Femoral stem and preparation method thereof

Abstract

The present invention relates to the technical field of artificial joint replacement, and proposes a femoral stem and a preparation method thereof, comprising a stem body, a microporous titanium layer and a rod body, wherein the stem body has a connecting section and a fixed section, and the connecting section is inclined relative to the fixed section; the microporous titanium layer is arranged on the outside of the fixed section; the rod body is connected to the fixed section, and the diameter of the rod body is smaller than the diameter of the fixed section; the fixed section is provided with a viewing hole, an injection flow channel and a return flow channel, wherein one end of the viewing hole is open and the other end extends toward the rod body; the injection flow channel runs through the fixed section, and the injection flow channel is connected to the viewing hole; the return flow channel is arranged relative to the injection flow channel, and the return flow channel is connected to the viewing hole and the injection flow channel. The present invention combines two fixing methods, biological fixation and bone cement fixation, and bone cement will not affect the biological fixation interface tissue, the tissue can effectively grow and fuse, and the femoral stem is fixed for a long time and stably with bone cement, and has immediate stability and long-term stability, and has excellent application effect.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial joint replacement, and in particular to a femoral stem and a preparation method thereof. Background Art

[0002] The femoral stem is a key implant in hip replacement surgery, used to replace damaged or diseased parts of the femur. The stem is inserted into the femoral medullary cavity, and the ball head at the end fits into the acetabulum (the socket in the pelvis) to restore normal hip function.

[0003] Currently, there are two main methods for fixing the femoral stem: bone cement fixation and biological fixation. Bone cement has the advantage of immediate stability, but it is prone to failure in the long term, which will affect the stability of the prosthesis. Although biological fixation has the advantage of long-term stability, it has poor postoperative stability and slow recovery. Therefore, in order to ensure that the femoral stem is stable after installation and does not fail during long-term use, more and more femoral stems are currently installed using bone cement plus biological fixation.

[0004] The existing utility model patent with authorization announcement number CN205322551U discloses a hybrid fixed artificial hip joint, which belongs to the field of medical devices and includes a hip joint handle, a hip joint body and a hip joint rod connected in sequence; the hip joint rod is used to be inserted into the cavity wall of the femur, and the hip joint rod includes a first rod part and a second rod part, the first rod part is connected to the hip joint body, the second rod part is connected to the bottom of the first rod part, the center line of the second rod part is collinear with the center line of the first rod part, the first rod part is inserted into the cavity wall, and the second rod part is fixed to the femur by bone cement.

[0005] As in the above technical solution, both bone cement fixation and biological fixation are combined. A protrusion is provided on the surface of the first rod portion, which relies on the protrusion to press against the wall of the femoral cavity, thereby achieving biological fixation. However, in this structure, the bone tissue and the femoral stem are difficult to fuse, and the pull-out resistance is poor. In addition, a guide groove is provided on the second rod portion. The edge of the groove is prone to friction with the bone cement bed, which will increase the wear of the bone cement bed and thus lead to failure.

[0006] In the first embodiment of the above scheme, a drainage groove is provided to accommodate excess bone cement. However, the drainage groove corresponds to the protruding portion used for biological fixation, and the bone cement will heat up during solidification. After the bone cement enters the drainage groove, it will contact the medullary cavity wall of that portion. The temperature increase and the release of the chemical components of the bone cement itself can easily cause inflammation or even necrosis of the surrounding tissue, thereby preventing the bone tissue from growing effectively and achieving biological fixation.

[0007] In its second embodiment, although the drainage groove is removed, a scheme of using a protrusion to resist the medullary cavity wall is adopted. If the protrusion fits tightly against the medullary cavity wall, the excess bone cement cannot be effectively discharged, which is not conducive to controlling the insertion depth of the femoral stem; if the injection amount of bone cement is reduced, it is also not conducive to controlling the insertion depth, and the stability of the femoral stem installation cannot be guaranteed.

