Extensible knee prosthesis

Abstract

This invention provides an extendable knee prosthesis, comprising a prosthesis body, an extension prosthesis, and a length adjustment frame. The prosthesis body includes a first prosthesis and a second prosthesis, and the length adjustment frame includes a frame, at least one pair of connecting rods, and a linear drive mechanism. In use, the first prosthesis is connected to the tibia or femur, and the second prosthesis is detachably connected to the first prosthesis. When there is unequal leg length, the connecting rods can be connected to the connecting holes on the first or second prosthesis, and then the distance between the paired connecting rods can be adjusted by the linear drive mechanism to extend the soft tissue. After extending to a certain length, the length adjustment frame is removed, and an extension prosthesis of appropriate length is connected between the first and second prostheses to extend the prosthesis body, thereby solving the problem of unequal leg length. The extendable knee prosthesis provided by this invention eliminates the need for multiple surgeries, reducing patient suffering and treatment costs.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to an extendable knee joint prosthesis. Background Technology

[0002] Osteosarcoma, the most common primary malignant bone tumor in children, frequently occurs in the metaphysis of long bones, with approximately 50% of cases involving the area around the knee joint, namely the distal femur and proximal tibia. With the widespread use of neoadjuvant chemotherapy and limb-sparing surgery, about 85% of children can achieve anatomical and functional reconstruction through tumor-type prostheses. However, to obtain sufficient surgical margins, it is often necessary to remove the distal femoral or proximal tibial epiphysis during surgery. Since the distal femoral and proximal tibial epiphysis contribute 35% and 30% of the lower limb growth potential, respectively, these children often develop progressive lower limb length discrepancy (LLD) postoperatively due to skeletal developmental imbalance. This can lead to secondary functional impairments such as gait abnormalities, pelvic tilt, and scoliosis, severely impacting their long-term quality of life.

[0003] Currently, clinical interventions for LLD mainly include extendable knee prostheses, epiphyseal fixation, and external compensation. Mechanically extendable knee prostheses require multiple surgical lengthening procedures, which inevitably increases patient suffering and the risk of infection. Magnetically controlled extendable knee prostheses are expensive, and postoperative MRI scans are not possible, limiting postoperative follow-up. These issues prevent the widespread application of these methods. Utility Model Content

[0004] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention provides an extendable knee prosthesis, aiming to solve the problems of increased patient suffering caused by the need for multiple surgical incisions for lengthening mechanically extendable knee prostheses and the high cost of magnetically controlled extendable knee prostheses in related technologies.

[0005] This utility model provides an extendable knee joint prosthesis, comprising:

[0006] The prosthesis body includes a first prosthesis and a second prosthesis. One end of the first prosthesis is used to connect to the end of the preserved segment of the tibia or femur near the knee joint. One end of the second prosthesis is used to detachably connect to the other end of the first prosthesis. The other end of the second prosthesis is used to engage with the end of the femur or tibia near the knee joint. Both the first prosthesis and the second prosthesis are provided with connection holes, and the axis of the connection holes is perpendicular to the extension direction of the tibia or femur.

[0007] An extension prosthesis, the extension prosthesis being detachably connected between the first prosthesis and the second prosthesis;

[0008] The length adjustment frame includes a frame body, at least one pair of connecting rods, and a linear drive mechanism. The connecting rods are parallel to each other and perpendicular to the extension direction of the tibia or femur. One of each pair of connecting rods is detachably connected to a connecting hole on a first prosthesis, and the other is detachably connected to a connecting hole on a second prosthesis. The other end of each connecting rod is slidably connected to the frame body, with the sliding direction parallel to the extension direction of the tibia or femur. The linear drive mechanism is disposed between the frame body and the connecting rods and is used to drive the paired connecting rods to move towards or away from each other.

[0009] According to the extendable knee prosthesis provided by this utility model, the first prosthesis and the extended prosthesis are provided with a tapered connector or tapered groove at the end near the knee joint, and the second prosthesis and the extended prosthesis are provided with a tapered groove or tapered connector at the end away from the knee joint. The tapered groove and the tapered connector have equal cone angles. The length of the tapered connector is less than or equal to the depth of the tapered groove. The distal outer diameter of the tapered connector is smaller than the distal inner diameter of the tapered groove. The proximal outer diameter of the tapered connector is larger than the distal inner diameter of the tapered groove.

