CN110584841B

CN110584841B - Extensible prosthesis

Info

Publication number: CN110584841B
Application number: CN201910944094.0A
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: 2024-04-12
Anticipated expiration: 2039-09-30
Also published as: CN110584841A

Abstract

The invention is provided with a first prosthesis, a second prosthesis and a deformation structure in the extensible prosthesis, wherein 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 piece in a penetrating way, and the screw rod is in threaded connection with the transmission piece; the deformation structure is arranged in the cavity of the lower sleeve, one end of the deformation structure is matched with the transmission piece, 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 so as to drive the transmission piece to rotate, and the driving screw and the intramedullary rod move in the direction away from the lower sleeve under the condition of rotation of the transmission piece so as to prolong the total length of the extensible prosthesis. Thus, after the prosthesis is implanted, the prosthesis can be prolonged by only applying a proper magnetic field from the outside, so that a traumatic operation is not required.

Description

Extensible prosthesis

Technical Field

The invention relates to the technical field of medical appliances, in particular to a prolonged prosthesis.

Background

The number of primary osteosarcoma cases per year in China is about 1 ten thousand. Osteosarcoma accounts for 10% of primary bone tumors, 20% of primary malignant tumors, and the annual incidence rate is 1-3/100 ten thousand, wherein 75% of patients are aged 10-30 years, and are malignant tumors which seriously affect physical and mental health in young and strong years.

The concept of limb protection has evolved and matured over the last 25 years. The limb-protecting operation mainly comprises complete excision of affected bone tumor segments and reconstruction of bone defects, various reconstruction techniques are used in bone tumor diagnosis and treatment centers in the United states and Europe in the past two, three decades, limbs after bone tumor excision are reconstructed, and along with the analysis of follow-up results of different reconstruction methods in recent years, the reconstruction of an artificial metal prosthesis obtains better mid-long term follow-up results, and the reconstruction of the artificial prosthesis has the following advantages: the internal fixation is durable, the immediate stability after operation is good, the prognosis of short-term and long-term functions is good, and the joint mobility after operation is good.

For adolescents, the growth of the distal femur and proximal tibia epiphyseal plate (bone growth site) accounts for 70% of the overall length of the lower limb's elevated development. Resection of the lower metaphyseal plate of the femur results in loss of the affected limb by about 1.6cm in length each year. For this reason, knee resections in very young bone tumor patients (less than 10 years old) necessarily result in severe limb inequality. For children bone tumor patients, complications such as limb inequality and lameness caused by reconstruction of tumor segment amputation prosthesis are increased gradually along with the prolonging of the life cycle. Children have great growth capacity due to bones, and any metal prosthesis needs to be repaired finally along with the growth of the children.

At present, about 10% of patients with primary tumors face the problem of limb inequality after limb protection surgery. The extendable prosthesis can better solve the problem, but as the current widely adopted extendable prosthesis needs to be subjected to operation each time, an incision with a certain length is cut to expose extension screws, the prosthesis is extended by using a mechanical driving device, the extension length of each time is limited (the vascular nerve cannot withstand traction), and the infection probability and tissue scarring are increased by a plurality of operations. Thus, the invasive extension prostheses currently employed by doctors greatly increase the number of operations and the probability of postoperative complications for pediatric patients. Such frequent surgical procedures will last ten years or more, causing considerable pain and economic burden to the patient.

Disclosure of Invention

The invention provides a prolonged prosthesis, which solves the problem that the prolonged prosthesis in the prior art can be prolonged only by performing a trauma operation.

In order to solve the above problems, the present invention provides a stretchable 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 piece in a penetrating way, and the screw rod is in threaded connection with the transmission piece; the deformation structure is arranged in the cavity of the lower sleeve, one end of the deformation structure is matched with the transmission piece, the deformation structure is made of magnetic memory alloy, and the deformation structure can be subjected to torsional deformation under the action of an external magnetic field so as to drive the transmission piece to rotate.

Further, the screw rod and the transmission piece are matched with a threaded structure which is a one-way threaded structure, and the screw rod can only move unidirectionally in a direction far away from the lower sleeve by the one-way threaded structure so as to prevent the screw rod from retreating after the movement is completed.