[0008] In response to the above problems, the inability to effectively control the interface between biological fixation and bone cement fixation is a common problem in existing femoral stem hybrid fixation solutions, and therefore it is urgently needed to be improved. Summary of the Invention

[0009] In view of this, the present invention proposes a femoral stem and a preparation method thereof that can effectively distinguish the interface between biological fixation and bone cement fixation to ensure stable installation of the femoral stem, so as to solve the problem that the interface between biological fixation and bone cement fixation cannot be effectively controlled in the existing femoral stem mixed fixation structure scheme, which easily affects tissue growth and leads to unstable installation.

[0010] The technical solution of the present invention is achieved as follows:

[0011] In one aspect, the present invention provides a femoral stem comprising a stem body, a microporous titanium layer and a rod body, wherein:

[0012] The handle body has a connecting section and a fixing section. The connecting section is used to install the ball head to connect to the acetabulum, and the connecting section is inclined relative to the fixing section.

[0013] The microporous titanium layer is arranged on the outside of the fixed section;

[0014] The rod body is connected to the fixed section, and the diameter of the rod body is smaller than the diameter of the fixed section;

[0015] The fixed section is provided with a viewing hole, an injection channel and a return channel, wherein:

[0016] One end of the viewing hole is open, and the other end extends toward the rod body;

[0017] The injection flow channel runs through the fixed section, and the injection flow channel is connected to the viewing hole;

[0018] The return flow channel is arranged opposite to the injection flow channel, and the return flow channel is communicated with the viewing hole and the injection flow channel.

[0019] On the basis of the above technical solution, preferably, the injection channel includes a large diameter section, a small diameter section and a tapered section, wherein:

[0020] The large diameter section is located on the side of the fixed section close to the connecting section and is connected to the outside world, the viewing hole and the return flow channel;

[0021] The small diameter section is relatively opened on the side of the fixed section close to the rod body and is connected to the outside world;

[0022] The tapered section connects the large diameter section with the small diameter section.

[0023] On the basis of the above technical solution, preferably, the reflux channel includes an access section, an intermediate section and a connecting section, wherein:

[0024] The access section is arranged opposite to the small path section and is connected to the outside world;

[0025] The middle section is arranged in an inclined shape, one end of the middle section is connected to the access section, and the other end is connected to the large diameter section;

[0026] One end of the connecting section is connected to the viewing hole, the other end is connected to the middle section, the side is connected to the large diameter section, and the flow cross-sectional area of ​​the connecting section is smaller than that of the middle section.

[0027] On the basis of the above technical solution, preferably, it further includes a plugging, which includes a plug and a positioning protrusion of an integrated structure, and the reflux channel also includes a process hole, which is formed by a contoured plugging, wherein,

[0028] The process hole is opened on the side of the middle section away from the connecting section, and the process hole is connected with the access section, the middle section and the outside world;

[0029] The plug and the positioning protrusion are arranged in the process hole, the plug is interference fit with the process hole, and the positioning protrusion protrudes relative to the plug.

[0030] On the basis of the above technical solution, preferably, the surface of the fixed section is frosted and the microporous titanium layer is coated on the fixed section;

[0031] The microporous titanium layer is formed by sintering spherical titanium powder to form a spherical microporous layer structure, and is coated and sealed;

[0032] The porosity of the microporous titanium layer is 30%~40%, the maximum pore diameter is 0.2 mm~0.3 mm, and the thickness is 2~5 mm.

[0033] On the basis of the above technical solution, preferably, the rod body includes an inserting section and an inserting section, wherein,

[0034] The plug-in section is plugged into the fixed section, the plug-in section is provided with an embedding groove, and a portion of the handle body is filled with the embedding groove;

[0035] The length of the plug-in section is less than or equal to the length of the small-diameter section, and the diameter of the plug-in section is less than the diameter of the insertion section;

[0036] The insertion section is connected to one end of the plug section away from the fixed section. The diameter of the insertion section is smaller than the diameter of the fixed section, and the end of the insertion section abuts against the end surface of the fixed section.

