Customized artificial lunar bone prosthesis

Abstract

The utility model discloses a customized artificial lunar bone prosthesis which comprises a lunar bone body, a joint cotyle is arranged in the middle of the lunar bone body, a head-moon joint protrusion capable of simulating the form and the movement track of a head-moon bone is installed in the joint cotyle, and the top of the head-moon joint protrusion is fixedly connected with a center nail. The free end of the center nail extends out of the lunar bone body and is arranged in a head-shaped bone of the wrist of the human body, and a plurality of sets of ligament suture holes are further formed in the back side of the lunar bone body. The customized artificial lunar bone prosthesis provided by the utility model aims to be applied to lunar bone replacement surgery, mainly aims to treat advanced lunar bone ischemic necrosis caused by non-traumatic or traumatic factors, and is beneficial to improving the stability of the prosthesis and improving the joint movement; basic biomechanics and clinical experiment research verify that the prosthesis has good mechanical properties and clinical curative effects, promote development of the lunar bone prosthesis, enable more patients to retain wrist joint movement, create more values for society and families, and contribute to achieving the goal of healthy China.

Description

TECHNICAL FIELD

[0001] The utility model relates to medical instrument technical field, concretely point to a kind of customized artificial lunate prosthesis. BACKGROUND

[0002] At present, there are various surgical methods for treating advanced lunate avascular necrosis, such as osteotomy, bone grafting, tendon plugging, joint fusion and lunate prosthesis replacement, which can reduce the load and relieve pain to some extent, but have obvious shortcomings, such as bone grafting cannot repair the shape and position of the lunate initially, which requires a long treatment process; osteotomy and joint fusion sacrifice the function of the wrist joint; and lunate prosthesis replacement may cause dislocation, loosening and other conditions. Overall, the current treatment plan is difficult to meet the goals of pain relief, movement preservation, strength maintenance and functional outcome. With the continuous development of society and medicine, more and more patients have higher demands for preserving the function of the wrist, and there is an urgent need to solve the problem of pain and preserve the function of the wrist.

[0003] The anatomical shape of the lunate and its surrounding ligament structure are relatively complex, making it difficult to design an artificial prosthesis. Early lunate prostheses include artificial silicone rubber, ceramic, bone cement and titanium alloy lunate prostheses, which can relieve pain and preserve some hand function and delay disease progression, but are prone to complications such as prosthesis loosening, dislocation, collapse, wrist joint degeneration, cartilage wear, reactive inflammation and carpal tunnel syndrome, and are no longer used in clinical practice. The above-mentioned postoperative complications of lunate prosthesis replacement are basically related to factors such as poor prosthesis matching and poor stability, making it difficult to restore the anatomical structure and movement of the lunate. With the development of digital medicine, 3D printing technology and biomaterial engineering, various new types of artificial lunate prostheses have been applied in clinical practice and have achieved the advantages of reconstructing the anatomical structure, maintaining the height and mobility of the wrist, preventing further collapse of the wrist joint and improving pain symptoms. Therefore, the application of artificial lunate prosthesis is an important research direction for the treatment of lunate avascular necrosis. Foreign scholars have reconstructed the normal lunate morphology of patients with stage IIIc lunate necrosis through reverse repair technology, and then replaced it with a 3D printed individualized polyethylene artificial lunate prosthesis. In the 12-month follow-up, wrist pain, wrist weakness and numbness disappeared, and the wrist function was well restored. There was no evidence of degenerative arthritis or prosthesis dislocation on the plain film, but the ligament structure of the lunate was not reconstructed, and there was a lack of tissue function connection. Domestic scholars improved the design of a customized 3D printed porous titanium, hoping to achieve the effect of soft tissue ingrowth to increase the stability of the prosthesis. However, some studies have shown that metal lunate prosthesis replacement can effectively relieve pain, but long-term follow-up has found that it is prone to long-term complications such as loosening and stress shielding. These designs are mostly short-term case reports, and lack of biomechanical and long-term clinical studies to prove their efficacy, especially the long-term stability of the prosthesis after surgery remains questionable and controversial.