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

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

Further, a convex rib is arranged on one of the inner wall of the upper sleeve and the outer wall of the intramedullary rod, and extends along the moving direction of the intramedullary rod; the other of the inner wall of the upper sleeve and the outer wall of the intramedullary rod is provided with a chute which extends along the moving direction of the intramedullary rod, and the convex rib is slidably arranged in the chute.

Further, one end of the deformation structure is connected with the transmission piece, 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 provided with 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 in lower telescopic diapire in order to carry out spacingly to the circumference of plate body.

Further, the screw rod comprises a first rod section and a second rod section which are connected with each other, the first rod section is penetrated in the intramedullary rod, the relative positions of the first rod section and the intramedullary rod in the circumferential direction are fixed, the second rod section is positioned outside the intramedullary rod, and the second rod section is in threaded connection with the transmission piece.

Further, the extensible prosthesis further comprises: a plurality of anti-back-out grooves disposed on one of the first prosthesis and the second prosthesis; the clamping part is used for being clamped with any one of the plurality of anti-withdrawal grooves and is movably arranged on the other one of the first prosthesis and the second prosthesis; when the second prosthesis moves in a direction away from the first prosthesis, the clamping part avoids the plurality of anti-withdrawal grooves so as to enable the second prosthesis to move unidirectionally; after the second prosthesis is moved, the clamping part is clamped into the corresponding anti-withdrawal groove to prevent the second prosthesis from withdrawing.

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

By applying the technical scheme of the invention, the extensible prosthesis is provided with the first prosthesis, the second prosthesis and the deformation structure, wherein 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 piece in a penetrating way, and the screw rod is in threaded connection with the transmission piece; the deformation structure is arranged in the cavity of the lower sleeve, one end of the deformation structure is matched with the transmission piece, 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 so as to drive the transmission piece to rotate, and the driving screw and the intramedullary rod move in the direction away from the lower sleeve under the condition of rotation of the transmission piece so as to prolong the total length of the extensible prosthesis. Because the deformation structure is made of magnetic control shape memory alloy, the deformation structure can be deformed by applying a magnetic field to the outside, so that the extensible prosthesis can be prolonged. Thus, after the prosthesis is implanted, the prosthesis can be prolonged by only applying a proper magnetic field from the outside, so that a traumatic operation is not required. Therefore, the pain caused by secondary or repeated operations on the infant is avoided, the extension times in unit time (such as 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 is more easily adapted to the problems of the length of the legs and balance after each time extension.

Drawings

The accompanying drawings, which 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. In the drawings:

FIG. 1 shows a schematic structural view of a malleable 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 shows a schematic view of the extensible prosthesis of FIG. 1 in another deformed configuration;

FIG. 5 shows a schematic view of the sealing 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 above figures include the following reference numerals:

10. a first prosthesis; 11. a lower sleeve; 12. an upper sleeve; 13. femoral condyles; 14. a transmission member; 20. a second prosthesis; 21. an intramedullary rod; 25. a screw; 30. a deformed structure; 51. convex ribs; 52. a chute; 61. sealing sleeve; 62. a seal ring; 71. a plate body; 72. limit teeth; 73. and a limit sleeve.

Detailed Description

The technical solutions 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 will be apparent that the described embodiments are only some, but not all, embodiments of the invention. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in the drawings, embodiments of the present invention provide a malleable 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 in the cavity of the lower sleeve 11; a second prosthesis 20, the second prosthesis 20 comprising an intramedullary rod 21 and a screw 25 connected to the intramedullary rod 21, the screw 25 being threaded in the transmission member 14, the screw 25 being 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 generate torsional deformation under the action of an external magnetic field so as to drive the transmission member 14 to rotate, and the driving screw 25 and the intramedullary rod 21 move in a direction away from the lower sleeve 11 under the condition that the transmission member 14 rotates so as to prolong the total length of the extensible prosthesis.