[0037] On the basis of the above technical solution, preferably, the insertion section is provided with an annular groove, a guide groove and an adjustment groove, wherein:

[0038] The annular groove is spaced apart from the plug-in section;

[0039] The guide groove is provided on the portion of the insertion section between the annular groove and the plug-in section. Two guide grooves are provided opposite to each other, one of which connects the annular groove with the small diameter section, and the other connects the annular groove with the access section.

[0040] The adjustment groove is located on the inner side of the guide groove.

[0041] On the basis of the above technical solution, preferably, it further comprises a fastener, the fastener comprises a screw and a filling block, wherein,

[0042] The screw passes through the handle body and is connected to the plug-in section through threaded engagement;

[0043] The filling block is filled in the limiting groove of the screw.

[0044] In another aspect, the present invention provides a method for preparing the femoral stem, comprising the following steps:

[0045] S1. Prepare the blanks of the handle and the rod;

[0046] S2. Opening a viewing hole, an injection channel, and a return channel on the handle body so that they are interconnected;

[0047] S3, using a plug to plug the process hole of the reflux channel;

[0048] S4. frosting the outer surface of the fixed section of the handle body, and loosely applying spherical powdered titanium on the outer surface of the fixed section;

[0049] S5. Sintering the spherical titanium powder at a temperature of 900° C. to 1500° C. to form a microporous titanium layer, which covers the fixed section and seals the plug;

[0050] S6. Grind the handle and the rod, and assemble and connect them.

[0051] In another aspect, the present invention provides another method for preparing the femoral stem, comprising the following steps:

[0052] P1. Prepare the blanks of the handle and the rod;

[0053] P2. Open a viewing hole, an injection channel, and a return channel on the handle to connect them to each other;

[0054] P3. Use plugging to block the process holes of the reflux channel;

[0055] P4. Frost the outer surface of the fixed section;

[0056] P5. Assemble and connect the rod body and the handle body, and lock and fix them with fasteners;

[0057] P6, loosely install spherical titanium powder on the outer surface of the fixed section;

[0058] P7. Sintering the spherical titanium powder at a temperature of 900°C to 1500°C to form a microporous titanium layer, which covers the fixing section, the plugging and the fastener;

[0059] P8. Polish the handle and rod.

[0060] The femoral stem and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0061] (1) The stem body is provided with a connecting section and a fixing section, wherein the connecting section is provided with a ball head to connect to the acetabulum, and the fixing section is used to be placed in the medullary cavity. Since the surface of the fixing section is provided with a microporous titanium layer, it can effectively fuse with the growing tissue to ensure long-term stability. It is also provided with an injection channel for subsequent supplementation of bone cement. Since the diameter of the rod body is smaller than the diameter of the fixing section of the stem body, after the fixing section fits the wall of the medullary cavity, when the bone cement is fully filled, it will not enter the contact interface between the fixing section and the medullary cavity, but will overflow into the viewing hole through the reflux channel. In this way, the bone cement can be fully filled without affecting the biological fixation interface tissue. The tissue can effectively grow and fuse, and cooperate with the bone cement to form a long-term and stable fixation of the femoral stem, thereby ensuring that the femoral stem has long-term stability and immediate stability.

[0062] (2) In the injection channel structure, the large diameter section is used to insert the bone cement injection tube to inject bone cement. The bone cement injection tube can fit tightly with the tapered section so that the bone cement can be directly injected into the bone marrow cavity through the small diameter section. After the bone cement is fully filled, it will flow back through the reflux channel and overflow into the optic hole. After observing that the optic hole has bone cement, the injection can be stopped. In this way, the amount of bone cement injected is effectively controlled to ensure that the bone cement is fully filled. After the bone cement injection tube is pulled out, it is convenient to clean up the excess bone cement, for example, to discharge the bone cement into the large diameter section so that the optic hole can be used for other purposes.

