Prosthesis for knee joint unicompartmental arthroplasty

Abstract

The invention provides a prosthesis for knee joint unicompartmental arthroplasty, which comprises a femoral condyle prosthesis arranged at the femoral end of a knee joint; the tibia base prosthesis is arranged at the tibia end of the knee joint; the tibia gaskets are arranged between the tibia base prosthesis and the femoral condyle prosthesis, are always in sliding contact with the bottom of the femoral condyle prosthesis, and comprise a fixed gasket and a movable gasket, and any tibia gasket can be matched with the tibia base prosthesis for use; the movable gasket is arranged at the upper end of the tibia base prosthesis in a sliding manner; the fixed gasket can be detachably assembled at the upper end of the tibia base prosthesis through an inserting structure. The dual-purpose tibia prosthesis base designed by the invention is compatible with a fixed gasket and a movable gasket, the fixed gasket and the movable gasket can be flexibly selected and replaced according to the specific condition of a patient during an operation, the fixed gasket and the tibia prosthesis base are convenient to disassemble and assemble, and the complexity of surgical operation and surgical instruments is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more particularly to a prosthesis for unicondylar replacement of a knee joint. Background Art

[0002] Unicompartmental knee arthroplasty, a minimally invasive surgical technique, significantly improves the patient experience through precise intervention. This procedure is primarily indicated for the treatment of unicompartmental joint pathology, including localized osteoarthritis, traumatic arthritis, and unilateral tibial plateau fractures. Its core prosthesis system consists of three components: a femoral condyle component, a tibial base component, and a tibial spacer made of highly cross-linked polyethylene.

[0003] Tibial spacers include movable spacers and fixed spacers. The connection between the fixed tibial spacer and the tibial prosthesis base is complex, involving many fixing parts, and is inconvenient to operate during surgery. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a prosthesis for unicompartmental knee replacement, which is designed with a dual-purpose tibial prosthesis base that is compatible with fixed gaskets and movable gaskets. During surgery, the gaskets can be flexibly selected and replaced according to the patient's specific conditions. The fixed gasket and the tibial prosthesis base are easy to disassemble and assemble, reducing the complexity of surgical operations and surgical instruments.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A prosthesis for unicompartmental knee replacement, comprising:

[0007] Femoral condyle prosthesis, which is placed at the femoral end of the knee joint;

[0008] The tibial base prosthesis is placed on the tibial end of the knee joint;

[0009] The tibial pad is placed between the tibial base prosthesis and the femoral condyle prosthesis. The upper surface serves as the friction interface on the tibial side of the knee joint and is in constant sliding contact with the bottom of the femoral condyle prosthesis. It includes a fixed pad and a movable pad. Either tibial pad can be used in conjunction with the tibial base prosthesis. The movable pad can be slidably placed on the upper end of the tibial base prosthesis. The fixed pad can be detachably assembled on the upper end of the tibial base prosthesis through a plug-in structure, with the lower end surface abutting against the upper end surface of the tibial base prosthesis. The plug-in structure includes two identical and parallel plug-in structures that are concave from the upper end of the tibial base prosthesis. The hole slot also includes two plug pins that are convex at the bottom of the fixed gasket; one end of the plug hole slot is a large hole and the other end is a small hole, a sliding cavity is provided between the large and small hole ends, and a locking point is provided near the small hole end. The two plug pins correspond to the two plug hole slots one by one, and rely on external force to make the plug pin that is fully inserted into the plug hole slot move from the large hole end, squeeze through the locking point and tightly fit in the small hole end, or make the plug pin squeeze through the locking point and move in the opposite direction to the large hole end. The plug pin placed in the large hole end can be disengaged from the plug hole slot, and when the plug pin moves, it relies on the sliding cooperation between the sliding cavity to limit and guide.

