A temporary prosthetic device capable of being extended and a method of use thereof

Abstract

This application relates to the field of medical device technology, and more particularly to an extendable temporary prosthesis device and its method of use. The extendable temporary prosthesis device includes: an intramedullary nail, a temporary prosthesis, and a hinge assembly. The intramedullary nail is inserted into the proximal femur and fixed by an external fixator. The temporary prosthesis is positioned between the femur and tibia and is slidably connected to the intramedullary nail. The hinge assembly is connected between the temporary prosthesis and the tibia, enabling flexion and extension of the knee joint. The extendable temporary prosthesis device of this invention can cooperate with the extension function of the external fixator to increase the distance between the femur and tibia, and drive the temporary prosthesis downward within the body, thus achieving the extension function of the temporary prosthesis. Through the hinge assembly positioned between the temporary prosthesis and the tibia, the tibia can flex and extend relative to the temporary prosthesis, facilitating early flexion and extension rehabilitation training of the knee joint after the temporary prosthesis has moved into place, ensuring the recovery of knee joint function.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to an extendable temporary prosthetic device and a method of use. Background Art

[0002] Children with limb bone tumors undergo surgical artificial joint replacement surgery many years later. As the children grow, their height and bones grow, resulting in unequal lengths of limbs, especially healthy limbs and affected limbs.

[0003] In the past, there were three main solutions for limb length discrepancy. The first was amputation; the second was replacement with an extendable artificial prosthesis. The prosthesis was mechanically extended by 1 to 2 cm each year after the wound was opened. It could not be extended to the full extent in one go and required multiple surgeries. The third method required at least three surgeries. The first surgery was to remove the original prosthesis and insert a temporary bone cement prosthesis, while placing an external extension fixator. The second surgery was to extend the external fixator, remove the original temporary prosthesis (short), and then insert a temporary bone cement prosthesis (long). After 3 to 6 months, it was confirmed that there was no infection in the external fixator in the limb nail channel. Then, the temporary prosthesis was replaced with an artificial prosthesis to complete the revision surgery.

[0004] As the most effective treatment option, the third method mainly includes three steps: removing the initial distal femoral prosthesis and implanting an intramedullary nail in the proximal femoral medullary cavity. The distal bone cement is molded into a temporary prosthesis and connected to the tibial end. After the external fixator is fixed to the proximal femur and distal tibia, it is extended by 1 mm per day. If it is extended by 10 cm, it will take about 100 days.

[0005] Regular check-ups are required. After the extension is in place, a second operation is required. The limb is opened to replace the intramedullary nail and the temporary prosthesis shaped with bone cement. A longer intramedullary nail replaces the short intramedullary nail before extension. The proximal femur and the proximal tibia are fixed to maintain normal force line. Wait 3 to 6 months for the pinholes of the external fixator to heal. Regular check-ups are performed to confirm that no inflammation occurs.

[0006] The third operation was to replace the formal revision prosthesis and complete the surgical treatment.

[0007] The above treatment process lasted nearly a year, which was very time-consuming. In addition, during the nearly one year after the second and third operations, the knee joint was immobilized for a long time and could not bend and move, which seriously affected the future recovery of the knee joint function. Summary of the Invention

[0008] The purpose of this application is to provide an extendable temporary prosthesis device and a method of use, which can cooperate with an external fixator to move the temporary prosthesis downward in the body, and enable the knee joint between the temporary prosthesis and the tibia to flex and extend during the recovery process of the secondary surgery, which is beneficial for the patient to exercise as soon as possible.

[0009] To achieve the above objectives, in a first aspect, the present invention provides an extendable temporary prosthesis device, comprising: an intramedullary nail, a temporary prosthesis, and a hinge assembly, wherein the intramedullary nail is inserted into the proximal end of the femur and fixed by an in vitro fixator, the temporary prosthesis is arranged between the femur and the tibia, and is slidably connected to the intramedullary nail, and the hinge assembly is connected between the temporary prosthesis and the tibia to enable flexion and extension of the knee joint.

[0010] In an optional embodiment, the extracorporeal fixation frame is connected to a femoral fixation nail for fixing the intramedullary nail, and a tibial fixation nail connected to the tibia, and a sliding frame capable of adjusting and extending the distance between the femur and tibia is provided between the femoral fixation nail and the tibial fixation nail.