[0063] (3) In the reflux channel structure, the bone cement is refluxed into the visual aperture through the connecting section. Since the side of the connecting section is connected to the injection channel, when the bone cement injection tube is placed for bone cement injection, the bone cement injection tube can completely fit the inner wall of the large diameter section of the injection channel, so that the bone cement injection tube passes through the large diameter section and the tapered section and maintains a relative seal with the small diameter section. Its posture is stable during use, thereby ensuring the filling effect;

[0064] (4) In order to facilitate the opening of the reflux channel, a process hole is provided to facilitate drilling and milling the middle section of the reflux channel, which can then be sealed with a plug to prevent overflow when injecting bone cement, thereby improving processing convenience and ensuring application stability;

[0065] (5) The rod body consists of two parts: the insertion section and the insertion section. It is connected to the handle body through the insertion section, which makes it convenient to loosely install spherical powder titanium on the handle body to sinter to form a microporous titanium layer. After sintering, the rod body and the handle body can be assembled. This will not affect the performance of the handle body. At the same time, according to the patient's femoral damage and related conditions, a rod body of appropriate size can be selected for installation, which improves the scope of application.

[0066] (6) The plug-in section of the rod body is matched with the handle body through a fastener, and the limiting groove of the screw in the fastener is filled with a filling block, so that the outer surface of the handle body can be flat, which is convenient for loose installation of spherical powder titanium and sintering to form a microporous titanium layer, so that the handle body can effectively fit with the medullary cavity tissue and ensure the biological fixation effect;

[0067] (7) In the preparation method of the femoral stem, the microporous titanium layer is formed by sintering spherical powder titanium. During the preparation process, the spherical powder will cover the plug and the fastener, so that after sintering, the connection structural strength of the plug and the fastener relative to the stem body and the rod body can be effectively improved, thereby ensuring the application stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0069] Figure 1 A three-dimensional diagram of the femoral stem of the present invention;

[0070] Figure 2 It is a front view of the femoral stem of the present invention;

[0071] Figure 3 is a side view of the femoral stem of the present invention;

[0072] Figure 4 For the present invention Figure 3 Middle AA section;

[0073] Figure 5 For the present invention Figure 4 A magnified view of the structure at point A;

[0074] Figure 6 An exploded view of the femoral stem of the present invention;

[0075] Figure 7 For the present invention Figure 6 A magnified view of the structure at point B;

[0076] Figure 8 A three-dimensional diagram of the plug of the femoral stem of the present invention;

[0077] Figure 9 A cross-sectional perspective view of the femoral stem of the present invention;

[0078] Figure 10 The femoral stem of the present invention Figure 9 A magnified view of the structure at point C;

[0079] In the figure: 1. handle body; 11. connecting section; 12. fixing section; 101. sight hole; 102. injection channel; 1021. large diameter section; 1022. small diameter section; 1023. tapered section; 103. return channel; 1031. access section; 1032. middle section; 1033. connecting section; 1034. process hole; 2. microporous titanium layer; 3. rod body; 31. plug section; 32. insertion section; 301. embedded groove; 302. ring groove; 303. guide groove; 304. adjustment groove; 4. plugging; 41. plug; 42. positioning protrusion; 5. fastener; 51. screw; 52. filling block; 501. limit groove. DETAILED DESCRIPTION

[0080] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0081] like Figures 1 to 10 As shown, the femoral stem of the present invention includes a stem body 1, a microporous titanium layer 2, a rod body 3, a plug 4 and a fastener 5.

[0082] like Figures 1-3 As shown, the handle body 1 has a connecting section 11 and a fixing section 12. The connecting section 11 is used to install the ball head to connect to the acetabulum, and the connecting section 11 is inclined relative to the fixing section 12. The microporous titanium layer 2 is arranged on the outside of the fixing section 12. The rod body 3 is connected to the fixing section 12, and the diameter of the rod body 3 is smaller than the diameter of the fixing section 12.