[0004] Late lunate avascular necrosis causes wrist pain, deformity, limited activity, and seriously affects the patient's life, study and work, and now more treatment programs such as osteotomy, proximal row carpectomy are used, but it cannot meet the needs of patients to solve pain and retain joint function. Lunate prosthesis replacement develops slowly, and restoring the anatomical structure and activity of the lunate is a clinical problem. Although with the development of 3D printing technology, customized anatomical prosthesis is gradually realized, but there are still many problems to be solved. Content of the utility model

[0005] The utility model discloses a kind of customized artificial lunate prosthesis, which restores the anatomical structure and activity of the lunate of the patient as much as possible and further strengthens fixation, which is helpful for the rehabilitation of the wrist of the patient.

[0006] The utility model realizes by the following technical scheme: a kind of customized artificial lunate prosthesis, including lunate body, the middle part of the lunate body is provided with joint socket, the joint socket is installed with the head lunate joint convex capable of simulating the form and activity track of head lunate, the head lunate joint convex top is fixedly connected with center nail, the free end of the center nail extends out of lunate body and is placed in the osseous head of human wrist, and lunate body back side is also provided with several groups of ligament suture holes.

[0007] The working principle of the technical solution is that the implantation of artificial lunate prosthesis not only needs to maintain the stability of wrist joint statics, but also should have high requirements for wrist joint dynamics. After years of clinical practice, it is found that although customized 3D printing lunate prosthesis has achieved the reconstruction of anatomical structure and the recovery of wrist height, due to the complex tissue structure around the lunate, a single anatomical lunate prosthesis is difficult to reconstruct the connection between the lunate and the surrounding tissue structure, which may be the reason for postoperative prosthesis loosening, especially dislocation of head lunate joint, and complications such as degenerative changes of wrist joint.

[0008] The design of the head-month joint (lunate concave surface) and the radius-month joint (lunate convex surface) of the artificial lunate prosthesis is important, and the design of the concave surface plays an important role in maintaining the stability of the prosthesis. In the design, the biomechanical structure of the head-month joint surface and the radius-month joint surface should be considered, and the reconstruction of the ligament around the lunate should also be considered, so as to restore the physiological mechanical state and achieve the stability of the intercarpal bones and the improvement of the postoperative wrist function. Therefore, the inventor innovatively designs a prosthesis head-month combined joint on the head-month joint surface: the joint socket of the high-molecular polyethylene lunate body and the cobalt-chromium-molybdenum alloy combined convex implanted into the capitatum are combined, and are connected with the upper porous tantalum capitatum central nail bolt. The lunate body and the capitatum can rotate in all directions to maintain the stable connection of the joint, so as to achieve the goal of increasing the motion stability of the prosthesis and improving the rotation function of the prosthesis. In the wrist movement, the stress and mechanical strength of the ligament between the scapholunate and the triquetral lunate are very large, and the ligament between the scapholunate is one of the important ligaments for maintaining the stability of the lunate. Therefore, the reconstruction of the ligament around the lunate is very important for restoring the physiological mechanical state and maintaining the stability of the wrist joint. Therefore, the multidirectional threading hole on the dorsal surface of the lunate body is further adjusted and improved to reconstruct the head-month ligament, the scapholunate ligament and the triquetral lunate ligament and other tissue structures, so as to increase the long-term stability of the prosthesis.

[0009] In order to better realize the utility model, further, the lower part of the central nail is a bolt with external threads, the top of the head-month combined convex is provided with a concave hole with internal threads, and the central nail is connected with the concave hole on the upper part of the head-month combined convex through the bolt of the lower part.

[0010] In order to better realize the utility model, further, the dorsal surface of the lunate body is provided with three groups of ligament suture holes, each group of ligament suture holes is two, the inner walls of the three groups of ligament suture holes are smooth, and the three groups of ligament suture holes are vertically arranged on the dorsal surface of the lunate body, and the three groups of ligament suture holes are respectively used for reconstructing the ligaments at the scapholunate, the triquetral lunate and the head-month.

