CN211213698U

CN211213698U - Extendable prosthesis

Info

Publication number: CN211213698U
Application number: CN201921663313.XU
Authority: CN
Inventors: 王彩梅
Original assignee: Beijing AK Medical Co Ltd
Current assignee: Beijing AK Medical Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-08-11
Anticipated expiration: 2029-09-30

Abstract

The utility model is provided with a first prosthesis, a second prosthesis and a deformation structure in the extendable prosthesis, wherein, the first prosthesis comprises a lower sleeve and a transmission piece, the transmission piece is rotatablely arranged in the cavity of the lower sleeve; the second prosthesis comprises an intramedullary rod and a screw rod connected with the intramedullary rod, the screw rod is arranged in the transmission member in a penetrating way, and the screw rod is in threaded connection with the transmission member; the deformation structure sets up in telescopic cavity down, and the one end and the driving medium cooperation of deformation structure, the deformation structure is made by magnetic memory alloy, and the deformation structure can take place to twist reverse under the effect of external magnetic field and warp to the drive driving medium rotates, and the driving medium is under the pivoted circumstances, and drive screw and intramedullary rod move to the direction of keeping away from down the sleeve, can prolong the total length of false body in order to the extension. Thus, after the prosthesis is implanted, the prosthesis can be extended only by applying a suitable magnetic field from the outside, and therefore no invasive surgery is applied.

Description

Extendable prosthesis

Technical Field

The utility model relates to the technical field of medical equipment, particularly, relate to a can prolong false body.

Background

The number of primary osteosarcoma cases per year in China is about 1 ten thousand. Osteosarcoma accounts for 10% of primary bone tumor, accounts for 20% of primary malignant tumor, has an annual incidence rate of 1-3 persons/100 ten thousand persons, wherein 75% of patients are 10-30 years old, and are malignant tumors seriously affecting physical and mental health of young adults.

The concept of limb amputation has evolved and matured over the last 25 years. The limb protection operation mainly comprises complete excision of an affected bone tumor section and reconstruction of bone defects, various reconstruction technologies are used in bone tumor diagnosis and treatment centers of the United states and Europe in the past two and thirty years, the limbs are reconstructed after the bone tumor is excised, and along with analysis and discovery of follow-up results of different reconstruction methods in recent years, the artificial metal prosthesis reconstruction obtains better medium and long-term follow-up results, and the advantages of the artificial prosthesis reconstruction comprise: the internal fixation is durable, the stability after the operation is good, the short-term and long-term functional prognosis is better, and the mobility of the joint after the operation is good.

For adolescents, the growth of the distal femoral and proximal tibial epiphyses (bone growth sites) accounts for 70% of the length of the overall lower limb development. Resection of the lower epiphyseal plate of the femur results in the loss of about 1.6cm of affected limb per year. For this reason, knee resection for patients with bone tumors of very small age (less than 10 years) necessarily causes severe limb inequality. For children bone tumor patients, with the prolonged life cycle, the complications such as limb inequality and lameness caused by the reconstruction of tumor segment amputation prosthesis are increasing. Children also have great growth capabilities due to the bone, and any metal prosthesis eventually needs to be refurbished as the child grows.

At present, about 10 percent of patients with bone primary tumor have the problem of unequal limb lengths after limb protection surgery. The extendable prosthesis can better solve the problem, but because the extendable prosthesis widely adopted at present needs to be operated every time of extension, an incision with a certain length is cut to expose an extension screw, the prosthesis is extended by using a mechanical driving device, the extension length is limited every time (the vascular nerve cannot endure traction), and the infection probability and tissue scarring are increased by multiple operations. Thus, the invasive extension prostheses currently employed by physicians greatly increase the number of surgeries and the chances of postoperative complications for pediatric patients. This frequent surgical procedure will last ten years or even longer, with a considerable pain and economic burden on the patient.

SUMMERY OF THE UTILITY MODEL

The utility model provides a prolonged prosthesis, which solves the problem that the prolonged prosthesis needs to be subjected to the operation of generating wound to be prolonged in the prior art.

