Multifunctional single-condyle prosthesis

Abstract

The invention provides a multifunctional unicondylar prosthesis which comprises a thighbone unicondylar arranged at the thighbone end of a knee joint; the tibia platform is arranged at the tibia end of the knee joint; the pad is arranged between the tibial plateau and the femur single condyle, and the upper surface of the pad serves as a knee joint tibia side friction interface and is always in sliding contact with the femur single condyle; the liner comprises a fixed liner and a movable liner, and any liner can be matched with the tibial plateau for use; the fixed liner can be detachably attached to the upper end of the tibial plateau through a limiting anti-falling structure between the fixed liner and the tibial plateau; the movable liner can be placed at the upper end of the tibial plateau and can slide relative to the tibial plateau. The tibial plateau designed by the invention is compatible with a fixed liner and a movable liner, so that the complexity of surgical instruments is reduced, dynamic selection in an operation is supported, and revision is convenient.

Description

Technical Field

[0001] The present invention relates to an orthopedic implant instrument, more particularly to a multifunctional unicondylar prosthesis. Background Art

[0002] Unicompartmental knee replacement is a commonly used surgical procedure for the treatment of knee osteoarthritis. It replaces the diseased femoral or tibial articular surface while preserving healthy bone and ligament tissue. The tibial plateau of traditional knee replacement prostheses is usually designed in a single mode. The liner of the fixed tibial plateau is rigidly locked to the tibial plateau (such as a clip or screw), which has high stability but limits the range of motion of the joint. The liner of the mobile tibial plateau is slidable, which can reduce wear but is not compatible with the fixed tibial plateau. Patients need to select the type of tibial plateau before surgery. It cannot be dynamically adjusted according to the actual ligament status during surgery. The instruments of the fixed tibial plateau and the mobile tibial plateau are incompatible, and hospitals need to have double stock. Summary of the Invention

[0003] To solve the above technical problems, the present invention proposes a multifunctional unicompartmental prosthesis for use in knee replacement surgery. The designed tibial platform is compatible with fixed and movable pads, which reduces the complexity of surgical instruments, supports dynamic selection during surgery, and facilitates revision.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A multifunctional unicondylar prosthesis, comprising:

[0006] Unicondylar femur, located at the femoral end of the knee joint;

[0007] The tibial plateau is located at the tibia end of the knee joint;

[0008] The pad is placed between the tibial plateau and the unicondyle of the femur. The upper surface serves as the friction interface on the tibial side of the knee joint and is always in sliding contact with the bottom of the unicondyle of the femur. The pad includes a fixed pad and a movable pad, and either pad can be used in conjunction with the tibial plateau. The fixed pad can be detachably attached to the upper end of the tibial plateau through a limiting and anti-detachment structure between the pad and the tibial plateau. The movable pad can be placed on the upper end of the tibial plateau and can slide relative to the tibial plateau.

[0009] In a specific implementation, the corresponding structural configuration of the multifunctional unicompartmental prosthesis also includes:

[0010] The position-limiting and anti-slip structure includes two buckles protruding downward from the bottom of the fixed pad and two holes and grooves concave downward from the upper end of the tibial plateau;

[0011] The first of the two slots is a cylindrical slot, and the second is an arc-shaped guide slot concentrically distributed around the cylindrical slot. The width of the arc-shaped guide slot decreases from the starting end to the locking end along the arc trajectory. The slot wall forms a locking point that bulges horizontally toward the inside of the slot near the locking end, and the slot width is smallest at the locking point.

[0012] Among the two clips, the first clip and the second clip are deformable. The first clip is used to cooperate with the cylindrical hole groove and adapt to the shape and size of the cylindrical hole groove. It can be detachably inserted coaxially in the cylindrical hole groove and rotatable in the cylindrical hole groove. The second clip is used to cooperate with the arc guide groove and adapt to the shape and size of the locking end of the arc guide groove. It can be inserted into the arc guide groove from the starting end, move along the arc trajectory, squeeze through the locking point and enter and be detachably inserted in the locking end. It can be moved in reverse along the arc trajectory to the starting end by relying on external force, and leave space between it and the groove wall when it is at the starting end.