[0011] In order to better realize the utility model, further, the size and shape of the lunate body are designed and customized according to the CT data of the lunate of the healthy wrist joint.

[0012] In order to better realize the utility model, further, the two sides of the non-articular surface of the lunate body are in contact with the surrounding soft tissues.

[0013] In order to better realize the utility model, further, the material of the lunate body is high-molecular polyethylene with a molecular weight of not less than 310 Da.

[0014] In order to better realize the utility model, further, the material of the head-month combined convex is cobalt-chromium-molybdenum alloy.

[0015] In order to better realize the utility model, further, the material of the central nail is porous tantalum.

[0016] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0017] (1) the utility model discloses a head month combined joint formed by the bone body and the head-shaped intramedullary nail assembly, improves the prosthetic rotation activity function, increases the motion stability of the prosthesis;

[0018] (2) the utility model discloses that the porous tantalum head-shaped bone center nail promotes the bone growth, improves the long-term stability;

[0019] (3) the utility model discloses the 3D printing high molecular polyethylene lunatomical body, has enough intensity, and long-term is not easy to loosen, reduces the risk of postoperative stress shielding and wrist joint degeneration;

[0020] (4) the utility model discloses the ligament suture hole on the dorsal metacarpal surface of lunatomical body reconstructs the head month ligament, the navicular lunatomical ligament and the lunotriquetral ligament and other tissue structures, increases the long-term stability of the prosthesis;

[0021] (5) the utility model discloses the customized artificial lunate prosthesis, is applied to lunate replacement operation, mainly treats the late lunate avascular necrosis caused by non-traumatic or traumatic factors, and the customized artificial lunate prosthesis helps to improve the stability of the prosthesis and improve the joint activity, and through basic biomechanics and clinical experimental research, it is verified that the prosthesis has good mechanical properties and clinical curative effect, promotes the development of lunate prosthesis, lets more patients retain the wrist joint activity, creates more value for society and family, and contributes to the realization of the goal of healthy China. BRIEF DESCRIPTION OF DRAWINGS

[0022] Other features, objects and advantages of the utility model will become more apparent through reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0023] Figure 1 It is the three-dimensional structure schematic diagram of the utility model;

[0024] Figure 2 It is the back side drawing of the utility model;

[0025] Figure 3 It is the side view of the utility model;

[0026] Figure 4 It is the sectional view of the side of the utility model;

[0027] Figure 5 It is the partial structure split schematic diagram of the utility model;

[0028] Figure 6 It is the implantation wrist joint back side schematic diagram of the utility model;

[0029] Figure 7The utility model implants wrist joint lateral position schematic diagram.

[0030] Among them: 1 - lunate body, 11 - joint socket, 2 - head lunate connecting convex, 3 - center nail, 4 - ligament suture hole, 5 - capitular bone. DETAILED DESCRIPTION

[0031] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the utility model and cannot be understood as a limitation of the utility model.

[0032] In the description of the utility model, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as a limitation of the utility model. In the description of the utility model, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be mechanical connection, or electrical connection, it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0033] Embodiment 1:

[0034] The main structure of this embodiment, as shown in Figures 1-4 It comprises a lunate body 1, a joint socket 11 is arranged in the middle of the lunate body 1, a head lunate joint convex 2 capable of simulating the shape and activity track of the head lunate bone is mounted in the joint socket 11, a center nail 3 is fixedly connected to the top of the head lunate joint convex 2, the free end of the center nail 3 extends out of the lunate body 1 and is placed in the capitular bone of the human wrist, and a plurality of groups of ligament suture holes 4 are further arranged on the back side of the lunate body 1.

[0035] The customized artificial lunate prosthesis, the lunate body 1 of the integral lunate assembly made by 3D printing is an anatomical type high crosslinking ultrahigh molecular weight polyethylene lunate body, which has sufficient strength, is not easy to loosen in the long term, and reduces the risk of postoperative stress shielding and wrist joint degeneration.