[0010] The structural characteristics of the present invention are also:

[0011] Along the moving trajectory of the plug pin, the plug hole groove is divided into a large hole end, a connecting section, and a small hole end in sequence. The large hole end and the small hole end are two hole grooves, one large and one small, which are connected by a connecting section. One end of the connecting section is tangent to the large hole end, and the other end intersects with the small hole end at the locking point. The locking point is a convex ridge with the groove walls on both sides of the plug hole groove protruding horizontally toward the groove, and the groove width is the smallest at the locking point; the groove wall at the lower end of the plug hole groove is formed with a horizontal concave sliding cavity, which extends from the small hole end toward the large hole end and smoothly connects to the large hole end; the plug pin faces downward and slides in the sliding cavity by relying on the head. When it moves to the small hole end, it is coaxially and tightly inserted into the small hole end through the pin column, and the head remains slidingly fitted in the sliding cavity. When it moves to the large hole end, a gap is left between it and the groove wall, and the head is separated from the sliding cavity.

[0012] The plug pin is a flat-headed pin with a head diameter that matches the diameter of the large hole end of the slot. With the head facing downward, the pin's outer diameter matches the diameter of the small hole end of the slot. The sliding cavity extends downward to the bottom of the slot. The cavity's top wall and side walls slide in contact with the pin's head to guide its movement. Furthermore, the step formed by the cavity's top wall and side walls limits the pin's head's position. The width of the cavity's top wall gradually narrows from the small hole end toward the large hole end.

[0013] The plug pin is made of elastic material. The fixed gasket and the movable gasket are both made of highly cross-linked polyethylene, and the plug pin and the fixed gasket are made of the same material.

[0014] Two insertion slots are aligned and spaced apart on the upper end of the tibial base prosthesis along the path of the insertion pin. The tibial base prosthesis is inserted into the groove on the horizontal end surface of the tibial osteotomy surface via a downwardly convex vertical plate at the bottom, and is attached to the vertical end surface of the tibial osteotomy surface via an upright side plate. The insertion pin's path of motion is parallel to the outer edge of the tibial base prosthesis where the side plate is located.

[0015] The upper end surface of the fixed gasket is flat, the bottom surface is in contact with the upper end surface of the tibial base prosthesis, and the top end is kept flush with the top end of the side plate of the tibial base prosthesis.

[0016] The bottom of the femoral condyle prosthesis is curved and convex downwardly. The upper surface of the movable spacer is concave downwardly to form a curved recess. The bottom of the femoral condyle prosthesis slides in this curved recess. The femoral condyle prosthesis is inserted into the femur via a primary and auxiliary insertion rod and secured to the lower end surface of the femur. The curved recess on the upper surface of the movable spacer can be formed by connecting multiple circular arcs. The movable spacer has a flat bottom surface and slides in a snug fit on the upper end surface of the tibial prosthesis base.

[0017] Notches are formed on both sides of the lower part of the movable gasket, which serve as clamping parts for surgical forceps to clamp and take out the movable gasket easily during surgery.

[0018] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0019] The present invention designs a dual-purpose tibial prosthesis base, which uses two specifically structured plug-in slots formed at the upper end of the tibial prosthesis base to form a downward inward concave shape and two downwardly convex plug-in pins at the bottom of the fixed gasket to respectively cooperate with each other, so that the fixed gasket and the tibial prosthesis base can be assembled and disassembled, and the assembly is firm, ensuring that no harm is caused to the patient due to dislocation during use. The disassembly and assembly are convenient and fast, the operation difficulty is low, and the operating space requirements are not high. There is no need for complex and small parts structures, which is convenient for doctors to install during surgery and can avoid the risk of small parts structures falling off during the disassembly and assembly process and during surgery. The outer surface shape of the tibial prosthesis base remains unchanged and can still be used in conjunction with the movable gasket, so that the tibial prosthesis base is compatible with both fixed gaskets and movable gaskets. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the present invention when a fixed gasket is used;

[0021] Figure 2 It is a structural diagram of a fixed gasket;

[0022] Figure 3 It is a cross-sectional structural diagram of the mating state of the plug pin and the plug hole groove;

[0023] Figure 4 It is a schematic diagram of the structure of the tibial base prosthesis;

[0024] Figure 5 This is a structural diagram of the tibial base prosthesis from another perspective;

[0025] Figure 6 This is a schematic diagram of the structure of the tibial base prosthesis from a bottom view;

[0026] Figure 7 is a schematic diagram of the structure of the femoral condyle prosthesis;

[0027] Figure 8 It is a structural diagram of a movable gasket;

[0028] Figure 9 It is a structural schematic diagram of the present invention when a movable gasket is used.

