A limiting structure for femoral head prosthesis replacement

Abstract

The present invention relates to the field of femoral head prosthesis replacement, and specifically to a limiting structure for femoral head prosthesis replacement, which solves the problem that the prior art is inconvenient to control and the patient has difficulty in moving after the muscle and soft tissue are recovered. The present invention comprises an acetabular cup and a liner in the acetabular cup, wherein the liner is provided with a receiving cavity for receiving the femoral head on the side away from the acetabular cup, wherein a plurality of through grooves are provided on the periphery of the acetabular cup, wherein a limiting mechanism is provided in the through groove, wherein the limiting mechanism comprises a fixing tube fixedly arranged in the through groove, wherein a limiting rod is provided for sliding at one end of the fixing tube close to the receiving cavity, and a sliding block is provided for sliding at one end away from the receiving cavity, wherein a top block is provided at one end of the sliding block away from the limiting rod, a transmission mechanism is provided between one end close to the limiting rod and the limiting rod, and a bioactive coating is provided at one end of the top block away from the sliding block, and further comprises an elastic positioning device for limiting the limiting rod and the sliding block; the present invention can gradually change the limiting range as the muscle, soft tissue and bone grow, so as to facilitate the patient's movement.

Description

Technical Field

[0001] The invention relates to the technical field of femoral heads, and in particular to a limiting structure for femoral head prosthesis replacement. Background Art

[0002] Femoral head replacement surgery is generally used for mid-to-late stage femoral head necrosis. During the operation, the femoral neck is cut off, the femoral head is removed, the femoral diameter is expanded and the corresponding prosthetic stem is placed. The femoral head prosthesis is placed on the prosthetic stem, and the acetabulum is polished and the acetabular cup is placed in the acetabulum. A pad is placed in the acetabular cup so that the femoral head prosthesis cooperates with the pad to restore the function of the hip joint.

[0003] After the femoral head replacement surgery is completed, the femoral head prosthesis may dislocate. In addition to surgical reasons, such as poor placement of the prosthesis or size mismatch, the main reason is that the patient performs large-scale, heavy-weight activities prematurely in the first month or so after the surgery because the muscles in the joints are damaged and have not fully recovered, and the soft tissue tension is insufficient. When the femoral head prosthesis dislocates, it generally requires another reduction surgery, which increases the patient's pain. Therefore, after the femoral head replacement surgery, it is very necessary to limit the femoral head prosthesis to prevent dislocation of the femoral head prosthesis.

[0004] At present, the method of preventing the prosthesis from falling out is usually to set a limiting high edge of a certain height at the periphery of the acetabular cup. The limiting high edge can prevent the femoral head prosthesis from being dislocated, but at the same time, the structure also limits the range of motion of the bone prosthesis, restricting the activity of the patient's hip joint, and affecting the patient's normal activity after surgery to a certain extent. After searching, a Chinese invention patent with a publication number of CN107550604B discloses an artificial acetabulum and an artificial hip joint, wherein the artificial acetabulum includes an acetabulum body, the acetabulum body has a receiving cavity for accommodating the femoral head prosthesis and a receiving cavity for accommodating the femoral head prosthesis. An opening connected to the receiving cavity; an anti-dislocation structure, which is arranged on the peripheral surface of the acetabulum body to increase the area of ​​the limiting surface of the acetabulum body and prevent the femoral head prosthesis from escaping from the accommodating cavity; wherein the limiting surface is formed by splicing the inner wall surface of the acetabulum body facing the accommodating cavity and a part of the wall surface of the anti-dislocation structure, and the anti-dislocation structure is made of degradable metal, degradable polymer material or degradable ceramic; the invention solves the problem in the prior art that the femoral prosthesis is easily dislocated from the acetabulum prosthesis and affects the success rate of artificial hip replacement surgery.