[0011] In an optional embodiment, at least a portion of the distal end of the intramedullary nail is inserted into the temporary prosthesis, and mutually cooperating slide rails and slide grooves are provided between the temporary prosthesis and the intramedullary nail. The temporary prosthesis can slide downward relative to the intramedullary nail as the distance between the femur and the tibia increases.

[0012] In an optional embodiment, a fixing hole for inserting the femoral fixing nail is provided at the proximal end of the intramedullary nail, and the fixing hole comprises an elliptical through hole that penetrates the intramedullary nail in a radial direction.

[0013] In an optional embodiment, the distal end of the intramedullary nail and the proximal end of the temporary prosthesis are respectively provided with an intramedullary nail connection hole and a prosthesis connection hole, so as to enable the temporary prosthesis to be fixedly connected to the intramedullary nail after being moved down into position.

[0014] In an optional embodiment, the penetration direction of the intramedullary nail connecting hole is perpendicular to the penetration direction of the fixing hole. During the downward movement of the temporary prosthesis, a nail cap is provided on the prosthesis connecting hole. After the temporary prosthesis is moved down into place, the intramedullary nail and the temporary prosthesis are fixedly connected by a connecting nail that is simultaneously inserted into the intramedullary nail connecting hole and the prosthesis connecting hole.

[0015] In an optional embodiment, the hinge assembly includes a movable block and a hinge shaft, the movable block includes a hinge block located at the top, the hinge block is provided with a hinge hole, the hinge shaft is passed through the hinge hole, and both ends of the hinge shaft are fixedly connected to the distal end of the temporary prosthesis.

[0016] In an optional embodiment, the movable block further comprises a plug-in block connected to the lower part of the hinge block, the plug-in block comprises a wedge-shaped structure, and the movable block is connected to the proximal end of the tibia via the plug-in block.

[0017] In an optional embodiment, a support assembly is further included, wherein the support assembly includes a support block that is clamped on the outside of the intramedullary nail, and the support block is arranged between the femur and the temporary prosthesis.

[0018] In a second aspect, the present invention provides a method for using the extendable temporary prosthetic device according to any one of the aforementioned embodiments, comprising the following steps:

[0019] An intramedullary nail is implanted in the femoral medullary cavity, and a temporary prosthesis is slidably connected to the distal end of the intramedullary nail;

[0020] The intramedullary nail is fixed to the proximal femur and the distal tibia through an external fixator, and the distance between the femur and tibia is adjusted and extended to allow the temporary prosthesis to slide downward;

[0021] After the temporary prosthesis is lowered into place, the proximal end of the temporary prosthesis is fixedly connected to the distal end of the intramedullary nail, and the external fixator is removed, allowing the patient to perform rehabilitation training while the knee joint can be flexed and extended;

[0022] After 3 to 6 months, when it is confirmed that there is no infection in the nail channel of the external fixator in the limb, the extended temporary prosthesis is replaced and the artificial joint revision surgery is completed.

[0023] Through the above technical solution, the distance between the femur and the tibia can be extended under the action of the external fixator, and the temporary prosthesis can be driven to move downward in the body, thereby realizing the extension function of the temporary prosthesis.

[0024] By setting up a hinge assembly between the temporary prosthesis and the tibia, the tibia can be flexed and extended relative to the temporary prosthesis, so that after the temporary prosthesis is moved down into place, the knee joint can be flexed and extended as soon as possible to ensure the recovery of knee joint function.

[0025] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 Schematic diagram of the structure of the intramedullary nail, temporary prosthesis and hinge assembly in this application;

[0028] Figure 2 This is a schematic diagram of the structure of the in vitro fixation frame in this application;

[0029] Figure 3This is a schematic diagram of the temporary prosthesis in this application after it has moved downward relative to the intramedullary nail;

[0030] Figure 4 This is a schematic diagram of the main structure of the intramedullary nail in this application;

[0031] Figure 5 for Figure 4 Schematic diagram of the top view structure;

[0032] Figure 6 This is a schematic side view of the temporary prosthesis in this application;

[0033] Figure 7 This is a top view of the coordination between the temporary prosthesis and the intramedullary nail;

[0034] Figure 8 It is a schematic diagram of the main structure of the activity block;

[0035] Figure 9 It is a side view structural diagram of the movable block;

[0036] Figure 10 Schematic diagram of the installation position of the support block;

[0037] Figure 11 Diagram of the coordination between the support block and the intramedullary nail.