By applying the technical scheme of the invention, the first prosthesis 10, the second prosthesis 20 and the deformation structure 30 are arranged in the extendable prosthesis, wherein the first prosthesis 10 comprises a lower sleeve 11 and a transmission member 14, and the transmission member 14 is rotatably arranged in 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 penetrated in the transmission member 14, and the screw rod 25 is in threaded connection with the transmission member 14; the deformation structure 30 is disposed 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 generate torsional deformation under the action of an external magnetic field to drive the transmission member 14 to rotate, and the driving screw 25 and the intramedullary rod 21 move away from the lower sleeve 11 under the condition that the transmission member 14 rotates, so that the total length of the extensible prosthesis is prolonged. Since the deformation structure 30 is made of a magnetic control shape memory alloy, the deformation structure 30 can be deformed by externally applying a magnetic field, thereby lengthening the extensible prosthesis. Thus, after the prosthesis is implanted, the prosthesis can be prolonged by only applying a proper magnetic field from the outside, so that a traumatic operation is not required. Therefore, the pain caused by secondary or repeated operations on the infant is avoided, the extension times in unit time (such as 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 is more easily adapted to the problems of the length of the legs and balance after each time extension. In use, the total length of the extensible prosthesis is controlled by precisely controlling the distance of movement of the second prosthesis 20 by controlling the strength and time of the externally applied magnetic field.

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

In this embodiment, the inner wall of the lower sleeve 11 has a limiting step, which is in limiting fit with one end of the transmission member 14, and the first prosthesis 10 further includes: 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. In this way, the limiting steps and the limiting sleeve 73 can limit the two axial directions of the transmission member 14, so that the transmission member 14 can only rotate and cannot axially move, and the driving screw 25 axially moves.

In this embodiment, the first prosthesis 10 further comprises: an upper sleeve 12, the upper sleeve 12 is connected with the lower sleeve 11, an intramedullary rod 21 passes 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 may be improved by providing the upper sleeve 12. By providing a sealing structure, a good sealing effect can be achieved, and the body fluid and the like can be prevented from entering the first prosthesis 10 to affect normal use. 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, the sealing sleeve 61 is provided with a limiting step to be in limiting fit with the end part of the upper sleeve 12, and a plurality of sealing rings 62 are positioned in the annular groove of the inner wall of the upper sleeve 12 so as to improve the sealing effect.

In the present embodiment, a bead 51 is provided on one of the inner wall of the upper sleeve 12 and the outer wall of the intramedullary rod 21, the bead 51 extending in the direction of movement 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 runner 52, the runner 52 extending in the direction of movement of the intramedullary rod 21, a bead 51 being slidably provided within the runner 52. By the above arrangement, the movement of the second prosthesis 20 can be guided and the relative rotation of the first prosthesis 10 and the second prosthesis 20 in the circumferential direction can be prevented. The bead 51 is provided on the inner wall of the upper sleeve 12 and the runner 52 is provided on the outer wall of the intramedullary rod 21.

In this embodiment, one end of the deformation structure 30 is connected to the transmission member 14, the other end of the deformation structure 30 is connected to the lower sleeve 11, and the deformation structure 30 is a spiral spring structure or the deformation structure 30 is a coil spring structure. Thus, under the action of an external magnetic field, the deformation structure 30 can be twisted for a plurality of turns as required to achieve axial movement of the screw 25.

In this embodiment, the first prosthesis 10 further comprises a bearing structure, the other end of the deformation structure 30 being connected to the lower sleeve 11 by the bearing structure, the bearing structure comprising: the plate body 71, the plate body 71 sets up the bottom of the cavity of the lower sleeve 11, another end of the deformation structure 30 is connected with plate body 71; the limiting teeth 72, the limiting teeth 72 are located on one side of the plate 71 away from the deformation structure 30, and the limiting teeth 72 are inserted into the bottom wall of the lower sleeve 11 to limit the circumference of the plate 71. This enables a secure fixation of the other end of the deformation structure 30 by means of the plate 71 and the stop tooth 72.

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

In this embodiment, the screw 25 includes a first rod segment and a second rod segment, which are connected to each other, the first rod segment is inserted into the intramedullary rod 21, the first rod segment is fixed to the intramedullary rod 21 in a relative position in the circumferential direction, the second rod segment is located outside the intramedullary rod 21, and the second rod segment is screwed to the transmission member 14. The second prosthesis 20 is facilitated to be manufactured and assembled by the arrangement described above. Alternatively, the first shaft segment and the intramedullary rod 21 may be circumferentially limited by means of keys and keyways.