In order to solve the above problems, the present invention provides an extendable prosthesis, comprising: the first prosthesis comprises a lower sleeve and a transmission piece, and the transmission piece is rotatably arranged in a cavity of the lower sleeve; the second prosthesis comprises an intramedullary rod and a screw rod connected with the intramedullary rod, the screw rod is arranged in the transmission member in a penetrating way, and the screw rod is in threaded connection with the transmission member; the deformation structure is arranged in the cavity of the lower sleeve, one end of the deformation structure is matched with the transmission part, the deformation structure is made of magnetic memory alloy, the deformation structure can be subjected to torsional deformation under the action of an external magnetic field to drive the transmission part to rotate, and the transmission part drives the screw rod and the intramedullary rod to move in the direction far away from the lower sleeve under the rotating condition to prolong the total length of the prosthesis.

Furthermore, the screw structure of the screw rod matched with the transmission piece is a one-way screw structure, and the one-way screw structure enables the screw rod to move only in one direction far away from the lower sleeve, so that the screw rod is prevented from returning after the movement is completed.

Further, have spacing step on the lower telescopic inner wall, spacing step and the spacing cooperation of one end of driving medium, first false body still includes: the stop collar is arranged in the cavity of the lower sleeve, and the end part of the stop collar is in limit fit with the other end of the transmission part.

Further, the first prosthesis further comprises: the intramedullary rod penetrates through the upper sleeve, and a sealing structure is arranged between the upper sleeve and the intramedullary rod.

Furthermore, a convex rib is arranged on one of the inner wall of the upper sleeve and the outer wall of the intramedullary rod, and the convex rib extends along the moving direction of the intramedullary rod; the other one of the inner wall of the upper sleeve and the outer wall of the intramedullary rod is provided with a sliding groove, the sliding groove extends along the moving direction of the intramedullary rod, and the convex rib is arranged in the sliding groove in a sliding way.

Furthermore, one end of the deformation structure is connected with the transmission part, the other end of the deformation structure is connected with the lower sleeve, and the deformation structure is a spiral spring structure or a coil spring structure.

Further, the first prosthesis further comprises a bearing structure, the other end of the deformation structure is connected with the lower sleeve through the bearing structure, and the bearing structure comprises: the plate body is arranged at the bottom of the cavity of the lower sleeve, and the other end of the deformation structure is connected with the plate body; spacing tooth, spacing tooth are located the one side that deviates from the deformation structure of plate body, and spacing tooth inserts and carries on spacingly in order to carry on the circumference of plate body in the diapire of lower sleeve.

Furthermore, the screw rod comprises a first rod section and a second rod section which are connected with each other, the first rod section is arranged in the intramedullary rod in a penetrating mode, the relative positions of the first rod section and the intramedullary rod in the circumferential direction are fixed, the second rod section is located outside the intramedullary rod, and the second rod section is in threaded connection with the transmission piece.

Further, the extendable prosthesis further comprises: a plurality of anti-recoil grooves disposed on one of the first prosthesis and the second prosthesis; the clamping part is used for clamping any one of the anti-withdrawal grooves and movably arranged on the other one of the first prosthesis and the second prosthesis; under the condition that the second prosthesis moves towards the direction far away from the first prosthesis, the clamping part avoids the anti-retreat grooves so as to enable the second prosthesis to move in a single direction; after the second prosthesis is moved, the clamping parts are clamped into the corresponding anti-withdrawal grooves to prevent the second prosthesis from withdrawing.

Further, the extendable prosthesis is a femoral prosthesis, the first prosthesis further comprising: the femur condyle and the lower sleeve are connected with the femur condyle.