[0036] The head month joint convexity 2 is made by 3D printing, and is based on the joint socket 11 of the polyethylene lunate body 1. The head month joint convexity 2 simulates the normal head month joint surface of the patient, and is used to simulate the shape and movement track of the head month joint. The lunate body 1 and the capitate bone can rotate in all directions and are stably connected, so that the movement stability of the prosthesis is improved, and the rotating function of the prosthesis is improved.

[0037] The customized artificial lunate prosthesis is mainly used for lunate replacement surgery, and is mainly used for treating late-stage lunate avascular necrosis caused by non-traumatic or traumatic factors. The manufacturing method is as follows: a 3D model of the lunate of the patient is established, the anatomical parameters such as the palmar tilt angle, the ulnar deviation angle, the carpal lunate height, the radial-carpal lunate joint curvature, and the area are measured, the design scheme of the new customized 3D printed lunate prosthesis is used, the structure adjustment point of the prosthesis model is adjusted, and the corresponding lunate prosthesis is customized according to the specific material by using the 3D printing technology.

[0038] The prepared lunate prosthesis is implanted into the new customized 3D printed lunate prosthesis through a standardized lunate replacement surgery, and the specific process is as follows:

[0039] The center pin 3 is inserted into the capitate bone, then the head month joint convexity 2 is installed into the joint socket 11 of the lunate body 1, and then the center pin 3 and the head month joint convexity 2 are fixedly connected to form a head month joint, so that the movement stability of the prosthesis is improved, and the rotating function of the prosthesis is improved. The lunate body 2 is provided with a ligament suture hole 4 on the back side, which is used to reconstruct the head month ligament, the carpal lunate ligament, and the lunate triangular ligament, and to improve the long-term stability of the prosthesis. After implantation, as shown in Figure 6 , Figure 7 ,

[0040] Embodiment 2

[0041] In the above embodiment, the structure and connection relationship of the center pin 3 and the head month joint convexity 2 are further limited, as shown in Figure 5 The lower part of the center pin 3 is a bolt with external threads, the top of the head month joint convexity 2 is provided with a recessed hole with internal threads, and the center pin 3 is connected to the head month joint convexity 2 by the bolt in the lower part and the recessed hole in the upper part. The center pin 3 connected to the head month joint convexity 2 by the bolt is implanted into the medullary cavity of the capitate bone under the guidance of the guide pin during the operation, and does not penetrate the capitate bone, so as to improve the long-term stability of the lunate prosthesis. The other parts of the embodiment are the same as those of the above embodiment, and will not be described herein again.

[0042] Embodiment 3

[0043] In the above embodiment, the number of ligament suture holes 4 is further limited, as shown in Figure 1 , Figure 2The dorsal side of the lunate body 1 is provided with three groups of ligament suture holes 4, each group of ligament suture holes 4 has two ligament suture holes 4, and the inner walls of the three groups of ligament suture holes 4 are smooth and vertically arranged on the dorsal side of the lunate body 1. The three groups of ligament suture holes 4 are used to reconstruct the ligaments at the scapholunate, lunotriquetral and capitulolunate joints, respectively. The smooth inner walls of the ligament suture holes 4 facilitate the passage of the suture needle through the ligament suture holes 4 and prevent the suture needle from jamming during the perforation process. The three groups of ligament suture holes 4 facilitate the reconstruction of the scapholunate, lunotriquetral and capitulolunate ligaments, and increase the long-term stability of the prosthesis. The other parts of this embodiment are the same as those of the above-mentioned embodiments and will not be described again.

[0044] Embodiment 4:

[0045] In this embodiment, the size of the lunate body 1 is further limited based on the above-mentioned embodiments. The size and shape of the lunate body 1 are designed and customized according to the CT data of the healthy side wrist joint lunate. This arrangement ensures the accuracy of the lunate body production, and further ensures good function of the wrist joint after surgery. The other parts of this embodiment are the same as those of the above-mentioned embodiments and will not be described again.