[0010] According to the extendable knee prosthesis provided by this utility model, anti-rotation structures are provided between the first prosthesis and the extended prosthesis, between the second prosthesis and the extended prosthesis, and between the first prosthesis and the second prosthesis.

[0011] According to the extendable knee prosthesis provided by this utility model, the anti-rotation structure includes an anti-rotation block and an anti-rotation groove. The anti-rotation block is disposed at one end of the first prosthesis, the second prosthesis, and the extended prosthesis where a tapered insertion joint is provided. The anti-rotation groove is disposed at one end of the first prosthesis, the second prosthesis, and the extended prosthesis where a tapered insertion slot is provided. The anti-rotation block and the anti-rotation groove are connected by insertion.

[0012] According to the extendable knee joint prosthesis provided by this utility model, the anti-rotation structure includes a key and a keyway. The key is disposed on the inner side of the tapered insertion groove or the outer side of the tapered insertion joint, and the keyway is disposed on the outer side of the tapered insertion joint or the inner side of the tapered insertion groove.

[0013] According to the extendable knee prosthesis provided by this utility model, the linear drive mechanism includes:

[0014] A slide rail is provided on the frame, and the extension direction of the slide rail is parallel to the extension direction of the tibia or the femur.

[0015] A slider is slidably connected to the slide rail, and the slider is provided with a first threaded hole that passes through the slider. The axis of the first threaded hole is parallel to the sliding direction of the slider, and the connecting rod is connected to the slider.

[0016] The first screw is rotatably connected to the frame, and the end of the first screw is threadedly connected to the first threaded hole.

[0017] According to the extendable knee joint prosthesis provided by this utility model, a nut is provided on the outer side of the first screw, and the nut is fixedly connected to the first screw.

[0018] According to the extendable knee joint prosthesis provided by this utility model, the frame is provided with scale lines and the slider is provided with indicator marks.

[0019] According to the extendable knee joint prosthesis provided by this utility model, the connecting hole is a second threaded hole, and the connecting rod is a second screw.

[0020] This utility model has the following advantages due to the adoption of the above technical solution:

[0021] This utility model provides an extendable knee prosthesis, comprising a prosthesis body, an extension prosthesis, and a length adjustment frame. The prosthesis body includes a first prosthesis and a second prosthesis. One end of the first prosthesis is used to connect to the end of a preserved segment of the tibia or femur near the knee joint. One end of the second prosthesis is detachably connected to the other end of the first prosthesis, and the other end of the second prosthesis is used to mate with the end of the femur or tibia near the knee joint. Both the first and second prostheses are provided with connecting holes, the axis of which is perpendicular to the extension direction of the tibia or femur. The extension prosthesis is used for a detachable connection between the first and second prostheses. The length adjustment frame includes a frame body, at least one pair of connecting rods, and a linear drive mechanism. The connecting rods are parallel to each other and perpendicular to the extension direction of the tibia or femur. One rod in each pair is detachably connected to a connection hole on a first prosthesis, and the other is detachably connected to a connection hole on a second prosthesis. The other end of each connecting rod is slidably connected to the frame body, with the sliding direction parallel to the extension direction of the tibia or femur. The linear drive mechanism is located between the frame body and the connecting rods and is used to drive the paired connecting rods to move closer to or further away from each other. In use, one end of the first prosthesis is connected to the end of the retained segment of the tibia or femur near the knee joint, and then one end of the second prosthesis is detachably connected to the other end of the first prosthesis. The other end of the second prosthesis is used to mate with the healthy femur or tibia. When a patient experiences progressive lower limb length discrepancy, a minimally invasive surgery can be performed to connect the ends of paired connecting rods furthest from the frame to the connecting holes on the first or second prosthesis, respectively. After connection, the distance between the paired connecting rods can be adjusted via a linear drive mechanism to extend the soft tissue length between the first and second prostheses, thus achieving equal lower limb length. Once the soft tissue between the first and second prostheses has been extended to a certain length, the length adjustment frame can be removed, and an open surgery can be performed to connect an extension prosthesis of appropriate length between the first and second prostheses, resolving the lower limb length discrepancy. The extendable knee prosthesis provided by this invention requires only one minimally invasive surgery and one open surgery, eliminating the need for multiple surgeries, thus reducing patient suffering and treatment costs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an extendable knee joint prosthesis provided in one embodiment of the present invention;