By applying the technical scheme of the utility model, a first prosthesis, a second prosthesis and a deformation structure are arranged in the extendable prosthesis, wherein the first prosthesis comprises a lower sleeve and a transmission part, and the transmission part is rotatably arranged in the cavity of the lower sleeve; the second prosthesis comprises an intramedullary rod and a screw rod connected with the intramedullary rod, the screw rod is arranged in the transmission member in a penetrating way, and the screw rod is in threaded connection with the transmission member; the deformation structure sets up in telescopic cavity down, and the one end and the driving medium cooperation of deformation structure, the deformation structure is made by magnetic memory alloy, and the deformation structure can take place to twist reverse under the effect of external magnetic field and warp to the drive driving medium rotates, and the driving medium is under the pivoted circumstances, and drive screw and intramedullary rod move to the direction of keeping away from down the sleeve, can prolong the total length of false body in order to the extension. Because the deformation structure is made of the magnetic control shape memory alloy, the deformation structure can be deformed by applying a magnetic field externally, thereby prolonging the prosthesis and prolonging the prosthesis. Thus, after the prosthesis is implanted, the prosthesis can be extended only by applying a suitable magnetic field from the outside, and therefore no invasive surgery is applied. Therefore, the pain caused by secondary or multiple operations to the infant cannot be caused, the extension times in unit time (such as within one year) can be increased according to the growth condition of the legs of the infant, and the extension length of each time is correspondingly reduced, so that the infant can be more easily adapted to the length and the balance problem of the two legs after each time of extension.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic structural view of an extendable prosthesis provided by an embodiment of the present invention;

FIG. 2 shows a cross-sectional view of the extensible prosthesis of FIG. 1;

FIG. 3 shows an enlarged view of the deformed configuration of FIG. 2;

FIG. 4 is a schematic view of the extensible prosthesis of FIG. 1 in another alternative configuration;

FIG. 5 shows a schematic view of the seal structure of FIG. 2;

FIG. 6 shows a schematic view of the upper sleeve of FIG. 2;

fig. 7 shows a schematic view of the intramedullary rod of fig. 2.

Wherein the figures include the following reference numerals:

10. a first prosthesis; 11. a lower sleeve; 12. an upper sleeve; 13. a femoral condyle; 14. a transmission member; 20. a second prosthesis; 21. an intramedullary rod; 25. a screw; 30. a deformed configuration; 51. a rib is protruded; 52. a chute; 61. sealing sleeves; 62. a seal ring; 71. a plate body; 72. limiting teeth; 73. a limiting sleeve.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As shown in the drawings, embodiments of the present invention provide an extendable prosthesis, comprising: a first prosthesis 10, the first prosthesis 10 comprising a lower sleeve 11 and a transmission member 14, the transmission member 14 being rotatably arranged within a cavity of the lower sleeve 11; the second prosthesis 20, the second prosthesis 20 includes the intramedullary rod 21 and the threaded spindle 25 connected with the intramedullary rod 21, the threaded spindle 25 is inserted in the driving member 14, the threaded spindle 25 is connected with the driving member 14 by screw thread; the deformation structure 30 is arranged in the cavity of the lower sleeve 11, one end of the deformation structure 30 is matched with the transmission part 14, the deformation structure 30 is made of magnetic memory alloy, the deformation structure 30 can be subjected to torsional deformation under the action of an external magnetic field to drive the transmission part 14 to rotate, and the transmission part 14 drives the screw rod 25 and the intramedullary rod 21 to move in the direction away from the lower sleeve 11 under the rotating condition so as to prolong the total length of the prosthesis.

