Tibia pad prosthesis assembly with embedded metal post

Abstract

The utility model discloses a tibia pad prosthesis assembly with an embedded metal column rod, and belongs to the technical field of medical instruments. The defect that in the prior art, long-term abrasion of a traditional tibia liner prosthesis assembly causes failure of a PS type prosthesis tibia liner stand column and further causes fracture of the tibia liner stand column is overcome. A main body structure of the tibia pad comprises a plastic cover cap, a metal column rod, a tibia pad main body and a base cover cap, the upper end of the metal column rod is provided with an inner taper hole used for being connected with the plastic cover cap in an assembled mode and an outer thread used for being connected with the base cover cap, and the tibia pad main body is provided with a tibia pad main body stepped hole and a bottom inner hole which are communicated with each other; an internal thread hole in threaded connection with the external thread is formed in the base cover cap, the metal column rod is assembled and connected with a tibia liner main body stepped hole in the tibia liner main body, and the base cover cap is assembled and connected with a bottom inner hole in the tibia liner main body. The total knee joint replacement device is mainly used for total knee joint replacement.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, and more specifically, it relates to a tibial liner prosthesis assembly with an embedded metal column. Background Technology

[0002] Knee osteoarthritis is a common chronic joint disease characterized by degeneration of articular cartilage and secondary osteophyte formation. Total knee arthroplasty is one of the most effective and widely used treatment options for advanced knee osteoarthritis. It can effectively remove damaged articular cartilage, meniscus, osteophytes, and synovium, and reconstruct lower limb alignment, correct deformities, and improve knee joint function. Posterior stabilized (PS) prostheses are widely used in total knee arthroplasty. The unique cam-column structure of the PS prosthesis replaces the function of the posterior cruciate ligament of the knee joint, preventing anterior femoral displacement. However, during movement, the PS prosthesis may experience premature cam-column contact due to increased posterior tibial base tilt; edge loads on the cam-column caused by femoral rotation; long-term creep of the plastic material itself; cam-column impact due to excessive flexion; and long-term wear of the cam-column under physiological conditions can all lead to failure of the PS prosthesis tibial liner column, and in severe cases, tibial liner column fracture. Tibial liner failure will cause severe pain and make it impossible for patients to perform normal daily activities. The prosthesis must be replaced through revision surgery, which will cause secondary damage to the patient and increase the patient's financial burden.

[0003] Therefore, in order to solve the problem of PS-type prosthetic tibial liner column failure and improve postoperative kinematic performance after TKA, it is necessary to take into account the long-term reliable stability of the column when designing PS-type prosthetic tibial liners.

[0004] For example, Chinese utility model patent CN 211243917 U discloses a tibial prosthesis locking component and an artificial knee joint prosthesis. It restricts the movement of the tibial pad by snapping it onto the tibial support, preventing the tibial pad from moving away from the tibial support. At the same time, the fixing part is inserted into the fixing groove between the tibial support and the tibial pad, forming resistance to prevent the rotation of the tibial pad relative to the tibial support, thus fixing the tibial pad to the tibial support. This alleviates the complexity of the locking structure between the tibial support and the tibial pad in the prior art. However, its shortcomings are that the tibial pad has poor durability and cannot effectively resist the impact of the femoral component on the pad post during knee joint movement, which can easily lead to the breakage of the tibial pad post. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a tibial liner prosthesis assembly with an embedded metal column.

[0006] To achieve the above objectives, this utility model employs the following technical solution:

[0007] A tibial liner prosthesis assembly with an embedded metal column includes a plastic cap, a metal column, a tibial liner body, and a base cap. The upper end of the metal column is provided with an inner conical hole for assembly and connection with the plastic cap and an external thread for connection with the base cap. The tibial liner body is provided with a stepped hole and a bottom inner hole that are interconnected. The base cap is provided with an internal threaded hole for connection with the external thread. The metal column is assembled and connected to the stepped hole of the tibial liner body, and the base cap is assembled and connected to the bottom inner hole of the tibial liner body.

[0008] Preferably, it also includes a locking screw, the side of the base cap is provided with a side positioning hole, and the tibial pad body is also provided with a side internal thread hole communicating with the bottom inner hole, and the locking screw is installed in the side internal thread hole on the tibial pad body.

[0009] Preferably, the locking screw is provided with external threads, and the locking screw is threadedly connected to the tibial pad body through the external threads and the side internal thread hole, and the top tip of the locking screw abuts against the side positioning hole on the base cap.

[0010] Preferably, the outer side of the base cap is the outer diameter of the contour, and the bottom inner hole on the tibia pad body is interference-fitted with the outer diameter of the contour.

[0011] Preferably, the metal column is threadedly connected to the base cap via external and internal threaded holes.