[0005] Among them, the anti-dislocation structure is made of degradable metal, degradable polymer material or degradable ceramic. Although it can be degraded, it is affected by the environment and generally takes months to years to completely degrade, which makes it inconvenient to control. Moreover, after the patient's muscles and soft tissues recover, the anti-dislocation structure has not yet degraded, which will still restrict the patient's activities for a long time and cause inconvenience. On the other hand, the cost of degradable materials is also relatively high.

[0006] Therefore, the present invention provides a limiting structure for femoral head prosthesis replacement to solve the above-mentioned problem. Summary of the invention

[0007] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a limiting structure for femoral head prosthesis replacement. The problem to be solved is: to provide a limiting structure for femoral head prosthesis replacement that can gradually change the limiting range as the muscles, soft tissues and bones grow to facilitate the patient's activities.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A limiting structure for replacement of a femoral head prosthesis, a limiting structure for replacement of a femoral head prosthesis, comprising an acetabular cup and a liner in the acetabular cup, wherein a receiving cavity for receiving a femoral head is provided on a side of the liner away from the acetabular cup, a plurality of through grooves are provided on the periphery of the acetabular cup, a limiting mechanism is provided in the through groove, the limiting mechanism comprises a fixing tube fixedly arranged in the through groove, a limiting rod is slidably provided at one end of the fixing tube close to the receiving cavity, a sliding block is slidably provided at one end of the fixing tube away from the receiving cavity, a top block is provided at one end of the sliding block away from the limiting rod, a transmission mechanism is provided between one end close to the limiting rod and the limiting rod, a bioactive coating is provided at one end of the top block away from the sliding block, the transmission mechanism is used to control the relative movement of the limiting rod and the sliding block, and also comprises an elastic positioning device for limiting the limiting rod and the sliding block;

[0010] During operation, the movement range of the femoral head in the accommodating cavity is limited by the limit rod. As the muscle and bone grow and recover, the bioactive coating promotes the connection between the top block and the bone, and the bone growth pushes the top block to move, driving the slider and the limit rod to move toward each other, gradually reducing the limit range of the limit rod.

[0011] Preferably, the transmission mechanism includes a rotating shaft arranged in a fixed tube, the rotating shaft is located between the limiting rod and the slider, a transmission gear is provided on the rotating shaft, a first rack is provided on the side of the limiting rod close to the transmission gear, and the first rack is meshed with the transmission gear through the first rack, and a second rack is provided on the side of the slider close to the transmission gear, and the second rack is meshed with the transmission gear through the second rack; and an elastic positioning device for elastically positioning the transmission gear is also included.

[0012] Preferably, a fixed block is fixed in the fixed tube, a rotating shaft is arranged on the fixed block, the elastic positioning device includes a ratchet arranged on the rotating shaft, a fixed plate is arranged on the fixed block, a pawl adapted to the ratchet is arranged on the fixed plate, a first elastic reset device is arranged on the pawl, and the first rack and the second rack only move toward each other.

[0013] Preferably, the limiting rod comprises a first rod body, one end of the first rod body close to the fixing tube is connected to a second rod body through a universal ball, and a second elastic reset device is provided between the first rod body and the second rod body.

[0014] Preferably, an extension block is provided at one end of the second rod body away from the universal ball, and is slidably connected to the fixing tube via the extension block.

[0015] Preferably, an isolating ring is provided at one end of the fixing tube close to the limiting rod, and the inner diameter of the isolating ring is equivalent to the outer diameter of the first rod body and the second rod body.

[0016] Preferably, the isolation ring is made of polyethylene material.

[0017] Preferably, a first fixing ring and a second fixing ring are respectively provided near both ends of the fixing pipe, and the inner diameters of the first fixing ring and the second fixing ring are equal to the outer diameter of the fixing pipe, and the outer diameters are equal to the inner diameter of the through groove.

[0018] Preferably, the end of the top block away from the sliding block is flush with the surface of the corresponding end of the through slot.