[0083] As described above, in the present femoral stem, the stem body 1 is connected to the rod body 3. When in use, the connecting section 11 of the stem body 1 is used to install the ball head to match the artificial ball socket installed in the acetabulum.

[0084] The fixing section 12 of the handle body 1 and the rod body 3 are placed in the femur; the rod body 3 and the femur are fixed by bone cement, and the fixing section 12 is fixed to the femur by biological fixation.

[0085] like Figure 4 and Figure 5 As shown, the fixed section 12 is provided with a viewing hole 101, an injection channel 102, and a return flow channel 103, wherein the viewing hole 101 is open at one end and extends toward the rod body 3 at the other end; the injection channel 102 runs through the fixed section 12 and is connected to the viewing hole 101; the return flow channel 103 is arranged opposite to the injection channel 102 and is connected to the viewing hole 101 and the injection channel 102;

[0086] For the above structure, when installing the femoral stem, follow the steps below:

[0087] N1: First, osteotomize the damaged or diseased femur, and then use an opener to open the medullary cavity;

[0088] N2, the medullary cavity is opened by drilling, the pyriform sinus is treated with a greater trochanteric file, and then the medullary cavity file is used to expand the medullary cavity step by step;

[0089] N3. Use a calcar file to flatten the femoral calcar, assemble the neck and ball head trial molds, reduce the hip joint, and evaluate function.

[0090] N4. Use the medullary cavity plug test mold to test the medullary cavity plug model and insert the appropriate medullary cavity plug;

[0091] N5. Inject bone cement and assemble the femoral stem;

[0092] During the specific assembly, first inject an appropriate amount of bone cement into the medullary cavity, so that the bone cement does not overflow to the fixed section 12 of the handle body 1 when the rod body 3 is placed;

[0093] When injecting bone cement, the bone cement injection tube is inserted into the medullary cavity for injection. As the bone cement interface rises, the bone cement injection tube is simultaneously withdrawn upward to prevent the bone cement from contaminating the upper medullary cavity wall interface. When the injection volume reaches the target, the injection is stopped and the bone cement injection tube is withdrawn.

[0094] Then, the femoral stem is inserted until the fixing section 12 of the stem body 1 is in contact with the medullary cavity wall. At this time, the rod body 3 is inserted into the bone cement, and the bone cement overflows but does not contact the stem body.

[0095] In order to eliminate the gap below the fixed section 12, the bone cement injection tube is inserted into the injection channel 102 to inject bone cement into the lower side of the fixed section 12; the gas is discharged through the return channel 103, and after the gap is filled, the bone cement will flow back through the return channel 103 and enter the viewing hole 101. At this time, it is determined that the bone cement filling is complete, the bone cement injection tube is pulled out, and the bone cement in the viewing hole 101 is cleaned into the injection channel 102 and the return channel 103; the viewing hole 101 can now be used for other purposes, such as accommodating a force sensing device;

[0096] After the above assembly process, bone cement will only remain around the rod body 3, with the interface located on the lower side of the fixing segment 12, without interfering with the biological fixing interface of the fixing segment 12;

[0097] In order to ensure that tissue growth can fuse with the fixed segment 12, a microporous titanium layer 2 is provided on the surface of the fixed segment 12 to allow tissue growth to fuse through the pores; in this way, the femoral stem realizes biological fixation combined with bone cement fixation, which can ensure immediate stability and long-term stability during assembly.

[0098] Specifically, the shape of the fixing segment 12 is not specifically limited, as long as it can completely fit the medullary cavity wall or most of its surface can fit the medullary cavity wall.

[0099] In some embodiments, an elastic member with good biocompatibility, such as thermoplastic polyurethane, is disposed below the fixing section 12 for sealing, to ensure that the bone cement can flow back through the reflux channel 103 .