In this embodiment, the extensible prosthesis further comprises: a plurality of anti-back-out grooves provided on one of the first prosthesis 10 and the second prosthesis 20; a clamping part for clamping with any one of the plurality of anti-withdrawal grooves, the clamping part being movably arranged on the other one of the first prosthesis 10 and the second prosthesis 20; when the second prosthesis 20 moves away from the first prosthesis 10, the engagement portions avoid the plurality of anti-back grooves to move the second prosthesis 20 in one direction; after the second prosthesis 20 is moved, the clamping part is clamped into the corresponding anti-withdrawal groove to prevent the second prosthesis 20 from withdrawing. By means of the anti-back-out structure it is achieved that the second prosthesis 20 can only move in a single direction away from the first prosthesis 10 and not in a direction towards the first prosthesis 10, whereby the extension of the prosthesis and the retraction thereof are avoided.

Optionally, the anti-back out structure includes: a plurality of anti-back-out grooves provided on one of the first prosthesis 10 and the second prosthesis 20; a clamping part for clamping with any one of the plurality of anti-withdrawal grooves, the clamping part being movably arranged on the other one of the first prosthesis 10 and the second prosthesis 20; when the second prosthesis 20 moves away from the first prosthesis 10, the engagement portions avoid the plurality of anti-back grooves to move the second prosthesis 20 in one direction; after the second prosthesis 20 is moved, the clamping part is clamped into the corresponding anti-withdrawal groove to prevent the second prosthesis 20 from withdrawing. This allows unidirectional movement of the second prosthesis 20 by engagement of the snap-fit portions with the plurality of anti-back-out grooves.

Optionally, a plurality of anti-withdrawal grooves are provided on the outer wall of the second prosthesis 20, and a plurality of clamping portions are provided on the inner wall of the first prosthesis 10 to improve reliability. The clamping part is telescopically arranged or rotatably arranged, the clamping part comprises a spring and a clamping block which are arranged in the groove of the first prosthesis 10, and the clamping block can extend out of or retract into the groove. The fixture block has first spacing plane and first direction inclined plane, and the anti-backing groove has second spacing plane and second direction inclined plane, and wherein, first spacing plane and the spacing cooperation of second spacing plane prevent to roll back when second prosthesis 20 receives outside axial pressure, and first direction inclined plane cooperates with the second direction inclined plane to promote the fixture block and withdraw in the recess when second prosthesis 20 moves to the extension direction.

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

Optionally, the lower sleeve 11 includes a barrel, a limiting post and a positioning post connected in sequence, the positioning post is in 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 so as to realize positioning and limiting.

The scheme is designed by combining the morphological requirements of thick distal end and thin proximal end of the femoral condyle of the human body, and the upper sleeve and the lower sleeve are manufactured separately and welded into a whole. Has sealing effect and can prevent body fluid from entering the interior of the prosthesis to cause corrosion damage to the internal materials. The end part of the prosthesis is made of PEEK plastic, and PEEK has excellent biocompatibility and wear resistance and prevents abrasion between metals of the end part under the bending stress environment.

To facilitate understanding of the present solution, the following description is given of the magnetic memory alloy:

after the traditional shape memory alloy is subjected to plastic deformation in a martensitic state, the shape memory alloy is heated to be above an Af temperature, so that the state of a parent phase can be automatically recovered; if it is cooled again below the Mf temperature, it returns automatically to its original plastically deformed or martensitic shape. But has a much larger strain than other driving materials, but the strain 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, and the like, have relatively low response frequencies (about 1 Hz) due to their being driven by a temperature field, although they have relatively large reversible recovery strains and large recovery forces. In recent years, a novel electromagnetic driving material, namely a magnetic control shape memory alloy, is silently developed, and the remarkable magnetic strain performance is widely focused.

