calculations, in this embodiment, the angle between the axis where the clamping pliers handle is located and the axis where the connecting rod handle is located is preferably α = 130° - 145°. Correspondingly, the angle between the head of the femoral stem and the main body of the femoral stem is β = 270° - α.

[0055] Furthermore, considering that there is also a risk of the femoral stem slipping when simply using the first clamping section 1-1 and the second clamping section 2-1 to clamp the femoral stem, the structure characteristics of the femoral stem itself can be used for clamping. In this embodiment, it is preferred to clamp the neck of the femoral stem. Specifically, as Figures 1-2, on the side of the first clamping section 1-1 close to the second clamping section 2-1, there is a first groove 1-2; on the side of the second clamping section 2-1 close to the first clamping section 1-1, there is a second groove 2-2; the first groove 1-2 and the second groove 2-2 correspond exactly. During clamping, just make the first groove 1-2 and the second groove 2-2 correspond to the neck of the femoral stem.

[0056] Furthermore, in order to further prevent the femoral stem from slipping off, such as Figures 1-2 , anti-slip lines are provided on both the wall surfaces of the first groove 1-2 and the first groove 1-2.

[0057] Furthermore, since this femoral stem extractor is a medical device and is used in the relatively narrow hip joint, during use, it is necessary to avoid damaging the surrounding soft tissues as much as possible. Therefore, a relatively compact and petite structure is required; specifically, such as Figure 2 , the first rod 1 includes a first receiving groove 1-4. The first receiving groove 1-4 is located on the side of the first rod 1 close to the second rod 2. The second end of the second rod 2 extends into the first receiving groove 1-4, and the second end of the second rod 2 is connected to the first receiving groove 1-4 through a first pin 7. The second end of the fourth rod 4 also extends into the first receiving groove 1-4, and the second end of the fourth rod 4 is connected to the first receiving groove 1-4 through a second pin 8; the third rod 3 includes a second receiving groove 3-2. The second receiving groove 3-2 is located on the side of the third rod 3 close to the fourth rod 4. The third end of the second rod 2 extends into the second receiving groove 3-2, and the third end of the second rod 2 is connected to the second receiving groove 3-2 through a third pin 9. The first end of the fourth rod 4 also extends into the second receiving groove 3-2, and the first end of the fourth rod 4 is connected to the second receiving groove 3-2 through a fourth pin 10.

[0058] Furthermore, after completing the clamping action of the femoral stem, it is also necessary to apply a force to remove the femoral stem, such as Figure 4 , so this femoral stem extractor further includes a sledgehammer 11. The sledgehammer 11 is located at the end of the fifth rod 5 away from the first rod 1, and the sledgehammer 11 is connected to the second end of the fifth rod 5, where the sledgehammer 11 is used to apply a continuous extraction force to the fifth rod 5.

[0059] Furthermore, such as Figures 1-2 , this femoral stem extractor also further includes a weight-reducing hole 12. The weight-reducing hole 12 includes one or more, which is used to reduce the weight of the extractor and facilitate the operation of the surgeon. In this embodiment, the weight-reducing hole 12 is preferably located on the second rod 2.

[0060] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0061] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A general-purpose powerful femoral stem extractor, characterized in that, Comprising: A first rod member (1), wherein the first end of the first rod member (1) is a free end; And a second rod member (2), wherein the first end of the second rod member (2) is a free end, and the second end of the second rod member (2) is hinged to the middle of the first rod member (1); And a third rod member (3), wherein the first end of the third rod member (3) is hinged to the third end of the second rod member (2), and the second end of the third rod member (3) is a free end; And a fourth rod member (4), wherein the first end of the fourth rod member (4) is hinged to the third end of the third rod member (3), and the second end of the fourth rod member (4) is hinged to the second end of the first rod member (1); And a fifth rod member (5), wherein the first end of the fifth rod member (5) is connected to the second end of the first rod member (1); And a locking member (6), which is placed at the connection between the first rod member (1) and the fourth rod member (4) for locking the connection state between the first rod member (1) and the fourth rod member (4); On one side of the third rod member (3) close to the fourth rod member (4), a first interference surface (3-1) is provided; On one side of the fourth rod member (4) close to the third rod member (3), a second interference surface (4-1) is provided; When the first rod member (1) and the second rod member (2) are closed, a pre-tightening force is generated between the first interference surface (3-1) and the second interference surface (4-1); The locking member (6) is a sleeve (6-1), and the sleeve (6-1) is sleeved on the connection between the first rod member (1) and the fourth rod member (4). The sleeve (6-1) includes: A first inner wall (6-2) provided with internal threads on the first inner wall (6-2), and the internal threads are screwed with external threads provided on the first rod member (1) or the fifth rod member (5); And a second inner wall (6-3), and the pre-tightening force generated by the second inner wall (6-3) on the first rod member (1) and the fourth rod member (4) can lock the connection state between the first rod member (1) and the fourth rod member (4); The first rod member (1) includes a first clamping section (1-1) and a first connecting rod section (1-3), and the first clamping section (1-1) is close to the free end of the first rod member (1); The second rod member (2) includes a second clamping section (2-1) and a second connecting rod section (2-3), and the second clamping section (2-1) is close to the free end of the second rod member (2); The first clamping section (1-1) and the second clamping section (2-1) together form a clamping pliers handle, and the first connecting rod section (1-3) and the second connecting rod section (2-3) together form a connecting rod handle. The axis where the clamping pliers handle is located and the axis where the connecting rod handle is located form an obtuse angle.

2. The general type of powerful femoral stem extractor according to claim 1, characterized in that: The included angle between the axis where the clamping pliers handle is located and the axis where the connecting rod handle is located is 130° - 145°.

3. The general-purpose powerful femoral stem extractor according to claim 1, characterized in that: On one side of the first clamping section (1-1) close to the second clamping section (2-1), a first groove (1-2) is provided; On one side of the second clamping section (2-1) close to the first clamping section (1-1), a second groove (2-2) is provided; The first groove (1-2) corresponds exactly to the second groove (2-2).

4. The universal powerful femoral stem extractor according to claim 3, characterized in that: Anti-slip patterns are provided on the walls of the first groove (1-2) and the first groove (1-2).

5. The general-purpose powerful femoral stem extractor according to claim 1, wherein: The first rod (1) includes a first receiving groove (1-4), the first receiving groove (1-4) is located on one side of the first rod (1) close to the second rod (2), the second end of the second rod (2) extends into the first receiving groove (1-4), and the second end of the second rod (2) is connected to the first receiving groove (1-4) by a first pin (7), and the second end of the fourth rod (4) also extends into the first receiving groove (1-4), and the second end of the fourth rod (4) is connected to the first receiving groove (1-4) by a second pin (8); The third rod (3) includes a second receiving groove (3-2), the second receiving groove (3-2) is located on one side of the third rod (3) close to the fourth rod (4), the third end of the second rod (2) extends into the second receiving groove (3-2), and the third end of the second rod (2) is connected to the second receiving groove (3-2) by a third pin (9), and the first end of the fourth rod (4) also extends into the second receiving groove (3-2), and the first end of the fourth rod (4) is connected to the second receiving groove (3-2) by a fourth pin (10).

6. A general type of powerful femoral stem extractor according to claim 1, characterized in that: It further includes a slide hammer (11), the slide hammer (11) is located at one end of the fifth rod (5) away from the first rod (1), and the slide hammer (11) is connected to the second end of the fifth rod (5).

7. A general-purpose powerful femoral stem extractor according to claim 1, characterized in that: It further includes a weight-reducing hole (12), and the weight-reducing hole (12) includes one or more.

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