Interphalangeal joint surface replacement prosthesis

Abstract

The utility model discloses an interphalangeal joint surface replacement prosthesis which comprises a near-end phalanx surface prosthesis, and a near-end phalanx fixing part is arranged on the side portion of the near-end phalanx surface prosthesis and used for being fixed to the radial back side bone surface or the ulnar back side bone surface of the near-end phalanx metaphysis. A far-end phalanx fixing part is arranged on the side part of the far-end phalanx surface prosthesis and is used for being fixed on the median bone surface of the back side of the far-end phalanx metaphysis; the far-end end face of the near-end phalanx surface prosthesis and the near-end end face of the far-end phalanx surface prosthesis are each provided with a curved surface part, so that the far-end phalanx surface prosthesis can rotate relative to the near-end phalanx surface prosthesis, and the prosthesis and the side portion of the phalanx are connected and fixed through the near-end phalanx fixing part and the far-end phalanx fixing part. The mode of fixing through the intramedullary cavity is avoided, fixing can be conducted without bone cement, and serious complications such as deep medullary cavity infection are avoided.

Description

Technical Field

[0001] This utility model relates to the field of medical replacement prosthesis technology, specifically a finger joint surface replacement prosthesis. Background Technology

[0002] The integrity and stability of hand joints are crucial to their function, with the proximal interphalangeal (PIP) joints of the fingers being key to finger function. For PIP joint injuries or lesions leading to stiffness and pain, conservative treatment often proves ineffective and can severely impair hand function. Currently, various treatment methods exist for these problems. For patients with PIP joint osteochondral damage, arthritis, or stiffness that cannot be surgically released or whose joint function cannot be restored, options include arthroplasty, free metatarsophalangeal joint grafting, and artificial interphalangeal joint replacement. Arthroplasty is currently the most common and relatively inexpensive, but it results in complete loss of joint function post-surgery. Free metatarsophalangeal joint grafting can reconstruct the PIP joint, preserving maximum joint mobility with minimal impact on the donor foot's function, but it has drawbacks such as requiring highly skilled surgeons, significant surgical trauma, unsuitability for multiple joint grafts, and uncertain post-operative range of motion recovery. Artificial joint replacement surgery effectively avoids these shortcomings, allowing patients with stiff and deformed hand joints to regain good joint function; however, the limited development of existing prostheses restricts its application.

[0003] With the development of medical technology, interphalangeal joint replacement has been increasingly used to treat various intractable diseases such as arthritis and joint defects. Patents CN202682099U, CN113425469A, CN112386375A, and CN111134908A all disclose an interphalangeal joint prosthesis. It can be seen that existing patents generally disclose interphalangeal joint prostheses that use intramedullary prostheses fixed with bone cement. However, this method suffers from poor postoperative stability due to poor bone quality at the affected area, a high risk of prosthesis loosening, periarticular fractures, and difficulties in revision surgery, as well as the potential for deep medullary canal infection. Therefore, developing novel interphalangeal joint replacement prostheses has significant clinical importance and application prospects for the treatment of related diseases. Utility Model Content

[0004] This invention provides a prosthesis for interphalangeal joint surface replacement, which can solve the complication problems associated with existing interphalangeal joint prostheses using intramedullary fixation.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a prosthetic for interphalangeal joint surface replacement, a proximal phalanx surface prosthesis, wherein the side of the proximal phalanx surface prosthesis is provided with a proximal phalanx fixation part for fixing to the radial or ulnar dorsolateral bone surface of the proximal phalanx metaphysis;

[0006] The distal phalanx surface prosthesis has a distal phalanx fixation part on its side for fixing to the dorsal midline bone surface of the distal phalanx metaphysis.

[0007] Both the distal end face of the proximal phalanx surface prosthesis and the proximal end face of the distal phalanx surface prosthesis are provided with curved surfaces, allowing the distal phalanx surface prosthesis to rotate relative to the proximal phalanx surface prosthesis. The prosthesis is connected and fixed to the side of the phalanx using the proximal phalanx fixation part and the distal phalanx fixation part, avoiding the method of fixation through the medullary cavity. Fixation can be performed without the use of bone cement, avoiding serious complications such as deep medullary cavity infection.