[0024] Figure 2This is a schematic diagram of the structure of the first prosthesis provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the first type of second prosthesis provided in an embodiment of the present invention;

[0026] Figure 4 This is a cross-sectional view of the first type of second prosthesis provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of the first type of elongation prosthesis provided in an embodiment of the present invention;

[0028] Figure 6 This is a cross-sectional view of the first type of elongation prosthesis provided in an embodiment of this utility model;

[0029] Figure 7 This is a top view of the first type of elongation prosthesis provided in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the structure of the second type of elongation prosthesis provided in an embodiment of the present invention;

[0031] Figure 9 This is a cross-sectional view of a second type of elongated prosthesis provided in an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the length adjustment frame provided in one embodiment of the present invention.

[0033] Figure label:

[0034] 110: First prosthesis; 120: Second prosthesis; 130: Extension prosthesis; 140: Connecting hole; 210: Frame; 220: Connecting rod; 231: Slide rail; 232: Slider; 233: First screw; 234: Nut; 310: Conical connector; 320: Conical slot; 410: Protrusion; 420: Blocking plane; 510: Key; 520: Keyway; 610: Scale line; 620: Indicator mark. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0041] This utility model provides an extendable knee prosthesis, comprising a prosthesis body, an extension prosthesis, and a length adjustment frame. The prosthesis body includes a first prosthesis and a second prosthesis. One end of the first prosthesis is used to connect to the end of a preserved segment of the tibia or femur near the knee joint. One end of the second prosthesis is detachably connected to the other end of the first prosthesis, and the other end of the second prosthesis is used to mate with the end of the femur or tibia near the knee joint. Both the first and second prostheses are provided with connecting holes, the axis of which is perpendicular to the extension direction of the tibia or femur. The extension prosthesis is used for a detachable connection between the first and second prostheses. The length adjustment frame includes a frame body, at least one pair of connecting rods, and a linear drive mechanism. The connecting rods are parallel to each other and perpendicular to the extension direction of the tibia or femur. One rod in each pair is detachably connected to a connection hole on a first prosthesis, and the other is detachably connected to a connection hole on a second prosthesis. The other end of each connecting rod is slidably connected to the frame body, with the sliding direction parallel to the extension direction of the tibia or femur. The linear drive mechanism is located between the frame body and the connecting rods and is used to drive the paired connecting rods to move closer to or further away from each other. In use, one end of the first prosthesis is connected to the end of the retained segment of the tibia or femur near the knee joint, and then one end of the second prosthesis is detachably connected to the other end of the first prosthesis. The other end of the second prosthesis is used to mate with the healthy femur or tibia. When a patient experiences progressive lower limb length discrepancy, a minimally invasive surgery can be performed to connect the ends of paired connecting rods furthest from the frame to the connecting holes on the first or second prosthesis, respectively. After connection, the distance between the paired connecting rods can be adjusted via a linear drive mechanism to extend the soft tissue length between the first and second prostheses, thus achieving equal lower limb length. Once the soft tissue between the first and second prostheses has been extended to a certain length, the length adjustment frame can be removed, and an open surgery can be performed to connect an extension prosthesis of appropriate length between the first and second prostheses, resolving the lower limb length discrepancy. The extendable knee prosthesis provided by this invention requires only one minimally invasive surgery and one open surgery, eliminating the need for multiple surgeries, thus reducing patient suffering and treatment costs.

[0042] The following is combined Figures 1 to 10 This invention describes an extendable knee prosthesis.

[0043] An embodiment of this utility model provides an extendable knee joint prosthesis, including a prosthesis body, an extension prosthesis 130, and a length adjustment frame. The prosthesis body includes a first prosthesis 110 and a second prosthesis 120, and the length adjustment frame includes a frame 210, at least one pair of connecting rods 220, and a linear drive mechanism.

[0044] One end of the first prosthesis 110 is used to connect to the end of the preserved segment of the tibia or femur near the knee joint. One end of the second prosthesis 120 is detachably connected to the other end of the first prosthesis 110, and the other end of the second prosthesis 120 is used to mate with the end of the femur or tibia near the knee joint. Both the first prosthesis 110 and the second prosthesis 120 are provided with connecting holes 140, the axis of which is perpendicular to the extension direction of the tibia or femur.