[0019] Preferably, the bioactive coating is a HA coating.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention places the acetabular cup on the acetabulum of the patient during installation. The limiting mechanism can limit the femoral head prosthesis placed in the liner through the limiting rod. In the early postoperative period, when the muscle tissue and bone have not grown and recovered, the limiting rod is relatively high relative to the liner, which can greatly limit the range of motion of the femoral head prosthesis and prevent the femoral head prosthesis from dislocating. As the muscle tissue grows and recovers, the top block in the limiting mechanism promotes the bone growth at the corresponding position of the acetabulum through the bioactive coating and is connected to the top block. As the bone grows, the top block is pushed by the bone to move, so that the top block is close to the fixed tube, and the limiting rod is driven close to the fixed tube through the transmission mechanism, thereby reducing the height of the limiting rod relative to the liner and reducing the range of restriction of the femoral head prosthesis by the limiting rod. That is, as the muscle tissue grows and recovers, the range of motion of the femoral head prosthesis can be gradually expanded, which can prevent the femoral head prosthesis from dislocating and not affect the free range of motion of the femoral head prosthesis after the muscle growth recovers.

[0022] 2. The limit rod in the present invention does not need to use degradable metal, degradable polymer material or degradable ceramic, which is convenient for accurately controlling the limit range of the limit rod, and the cost is relatively low, which is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the limiting mechanism in the present invention;

[0025] Figure 3 It is a schematic diagram of the internal structure of the fixed tube in the limiting mechanism of the present invention;

[0026] Figure 4 for Figure 3 The enlarged schematic diagram of point A in the middle;

[0027] Figure 5 It is a schematic diagram of the structure of the extension block in the present invention;

[0028] Figure 6 for Figure 3 The enlarged schematic diagram of point B in the middle;

[0029] Figure 7 It is a schematic diagram of the limit rod in the present invention after the muscle tissue is restored;

[0030] Figure 8 It is a schematic diagram of the present invention after muscle tissue recovery.

[0031] In the figure: 1. acetabular cup, 2. liner, 3. through groove, 4. limiting mechanism, 401. limiting rod, 4011. first rod body, 4012. universal ball, 4013. second elastic reset device, 4014. second rod body, 4015. isolation ring, 4016. extension block, 402. first fixing ring, 403. fixing tube, 404. second fixing ring, 405. slider, 406. top block, 407. transmission mechanism, 4071. first rack, 4072. transmission gear, 4073. ratchet, 4074. rotating shaft, 4075. fixing block, 4076. fixing plate, 4078. second rack, 5. accommodating cavity. DETAILED DESCRIPTION

[0032] The following will refer to the attached Figures 1 to 8 The embodiments of the present invention are described in detail. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0033] A limiting structure for femoral head prosthesis replacement, as shown in the attached Figure 1 As shown, it includes an acetabular cup 1 and a liner 2 in the acetabular cup 1. A cavity is provided on the left side of the acetabular cup 1 and the liner 2 is placed in the cavity. The liner 2 is away from one side of the acetabular cup 1. In this embodiment, a accommodating cavity 5 for accommodating a femoral head prosthesis (not shown) is provided on the left side of the liner 2. During the operation, the right side of the acetabular cup 1 is placed in the acetabulum, and the accommodating cavity 5 cooperates with the femoral head prosthesis. This part is the prior art and will not be described in detail here. A plurality of through grooves 3 are provided on the periphery of the acetabular cup 1, and a limiting mechanism 4 is provided in the through grooves 3. In this embodiment, the through grooves 3 are along the left and right directions, and a total of 8 through grooves 3 are provided, which are evenly spaced at the position where the acetabular cup 1 is located in the peripheral direction of the liner 2. The femoral head prosthesis can be limited in all directions by a plurality of limiting mechanisms 4 provided in the through grooves 3 to prevent dislocation of the femoral head prosthesis.