[0008] Preferably, the proximal phalanx fixation part includes a malleable fixation plate and first screw holes symmetrically and obliquely arranged on both sides of the malleable fixation plate. By providing two first screw holes, it is convenient to firmly connect the prosthesis on the surface of the proximal phalanx to the metaphysis of the proximal phalanx with screws without loosening, and it can also reduce interference with soft tissues such as extensor tendons. After the malleable fixation plate is shaped, it can be fitted and fixed to the bone surface.

[0009] Preferably, the distal phalanx fixation part includes a malleable fixation plate and a second screw hole obliquely disposed in the middle of the malleable fixation plate. A fixation screw can be obliquely inserted into the second screw hole, hiding the tail of the screw and avoiding interference with the extensor tendon.

[0010] Preferably, the proximal phalanx surface prosthesis has multiple first fixation cones fixed to the metaphysis of the proximal phalanx of the interphalangeal joint on its proximal end face, and multiple second fixation cones fixed to the metaphysis of the distal phalanx of the interphalangeal joint on its distal end face. The first and second fixation cones can provide a good anti-rotation effect and improve the stability of the prosthesis fixation.

[0011] Preferably, there are two first fixation cones arranged side by side, and a third fixation cone with a height greater than the first fixation cone is provided between the two first fixation cones. The third fixation cone can improve the connection and installation firmness of the proximal phalanx surface prosthesis.

[0012] Preferably, the distal end face of the proximal phalanx surface prosthesis is a stepped convex curved surface, and the proximal end face of the distal phalanx surface prosthesis is a concave curved surface that matches the stepped convex curved surface, which can play an anti-rotation role.

[0013] Preferably, both the proximal and distal phalangeal surface prostheses have a hydroxyapatite coating on the surfaces that contact the phalanges, which promotes bone ingrowth and enhances long-term stability.

[0014] Preferably, the curved surfaces of both the proximal and distal phalangeal surface prostheses are made of high-molecular-weight polyethylene material, which has excellent lubrication and wear resistance.

[0015] Preferably, the proximal phalanx surface prosthesis and / or distal phalanx surface prosthesis comprises a metal matrix made of titanium alloy or cobalt-chromium-molybdenum alloy. The curved surface is combined with the metal matrix, resulting in high overall strength and resistance to deformation.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. The fixation method uses an extramedullary fixation plate, which is fixed to the corresponding phalanx bone surface with screws, making it more stable and avoiding complications such as prosthesis loosening and subsidence; the fixation plate has a certain degree of plasticity and can conform to the bone surface; the fixation plate reduces the number of screw holes and reduces interference with soft tissues such as tendons; the oblique installation of screws can hold more bone volume and improve stability; the addition of a fixation cone at the joint of the prosthesis can enhance stability while resisting rotation.

[0018] 2. The contact surface between the prosthesis and bone is coated with hydroxyapatite to promote bone ingrowth, enhance prosthesis stability, and reduce the risk of long-term loosening and fracture.

[0019] 3. The prosthesis uses surface replacement without intramedullary manipulation, which greatly reduces damage to non-articular bone, preserves bone volume to the maximum extent, and avoids serious complications such as deep medullary infection. Attached Figure Description

[0020] Figure 1 This is a first-view perspective three-dimensional structural diagram of the present invention;

[0021] Figure 2 This is a second-view perspective three-dimensional structural diagram of the present invention;

[0022] Figure 3 This is a three-dimensional structural diagram of the proximal phalanx surface prosthesis of this utility model;

[0023] Figure 4 This is a side view of the proximal phalanx surface prosthesis of this utility model;

[0024] Figure 5 This is a side view of the distal phalanx surface prosthesis of this utility model.

[0025] Figure label:

[0026] 1. Proximal phalanx surface prosthesis; 11. Stepped convex facet; 2. Distal phalanx surface prosthesis; 3. First fixation cone; 4. Proximal phalanx fixation part; 5. Distal phalanx fixation part; 6. First screw hole; 7. Second fixation cone; 8. Second screw hole; 9. Third fixation cone; 10. Concave facet. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0028] This invention addresses the complications associated with intramedullary fixation in existing interphalangeal joint prostheses. For example... Figure 1-5 As shown, the following technical solution is provided: a prosthetic replacement for the surface of an interphalangeal joint, a proximal phalanx surface prosthesis 1, wherein the side of the proximal phalanx surface prosthesis 1 is provided with a proximal phalanx fixation part 4 for fixing to the radial or ulnar dorsolateral bone surface of the proximal phalanx metaphysis.