[0100] like Figure 5 As shown, the injection channel 102 includes a large diameter section 1021, a small diameter section 1022 and a tapered section 1023, wherein the large diameter section 1021 is provided on the side of the fixed section 12 close to the connecting section 11 and is connected to the outside, the viewing hole 101 and the return flow channel 103; the small diameter section 1022 is relatively provided on the side of the fixed section 12 close to the rod body 3 and is connected to the outside; the tapered section 1023 connects the large diameter section 1021 with the small diameter section 1022;

[0101] As shown in the above structure, the injection channel 102 is reduced in diameter from top to bottom. Thus, when injecting bone cement, a bone cement injection tube with a tapered head can be used to fully fit the tapered section 1023, ensuring that the bone cement is directly injected into the bone marrow cavity through the small diameter section 1022.

[0102] In this structure, the large diameter section 1021 is also connected to the return flow channel 103, so that the cone head of the bone cement injection tube can directly pass over the connection between the large diameter section 1021 and the return flow channel 103, avoiding the bone cement from being injected through the return flow channel 103 at the same time, thereby preventing the problem of incomplete filling.

[0103] The diameter of the bone cement injection tube used is slightly smaller than the large diameter section 1021 so that there is space for the bone cement to flow into the viewing hole 101 and achieve backflow.

[0104] like Figure 5As shown, the return flow channel 103 includes an access section 1031, an intermediate section 1032, and a connecting section 1033, wherein the access section 1031 is arranged opposite to the small-diameter section 1022 and is connected to the outside; the intermediate section 1032 is arranged in an inclined shape, with one end of the intermediate section 1032 connected to the access section 1031 and the other end connected to the large-diameter section 1021; the connecting section 1033 is connected to the viewing hole 101 at one end and to the intermediate section 1032 at the other end, and is connected to the large-diameter section 1021 on the side, and the flow cross-sectional area of ​​the connecting section 1033 is smaller than the flow cross-sectional area of ​​the intermediate section 1032;

[0105] As in the above structure, when the bone cement is refluxed, the reflux channel 103 sequentially refluxes through the access section 1031, the middle section 1032 and the connecting section 1033;

[0106] To ensure complete filling of bone cement, the access section 1031 and the small diameter section 1022 are arranged opposite to each other so that the bone cement can be evenly distributed on both sides.

[0107] In this structure, the connecting section 1033 of the reflux channel 103 is connected to the middle section 1032, the viewing hole 101, and the large-diameter section 1021 at the same time. Therefore, a bone cement injection tube with a larger diameter can be used to fully fill the large-diameter section 1021, and the cone head can fit the tapered section 1023. After filling, the connecting section 1033 can be used for reflux. This structure is conducive to positioning the bone cement injection tube and ensuring the stability of bone cement injection.

[0108] At the same time, the flow cross-sectional area of ​​the connecting section 1033 is controlled to be smaller than the flow cross-sectional area of ​​the middle section 1032, which can reduce the discharge rate of bone cement into the viewing hole 101 to ensure that the area below the fixing section 12 is completely filled;

[0109] Even if there is a slight gap, since the middle section 1032 is tilted, the posture of the femur can be adjusted so that the bone cement is deposited toward the lower side of the fixation section 12 to ensure complete filling.

[0110] Furthermore, in this structure, the viewing hole 101, the injection channel 102 and the connecting section 1033 of the return channel 103 are opened on the same side of the fixed section 12, thereby ensuring the convenience of processing.

[0111] like Figures 5 to 8As shown, the plug 4 includes an integrated plug 41 and a positioning protrusion 42. The return flow channel 103 also includes a process hole 1034. The process hole 1034 is formed in the shape of the plug 4. The process hole 1034 is formed on a side of the middle section 1032 away from the connecting section 1033. The process hole 1034 is connected to the access section 1031, the middle section 1032 and the outside world. The plug 41 and the positioning protrusion 42 are arranged in the process hole 1034. The plug 41 and the process hole 1034 have an interference fit, and the positioning protrusion 42 protrudes relative to the plug 41.

[0112] As in the above structure, when opening the middle section 1032 of the reflux channel 103, it is necessary to drill the hole at an angle, thus forming a process hole 1034. In order to prevent the overflow of bone cement from affecting the biological fixation interface, the process hole 1034 needs to be sealed with a plug 4.