[0012] Preferably, the bottom of the plastic cap is provided with a lower conical post, which is assembled into the inner conical hole on the metal column through a conical connection.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. By interfering with the inner bottom hole of the tibial pad body and the outer diameter of the base cap, the rotation of the base cap is prevented, thus achieving circumferential positioning and fixation; at the same time, the external thread of the locking screw is screwed into the side internal thread hole of the tibial pad body until the tip of the locking screw enters the side positioning hole of the base cap, thus achieving axial positioning and fixation of the base cap.

[0015] 2. Insert the metal rod into the stepped hole of the tibial liner body from the top. Tighten the metal rod with a special tool so that its external thread is screwed into the internal thread hole of the base cap until the stepped shaft of the metal rod fits into the stepped hole of the tibial liner body, thereby achieving axial and circumferential positioning and fixation of the metal rod.

[0016] 3. From the top, assemble the lower tapered end of the plastic cap into the inner tapered hole at the upper end of the metal column through a tapered connection to achieve axial and circumferential fixation of the plastic cap;

[0017] 4. This utility model can significantly improve the fatigue service life of the metal column, realize the long-term reliable stability of the PS type prosthesis, reduce the failure rate of the knee joint prosthesis due to the failure of the existing pad column, and at the same time, the embedded metal column can be designed with different shapes and diameters according to the characteristics of the tibial pad body, so as to achieve flexible matching.

[0018] 5. Through the precise fit between the metal column and the tibial pad body, and the interference fit between the base cap and the tibial pad body, the overall stability and reliability of the prosthesis assembly are significantly improved, reducing the risk of loosening or falling off the prosthesis during use and extending the service life of the prosthesis.

[0019] In summary, this invention achieves enhanced impact resistance by embedding metal columns within the tibial pad body. Furthermore, the metal columns can be designed with different shapes and diameters according to the characteristics of the tibial pad body to meet different restrictive requirements during exercise. Attached Figure Description

[0020] Figure 1 This is an exploded view of the present invention;

[0021] Figure 2 This is an internal sectional view of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure during assembly of this utility model;

[0023] Figure 4 for Figure 3 Sectional view of AA.

[0024] In the diagram: 1. Plastic cap; 2. Metal column; 3. Tibial liner body; 4. Locking screw; 5. Base cap; 6. Lower tapered column; 7. Inner tapered hole; 8. Stepped shaft; 9. External thread; 10. Stepped hole in tibial liner body; 11. Bottom inner hole; 12. Side internal threaded hole; 13. External thread; 14. Top tip of locking screw; 15. Internal threaded hole; 16. Side positioning hole; 17. Outer diameter of the profile. Detailed Implementation

[0025] The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

[0026] Example 1:

[0027] like Figure 1-4As shown, a tibial liner prosthesis assembly with an embedded metal column includes a plastic cap 1, a metal column 2, a tibial liner body 3, and a base cap 5. The upper end of the metal column 2 is provided with an inner conical hole 7 for assembly and connection with the plastic cap 1 and an external thread 9 for connection with the base cap 5. The tibial liner body 3 is provided with a stepped hole 10 and a bottom inner hole 11 that are interconnected. The base cap 5 is provided with an internal threaded hole 15 for threaded connection with the external thread 9. The metal column 2 is assembled and connected to the stepped hole 10 on the tibial liner body 3, and the base cap 5 is assembled and connected to the bottom inner hole 11 on the tibial liner body 3.

[0028] Specifically, this invention uses an interference fit between the bottom inner hole 11 of the tibial pad body 3 and the outer diameter 17 of the base cap 5 to prevent rotation of the base cap 5, achieving circumferential positioning and fixation. Simultaneously, the external thread 13 of the locking screw 4 is screwed into the side internal thread hole 12 of the tibial pad body 3 until the tip 14 of the locking screw enters the side positioning hole 16 of the base cap 5, achieving axial positioning and fixation of the base cap 5. From the top, the metal rod 2 is inserted into the tibial pad body stepped hole 10 of the tibial pad body 3. A special tool is used to tighten the metal rod 2 so that its external thread 9 enters the internal thread hole 15 of the base cap 5, until the stepped shaft 8 of the metal rod 2 fits against the stepped hole 10 of the tibial pad body, achieving axial and circumferential positioning and fixation of the metal rod 2. From the top, the lower conical column 6 of the plastic cap 1 is assembled into the inner conical hole 7 of the upper end of the metal rod 2 via a conical connection, achieving axial and circumferential fixation of the plastic cap 1. This structure enables the embedded metal column 2 of the tibial pad body 3 to enhance impact resistance. At the same time, the metal column 2 can be designed with different shapes and diameters according to the characteristics of the tibial pad body 3 to meet different restrictive requirements during sports.

[0029] Example 2:

[0030] A tibial liner prosthesis assembly with an embedded metal column, differing from Embodiment 1 in that it further includes a locking screw 4. The base cap 5 has a side positioning hole 16, and the tibial liner body 3 also has a side internal threaded hole 12 communicating with the bottom inner hole 11. The locking screw 4 is installed in the side internal threaded hole 12 on the tibial liner body 3. Specifically, the locking screw 4 has an external thread 13, and is threadedly connected to the tibial liner body 3 through the external thread 13 and the side internal threaded hole 12. The tip 14 of the locking screw 4 abuts against the side positioning hole 16 on the base cap 5. The locking screw 4 further enhances the connection strength between the base cap 5 and the tibial liner body 3, effectively preventing loosening due to accidental impact or movement, and increasing safety during use.