[0045] For example, the bottom end of the first prosthesis 110 is connected to the top end of the retained segment of the tibia, the bottom end of the second prosthesis 120 is used for detachable connection with the top end of the first prosthesis 110, and the top end of the second prosthesis 120 is used to engage with the end of the femur above the tibia.

[0046] Of course, the top of the first prosthesis 110 can also be connected to the bottom of the preserved segment of the femur, the top of the second prosthesis 120 is used to be detachably connected to the bottom of the first prosthesis 110, and the bottom of the second prosthesis 120 is used to engage with the top of the tibia below the femur.

[0047] A connection hole 140 is provided on the side of the first prosthesis 110 and the second prosthesis 120. The connection hole 140 can extend in a direction perpendicular to the extension of the tibia or femur, and can be located on the side away from the healthy lower limb.

[0048] The extension prosthesis 130 is used for a detachable connection between the first prosthesis 110 and the second prosthesis 120.

[0049] Multiple connecting rods 220 are parallel to each other and perpendicular to the extension direction of the tibia or femur. One of each pair of connecting rods 220 is detachably connected to the connecting hole 140 on the first prosthesis 110, and the other is detachably connected to the connecting hole 140 on the second prosthesis 120. The other end of the connecting rod 220 is slidably connected to the frame 210, and the sliding direction is parallel to the extension direction of the tibia or femur. A linear drive mechanism is disposed between the frame 210 and the connecting rods 220 to drive the two pairs of connecting rods 220 to move towards or away from each other.

[0050] For example, two pairs of connecting rods 220 can be provided. One of the two connecting rods 220 in a pair is detachably connected to the connecting hole 140 on the first prosthesis 110, and the other is detachably connected to the connecting hole 140 on the second prosthesis 120. That is, the first prosthesis 110 and the second prosthesis 120 are respectively connected to the two connecting rods 220.

[0051] One end of the connecting rod 220 can be connected to the corresponding first prosthesis 110 or second prosthesis 120, and the other end is used to extend away from the tibia or femur. For example, when the prosthesis body is connected to the tibia of the left leg, the right end of the connecting rod 220 is connected to the corresponding first prosthesis 110 or second prosthesis 120, and the left end of the connecting rod 220 extends to the left.

[0052] The end of the connecting rod 220 away from the main body of the prosthesis is slidably connected to the frame 210, and the sliding direction is along the extension direction of the frame 210.

[0053] The linear drive mechanism is located between the frame 210 and the connecting rod 220. The linear drive mechanism can be a unidirectional movement mechanism or a bidirectional movement mechanism.

[0054] When the linear drive mechanism is a unidirectional movement mechanism, the linear drive mechanism is set in two sets. One set is used to drive multiple connecting rods 220 connected to the first prosthesis 110 to move synchronously, and the other set is used to drive multiple connecting rods 220 connected to the second prosthesis 120 to move synchronously, so as to realize that the pairs of connecting rods 220 move towards each other or away from each other, thereby achieving the effect of adjusting the length of the prosthesis body.

[0055] When the linear drive mechanism is a bidirectional moving mechanism, a set of linear drive mechanisms is provided. One moving end of the linear drive mechanism is used to drive multiple connecting rods 220 connected to the first prosthesis 110 to move synchronously, and the other moving end is used to drive multiple connecting rods 220 connected to the second prosthesis 120 to move synchronously, so as to realize that the pairs of connecting rods 220 move towards each other or away from each other, thereby achieving the effect of adjusting the length of the prosthesis body.

[0056] In addition, anti-rotation structures are provided between the first prosthesis 110 and the extension prosthesis 130, between the second prosthesis 120 and the extension prosthesis 130, and between the first prosthesis 110 and the second prosthesis 120.

[0057] Taking the use of this extendable knee prosthesis for tibial treatment as an example, medical staff connect the bottom end of the first prosthesis 110 to the top end of the preserved segment of the tibia through open surgery, then detachably connect the bottom end of the second prosthesis 120 to the top end of the first prosthesis 110, and then fit the top end of the second prosthesis 120 with the bottom end of the healthy femur.