[0113] Specifically, the plug 4 comprises a plug 41 and a positioning protrusion 42. During installation, the plug 41 is used to seal the process hole 1034, and the positioning protrusion 42 is used to position the plug 4 to prevent the plug 4 from being over-inserted and affecting the flow of the return flow channel 103.

[0114] When installing the plug 4 , the outer end surface of the plug 4 may be processed first and then installed, or the outer end surface may be processed first and then installed, to ensure that the outer end surface of the plug 4 is flush with the surface of the fixing section 12 .

[0115] In the present femoral stem structure, the surface of the fixation section 12 is frosted, and the microporous titanium layer 2 is coated on the fixation section 12; the microporous titanium layer 2 is formed by sintering spherical titanium powder to form a spherical microporous layer structure, and covers the plug 4; the porosity of the microporous titanium layer 2 is 30% to 40%, the maximum pore diameter is 0.2 mm to 0.3 mm, and the thickness is 2 to 5 mm;

[0116] As in the above structure, when the microporous titanium layer 2 is provided on the fixed section 12 of the handle body 1, it is first made by loosely loading spherical titanium powder on the fixed section 12 and then sintering it; this structure helps to ensure that the microporous titanium layer 2 is tightly fitted to the handle body 1. At the same time, since it covers the plug 4, it can ensure that the plug 4 does not bulge outward or detach, thereby ensuring structural stability;

[0117] The parameters of the microporous titanium layer 2 are controlled to be 30% to 40% in porosity, 0.2 mm to 0.3 mm in maximum pore size, and 2 to 5 mm in thickness to ensure good bonding with the tissue.

[0118] like Figure 5 、 Figure 7 、 Figure 9 and Figure 10As shown, the rod body 3 includes an inserting section 31 and an inserting section 32, wherein the inserting section 31 is inserted into the fixed section 12, and the inserting section 31 defines an embedding groove 301, in which a portion of the handle body 1 is filled and embedded; the length of the inserting section 31 is less than or equal to the length of the small-diameter section 1022, and the diameter of the inserting section 31 is smaller than the diameter of the inserting section 32; the inserting section 32 is connected to the end of the inserting section 31 away from the fixed section 12, the diameter of the inserting section 32 is smaller than the diameter of the fixed section 12, and the end of the inserting section 32 abuts against the end surface of the fixed section 12;

[0119] As in the above structure, the rod body 3 is connected to the handle body 1 through the plug-in section 31, and the insertion section 32 is used to contact the bone cement;

[0120] To ensure connection stability, the plug section 31 defines a beading groove 301. The beading groove 301 is an annular groove with a diameter slightly smaller than the outer diameter of the rod body 3. The handle body 1 has a corresponding opening and is provided with an annular protrusion that engages with the beading groove 301. This mating structure can be controlled to a degree that allows liquid nitrogen cold assembly, or other structures that support an interference fit can be designed.

[0121] In some embodiments, the annular protrusion and the embedding groove 301 may not be provided;

[0122] In this structure, the length of the plug section 31 is controlled to be less than or equal to the length of the small-diameter section 1022 to avoid interfering with the opening of the return flow channel 103; at the same time, it is convenient to open it synchronously with the small-diameter section 1022, thereby improving the convenience of processing;

[0123] In this structure, the diameter of the plug-in section 31 is smaller than the diameter of the insertion section 32, and the diameter of the insertion section 32 is smaller than the diameter of the fixed section 12. In this way, during assembly, after the plug-in section 31 is inserted into the fixed section 12, the insertion section 32 can be abutted against the end face of the fixed section 12 to ensure structural stability.