[0031] Furthermore, the outer surface of the base cap 5 has an outer diameter of 17, and the bottom inner hole 11 on the tibial pad body 3 is interference-fitted with the outer diameter of 17. By interfering with the bottom inner hole 11 of the tibial pad body 3 and the outer diameter of 17 of the base cap 5, rotation of the base cap 5 is prevented, achieving circumferential positioning and fixation.

[0032] Furthermore, the metal column 2 is threadedly connected to the base cap 5 via the external thread 9 and the internal thread hole 15.

[0033] Furthermore, the bottom of the plastic cap 1 is provided with a lower conical post 6, which is assembled into the inner conical hole 7 on the metal rod 2 via a conical connection. The plastic cap 1 and the metal rod 2 are connected in a conical shape, and the base cap 5 and the metal rod 2 are connected by threads. These designs make the installation of the prosthesis components simpler and faster, and also facilitate possible adjustments or replacements after surgery.

[0034] Currently, the main materials used for PS-type tibial liner pillars on the market are plastics, such as ultra-high molecular weight polyethylene, highly cross-linked polyethylene, and polyethylene containing antioxidants. Although the strength of the liner pillars has been improved through certain processes, the strength improvement is limited because they are still based on polyethylene. Therefore, the impact resistance of the liner pillars is also limited. This utility model of a tibial liner prosthesis component achieves the integration of a stronger metal pillar 2 into a plastic tibial liner body 3, thus combining metal and plastic materials. The metal pillar 2 can be made of a cobalt-chromium-molybdenum alloy (approximately 30 times stronger than polyethylene) with good biocompatibility and higher strength. Compared with existing plastic liner pillars, this significantly improves the overall strength, making it more effective in resisting the impact of the femoral component on the metal pillar 2 during knee joint movement, and improving the durability of the tibial liner body 3. At the same time, the top of the component is designed with a plastic cap 1 of the same material as the tibial liner body 3 to prevent foreign objects from intruding and affecting the metal pillar 2. This invention can significantly improve the fatigue life of the metal column 2, achieve long-term reliable stability of the PS type prosthesis, reduce the failure rate of the knee joint prosthesis due to the failure of the existing pad column, and at the same time, the embedded metal column 2 can be designed with different shapes and diameters according to the characteristics of the tibial pad body 3, so as to achieve flexible matching and meet different restrictive requirements in knee joint movement.

Claims

1. A tibial liner prosthesis assembly with an embedded metal column, characterized in that: The device includes a plastic cap (1), a metal rod (2), a tibial pad body (3), and a base cap (5). The upper end of the metal rod (2) is provided with an inner conical hole (7) for assembly and connection with the plastic cap (1) and an external thread (9) for connection with the base cap (5). The tibial pad body (3) is provided with a tibial pad body stepped hole (10) and a bottom inner hole (11) that are interconnected. The base cap (5) is provided with an internal thread hole (15) for threaded connection with the external thread (9). The metal rod (2) is assembled and connected with the tibial pad body stepped hole (10) on the tibial pad body (3), and the base cap (5) is assembled and connected with the bottom inner hole (11) on the tibial pad body (3).

2. The tibial liner prosthesis assembly with an embedded metal column as described in claim 1, characterized in that: It also includes a locking screw (4), and the side of the base cap (5) is provided with a side positioning hole (16). The tibial pad body (3) is also provided with a side internal thread hole (12) that communicates with the bottom inner hole (11). The locking screw (4) is installed in the side internal thread hole (12) on the tibial pad body (3).

3. The tibial liner prosthesis assembly with an embedded metal column as described in claim 2, characterized in that: The locking screw (4) is provided with an external thread (13). The locking screw (4) is threadedly connected to the tibial pad body (3) through the external thread (13) and the side internal thread hole (12). The top tip (14) of the locking screw (4) abuts against the side positioning hole (16) on the base cap (5).

4. The tibial liner prosthesis assembly with an embedded metal column as described in any one of claims 1-3, characterized in that: The outer side of the base cap (5) is the outer diameter (17), and the bottom inner hole (11) on the tibial pad body (3) is an interference fit with the outer diameter (17).

5. The tibial liner prosthesis assembly with an embedded metal column according to any one of claims 1-3, characterized in that: The metal column (2) is threadedly connected to the base cap (5) through an external thread (9) and an internal thread hole (15).

6. The tibial liner prosthesis assembly with an embedded metal column according to any one of claims 1-3, characterized in that: The bottom of the plastic cap (1) is provided with a lower cone (6), which is assembled into the inner cone hole (7) on the metal rod (2) through a cone connection.

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