[0058] Since osteosarcoma patients are mostly adolescents in their growth period, the lower limbs will stop growing after surgery, while the unaffected lower limbs will continue to grow, eventually leading to progressive unequal leg lengths. When this problem occurs, medical staff use minimally invasive surgery to connect the connecting rods 220 of the length adjustment frame to the connecting holes 140 on the first prosthesis 110 and the second prosthesis 120, respectively. After connection, the distance between the paired connecting rods 220 can be adjusted through an external linear drive mechanism to adjust the length of the prosthesis body and make the lower limbs of both sides equal in length.

[0059] When the patient's height stops increasing, or when the length of the affected lower limb is adjusted to the predetermined length, medical staff can perform open surgery to connect the extension prosthesis 130 between the first prosthesis 110 and the second prosthesis 120.

[0060] Compared to existing treatment options, the extendable knee prosthesis provided by this invention only requires one minimally invasive surgery and one open surgery in the later stages, eliminating the need for multiple open surgeries to adjust the length of the prosthesis body, reducing patient suffering and saving treatment costs.

[0061] In some embodiments, the first prosthesis 110 and the extension prosthesis 130 are provided with a tapered connector 310 or a tapered connector groove 320 at the end near the knee joint, and the second prosthesis 120 and the extension prosthesis 130 are provided with a tapered connector groove 320 or a tapered connector 310 at the end away from the knee joint. The tapered connector groove 320 and the tapered connector 310 have equal taper angles. The length of the tapered connector 310 is less than or equal to the depth of the tapered connector groove 320. The distal outer diameter of the tapered connector 310 is less than the distal inner diameter of the tapered connector groove 320, and the proximal outer diameter of the tapered connector 310 is greater than the distal inner diameter of the tapered connector groove 320.

[0062] For example, a tapered connector 310 can be provided at the end of the first prosthesis 110 and the extended prosthesis 130 near the knee joint, and a tapered groove 320 can be provided at the end of the second prosthesis 120 and the extended prosthesis 130 away from the knee joint. The tapered groove 320 and the tapered connector 310 have the same conical angle, the length of the tapered connector 310 is less than or equal to the depth of the tapered groove 320, and the distal outer diameter of the tapered connector 310 is smaller than the distal inner diameter of the tapered groove 320, while the proximal outer diameter of the tapered connector 310 is larger than the distal inner diameter of the tapered groove 320.

[0063] The distal outer diameter of the tapered connector 310 is smaller than the distal inner diameter of the tapered groove 320, allowing the distal end of the tapered connector 310 to be smoothly inserted into the tapered groove 320. The tapered angles of the tapered groove 320 and the tapered connector 310 are equal, ensuring that when the tapered connector 310 is inserted to a position where its outer diameter equals the distal inner diameter of the tapered groove 320, the outer surface of the tapered connector 310 can completely fit against the inner surface of the tapered groove 320. This increases the contact area between the two, thereby increasing the compressive and frictional forces between them. The length of the tapered connector 310 is less than or equal to the depth of the tapered groove 320, and the outer diameter of the proximal end of the tapered connector 310 is greater than the inner diameter of the distal end of the tapered groove 320. This allows the outer surface of the tapered connector 310 to be fully fitted with the inner surface of the tapered groove 320, and the tapered connector 310 to continue moving into the tapered groove 320. This causes a slight deformation of the tapered connector 310 and the tapered groove 320, increasing the compressive force between them and preventing them from separating.

[0064] It should be noted that, taking the tapered connector 310 and tapered insertion groove 320 provided on the extension prosthesis 130 as examples, the distal end of the tapered connector 310 refers to the end away from the extension prosthesis 130, and the proximal end of the tapered connector 310 refers to the end close to the extension prosthesis 130. Similarly, the distal end of the tapered insertion groove 320 refers to the end away from the extension prosthesis 130, and the proximal end of the tapered insertion groove 320 refers to the end close to the extension prosthesis 130. The distal and proximal ends of the tapered connector 310 and tapered insertion groove 320 provided on the first prosthesis 110 and the second prosthesis 120 are similarly described, and will not be repeated here.

[0065] In some embodiments, the anti-rotation structure includes an anti-rotation block and an anti-rotation groove. The anti-rotation block is disposed at one end of the first prosthesis 110, the second prosthesis 120, and the extended prosthesis 130 where the tapered connector 310 is provided, and the anti-rotation groove is disposed at one end of the first prosthesis 110, the second prosthesis 120, and the extended prosthesis 130 where the tapered insertion groove 320 is provided. The anti-rotation block and the anti-rotation groove are connected by insertion.