[0034] As attached Figure 1 , Figure 2 , Figure 3 As shown, the limiting mechanism 4 includes a fixed tube 403 fixedly arranged in the through groove 3 along the left-right direction, the fixed tube 403 is close to one end of the accommodating chamber 5, in this embodiment, a limiting rod 401 is slidably provided at the left end of the fixed tube 403 along the left-right direction, away from one end of the accommodating chamber 5, in this embodiment, a slider 405 is slidably provided at the right end of the fixed tube 403 along the left-right direction, the slider 405 is away from one end of the limiting rod 401, in this embodiment, a top block 406 is provided at the right end of the slider 405, and a transmission mechanism 407 is provided between the left end and the limiting rod 401, the top block 406 is away from one end of the slider 405, in this embodiment, a bioactive coating is provided at the right end of the top block 406, and the bioactive coating is HA coating, the transmission mechanism 407 is used to control the limiting rod 401 and the slider 405 to move toward each other, and also includes an elastic positioning device for limiting the limiting rod 401 and the slider 405, specifically, the state diagram of the limiting rod 401 and the entire device after muscle tissue recovery can be referred to the attached Figure 7 and Figure 8 .

[0035] Working principle: Multiple limiting rods 401 are arranged on the periphery of the femoral head prosthesis, which can limit the range of motion of the femoral head in the accommodating cavity 5. When the limiting rod 401 extends to the left of the fixing tube 403 for a long time, the range of motion of the femoral head prosthesis is limited to a small extent. When the limiting rod 401 extends to the left of the fixing tube 403 for a short time, the range of motion of the femoral head prosthesis is limited to a large extent. When the replacement surgery is just completed, the limiting rod 401 extends to the left of the fixing tube 403 for a long time, and is elastically positioned by the elastic positioning device. When the muscle tissue has not grown and recovered, the femoral head can be limited. The prosthesis moves within a smaller range to prevent dislocation. During the postoperative recovery stage, as the muscle and bone growth recover, the bone on the right side of the through groove 3 is promoted to grow and connected to the top block 406 through the bioactive coating. The HA coating can achieve the support and connection of the bone to the prosthesis earlier and faster, and through bone growth, it pushes the top block 406 to overcome the elastic positioning device to move, drive the top block 406 to move to the left, and then drive the slider 405 and the limit rod 401 to move towards each other, so that the limit rod 401 moves to the right, thereby gradually reducing the limit range of the limit rod 401.

[0036] The present invention can gradually reduce the limiting range of the femoral head prosthesis as the muscle tissue gradually recovers, so that the range of motion of the femoral head prosthesis gradually increases. During the recovery period, the patient can gradually expand the range of motion and conduct appropriate rehabilitation training to promote recovery and avoid dislocation of the femoral head prosthesis. Until the slider 405 and the limiting rod 401 move toward each other to the maximum distance and the muscle tissue is fully recovered, the limiting rod 401 no longer limits the femoral head prosthesis and the patient can move freely. The limiting rod 401 in the present invention can be made of general alloy materials, which is lower in cost than the prior art using degradable metals, polymer materials or degradable ceramics, is conducive to promotion, and is easy to accurately control the limiting rod 401. The patient is not affected by the degradation time of the material, which is conducive to rapid activities after recovery.

[0037] As attached Figure 2 , Figure 3 , Figure 6 As shown, in this embodiment, the transmission mechanism 407 includes a rotating shaft 4074 disposed in the fixed tube 403, the rotating shaft 4074 is along the vertical direction, the rotating shaft 4074 is located between the limiting rod 401 and the slider 405, a transmission gear 4072 is provided on the rotating shaft 4074, and a first rack 4071 is provided on the side of the limiting rod 401 close to the transmission gear 4072, and is meshed and connected with the transmission gear 4072 through the first rack 4071, and the slider 405 is close to the transmission gear 4072. A second rack 4078 is provided on one side, and is meshed with the transmission gear 4072 through the second rack 4078; the first rack 4071 and the second rack 4078 are arranged front and back. When the slider 405 moves to the left, the second rack 4078 is driven to move to the left, and then the transmission gear 4072 is driven to rotate counterclockwise, and then the first rack 4071 is driven to move to the right, and then the limiting rod 401 is driven to move to the right, so as to control the slider 405 and the limiting rod 401 to move towards each other.