[0038] icon:

[0039] 1- intramedullary nail; 11- slide groove; 12- fixation hole; 13- intramedullary nail connection hole;

[0040] 2-temporary prosthesis; 21-slide rail; 22-prosthesis connection hole;

[0041] 3- hinge assembly; 31- movable block; 32- hinge shaft; 33- hinge block; 34- hinge hole; 35- plug-in block;

[0042] 4-external fixator; 41-femoral fixation nail; 42-tibial fixation nail; 43-sliding frame;

[0043] 5-support block; 51-screw;

[0044] 10-femur; 20-tibia. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0046] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0047] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0048] The extendable temporary prosthetic device in the present application is mainly used to solve the problem of limb length discrepancy caused by children's bone growth after artificial joint replacement surgery.

[0049] After the existing excision of limb bone tumors, especially after artificial joint replacement surgery between the femur and tibia, the artificial joint fixed between the femur and tibia does not change in length and cannot lengthen with the growth of the child's bones, resulting in a difference in length between the affected limb and the healthy limb.

[0050] During the existing extension and replacement process of the temporary prosthesis, since the temporary prosthesis is connected to the tibia and the length of the affected limb is stretched by the downward movement of the intramedullary nail, the knee joint is easily restricted by the connection between the tibia and the temporary prosthesis, and cannot be flexed and extended after the second stretching operation, which can easily lead to loss of knee joint movement function.

[0051] Specifically, the present invention changes the position of the temporary prosthesis on the affected limb side, so that the temporary prosthesis is gradually stretched and extended in the body by the external fixator on the distance between the femur and the tibia, and moves downward relative to the intramedullary nail fixed on the femur. After the secondary operation when the temporary prosthesis is moved downward into place, the knee joint is allowed to flex as soon as possible, avoiding missing the best time for rehabilitation training and further ensuring the recovery of knee joint function.

[0052] See also Figure 1-Figure 3The extendable temporary prosthesis device of the present invention mainly includes an intramedullary nail 1, a temporary prosthesis 2 and a hinge assembly 3. The intramedullary nail 1 is fixed to the femur 10 through an external fixator 4, and the intramedullary nail 1 is inserted into the proximal end of the femur 10. Unlike the existing intramedullary nail 1 that can be displaced, the intramedullary nail 1 inserted into the proximal end of the femur 10 mainly plays an anchoring role.

[0053] The temporary prosthesis 2 is arranged between the femur 10 and the tibia 20 and is slidably connected to the intramedullary nail 1. The hinge assembly 3 is connected between the temporary prosthesis 2 and the tibia 20. The exterior of the temporary prosthesis 2 is a 3D printed grid structure for filling with antibiotic bone cement.

[0054] The 3D printed grid structure of the temporary prosthesis 2 can be used to specifically design the temporary prosthesis 2 in three dimensions according to the unequal lengths between the affected and healthy limbs of different patients, meeting the specific processing size and shape requirements to meet the actual usage needs of the patients and effectively ensure flexibility.

[0055] By filling the interior of the grid structure of the temporary prosthesis 2 with antibiotic bone cement, the temporary prosthesis 2 can be effectively prevented from being infected during the downward movement process and the possibility of inflammation can be avoided.

[0056] Based on the anchoring effect of the intramedullary nail 1, the distance between the femur 10 and the tibia 20 is stretched and extended by the extracorporeal fixator 4, so that the temporary prosthesis 2 can slide downward relative to the intramedullary nail 1. Compared with the movement of the existing intramedullary nail 1, the sliding downward movement of the temporary prosthesis 2 can improve the smoothness of the extension of the affected limb and ensure the stability of the temporary prosthesis 2 when it moves downward into place.

[0057] By connecting the hinge assembly 3 between the temporary prosthesis 2 and the tibia 20, the knee joint is freed from the constraints of the temporary prosthesis 2 maintaining a specific connection with the tibia 20, ensuring that the knee joint can flex and extend. After the temporary prosthesis 2 is lowered into place, the knee joint can be trained as quickly as possible, effectively ensuring the recovery of knee joint function.

[0058] See also Figure 2 In one embodiment, the external fixator 4 fixes the proximal end of the femur 10 and the distal end of the tibia 20 respectively, and the distance between the distal end of the femur 10 and the proximal end of the tibia 20 is stretched and extended by the sliding frame 43 on the external fixator 4.