[0046] Embodiment 5:

[0047] In this embodiment, the position of the lunate body 1 after transplantation is further limited based on the above-mentioned embodiments. The non-articular surface sides of the lunate body 1 are in contact with the surrounding soft tissues. The other parts of this embodiment are the same as those of the above-mentioned embodiments and will not be described again.

[0048] Embodiment 6:

[0049] In this embodiment, the material of the lunate body 1 is further limited based on the above-mentioned embodiments. The material of the lunate body 1 is high molecular weight polyethylene with a molecular weight not less than 310 Da. 3D printing of high molecular weight polyethylene lunate body has sufficient strength and is not prone to loosening in the long term, reducing the risk of postoperative stress shielding and wrist joint degeneration. High molecular weight polyethylene has good biocompatibility and durability, and has high stability, and will not cause allergy, so it is the preferred material for the lunate body 1. Other materials that can achieve the same function can also be selected. The other parts of this embodiment are the same as those of the above-mentioned embodiments and will not be described again.

[0050] Embodiment 7:

[0051] In this embodiment, the material of the capitulolunate joint convexity 2 is further limited based on the above-mentioned embodiments. The material of the capitulolunate joint convexity 2 is cobalt-chromium-molybdenum alloy. Cobalt-chromium-molybdenum alloy is a high-strength and high-corrosion-resistant metal material, which has excellent mechanical properties and chemical stability, and is widely used in the medical field. Therefore, it is the preferred material for the capitulolunate joint convexity 2. Other materials that can achieve the same function can also be selected. The other parts of this embodiment are the same as those of the above-mentioned embodiments and will not be described again.

[0052] Embodiment 8:

[0053] The material of the central nail 3 is porous tantalum. The central nail 3 is implanted into the capitulum under the guidance of the guide pin without penetrating the capitulum. The porous tantalum promotes bone growth, thereby enhancing the long-term stability of the artificial capitulum prosthesis. Therefore, the material of the central nail 3 is preferred, and other materials having the same function can also be selected. The other parts of the embodiment are the same as those of the above-described embodiments, and will not be described again.

[0054] It can be understood that the properties and performances of the customized artificial capitulum prosthesis structure according to one embodiment of the present application, such as polyethylene and porous tantalum, are all prior art and are well known to those skilled in the art, and will not be described in detail herein.

[0055] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A customized artificial lunate prosthesis, characterized in that, It includes a lunate body (1), a acetabulum (11) is provided in the middle of the lunate body (1), a cephalunate syndesmoid (2) that can simulate the shape and movement trajectory of the cranial lunate is installed in the acetabulum (11), a central nail (3) is fixedly connected to the top of the cephalunate syndesmoid (2), the free end of the central nail (3) extends out of the lunate body (1) and is placed in the capitate bone of the human wrist, and several sets of ligament suture holes (4) are also provided on the dorsal side of the lunate body (1).

2. The customized artificial lunate prosthesis according to claim 1, characterized in that, The lower part of the central nail (3) is a bolt with external threads, and the top of the head-moon joint protrusion (2) is provided with a concave hole with internal threads. The central nail (3) is connected to the upper concave hole bolt of the head-moon joint protrusion (2) by the screw at the lower part.

3. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The dorsal side of the lunar body (1) is provided with three sets of ligament suture holes (4), each set of ligament suture holes (4) consists of two holes, and the inner walls of the three sets of ligament suture holes (4) are smooth and arranged vertically on the dorsal side of the lunar body (1). The three sets of ligament suture holes (4) are used to reconstruct the ligaments at the scaphoid, lunar triangle and cranial regions, respectively.

4. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The size and shape of the lunar bone body (1) are designed and customized based on the CT data of the lunar bone of the healthy wrist joint.

5. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The non-articular surfaces of the lunar body (1) are in contact with the surrounding soft tissues.

6. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The material of the lunar bone body (1) is high molecular weight polyethylene with a molecular weight of not less than 310 Da.

7. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The material of the first-month joint convex (2) is a cobalt-chromium-molybdenum alloy.

8. A customized artificial lunate prosthesis according to claim 1 or 2, characterized in that, The central nail (3) is made of porous tantalum.

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