[0013] The second buckle inserted in the locking end of the arc-shaped guide groove is interference-fitted with the locking end.

[0014] The second clip is a flat-head pin structure with the head facing downward, and the pin is connected to the bottom end of the fixed liner; the groove wall at the lower end of the arc-shaped guide groove is formed with a horizontally concave arc-shaped slide groove, and the arc-shaped slide groove extends from the locking end along the arc track toward the starting end, the groove width gradually narrows, and smoothly connects to the starting end; the second clip extends into the arc-shaped guide groove from the starting end with the head facing downward, and moves along the arc track. When it moves to the arc-shaped slide groove, it relies on the head to slide in the arc-shaped slide groove. When it reaches the locking end, the head maintains an adaptive sliding fit in the arc-shaped slide groove at the lower end of the locking end, and the pin is coaxially inserted in the hole groove above the arc-shaped slide groove, and has an interference fit with the hole groove.

[0015] The surface of the second buckle has a rough texture to enhance the locking friction.

[0016] The first clip is a semicircular head pin structure with the head facing downward, the pin diameter is 3.2-6.2mm, and it is connected to the bottom end of the fixed pad; the cylindrical hole is adapted to the outer dimensions of the first clip, and the large end slot is facing downward; the first clip is adapted to be snapped into the large end slot of the cylindrical hole with the head facing downward, and the pin is coaxially inserted into the small end slot of the cylindrical hole, and the whole can rotate in the cylindrical hole, and a step surface is formed at the junction of the large end slot and the small end slot. The cylindrical hole with the step surface is plug-in matched with the first clip to form axial positioning when the fixed tibial pad and the tibial plateau are assembled.

[0017] The fixed liner is rotatably engaged with the columnar hole groove through the first buckle and can be rotated within a range of 5-15 degrees along the arc track of the arc guide groove through the second buckle.

[0018] The diameter of the cylindrical hole is 3-6mm, the width of the arc-shaped guide groove is 6-8mm, and based on the central axis of the cylindrical hole, the central angle corresponding to the arc of the arc-shaped guide groove is 10-20°. The groove wall of the arc-shaped guide groove forms a locking point that bulges 0.1-0.3mm horizontally toward the groove near the locking end. The arc-shaped guide groove can be roughly divided into three sections: the starting end, the connecting section, and the locking end. The starting end and the locking end are two holes, one large and one small, connected by an arc-shaped connecting section. One end of the arc-shaped connecting section is tangent to the starting end, and the other end intersects with the locking end at the locking point. The inner diameter of the hole at the starting end is larger than the outer diameter of the second buckle. The hole at the locking end has an interference fit with the pin of the second buckle, and the interference is 0.1-0.3mm.

[0019] The tibial plateau is inserted into the groove on the horizontal end surface of the tibial osteotomy surface through the vertical plate with a downwardly convex bottom, and is attached to the vertical end surface of the tibial osteotomy surface through the upright side plate. The locking end of the arc-shaped guide groove faces the side plate of the tibial plateau, and the starting end faces the outer edge of the tibial plateau opposite the side plate, adjacent to the outer edge of the side.

[0020] The fixed liner is made entirely of highly cross-linked polyethylene.

[0021] The movable pad is made entirely of highly cross-linked polyethylene.

[0022] The bone contact surface of the tibial plateau is provided with a porous coating with a pore size of 300-500 μm and a porosity of 50%-70%.

[0023] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0024] The multifunctional unicondylar prosthesis of the present invention proposes a novel tibial plateau structure. This tibial plateau, while compatible with a removable liner, utilizes a position-limiting and anti-detachment structure between the fixed liner and the tibial plateau, allowing for removable assembly and disassembly. This provides ample operating space for assembly and disassembly, facilitating easy intraoperative revisions. After installation, the fixed liner is securely locked to the tibial plateau by the position-limiting and anti-detachment structure. Consequently, the present invention is compatible with both fixed and removable liners, reducing the complexity of surgical instruments and enabling flexible intraoperative adaptation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the exploded structure of the present invention when a fixed liner is used;

[0026] Figure 2 is a schematic cross-sectional view of the present invention when a fixed liner is used;

[0027] Figure 3 It is a structural diagram of a fixed liner;

[0028] Figure 4It is a schematic diagram of the structure of the tibial plateau;

[0029] Figure 5 This is a structural diagram of the tibial plateau from another perspective;

[0030] Figure 6 This is a schematic diagram of the tibial plateau structure when viewed from above;

[0031] Figure 7 It is a schematic diagram of the exploded structure of the present invention when a movable pad is used.