[0066] In one specific embodiment, an extendable knee prosthesis is positioned at the top of the retained segment of the tibia, taking the anti-rotation structure between the first prosthesis 110 and the second prosthesis 120 as an example. Two downwardly extending protrusions 410 are provided at the bottom edge of the second prosthesis 120, spaced 180 degrees apart. The opposite sides of the two protrusions 410 are flat, forming an anti-rotation groove. An anti-rotation stop is provided at the proximal end of the tapered connector 310 of the first prosthesis 110. Two blocking planes 420 are provided on the outer peripheral surface of the anti-rotation stop, spaced 180 degrees apart. When the tapered connector 310 is inserted into the tapered connector groove 320, the anti-rotation stop is inserted between the two protrusions 410, and the inner surfaces of the protrusions 410 contact the two blocking planes 420 of the anti-rotation stop, thereby restricting the relative rotation between the first prosthesis 110 and the second prosthesis 120.

[0067] Similarly, the anti-rotation structure between the first prosthesis 110 and the elongation prosthesis 130, and between the second prosthesis 120 and the elongation prosthesis 130, is the same as the structure described above, and will not be repeated here.

[0068] In another specific embodiment, a key 510 can be provided on the outer side of the tapered connector 310, the key 510 extending along the generatrix of the tapered connector 310, and a keyway 520 can be provided on the inner side of the tapered connector groove 320, the keyway 520 extending along the generatrix of the tapered connector groove 320. When the tapered connector 310 moves into the tapered connector groove 320, the key 510 slides in the keyway 520, thereby restricting the relative rotation between the tapered connector 310 and the tapered connector groove 320.

[0069] In some embodiments, the linear drive mechanism includes a slide rail 231, a slider 232, and a first screw 233.

[0070] The slide rail 231 is mounted on the frame 210, and its extension direction is parallel to the extension direction of the tibia or femur. The slider 232 is slidably connected to the slide rail 231, and its sliding direction is along the extension direction of the slide rail 231. The connecting rod 220 is connected to the slider 232, so that the connecting rod 220 and the slider 232 move synchronously.

[0071] A first threaded hole is provided on the slider 232, the axis of the first threaded hole is parallel to the sliding direction of the slider 232, the first screw 233 is rotatably connected to the frame 210, and the end of the first screw 233 is threadedly connected to the first threaded hole.

[0072] Specifically, the frame 210 is provided with a slide rail 231 extending along the extension direction of the frame 210. A slider 232 is slidably connected to the slide rail 231, and a connecting rod 220 is connected to the slider 232. The middle part of the first screw 233 is rotatably connected to the frame 210, and the extension direction of the first screw 233 is along the extension direction of the frame 210, while the rotation axis of the first screw 233 is parallel to the extension direction of the frame 210. The slider 232 corresponding to the first prosthesis 110 is connected to one end of the first screw 233 through a first threaded hole, and the slider 232 corresponding to the second prosthesis 120 is connected to the other end of the second screw through a first threaded hole. The threads at both ends of the first screw 233 have opposite directions of rotation.

[0073] When the first screw 233 rotates, the slider 232 corresponding to the first prosthesis 110 and the slider 232 corresponding to the second prosthesis 120 move toward each other or away from each other.

[0074] In some embodiments, a nut 234 is provided on the outside of the first screw 233, and the nut 234 is fixedly connected to the first screw 233. Thus, when rotating the first screw 233, a wrench can be used in conjunction with the nut 234 to rotate the first screw 233.

[0075] In some embodiments, a scale line 610 is provided on the frame 210, and an indicator mark 620 is provided on the slider 232.

[0076] Specifically, the zero mark 610 is located in the middle of the frame 210. The distance values ​​corresponding to the marks 610 gradually increase towards both ends of the frame 210. An arrow extending horizontally can be provided on the slider 232 as an indicator mark 620. Thus, as the slider 232 slides, the distance it has slid can be clearly observed.