By applying the technical scheme of the utility model, a first prosthesis 10, a second prosthesis 20 and a deformation structure 30 are arranged in the extendable prosthesis, wherein the first prosthesis 10 comprises a lower sleeve 11 and a transmission part 14, and the transmission part 14 is rotatably arranged in the cavity of the lower sleeve 11; the second prosthesis 20 comprises an intramedullary rod 21 and a screw rod 25 connected with the intramedullary rod 21, the screw rod 25 is arranged in the transmission member 14 in a penetrating way, and the screw rod 25 is in threaded connection with the transmission member 14; the deformation structure 30 is arranged in the cavity of the lower sleeve 11, one end of the deformation structure 30 is matched with the transmission member 14, the deformation structure 30 is made of magnetic memory alloy, the deformation structure 30 can be subjected to torsional deformation under the action of an external magnetic field to drive the transmission member 14 to rotate, and under the condition that the transmission member 14 rotates, the driving screw rod 25 and the intramedullary rod 21 move in the direction away from the lower sleeve 11 to prolong the total length of the prosthesis. Because the deformation structure 30 is made of magnetically controlled shape memory alloy, the deformation structure 30 can be deformed by applying a magnetic field externally, thereby lengthening the extendable prosthesis. Thus, after the prosthesis is implanted, the prosthesis can be extended only by applying a suitable magnetic field from the outside, and therefore no invasive surgery is applied. Therefore, the pain caused by secondary or multiple operations to the infant cannot be caused, the extension times in unit time (such as within one year) can be increased according to the growth condition of the legs of the infant, and the extension length of each time is correspondingly reduced, so that the infant can be more easily adapted to the length and the balance problem of the two legs after each time of extension. In use, the moving distance of the second prosthesis 20 is precisely controlled by controlling the strength and time of the magnetic field applied from the outside, thereby controlling the total length of the extendable prosthesis.

In order to improve the reliability, in the present embodiment, the thread structure of the screw 25 engaged with the transmission member 14 is a one-way thread structure, and the one-way thread structure enables the screw 25 to move only in one direction away from the lower sleeve 11, so as to prevent the screw 25 from backing after the movement is completed.

In this embodiment, the lower sleeve 11 has a limit step on its inner wall, and the limit step is in limit fit with one end of the transmission member 14, and the first prosthesis 10 further includes: and the limiting sleeve 73 is arranged in the cavity of the lower sleeve 11, and the end part of the limiting sleeve 73 is in limiting fit with the other end of the transmission piece 14. Therefore, the axial two directions of the transmission piece 14 can be limited by the limiting step and the limiting sleeve 73, so that the transmission piece 14 can only rotate and cannot axially move, and the driving screw rod 25 axially moves.

In this embodiment, the first prosthesis 10 further comprises: the intramedullary rod 21 penetrates through the upper sleeve 12, and a sealing structure is arranged between the upper sleeve 12 and the intramedullary rod 21. The stability of the intramedullary rod 21 can be improved by providing the upper sleeve 12. By arranging the sealing structure, a good sealing effect can be achieved, and the influence on normal use caused by the body fluid and the like entering the first prosthesis 10 is avoided. Optionally, the upper sleeve 12 and the lower sleeve 11 are screwed or welded, and the end of the upper sleeve 12 has a limit step for mating with the end face of the lower sleeve 11.

Optionally, the sealing structure comprises: the sealing sleeve 61 is sleeved on the intramedullary rod 21, a limiting step is arranged on the sealing sleeve 61 to be in limiting fit with the end part of the upper sleeve 12, and the plurality of sealing rings 62 are arranged in the annular groove on the inner wall of the upper sleeve 12 to improve the sealing effect.

In the present embodiment, a rib 51 is provided on one of the inner wall of the upper sleeve 12 and the outer wall of the intramedullary rod 21, the rib 51 extending in the moving direction of the intramedullary rod 21; the other of the inner wall of the upper sleeve 12 and the outer wall of the intramedullary rod 21 is provided with a sliding groove 52, the sliding groove 52 extends along the moving direction of the intramedullary rod 21, and the convex rib 51 is slidably arranged in the sliding groove 52. By means of the arrangement, it is possible to guide the movement of the second prosthesis 20 and to avoid relative rotation of the first prosthesis 10 and the second prosthesis 20 in the circumferential direction. The rib 51 is provided on the inner wall of the upper sleeve 12, and the slide groove 52 is provided on the outer wall of the intramedullary rod 21.

In the present embodiment, one end of the deforming structure 30 is connected to the transmission member 14, the other end of the deforming structure 30 is connected to the lower sleeve 11, the deforming structure 30 is a spiral spring structure or the deforming structure 30 is a coil spring structure. Thus, under the action of the external magnetic field, the deforming structure 30 may be twisted as many turns as necessary to effect axial movement of the screw 25.