[0032] In the figure, 1 is a tibial plateau; 11 is a vertical plate; 12 is a side plate; 21 is a fixed pad; 22 is a movable pad; 3 is a unicondyle of the femur; 4 is a columnar hole groove; 5 is an arc-shaped guide groove; 51 is a starting end; 52 is a locking end; 53 is a locking point; 54 is an arc-shaped slide groove; 55 is a connecting section; 61 is a first buckle; 62 is a second buckle. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1

[0035] Please refer to Figures 1 to 6 , the multifunctional unicondylar prosthesis includes:

[0036] The femoral condyle is located at the femoral end of the knee joint and has a structure that is substantially identical to that of the femoral condyle in existing unicondylar prostheses.

[0037] The tibial plateau is located at the tibia end of the knee joint;

[0038] The fixed pad can be detachably attached to the upper end of the tibial plateau through a limiting anti-detachment structure between the tibial plateau and the femoral condyle. The upper surface serves as the friction interface on the tibial side of the knee joint and is always in sliding contact with the femoral condyle.

[0039] The installation and removal of the fixed pad on the tibial plateau is similar, please refer to:

[0040] Initial positioning: After installing the tibial plateau, align the first buckle of the fixed liner with the cylindrical hole of the tibial plateau and insert it to complete the axial positioning of the fixed liner;

[0041] Rotational locking: The fixed gasket is rotated around the central axis of the cylindrical hole groove, so that the second clip is aligned with the starting end of the arc guide groove and inserted. Then, the second clip is rotated along the arc track of the arc guide groove, utilizing the sliding cooperation between the arc guide groove and the head of the second clip until the second clip squeezes through the locking point and locks into the locking end. At this point, the cooperation between the two clips and the two hole grooves realizes the bidirectional locking of the fixed gasket.

[0042] Disassembly and renovation: Rotate the fixed gasket in the opposite direction around the central axis of the cylindrical hole groove, so that the second clip is squeezed through the locking point in the reverse direction to disengage from the locking end, and move it along the arc trajectory to the starting end to remove the fixed gasket.

[0043] Example 2

[0044] Please refer to Figures 4 to 7 , the multifunctional unicondylar prosthesis includes:

[0045] The femoral condyle is located at the femoral end of the knee joint and has a structure that is substantially identical to that of the femoral condyle in existing unicondylar prostheses.

[0046] The tibial plateau is located at the tibia end of the knee joint;

[0047] The movable liner is positioned at the top of the tibial plateau and slides relative to it, positioned between the tibial plateau and the unicondyle of the femur. Its upper surface serves as the friction interface on the tibial side of the knee joint, maintaining constant sliding contact with the base of the unicondyle of the femur. The base of the unicondyle of the femur forms a downwardly convex spherical surface, while the upper surface of the movable liner forms a downwardly concave spherical surface, within which the base of the unicondyle of the femur slides.

[0048] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A multifunctional unicondylar prosthesis, characterized by include: Unicondylar femur (3), located at the femoral end of the knee joint; A tibial plateau (1), provided at the tibial end of the knee joint; A pad is placed between the tibial plateau (1) and the femoral condyle (3), with the upper surface serving as a friction interface on the tibial side of the knee joint and always in sliding contact with the femoral condyle (3); the pad comprises a fixed pad (21) and a movable pad (22), either of which can be used in conjunction with the tibial plateau (1); the fixed pad (21) can be detachably attached to the upper end of the tibial plateau (1) through a limiting anti-detachment structure between the fixed pad (21) and the tibial plateau (1); the movable pad (22) can be placed on the upper end of the tibial plateau (1) and can slide relative to the tibial plateau (1).