[0029] In the figure, 1 is a tibial base prosthesis; 11 is a vertical plate; 12 is a side plate; 2 is a femoral condyle prosthesis; 21 is a main insertion rod; 22 is an auxiliary insertion rod; 31 is a fixed gasket; 32 is a movable gasket; 321 is a curved recess; 322 is a notch; 4 is a connecting hole groove; 41 is a large hole end; 42 is a connecting section; 43 is a locking point; 44 is a small hole end; 45 is a sliding cavity; 5 is a connecting pin. DETAILED DESCRIPTION

[0030] 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.

[0031] Example 1

[0032] Please refer to Figures 1 to 7 The prosthesis for unicompartmental knee replacement of this embodiment includes:

[0033] Femoral condyle prosthesis, which is placed at the femoral end of the knee joint;

[0034] The tibial base prosthesis is placed on the tibial end of the knee joint;

[0035] The fixed gasket is placed between the tibial base prosthesis and the femoral condyle prosthesis. 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 femoral condyle prosthesis.

[0036] The disassembly and assembly of the fixed spacer and the tibial base prosthesis are similar and can be performed as follows:

[0037] First, the tibial base prosthesis is inserted into the groove of the horizontal end surface of the tibial osteotomy surface through the vertical plate with a downward convex bottom, and is attached to the vertical end surface of the tibial osteotomy surface through the vertical side plate;

[0038] Then, the femoral condyle prosthesis is inserted into the femur through the main insertion rod and the auxiliary insertion rod, and fixed on the lower end surface of the femur;

[0039] Then align the two plug pins of the fixed gasket with the large hole ends of the two plug slots respectively and insert them, move the fixed gasket along the plug slot toward the small hole end, and move it until the head of the plug pin slides and fits into the sliding cavity of the plug slot. With the help of the sliding fit between the two, a guide and limit is provided for the movement of the fixed gasket, until the pin column of the plug pin squeezes through the locking point and is inserted into the small hole end. At this point, the fixed gasket is installed in place, and the femoral condyle prosthesis can slide on the upper end of the fixed gasket;

[0040] If you need to remove the fixed gasket, just move it in the opposite direction to move the plug pin from the small hole end to the large hole end, then pull the plug pin upward to disengage it from the plug hole slot, and then you can take out the fixed gasket.

[0041] Example 2

[0042] Please refer to Figures 4 to 9 The prosthesis for unicompartmental knee replacement of this embodiment includes:

[0043] Femoral condyle prosthesis, which is placed at the femoral end of the knee joint;

[0044] The tibial base prosthesis is placed on the tibial end of the knee joint;

[0045] The movable gasket is slidably placed on the upper end of the tibial base prosthesis and between the tibial base prosthesis and the femoral condyle prosthesis. 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 femoral condyle prosthesis.

[0046] The prosthesis for unicompartmental knee replacement in this embodiment can be installed in the following manner:

[0047] First, the tibial base prosthesis is inserted into the groove of the horizontal end surface of the tibial osteotomy surface through the vertical plate with a downward convex bottom, and is attached to the vertical end surface of the tibial osteotomy surface through the vertical side plate;

[0048] Then, the femoral condyle prosthesis is inserted into the femur through the main insertion rod and the auxiliary insertion rod, and fixed on the lower end surface of the femur;

[0049] Then the movable gasket is directly placed on the upper end surface of the tibial prosthesis base, with the bottom surface abutting against the upper end surface of the tibial prosthesis base, and the arc notch on the upper surface is used to slide and support the bottom of the tibial base prosthesis.