[0059] A femoral fixation nail 41 is connected to the external fixation frame 4, which is used to secure the intramedullary nail 1. In this embodiment, the position of the femur 10 in the body is fixed. The proximal end of the intramedullary nail 1 is fixed to the proximal end of the femur 10, while the distal end of the intramedullary nail 1 extends from the distal end of the femur 10 to provide a flexible connection with the proximal end of the temporary prosthesis 2. By inserting the femoral fixation nail 41 from the outside into the body and passing it through the fixation hole 12 at the proximal end of the intramedullary nail 1, the installation position of the intramedullary nail 1 is fixed, ensuring the anchoring effect of the intramedullary nail 1.

[0060] To facilitate insertion and installation of the femoral fixation nail 41 into the intramedullary nail 1, the fixation hole 12 comprises an elliptical through-hole extending radially through the intramedullary nail 1. The minor diameter of the elliptical through-hole is the same as the diameter of the femoral fixation nail 41, and the major diameter is 1.5 times the minor diameter. The holes are spaced 2 cm apart, facilitating insertion of the femoral fixation nail 41.

[0061] The external fixator 4 is also connected to a tibial fixation nail 42 for securing the tibia 20. The nail 42 is inserted from outside the body and passes through the tibia 20, connecting the external fixator 4 to the tibia 20. The distance between the femur 10 and tibia 20 is stretched and extended by a sliding frame 43 between the femoral fixation nail 41 and the tibial fixation nail 42. This stretching and extending of the distance between the femur 10 and tibia 20 by the sliding frame 43, combined with the sliding connection between the temporary prosthesis 2 and the intramedullary nail 1 and the anchoring effect of the intramedullary nail 1, allows the temporary prosthesis 2 to slide downward, thereby adjusting the length of the affected limb.

[0062] See also Figure 4-Figure 7 In order to ensure that the temporary prosthesis 2 can slide normally on the intramedullary nail 1, the temporary prosthesis 2 needs to maintain a connection relationship with the intramedullary nail 1 at all times. Specifically, at least a portion of the distal end of the intramedullary nail 1 is inserted into the temporary prosthesis 2. In order to enable the temporary prosthesis 2 to slide relative to the intramedullary nail 1, a mutually cooperating slide rail 21 and a slide groove 11 are provided between the temporary prosthesis 2 and the intramedullary nail 1. While the sliding frame 43 causes the distance between the femur 10 and the tibia 20 to be extended, the temporary prosthesis 2 can slide downward relative to the intramedullary nail 1 as it is extended and stretched. In this embodiment, with the knee joint as the main viewing direction, slide grooves 11 are provided on both sides of the intramedullary nail 1. The slide grooves 11 are through grooves extending along the length direction of the intramedullary nail 1, and slide rails 21 cooperating with the slide grooves 11 are provided on both sides of the temporary prosthesis 2. Through this arrangement, on the one hand, it can be ensured that the temporary prosthesis 2 can slide downward in a straight line. On the other hand, the mutual slide rails 21 and slide grooves 11 can also prevent the temporary prosthesis 2 from rotating relative to the intramedullary nail 1, so as to enhance the stability of the overall extension of the affected limb.

[0063] After the temporary prosthesis 2 is moved down into position, in order to prevent the temporary prosthesis 2 from shortening when the intramedullary nail 1 is in place and causing extension failure, the proximal end of the temporary prosthesis 2 needs to be connected and fixed to the distal end of the intramedullary nail 1 through a connecting nail (not shown in the figure). An intramedullary nail connecting hole 13 is provided at the distal end of the intramedullary nail 1, and a prosthesis connecting hole 22 is provided at the proximal end of the temporary prosthesis 2. When the prosthesis connecting hole 22 is moved down to a position that overlaps with the intramedullary nail connecting hole 13, the connecting nail is used to simultaneously penetrate the connecting holes in both, so that the temporary prosthesis 2 that has been moved down into position can be fixedly connected to the intramedullary nail 1. In this embodiment, the diameter of the intramedullary nail connecting hole 13 is 3.5 mm, and the spacing is 2 cm, which can ensure the stability of the connection between the connecting nail and the temporary prosthesis 2 and the intramedullary nail 1.

[0064] In this embodiment, the through direction of the intramedullary nail connecting hole 13 is perpendicular to the through direction of the fixing hole 12, and the intramedullary nail 1 can be fixed in two mutually perpendicular directions, thereby ensuring that its fixing force and connecting force are distributed in two dimensions, thereby enhancing the stability of the overall structure.