[0029] The distal phalanx surface prosthesis 2 has a distal phalanx fixation part 5 on its side, which is used to fix it to the dorsal midline bone surface of the distal phalanx metaphysis.

[0030] Both the distal end face of the proximal phalanx surface prosthesis 1 and the proximal end face of the distal phalanx surface prosthesis 2 are provided with curved surfaces, allowing the distal phalanx surface prosthesis 2 to rotate relative to the proximal phalanx surface prosthesis 1. The proximal phalanx fixation part 4 and the distal phalanx fixation part 5 are used to connect and fix the prosthesis to the side of the phalanx, avoiding fixation through the medullary cavity. Fixation can be performed without the use of bone cement, avoiding serious complications such as deep medullary cavity infection.

[0031] Specifically, the proximal phalanx surface prosthesis 1 is connected to the proximal phalanx, and the distal phalanx surface prosthesis 2 is fixed to the distal phalanx. Here, proximal and distal are relative to the palm. The proximal phalanx refers to the phalanx close to the palm, and the distal phalanx refers to the phalanx far from the palm. The proximal and distal phalanxes rotate in coordination through the proximal phalanx surface prosthesis 1 and the distal phalanx surface prosthesis 2.

[0032] The proximal phalanx surface prosthesis 1 and / or distal phalanx surface prosthesis 2 include a metal matrix made of titanium alloy or cobalt-chromium-molybdenum alloy. The curved surface is combined with the metal matrix, resulting in high overall strength and resistance to deformation. In addition, the curved surfaces of the proximal phalanx surface prosthesis 1 and distal phalanx surface prosthesis 2 are made of high molecular weight polyethylene material, which has good lubrication and wear resistance.

[0033] In this embodiment, as Figure 1-2As shown, the proximal phalanx fixation part 4 includes a malleable fixation plate and two first screw holes 6 symmetrically arranged obliquely on both sides of the malleable fixation plate. The two first screw holes 6 facilitate a secure connection between the proximal phalanx surface prosthesis 1 and the proximal phalanx metaphysis using screws, preventing loosening and reducing interference with soft tissues such as extensor tendons. After being molded, the malleable fixation plate can be fitted and fixed to the bone surface. The upper two sides of the proximal phalanx fixation part 4 can be provided with bevels, and the first screw holes 6 are located on these bevels. A secure connection between the proximal phalanx surface prosthesis 1 and the proximal phalanx metaphysis can be achieved using two screws passing through the first screw holes 6, requiring a relatively small number of screws. The malleable fixation plate can be a commonly used medical-grade steel plate molding sheet, which not only has higher strength and better corrosion resistance, but some medical-grade steel plate molding sheets also employ bioactive coatings or drug sustained-release technology to promote fracture healing and reduce complications.

[0034] In this embodiment, as Figure 1-2 As shown, the distal phalanx fixation part 5 includes a malleable fixation plate and a second screw hole 8 obliquely disposed in the middle of the malleable fixation plate. Fixation screws can be obliquely inserted into the second screw hole 8, hiding the tail of the screw and avoiding interference with the extensor tendon. Similarly, the malleable fixation plate on the distal phalanx fixation part 5 can also be a medical steel plate molding sheet.

[0035] To improve the anti-rotation effect of the proximal phalanx surface prosthesis 1 and the distal phalanx surface prosthesis 2 after installation, the proximal end face of the proximal phalanx surface prosthesis 1 is provided with multiple first fixation cones 3 fixed to the bone surface of the proximal phalanx metaphysis of the interphalangeal joint, and the distal end face of the distal phalanx surface prosthesis 2 is provided with multiple second fixation cones 7 fixed to the bone surface of the distal phalanx metaphysis of the interphalangeal joint. The first fixation cones 3 and the second fixation cones 7 can play a good anti-rotation role and improve the stability of the prosthesis fixation. The first fixation cones 3 and the second fixation cones 7 are directly inserted into the cancellous bone of the metaphysis. The cancellous bone has relatively low hardness, so the first fixation cones 3 and the second fixation cones 7 can be smoothly inserted and directly hammered in without drilling.