[0038] It also includes an elastic positioning device for elastically positioning the transmission gear 4072. The elastic positioning device is used to elastically limit the first rack 4071, the transmission gear 4072, and the second rack 4078. Within a certain external force range, the current state can be maintained. During specific use, the initial positions of the limit rod 401 and the slider 405 can be maintained during surgery to prevent the limit rod 401 and the slider 405 from moving toward each other on their own, affecting the limiting effect of the limit rod 401 and the connection effect between the top block 406 and the bone. Specifically, in the initial recovery stage after the operation, the limiting height of the limit rod 401 and the distance between the top block 406 and the acetabulum are maintained. When the bone grows through the bioactive coating and the top block 406 is connected, the top block 406 is gradually pushed to overcome the elasticity of the elastic positioning device and move.

[0039] In this embodiment, a fixed block 4075 is fixedly arranged in the fixed tube 403, and the rotating shaft 4074 is rotatably arranged on the fixed block 4075. The elastic positioning device includes a ratchet 4073 arranged on the rotating shaft 4074, a fixed plate 4076 is arranged on the fixed block 4075, and a pawl 4077 adapted to the ratchet 4073 is arranged on the fixed plate 4076. The pawl 4077 is provided with a first elastic reset device, which can be a spring. The first rack 4071 and the second rack 4078 only move toward each other, that is, under the action of the ratchet 4073 and the pawl 4077, the rotating shaft 4074 can only rotate counterclockwise, and then the transmission gear 4072 can only rotate counterclockwise, so that the first rack 4071 and the second rack 4078 can only move towards each other, and the ratchet 4073, the pawl 4077 and the first elastic reset device set at the pawl 4077 form an elastic positioning device, which can achieve a certain elastic positioning of the transmission gear 4072. When the transmission gear 4072 rotates, it is necessary to overcome the elastic force of the first elastic reset device at the pawl 4077, and the elastic force overcome each time is the same, which can ensure that the top block 406 can be pushed smoothly to move with the growth of bone.

[0040] During specific use, after the muscle tissue and bone are fully recovered, the slider 405 and the limit rod 401 move toward each other to the maximum distance. In this embodiment, the transmission gear 4072 is set in the middle position between the limit rod 401 and the slider 405, and the first rack 4071 and the second rack 4078 are equal in length, that is, the right end of the first rack 4071 contacts the slider 405, and the left end of the second rack 4078 contacts the limit rod 401. The limit rod 401 and the limit rod 401 restrict each other from moving toward each other, and the ratchet 4073 and the pawl 4077 restrict the movement away from each other, which can assist in fixing the position of the limit rod 401 and the slider 405 and reduce the force at the connection between the bone and the top block 406.

[0041] As attached Figure 3 , Figure 4 As shown, in this embodiment, the limiting rod 401 includes a first rod body 4011, and the first rod body 4011 is close to one end of the fixed tube 403. In this embodiment, the right end of the first rod body 4011 is connected to the second rod body 4014 through a universal ball 4012, and a second elastic reset device 4013 is provided between the first rod body 4011 and the second rod body 4014. The second elastic reset device 4013 can be a spring.

[0042] In the early postoperative period, the second rod body 4014 of the limiting rod 401 is first slidably set in the fixing tube 403, and the motion range of the femoral head prosthesis is limited by the first rod body 4011. When the femoral head prosthesis moves to contact with the first rod body 4011, the first rod body 4011 can be offset a certain distance in all directions through the universal ball 4012, and then the right end of the first rod body 4011 contacts and limits the device of the universal ball 4012, thereby being able to appropriately expand the motion range of the femoral head prosthesis and still control the femoral head prosthesis. The limit can appropriately increase the patient's range of motion and prevent the femoral head prosthesis from dislocating. The patient can feel the pulling force generated by the second elastic reset device 4013, thereby reminding the patient to control the activity. When the femoral head prosthesis is not in contact with the corresponding first rod body 4011, the corresponding first rod body 4011 is elastically reset by the second elastic reset device 4013. After resetting, the corresponding first rod body 4011 and the second rod body 4014 resume coaxiality, so that the first rod body 4011 can smoothly slide into the fixing tube 403.