[0065] During the downward movement of the temporary prosthesis 2, a nail cap is provided on the prosthesis connecting hole 22 to prevent fibrous tissue from growing into the temporary prosthesis 2. After the temporary prosthesis 2 is moved down into place, the nail cap is removed, and the intramedullary nail 1 and the temporary prosthesis 2 are fixedly connected by a connecting nail that is simultaneously inserted into the intramedullary nail connecting hole 13 and the prosthesis connecting hole 22.

[0066] The intramedullary nail connecting hole 13 is provided at the distal end of the intramedullary nail 1 and is located at the portion inserted into the temporary prosthesis 2 , and thus can be in the form of a clear hole to facilitate immediate insertion of the connecting nail.

[0067] In another embodiment, see Figures 8-10 The hinge assembly 3 includes a movable block 31 and a hinge shaft 32. The hinge shaft 32 passes through the movable block 31 and is fixedly connected to the distal end of the temporary prosthesis 2. The movable block 31 is capable of deflecting and moving on the hinge shaft 32. Specifically, the movable block 31 includes a hinge block 33 at the top. The hinge block 33 is provided with a hinge hole 34. The hinge shaft 32 passes through the hinge hole 34, and both ends of the hinge shaft 32 are fixedly connected to the distal end of the temporary prosthesis 2. The hinge hole 34 enables the movable block 31 to deflect on the hinge shaft 32, thereby facilitating flexion and extension between the temporary prosthesis 2 and the tibia 20.

[0068] The movable block 31 also includes a plug-in block 35 connected to the lower portion of the hinge block 33. The plug-in block 35 and the hinge block 33 are integrally formed and comprise a wedge-shaped structure. The movable block 31 is connected to the proximal end of the tibia 20 via the plug-in block 35. This arrangement enables the movable block 31 to drive the tibia 20 to flex and extend relative to the temporary prosthesis 2, thereby facilitating the downward movement of the temporary prosthesis 2 into position and allowing for knee joint rehabilitation training after removal of the external fixator 4.

[0069] When the proximal end of the temporary prosthesis 2 is connected to the distal end of the intramedullary nail 1, the part exposed at the distal end of the femur 10 and the proximal end of the temporary prosthesis 2 is only the intramedullary nail 1 structure. In order to improve the stability of the overall structure, a support component is also included between the femur 10 and the temporary prosthesis 2. Figure 10-11 The support assembly includes a support block 5 on the outside of the intramedullary nail 1 that is clamped between the femur 10 and the temporary prosthesis 2. The support block 5 is embedded and fixed in the front and rear parts of the intramedullary nail 1 according to the exposed distance of the intramedullary nail 1, and is fastened by passing screws 51 through the support block 5 and the screw holes of the intramedullary nail 1 to maintain the stability of the connection between the support block 5 and the intramedullary nail 1.

[0070] By setting up the movable block 31 between the temporary prosthesis 2 and the tibia 20, rehabilitation training of the knee joint can be carried out after the temporary prosthesis 2 is moved down, that is, the length of the affected limb is extended to the right position, effectively seizing the opportunity for rehabilitation. Compared with the existing extension method, it can ensure the functional recovery of the knee joint to the greatest extent and prevent the occurrence of limb stiffness and other conditions.

[0071] The present invention also provides a method for using the above-mentioned extendable temporary prosthetic device, comprising the following steps:

[0072] The initial artificial prosthesis at the distal end of the femur 10 is removed, an intramedullary nail 1 is implanted in the medullary cavity of the femur 10, and a temporary prosthesis 2 is slidably connected to the distal end of the intramedullary nail 1;

[0073] The intramedullary nail 1 is fixed to the proximal end of the femur 10 and the distal end of the tibia 20 by an external fixator 4. The distance between the femur 10 and the tibia 20 is adjusted and extended, so that the temporary prosthesis 2 slides downward. The distance between the femur 10 and the tibia 20 is extended by 1 mm every day, which drives the temporary prosthesis 2 to move downward by 1 mm every day. If the extension is 10 cm, it will take about 100 days.

[0074] Regular check-ups are conducted. After the temporary prosthesis 2 is moved down into place, a second operation is required to fix the proximal end of the temporary prosthesis 2 to the distal end of the intramedullary nail 1, remove the external fixator 4, and allow the patient to undergo rehabilitation training while the knee joint can be flexed and extended. Wait for 3 to 6 months for the fixation pin holes of the external fixator 4 on the femur and tibia to heal. Regular check-ups are conducted to confirm that there is no infection or inflammation in the bone nail channel.