[0036] Among them, such as Figure 1 As shown, there are two first fixing cones 3 arranged side by side, and a third fixing cone 9 with a height greater than the first fixing cones 3 is provided between the two first fixing cones 3. The third fixing cone 9 can improve the connection and installation firmness of the proximal phalanx surface prosthesis 1.

[0037] like Figure 1-2 As shown, the distal end face of the proximal phalanx surface prosthesis 1 is a stepped convex curved surface 11, and the proximal end face of the distal phalanx surface prosthesis 2 is a concave curved surface 10 that matches the stepped convex curved surface 11, which can play an anti-rotation role.

[0038] In this embodiment, the surfaces of the proximal phalanx surface prosthesis 1 and the distal phalanx surface prosthesis 2 that come into contact with the phalanx are coated with hydroxyapatite to promote bone ingrowth and enhance later stability.

[0039] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0040] Furthermore, in this utility model, descriptions involving terms such as "primary," "secondary," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "primary" or "secondary" may explicitly or implicitly include at least one of those features. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0041] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0042] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A prosthesis for interphalangeal joint surface replacement, characterized in that, include: The proximal phalanx surface prosthesis (1) has a proximal phalanx fixation part (4) on its side, which is used to fix it to the radial or ulnar dorsolateral bone surface of the proximal phalanx metaphysis. The distal phalanx surface prosthesis (2) is provided with a distal phalanx fixation part (5) on its side, which is used to fix it to the dorsal midline bone surface of the distal phalanx metaphysis. Both the distal end face of the proximal phalanx surface prosthesis (1) and the proximal end face of the distal phalanx surface prosthesis (2) are provided with curved surfaces, so that the distal phalanx surface prosthesis (2) can rotate relative to the proximal phalanx surface prosthesis (1).

2. The interphalangeal joint surface replacement prosthesis according to claim 1, characterized in that: The proximal phalanx fixation part (4) includes a malleable fixation plate and first screw holes (6) symmetrically and obliquely arranged on both sides of the malleable fixation plate.

3. The interphalangeal joint surface replacement prosthesis according to claim 2, characterized in that: The distal phalanx fixation part (5) includes a malleable fixation plate and a second screw hole (8) obliquely disposed in the middle of the malleable fixation plate.

4. The interphalangeal joint surface replacement prosthesis according to claim 1, characterized in that: The proximal phalanx surface prosthesis (1) has multiple first fixation cones (3) fixed to the bone surface of the proximal phalanx of the interphalangeal joint on its proximal end face, and the distal phalanx surface prosthesis (2) has multiple second fixation cones (7) fixed to the bone surface of the distal phalanx of the interphalangeal joint on its distal end face.

5. The interphalangeal joint surface replacement prosthesis according to claim 4, characterized in that: The first fixed cone (3) consists of two arranged side by side, and a third fixed cone (9) with a height greater than the first fixed cone (3) is set between the two first fixed cones (3).

6. The interphalangeal joint surface replacement prosthesis according to claim 1, characterized in that: The distal end face of the proximal phalanx surface prosthesis (1) is a stepped convex curved surface (11), and the proximal end face of the distal phalanx surface prosthesis (2) is a concave curved surface (10) that matches the stepped convex curved surface (11).

7. The interphalangeal joint surface replacement prosthesis according to any one of claims 1-6, characterized in that: The surfaces of the proximal phalanx surface prosthesis (1) and the distal phalanx surface prosthesis (2) that come into contact with the phalanx are coated with hydroxyapatite.

8. The interphalangeal joint surface replacement prosthesis according to claim 7, characterized in that: The curved surfaces of the proximal phalanx surface prosthesis (1) and the distal phalanx surface prosthesis (2) are both made of high molecular weight polyethylene material.

9. The interphalangeal joint surface replacement prosthesis according to claim 8, characterized in that: The proximal phalanx surface prosthesis (1) and / or distal phalanx surface prosthesis (2) comprises a metal matrix made of titanium alloy or cobalt chromium molybdenum alloy, wherein the curved surface is combined with the metal matrix.

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