[0043] As attached Figure 3 , Figure 4 , Figure 5 As shown, in this embodiment, the second rod body 4014 is away from one end of the universal ball 4012. In this embodiment, an extension block 4016 is provided at the right end of the second rod body 4014, which is slidably connected to the fixed tube 403 through the extension block 4016. When the universal ball 4012 and the second elastic reset device 4013 enter the fixed tube 403, the movement of the entire limit rod 401 along the left and right directions is not affected.

[0044] In this embodiment, the fixed tube 403 is close to one end of the limiting rod 401. In this embodiment, an isolation ring 4015 is provided at the left end of the fixed tube 403. Specifically, the isolation ring 4015 is made of polyethylene material, which has good wear resistance, strong corrosion resistance, and certain elasticity. The inner diameter of the isolation ring 4015 is equivalent to the outer diameter of the first rod body 4011 and the second rod body 4014, and the circumference of the isolation ring 4015 is sealed and connected to the fixed tube 403. When the limiting rod 401 moves, the isolation ring 4015 is used to isolate the inside and outside of the fixed tube 403. A sealed sliding connection structure can be directly used between the slider 405 and the fixed tube 403, thereby isolating the inside of the fixed tube 403 from the outside to prevent pollution to the internal structure.

[0045] As attached Figure 1 , Figure 4As shown, in this embodiment, a first fixing ring 402 and a second fixing ring 404 are respectively provided near both ends of the fixing tube 403, the inner diameters of the first fixing ring 402 and the second fixing ring 404 are equivalent to the outer diameter of the fixing tube 403, and the outer diameters are equivalent to the inner diameter of the through groove 3, the first fixing ring 402 and the second fixing ring 404 are detachably connected to the through groove 3, and the entire limiting mechanism 4 can be installed and removed, and the interior of the through groove 3 is isolated from the outside world from both ends of the fixing tube 403 by two fixing rings to prevent contamination of the interior. In specific use, it is also convenient to disinfect the entire device before surgery.

[0046] As attached Figure 1 As shown, in this embodiment, the top block 406 is away from one end of the slider 405. In this embodiment, the right end of the top block 406 is flush with the surface of the corresponding end of the through groove 3, that is, it is adapted to the surface of the acetabular cup 1. When used specifically, after the acetabular cup 1 is placed on the acetabulum, the right end of the top block 406 can be in close contact with the acetabulum, so that the bioactive coating on the right end of the top block 406 can contact the surface of the acetabulum to maximize its effect, promote bone growth, and then promote the connection between the bone and the top block 406; in addition, when used specifically, the surface of the acetabular cup 1 also needs to be provided with a bioactive coating so that the bone can be connected to the surface of the acetabular cup 1, but the bioactive coating is not provided on the surface of the acetabular cup 1 located on the side around the through groove 3, or a circle of isolation layer is provided on the side around the right end of the through groove 3 to prevent the surrounding bone from affecting the top block 406, so that the top block 406 can be accurately connected to the bone at the corresponding position.