[0050] 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 prosthesis for unicompartmental knee replacement, characterized by include: A femoral condyle prosthesis (2), which is arranged at the femoral end of the knee joint; A tibial base prosthesis (1) is provided at the tibial end of the knee joint; The tibial pad is placed between the tibial base prosthesis (1) and the femoral condyle prosthesis (2), and is always in sliding contact with the bottom of the femoral condyle prosthesis (2). It includes a fixed pad (31) and a movable pad (32). Any tibial pad can be used in conjunction with the tibial base prosthesis (1); the movable pad (32) can be slidably placed on the upper end of the tibial base prosthesis (1); the fixed pad (31) can be detachably assembled on the upper end of the tibial base prosthesis (1) through a plug-in structure; the plug-in structure includes two identical and parallel plug-in slots (4) that are concave from the upper end of the tibial base prosthesis (1), and also includes two plug-in pins (5) that are convex at the bottom of the fixed pad (31); the plug-in slot (4 ) one end is a large hole, the other end is a small hole, a sliding cavity (45) is provided between the large and small hole ends (44), a locking point (43) is provided near the small hole end (44), the two plug pins (5) are matched with the two plug hole slots (4) in a one-to-one manner, and the plug pin (5) completely inserted into the plug hole slot (4) is moved from the large hole end (41) by external force, squeezed through the locking point (43) and tightly matched in the small hole end (44), or the plug pin (5) is squeezed through the locking point (43) and moved in the opposite direction to the large hole end (41), and the plug pin (5) placed in the large hole end (41) and the plug hole slot (4) can be separated, and the plug pin (5) relies on the sliding cooperation between the sliding cavity (45) to limit and guide when moving.

2. The prosthesis for unicompartmental knee replacement according to claim 1, wherein: Along the moving track of the plug pin (5), the plug hole groove (4) is divided into a large hole end (41), a connecting section (42), and a small hole end (44) in sequence. The large hole end (41) and the small hole end (44) are two hole grooves, one large and one small, which are connected by the connecting section (42). One end of the connecting section (42) is tangent to the large hole end (41), and the other end intersects with the small hole end (44) at a locking point (43). The locking point (43) is a convex ridge of the groove walls on both sides of the plug hole groove (4) that bulges horizontally outward toward the groove. The groove width at the locking point (43) is the smallest. The lower end groove wall is formed with a horizontal concave sliding cavity (45), and the sliding cavity (45) extends from the small hole end (44) toward the large hole end (41) and smoothly connects to the large hole end (41); the plug pin (5) is slidably fitted in the sliding cavity (45) with its head facing downward, and when it moves to the small hole end (44), it is coaxially and tightly inserted into the small hole end (44) through the pin column, and the head keeps slidingly fitting in the sliding cavity (45). When it moves to the large hole end (41), a gap is left between it and the groove wall, and the head is separated from the sliding cavity (45).

3. The prosthesis for unicompartmental knee replacement according to claim 1 or 2, characterized in that: The plug pin (5) is a flat-head pin structure, and the outer diameter of the head portion is adapted to the hole diameter of the large hole end (41) of the plug hole slot (4).

4. The prosthesis for unicompartmental knee replacement according to claim 1 or 2, characterized in that: The plug pin (5) is made of elastic material.

5. The prosthesis for unicompartmental knee replacement according to claim 1 or 2, characterized in that: The two plug-in slots (4) are aligned and spaced apart at the upper end of the tibial base prosthesis (1) along the moving track of the plug-in pin (5).

6. The prosthesis for unicompartmental knee replacement according to claim 1, wherein: The upper end surface of the fixed gasket (31) is flat.

7. The prosthesis for unicompartmental knee replacement according to claim 1, wherein: The bottom of the femoral condyle prosthesis (2) is in the shape of a downwardly convex arc surface, and the upper surface of the movable gasket (32) is concave downwardly to form an arc surface recess (321), and the bottom of the femoral condyle prosthesis (2) is adaptively slidably placed in the arc surface recess (321).

8. The prosthesis for unicompartmental knee replacement according to claim 1, wherein: Notches (322) are formed on both sides of the lower portion of the movable gasket (32) to serve as clamping portions for surgical forceps to clamp.

Images