In this embodiment, the first prosthesis 10 further comprises a bearing structure, through which the other end of the deformation structure 30 is connected to the lower sleeve 11, the bearing structure comprising: a plate body 71, wherein the plate body 71 is arranged at the bottom of the cavity of the lower sleeve 11, and the other end of the deformation structure 30 is connected with the plate body 71; and the limiting teeth 72 are positioned on one side, away from the deformation structure 30, of the plate body 71, and the limiting teeth 72 are inserted into the bottom wall of the lower sleeve 11 to limit the circumferential direction of the plate body 71. In this way, the plate 71 and the limit tooth 72 can reliably fix the other end of the deformation structure 30.

Optionally, the load bearing structure is integral with the stop collar 73. The driving member 14 has a recess for receiving one end of the deformable structure 30, and the plate body 71 has a recess for receiving the other end of the deformable structure 30.

In the present embodiment, the screw 25 includes a first rod section and a second rod section connected to each other, the first rod section is inserted into the intramedullary rod 21, the relative position of the first rod section and the intramedullary rod 21 in the circumferential direction is fixed, the second rod section is located outside the intramedullary rod 21, and the second rod section is in threaded connection with the transmission member 14. The manufacture and assembly of the second prosthesis 20 is facilitated by the above arrangement. Alternatively, the first rod segment and the intramedullary rod 21 may be circumferentially limited by means of a key and keyway.

In this embodiment, the extendable prosthesis further comprises: a plurality of anti-back grooves provided on one of the first prosthesis 10 and the second prosthesis 20; the clamping part is used for clamping any one of the anti-withdrawal grooves and is movably arranged on the other one of the first prosthesis 10 and the second prosthesis 20; when the second prosthesis 20 moves in a direction away from the first prosthesis 10, the clamping parts avoid a plurality of anti-withdrawal grooves so that the second prosthesis 20 moves in a single direction; after the second prosthesis 20 is moved, the clamping parts are clamped into the corresponding anti-withdrawal grooves to prevent the second prosthesis 20 from withdrawing. The anti-back structure realizes that the second prosthesis 20 can only move in a single direction in a direction away from the first prosthesis 10 but can not move in a direction close to the first prosthesis 10, thereby avoiding the prosthesis from contracting after being prolonged.

Optionally, the anti-retreat structure includes: a plurality of anti-back grooves provided on one of the first prosthesis 10 and the second prosthesis 20; the clamping part is used for clamping any one of the anti-withdrawal grooves and is movably arranged on the other one of the first prosthesis 10 and the second prosthesis 20; when the second prosthesis 20 moves in a direction away from the first prosthesis 10, the clamping parts avoid a plurality of anti-withdrawal grooves so that the second prosthesis 20 moves in a single direction; after the second prosthesis 20 is moved, the clamping parts are clamped into the corresponding anti-withdrawal grooves to prevent the second prosthesis 20 from withdrawing. Thus, the single-direction movement of the second prosthesis 20 can be realized through the matching of the clamping parts and the anti-receding grooves.

Optionally, a plurality of anti-receding grooves are formed in the outer wall of the second prosthesis 20, and the plurality of clamping portions are formed in the inner wall of the first prosthesis 10, so as to improve reliability. The clamping portion is telescopically arranged or rotatably arranged, the clamping portion comprises a spring and a clamping block which are arranged in a groove of the first prosthesis 10, and the clamping block can extend out of or retract into the groove. The fixture block is provided with a first limiting plane and a first guiding inclined plane, the anti-withdrawal groove is provided with a second limiting plane and a second guiding inclined plane, the first limiting plane is in limiting fit with the second limiting plane to prevent withdrawal when the second prosthesis 20 is subjected to external axial pressure, and the first guiding inclined plane is matched with the second guiding inclined plane to push the fixture block to withdraw into the groove when the second prosthesis 20 moves towards the extension direction.

The extendable prosthesis can be used for implanting bones such as tibia, radius, ulna and the like. In this embodiment, the extendable prosthesis is a femoral prosthesis, and the first prosthesis 10 further comprises: the femoral condyle 13 and the lower sleeve 11 are connected to the femoral condyle 13. The extendable prosthesis can then be used for implantation in the residual femur.