[0075] In the third operation, the extended temporary prosthesis 2 was replaced and a prosthesis of the appropriate length was implanted into the body to complete the revision surgery for the artificial joint.

[0076] Through the above-mentioned usage method, the patient can perform flexion and extension of the knee joint between the temporary prosthesis 2 and the tibia 20 during the recovery process after the second operation, which is beneficial for the patient to exercise as soon as possible.

[0077] In addition to the hinged hinge assembly in the present invention, the movable connection structure between the temporary prosthesis and the tibia can also be a rotational or fusion type, both of which can achieve the technical purpose of allowing patients to practice knee joint function and muscle strength.

[0078] It should be noted that, unless there is any conflict, the features in the embodiments of this application can be combined with each other.

[0079] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An extendable temporary prosthetic device, characterized in that: include: An intramedullary nail, a temporary prosthesis and a hinge assembly, wherein the intramedullary nail is inserted into the proximal end of the femur and fixed by an external fixator, the temporary prosthesis is arranged between the femur and the tibia and is slidably connected to the intramedullary nail, and the hinge assembly is connected between the temporary prosthesis and the tibia to enable the knee joint to flex and extend; The external fixation frame is connected with a femoral fixation nail for fixing the intramedullary nail, and a tibial fixation nail connected to the tibia, and a sliding frame capable of adjusting and extending the distance between the femur and the tibia is arranged between the femoral fixation nail and the tibial fixation nail; At least a portion of the distal end of the intramedullary nail is inserted into the temporary prosthesis, and a slide rail and a slide groove that cooperate with each other are provided between the temporary prosthesis and the intramedullary nail, and the temporary prosthesis can slide downward relative to the intramedullary nail as the distance between the femur and the tibia is extended; The distal end of the intramedullary nail and the proximal end of the temporary prosthesis are respectively provided with an intramedullary nail connection hole and a prosthesis connection hole, so as to fix the temporary prosthesis and the intramedullary nail after it is moved down into place.

2. The extendable temporary prosthetic device according to claim 1, characterized in that: The proximal end of the intramedullary nail is provided with a fixing hole for inserting the femoral fixing nail, and the fixing hole comprises an elliptical through hole penetrating in the radial direction of the intramedullary nail.

3. The extendable temporary prosthetic device according to claim 1, characterized in that: The through direction of the intramedullary nail connecting hole is perpendicular to the through direction of the fixing hole. When the temporary prosthesis is moved downward, a nail cap is provided on the prosthesis connecting hole. After the temporary prosthesis is moved downward into place, the intramedullary nail and the temporary prosthesis are fixedly connected by a connecting nail that is simultaneously inserted into the intramedullary nail connecting hole and the prosthesis connecting hole.

4. The extendable temporary prosthetic device according to any one of claims 1 to 3, characterized in that: The hinge assembly includes a movable block and a hinge shaft. The movable block includes a hinge block located at the top. The hinge block is provided with a hinge hole. The hinge shaft is passed through the hinge hole, and both ends of the hinge shaft are fixedly connected to the distal end of the temporary prosthesis.

5. The extendable temporary prosthetic device according to claim 4, characterized in that: The movable block also includes an inserting block connected to the lower part of the hinge block, the inserting block includes a wedge-shaped structure, and the movable block is connected to the proximal end of the tibia through the inserting block.

6. The extendable temporary prosthetic device according to claim 4, characterized in that: It also includes a support assembly, which includes a support block that is clamped on the outside of the intramedullary nail, and the support block is arranged between the femur and the temporary prosthesis.

7. The extendable temporary prosthetic device according to claim 1, characterized in that: The extendable temporary prosthetic device, during use, comprises the following steps: An intramedullary nail is implanted in the femoral medullary cavity, and a temporary prosthesis is slidably connected to the distal end of the intramedullary nail; The intramedullary nail is fixed to the proximal femur and the distal tibia through an external fixator, and the distance between the femur and tibia is adjusted and extended to allow the temporary prosthesis to slide downward. After the temporary prosthesis is moved down to its proper position, the proximal end of the temporary prosthesis is fixedly connected to the distal end of the intramedullary nail, and the external fixator is removed, so that the patient can perform rehabilitation training while the knee joint can be flexed and extended; After 3 to 6 months, when it is confirmed that there is no infection in the nail channel of the external fixator in the limb, the extended temporary prosthesis is replaced and the artificial joint revision surgery is completed.

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