[0077] In some embodiments, the connecting hole 140 can be a second threaded hole, the connecting rod 220 can be a second screw, and the connecting rod 220 is threadedly connected to the connecting hole 140.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An extendable knee joint prosthesis, characterized in that, include: The prosthesis body includes a first prosthesis (110) and a second prosthesis (120). One end of the first prosthesis (110) is used to connect to the end of the preserved segment of the tibia or femur near the knee joint. One end of the second prosthesis (120) is used to detachably connect to the other end of the first prosthesis (110). The other end of the second prosthesis (120) is used to engage with the end of the femur or tibia near the knee joint. Both the first prosthesis (110) and the second prosthesis (120) are provided with connecting holes (140). The axis of the connecting holes (140) is perpendicular to the extension direction of the tibia or femur. An extension prosthesis (130) is provided for detachable connection between the first prosthesis (110) and the second prosthesis (120); The length adjustment frame includes a frame body (210), at least one pair of connecting rods (220), and a linear drive mechanism. The multiple connecting rods (220) are parallel to each other and perpendicular to the extension direction of the tibia or the femur. One of the connecting rods (220) in each pair is detachably connected to the connecting hole (140) on the first prosthesis (110), and the other is detachably connected to the connecting hole (140) on the second prosthesis (120). The other end of the connecting rod (220) is slidably connected to the frame body (210) in a sliding direction parallel to the extension direction of the tibia or the femur. The linear drive mechanism is disposed between the frame body (210) and the connecting rods (220) and is used to drive the two pairs of connecting rods (220) to move towards each other or away from each other.

2. The extendable knee prosthesis according to claim 1, characterized in that, The first prosthesis (110) and the extended prosthesis (130) are provided with a conical connector (310) or a conical connector groove (320) at the end near the knee joint, and the second prosthesis (120) and the extended prosthesis (130) are provided with a conical connector groove (320) or the conical connector (310) at the end away from the knee joint. The conical angles of the conical connector groove (320) and the conical connector (310) are equal. The length of the conical connector (310) is less than or equal to the depth of the conical connector groove (320). The distal outer diameter of the conical connector (310) is less than the distal inner diameter of the conical connector groove (320). The proximal outer diameter of the conical connector (310) is greater than the distal inner diameter of the conical connector groove (320).

3. The extendable knee prosthesis according to claim 2, characterized in that, Anti-rotation structures are provided between the first prosthesis (110) and the extended prosthesis (130), between the second prosthesis (120) and the extended prosthesis (130), and between the first prosthesis (110) and the second prosthesis (120).

4. The extendable knee prosthesis according to claim 3, characterized in that, The anti-rotation structure includes an anti-rotation block and an anti-rotation groove. The anti-rotation block is disposed at one end of the first prosthesis (110), the second prosthesis (120), and the extended prosthesis (130) where a tapered connector (310) is provided. The anti-rotation groove is disposed at one end of the first prosthesis (110), the second prosthesis (120), and the extended prosthesis (130) where a tapered insertion groove (320) is provided. The anti-rotation block and the anti-rotation groove are connected by insertion.

5. The extendable knee prosthesis according to claim 3, characterized in that, The anti-rotation structure includes a key (510) and a keyway (520). The key (510) is disposed on the inner side of the tapered insertion groove (320) or the outer side of the tapered insertion joint (310). The keyway (520) is disposed on the outer side of the tapered insertion joint (310) or the inner side of the tapered insertion groove (320).

6. The extendable knee prosthesis according to claim 1, characterized in that, The linear drive mechanism includes: A slide rail (231) is disposed on the frame (210), and the extension direction of the slide rail (231) is parallel to the extension direction of the tibia or the femur. The slider (232) is slidably connected to the slide rail (231), and the slider (232) is provided with a first threaded hole that passes through the slider (232). The axis of the first threaded hole is parallel to the sliding direction of the slider (232). The connecting rod (220) is connected to the slider (232). The first screw (233) is rotatably connected to the frame (210), and the end of the first screw (233) is threadedly connected to the first threaded hole.

7. The extendable knee prosthesis according to claim 6, characterized in that, A nut (234) is provided on the outside of the first screw (233), and the nut (234) is fixedly connected to the first screw (233).

8. The extendable knee prosthesis according to claim 6, characterized in that, The frame (210) is provided with scale lines (610), and the slider (232) is provided with indicator marks (620).

9. The extendable knee prosthesis according to claim 1, characterized in that, The connecting hole (140) is a second threaded hole, and the connecting rod (220) is a second screw.

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