Optionally, the lower sleeve 11 includes a barrel, a limiting post and a positioning post connected in sequence, the positioning post is a conical structure, the diameter of the positioning post is smaller than that of the limiting post, and the limiting post and the positioning post are arranged in the femoral condyle 13 in a penetrating manner to realize positioning and limiting.

The scheme combines the morphological requirement design of the far end thickness and the near end thickness of the human femoral condyle, and the upper sleeve and the lower sleeve are manufactured in a split mode and then welded into a whole. Has sealing effect, and can prevent body fluid from entering the prosthesis to cause corrosion damage to internal materials. The prosthesis end is made of PEEK plastic, and the PEEK has excellent biocompatibility and wear resistance and prevents abrasion between metals at the end under a bending stress environment.

For the purpose of facilitating understanding of the present solution, the following description will be made appropriately for the magnetic memory alloy:

after the traditional shape memory alloy is subjected to plastic deformation in a martensite state, the shape memory alloy is heated to be above Af temperature and can automatically return to a parent phase state; if it is cooled again below the Mf temperature, it will automatically return to its original plastically deformed or martensitic shape. And has a much larger amount of strain than other driving materials, but must be obtained by changing the temperature of the alloy, so its response speed is slow. Conventional shape memory alloys, such as TiNi-based, Fe-based, Cu-based alloys, etc., have a relatively large reversible recovery strain and a large recovery force, but have a relatively low response frequency (about 1 Hz) because they are driven by a temperature field. In recent years, a new electromagnetic driving material, magnetically controlled shape memory alloy, has been quietly developed and has received much attention due to its outstanding magnetic strain properties.

The magnetic shape memory alloy has the advantages of combining ferromagnetism and thermoelastic martensite phase transformation, and combining the advantages of large strain of the shape memory alloy and quick response of a magnetostrictive material. Zeeman static magnetic force of the magnetic field on the unfavorable orientation martensite variants in the alloy is utilized to promote the favorable orientation martensite variants to grow and swallow the unfavorable orientation martensite variants (represented by movement of twin boundaries), so that macroscopic deformation is generated.

The magnetic shape memory effect can only be present in magnetic alloys with a thermo-elastic martensitic transformation. Typical ferromagnetic shape memory alloys include Ni-Mn-Ga, Ni-Fe-Ga, Fe-based alloys (Fe-Pd, Fe-Ni-Co-Ti, etc.), Co-based alloys (Co-Ni, Co-Mn based alloys, etc.), and the like.

Magnetic shape memory alloys are of particular interest because: 1. the performance is excellent. The most important performance index is dependent variable, which is 1-2 orders of magnitude higher than the performance of the existing material. Magnetic shape memory alloys have a two-way strain effect and these unique properties are well suited for developing new actuators. 2. Compared with the giant magnetostrictive material, the material has lower price. Because the giant magnetostrictive material contains a large amount of expensive metal Tb, the price of the magnetic control shape memory alloy is about one tenth of that of the giant magnetostrictive material. 3. There are a number of important applications. The magnetic shape memory alloy is used as an intelligent material and is a material basis in the future national defense and high technology fields. The high-strain-rate ultrasonic transducer has high strain characteristic and high response frequency, and is expected to be applied to the aspects of sensors, surface intelligent structures, automatic control, airplane wing regulating and controlling systems, ultra-high-power ultrasonic transducer technology and the like.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An extendable prosthesis, comprising:

a first prosthesis (10), the first prosthesis (10) comprising a lower sleeve (11) and a transmission member (14), the transmission member (14) being rotatably arranged within a cavity of the lower sleeve (11);

the second prosthesis (20) comprises an intramedullary rod (21) and a screw rod (25) connected with the intramedullary rod (21), the screw rod (25) is arranged in the transmission member (14) in a penetrating way, and the screw rod (25) is in threaded connection with the transmission member (14);

the deformation structure (30) is arranged in the cavity of the lower sleeve (11), one end of the deformation structure (30) is matched with the transmission piece (14), the deformation structure (30) is made of magnetic memory alloy, the deformation structure (30) can be subjected to torsional deformation under the action of an external magnetic field to drive the transmission piece (14) to rotate, and the transmission piece (14) drives the screw rod (25) and the intramedullary rod (21) to move in the direction away from the lower sleeve (11) under the rotating condition to prolong the total length of the prosthesis.