The magnetic shape memory alloy has the advantages of ferromagnetism and thermoelastic martensitic transformation, and combines the advantages of large strain and quick response of magnetostrictive materials. Zeeman's static magnetic force of the magnetic field on the martensite variants with unfavorable orientation in the alloy promotes the martensite variants with favorable orientation to grow and swallow the variants with unfavorable orientation (expressed as movement of twin boundaries), thereby generating macroscopic deformation.

The magnetic shape memory effect can only exist in magnetic alloys with thermoelastic martensitic transformation. Typical ferromagnetic shape memory alloys are 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.

Magneto shape memory alloys are particularly appreciated because: 1. excellent performance. The most important performance index is the strain quantity, which is 1-2 orders of magnitude higher than the performance of the existing material. Magnetic shape memory alloys have a bi-directional 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. As 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 foundation in the fields of national defense and high technology in the future. The high strain characteristic and the high response frequency of the high strain sensor are expected to be applied to the aspects of sensors, surface intelligent structures, automatic control, aircraft wing regulation and control systems, ultra-high power ultrasonic transducer technologies and the like.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An extensible 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 in a cavity of the lower sleeve (11) and the transmission member (14) being axially immovable with respect to the lower sleeve (11);

a second prosthesis (20), wherein 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 penetrated in the transmission piece (14), the screw rod (25) is in threaded connection with the transmission piece (14), and the screw rod (25) and the lower sleeve (11) cannot rotate relatively in the circumferential direction;

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 so as 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 a direction away from the lower sleeve (11) under the condition of rotation so as to prolong the total length of the extensible prosthesis;

the screw thread structure of the screw (25) matched with the transmission piece (14) is a one-way screw thread structure, and the one-way screw thread structure enables the screw (25) to move unidirectionally only in a direction away from the lower sleeve (11) so as to prevent the screw (25) from backing after the movement is completed;

one end of the deformation structure (30) is connected with the transmission piece (14), the other end of the deformation structure (30) is connected with the lower sleeve (11), and the deformation structure (30) is a spiral spring structure or the deformation structure (30) is a coil spring structure.

2. The extensible prosthesis according to claim 1, characterized in that said lower sleeve (11) has on its inner wall a limit step in limit engagement with one end of said transmission member (14), said first prosthesis (10) further comprising:

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).

3. The extensible prosthesis according to claim 1, characterized in that said first prosthesis (10) further comprises:

the upper sleeve (12), upper sleeve (12) with lower sleeve (11) are connected, intramedullary rod (21) pass upper sleeve (12), be provided with seal structure between upper sleeve (12) and intramedullary rod (21).

4. The extensible prosthesis of claim 3, wherein,

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

a chute (52) is arranged on the other of the inner wall of the upper sleeve (12) and the outer wall of the intramedullary rod (21), the chute (52) extends along the moving direction of the intramedullary rod (21), and the convex rib (51) is slidably arranged in the chute (52).

5. The extensible prosthesis according to claim 1, characterized in that said first prosthesis (10) further comprises a bearing structure, through which the other end of said deformation structure (30) is connected to said lower sleeve (11), said bearing structure comprising:

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

spacing tooth (72), spacing tooth (72) are located the plate body (71) deviate from the one side of deformation structure (30), spacing tooth (72) insert in the diapire of lower sleeve (11) in order to carry out spacingly to the circumference of plate body (71).

6. The extensible prosthesis according to claim 1, characterized in that said screw (25) comprises a first rod segment and a second rod segment connected to each other, said first rod segment being threaded in said stem (21), said first rod segment being fixed in position with respect to said stem (21) in the circumferential direction, said second rod segment being external to said stem (21), said second rod segment being screwed with said transmission member (14).

7. The extensible prosthesis of claim 1, wherein the extensible prosthesis further comprises:

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

a clamping part which is used for clamping with any one of a plurality of 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 away from the first prosthesis (10), the clamping parts avoid a plurality of anti-withdrawal grooves so as to enable the second prosthesis (20) to move unidirectionally; after the second prosthesis (20) is moved, the clamping part is clamped into the corresponding anti-withdrawal groove to prevent the second prosthesis (20) from withdrawing.

8. The extensible prosthesis according to claim 1, characterized in that it 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).