[0047] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0048] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A positioning structure for femoral head prosthesis replacement, comprising an acetabular cup (1) and a liner (2) in the acetabular cup (1), wherein a side of the liner (2) away from the acetabular cup (1) is provided with an accommodating cavity (5) for accommodating a femoral head, characterized in that: The acetabular cup (1) is provided with a plurality of through grooves (3) on its periphery. A limiting mechanism (4) is provided in the through grooves (3). The limiting mechanism (4) comprises a fixing tube (403) fixedly arranged in the through grooves (3). A limiting rod (401) is slidably provided at one end of the fixing tube (403) close to the accommodating cavity (5), and a sliding block (405) is slidably provided at one end of the fixing tube (403) away from the accommodating cavity (5). A top block (406) is provided at one end of the sliding block (405) away from the limiting rod (401). A transmission mechanism (407) is provided between one end close to the limiting rod (401) and the limiting rod (401). A bioactive coating is provided at one end of the top block (406) away from the sliding block (405). The transmission mechanism (407) is used to control the relative movement of the limiting rod (401) and the sliding block (405). The transmission mechanism also comprises an elastic positioning device for limiting the limiting rod (401) and the sliding block (405). During operation, the range of motion of the femoral head in the accommodating cavity (5) is limited by the limiting rod (401). As the muscle and bone grow and recover, the bioactive coating promotes the connection between the top block (406) and the bone, and the top block (406) is pushed to move by bone growth, driving the slider (405) and the limiting rod (401) to move towards each other, gradually reducing the limiting range of the limiting rod (401).

2. A limiting structure for femoral head prosthesis replacement according to claim 1, characterized in that: The transmission mechanism (407) comprises a rotating shaft (4074) arranged in the fixed tube (403), the rotating shaft (4074) being located between the limiting rod (401) and the slider (405), a transmission gear (4072) being arranged on the rotating shaft (4074), a first rack (4071) being arranged on the side of the limiting rod (401) close to the transmission gear (4072), and being meshedly connected to the transmission gear (4072) via the first rack (4071), and a second rack (4078) being arranged on the side of the slider (405) close to the transmission gear (4072), and being meshedly connected to the transmission gear (4072) via the second rack (4078).

3. A limiting structure for femoral head prosthesis replacement according to claim 2, characterized in that: A fixed block (4075) is fixedly arranged in the fixed tube (403); a rotating shaft (4074) is arranged on the fixed block (4075); the elastic positioning device comprises a ratchet (4073) arranged on the rotating shaft (4074); a fixed plate (4076) is arranged on the fixed block (4075); a ratchet (4077) adapted to the ratchet (4073) is arranged on the fixed plate (4076); a first elastic reset device is arranged on the ratchet (4077); and the first rack (4071) and the second rack (4078) only move towards each other.

4. A limiting structure for femoral head prosthesis replacement according to claim 1, characterized in that: The limiting rod (401) comprises a first rod body (4011), one end of the first rod body (4011) close to the fixing tube (403) is connected to a second rod body (4014) via a universal ball (4012), and a second elastic reset device (4013) is provided between the first rod body (4011) and the second rod body (4014).

5. A limiting structure for femoral head prosthesis replacement according to claim 4, characterized in that: An extension block (4016) is provided at one end of the second rod body (4014) away from the universal ball (4012), and is slidably connected to the fixed tube (403) via the extension block (4016).

6. A limiting structure for femoral head prosthesis replacement according to claim 5, characterized in that: An isolation ring (4015) is provided at one end of the fixed tube (403) close to the limiting rod (401), and the inner diameter of the isolation ring (4015) is equivalent to the outer diameters of the first rod body (4011) and the second rod body (4014).

7. A limiting structure for femoral head prosthesis replacement according to claim 6, characterized in that: The isolation ring (4015) is made of polyethylene.

8. A limiting structure for femoral head prosthesis replacement according to any one of claims 1 to 7, characterized in that: A first fixing ring (402) and a second fixing ring (404) are respectively provided near both ends of the fixing tube (403); the inner diameters of the first fixing ring (402) and the second fixing ring (404) are equivalent to the outer diameter of the fixing tube (403); and the outer diameters are equivalent to the inner diameter of the through groove (3).

9. A limiting structure for femoral head prosthesis replacement according to any one of claims 1 to 7, characterized in that: One end of the top block (406) away from the slider (405) is flush with the surface of the corresponding end of the through slot (3).

10. A limiting structure for femoral head prosthesis replacement according to any one of claims 1 to 7, characterized in that: The bioactive coating is a HA coating.

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