2. The extensible prosthesis according to claim 1, characterized in that the screw (25) has a screw-thread configuration cooperating with the transmission element (14) which is a one-way screw-thread configuration which allows a one-way movement of the screw (25) only in a direction away from the lower sleeve (11) to prevent the screw (25) from retracting after the movement is completed.

3. The extensible prosthesis according to claim 1, characterized in that the lower sleeve (11) has, on its inner wall, a stop step which is in stop engagement with one end of the transmission element (14), the first prosthesis (10) further comprising:

and the limiting sleeve (73) is arranged in the cavity of the lower sleeve (11), and the end part of the limiting sleeve (73) is in limiting fit with the other end of the transmission piece (14).

4. The extendable prosthesis of claim 1, wherein said first prosthesis (10) further comprises:

the intramedullary nail is characterized by comprising an upper sleeve (12), the upper sleeve (12) is connected with the lower sleeve (11), the intramedullary rod (21) penetrates through the upper sleeve (12), and a sealing structure is arranged between the upper sleeve (12) and the intramedullary rod (21).

5. The extendable prosthesis of claim 4,

one of the inner wall of the upper sleeve (12) and the outer wall of the intramedullary rod (21) is provided with a convex rib (51), and the convex rib (51) extends along the moving direction of the intramedullary rod (21);

the other one of the inner wall of the upper sleeve (12) and the outer wall of the intramedullary rod (21) is provided with a sliding groove (52), the sliding groove (52) extends along the moving direction of the intramedullary rod (21), and the convex rib (51) is arranged in the sliding groove (52) in a sliding manner.

6. The extendable prosthesis of claim 1, wherein one end of said deformation structure (30) is connected to said transmission member (14), the other end of said deformation structure (30) is connected to said lower sleeve (11), said deformation structure (30) is a helical spring structure or said deformation structure (30) is a coil spring structure.

7. The extensible prosthesis of claim 6, wherein the first prosthesis (10) further comprises a bearing structure by which the other end of the deformation structure (30) is connected with the lower sleeve (11), the bearing structure comprising:

the plate body (71), the plate body (71) is arranged at the bottom of the cavity of the lower sleeve (11), and the other end of the deformation structure (30) is connected with the plate body (71);

the limiting teeth (72) are located on one side, away from the deformation structure (30), of the plate body (71), and the limiting teeth (72) are inserted into the bottom wall of the lower sleeve (11) to limit the circumferential direction of the plate body (71).

8. The extendable prosthesis of claim 1, wherein said screw (25) comprises a first and a second interconnected rod segments, said first rod segment being inserted into said intramedullary rod (21), said first rod segment being fixed in position circumferentially relative to said intramedullary rod (21), said second rod segment being located outside said intramedullary rod (21), said second rod segment being in threaded connection with said transmission member (14).

9. The extendable prosthesis of claim 1, further comprising:

a plurality of anti-back grooves provided on one of the first prosthesis (10) and the second prosthesis (20);

the clamping part is used for clamping any one of the anti-withdrawal grooves and movably arranged on the other one of the first prosthesis (10) and the second prosthesis (20);

when the second prosthesis (20) moves in a direction away from the first prosthesis (10), the clamping parts avoid the anti-withdrawal grooves so that the second prosthesis (20) moves in one direction; after the second prosthesis (20) is moved, the clamping parts are clamped into the corresponding anti-withdrawal grooves to prevent the second prosthesis (20) from withdrawing.

10. The extendable prosthesis of claim 1, wherein said extendable prosthesis is a femoral prosthesis, said first prosthesis (10) further comprising:

a femoral condyle (13), the lower sleeve (11) being connected to the femoral condyle (13).