2. The multifunctional unicompartmental prosthesis according to claim 1, characterized in that: The position limiting and anti-slip structure comprises two buckles protruding downward from the bottom of the fixed pad (21) and two holes and grooves concave downward from the upper end of the tibial plateau (1); Of the two hole grooves, the first is a cylindrical hole groove (4), and the second is an arc-shaped guide groove (5) concentrically distributed on the periphery of the cylindrical hole groove (4); the groove width of the arc-shaped guide groove (5) decreases from a large width along the arc-shaped trajectory from a starting end (51) to a locking end (52), and the groove wall forms a locking point (53) protruding horizontally toward the inside of the groove near the locking end (52), and the groove width is smallest at the locking point (53); The first buckle (61) and the second buckle (62) are deformable. The first buckle (61) is used to cooperate with the cylindrical hole groove (4) and is adapted to the shape and size of the cylindrical hole groove (4). It can be detachably coaxially inserted in the cylindrical hole groove (4) and can rotate in the cylindrical hole groove (4). The second buckle (62) is used to cooperate with the arc guide groove (5) and is adapted to the shape and size of the locking end (52) of the arc guide groove (5). It can be inserted into the arc guide groove (5) from the starting end (51), move along the arc track, squeeze through the locking point (53) to enter and be detachably inserted in the locking end (52). It can move in the reverse direction along the arc track to the starting end (51) by relying on external force, and leave a space between it and the groove wall when it is at the starting end (51).

3. The multifunctional unicompartmental prosthesis according to claim 2, characterized in that: The second buckle (62) inserted into the locking end (52) of the arc-shaped guide groove (5) is interference-fitted with the locking end (52).

4. The multifunctional unicondylar prosthesis according to claim 2 or 3, characterized in that: The second buckle (62) is a flat-head pin structure with its head facing downward, and the pin is connected to the bottom end of the fixed liner (21); the groove wall at the lower end of the arc-shaped guide groove (5) is formed with a horizontal concave arc-shaped slide groove (54), and the arc-shaped slide groove (54) extends from the locking end (52) along the arc track toward the starting end (51), the groove width gradually narrows, and smoothly connects to the starting end (51); the second buckle (62) extends into the arc-shaped guide groove (5) from the starting end (51) with its head facing downward, moves along the arc track, and when it moves to the arc-shaped slide groove (54), it relies on the head to slide in the arc-shaped slide groove (54), and when it reaches the locking end (52), the head remains adaptively slidably fitted in the arc-shaped slide groove (54) at the lower end of the locking end (52), and the pin is coaxially inserted into the hole groove above the arc-shaped slide groove (54), and has an interference fit with the hole groove.

5. The multifunctional unicondylar prosthesis according to claim 2, characterized in that: The first clip (61) is a semicircular head pin structure with its head facing downwards, and the pin is connected to the bottom end of the fixed liner (21); the cylindrical hole (4) is adapted to the outer dimensions of the first clip (61), and the large end slot is facing downwards; the first clip (61) is adapted to be inserted into the large end slot of the cylindrical hole (4) with its head facing downwards, and the pin is coaxially inserted into the small end slot of the cylindrical hole (4), and the whole is rotatable in the cylindrical hole (4).

6. The multifunctional unicompartmental prosthesis according to claim 2, characterized in that: The fixed liner (21) is rotatably engaged with the columnar hole groove (4) through the first buckle (61) and can be rotated within a range of 5-15 degrees along the arc track of the arc guide groove (5) through the second buckle (62).

7. The multifunctional unicompartmental prosthesis according to claim 2, characterized in that: The groove wall of the arc-shaped guide groove (5) is formed with a locking point (53) protruding 0.1-0.3 mm horizontally toward the groove near the locking end (52).

8. The multifunctional unicompartmental prosthesis according to claim 2, characterized in that: The fixed liner (21) is made entirely of cross-linked polyethylene.

9. The multifunctional unicompartmental prosthesis according to claim 1, characterized in that: The movable liner (22) is made entirely of cross-linked polyethylene.

10. The multifunctional unicompartmental prosthesis according to claim 1, characterized in that: The bone contact surface of the tibial plateau (1) is provided with a porous coating with a pore size of 300-500 μm and a porosity of 50%-70%.

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