[0124] like Figure 5 and Figure 7 As shown, the insertion section 32 is provided with an annular groove 302, a guide groove 303 and an adjustment groove 304, wherein the annular groove 302 is spaced apart from the plug-in section 31; the guide groove 303 is provided on the portion of the insertion section 32 between the annular groove 302 and the plug-in section 31, and two guide grooves 303 are provided opposite to each other, one of which connects the annular groove 302 with the small-diameter section 1022, and the other connects the annular groove 302 with the access section 1031;

[0125] As in the above structure, the annular groove 302 is provided to compensate for the error in the amount of bone cement injected before assembly, so as to accommodate excess bone cement when a large amount of bone cement is injected, thereby preventing the biological fixation interface from being affected.

[0126] Specifically, the edge of the annular groove 302 is chamfered to reduce friction with the bone cement bed;

[0127] In order to ensure that bone cement can be better injected through the injection channel 102 and better returned through the return channel 103 after the femoral stem is assembled, a guide groove 303 is provided on the portion of the insertion section 31 located between the annular groove 302 and the insertion section 32 to allow bone cement to flow smoothly. At the same time, the guide effect of the annular groove 302 is also conducive to ensuring that bone cement is fully filled and the pull-out resistance of the femoral stem is improved.

[0128] In order to ensure that the guide groove 303 can be aligned with the injection channel 102 and the return channel 103, an adjustment groove 304 is provided in the insertion section 32. After the rod body 3 and the handle body 1 are plugged in, a tool can be inserted into the adjustment groove 304 to drive the rod body 3 to rotate so that the guide groove 303 is positioned correctly.

[0129] like Figure 7 As shown, the fastener 5 includes a screw 51 and a filling block 52, wherein the screw 51 passes through the handle body 1 and is connected to the plug-in section 31 through threaded engagement; the filling block 52 is filled in the limiting groove 501 of the screw 51;

[0130] As in the above structure, after the rod body 3 and the handle body 1 are plugged together, they are locked and fixed by the fastener 5;

[0131] The screw 51 passes through the handle body 1 and is screwed and fixed with the plug section 31. The screw 51 is countersunk in the handle body 1. The limiting groove 501 for assembly at the end of the screw 51 is filled with a filling block 52 to ensure that it has a complete plane and is flush with the outer surface of the handle body 1, thereby better fitting with the medullary cavity wall and ensuring structural stability.

[0132] Specifically, after the rod body 3 and the handle body 1 are plugged together and the fastener 5 is installed, the spherical powdered titanium is loosely packed and sintered, and the fastener 5 is reinforced by the formed microporous titanium layer 2 .

[0133] A method for preparing a femoral stem of the present invention comprises the following steps:

[0134] S1, preparing the blanks of the handle body 1 and the rod body 3;

[0135] S2. Opening a viewing hole 101, an injection channel 102, and a return channel 103 on the handle body 1 so that they are interconnected;

[0136] S3, using the plug 4 to plug the process hole 1034 of the return flow channel 103;

[0137] S4, frosting the outer surface of the fixing section 12 of the handle body 1, and loosely applying spherical powdered titanium on the outer surface of the fixing section 12;

[0138] S5. Sintering the spherical titanium powder at a temperature of 900° C. to 1500° C. to form a microporous titanium layer 2, which covers the fixing section 12 and the plugging member 4.

[0139] S6. Grind the handle body 1 and the rod body 3, and assemble and connect them.

[0140] Another method for preparing a femoral stem of the present invention comprises the following steps:

[0141] P1, prepare the blank of handle body 1 and rod body 3;

[0142] P2. A viewing hole 101, an injection channel 102, and a return channel 103 are formed on the handle 1 so as to communicate with each other;

[0143] P3, use the plug 4 to plug the process hole 1034 of the return flow channel 103;

[0144] P4, frosting the outer surface of the fixed section 12;

[0145] P5. Assemble and connect the rod body 3 and the handle body 1, and lock and fix them with fasteners 5;

[0146] P6, loosely install spherical titanium powder on the outer surface of the fixed section 12;

[0147] P7. Sintering the spherical titanium powder at a temperature of 900° C. to 1500° C. to form a microporous titanium layer 2, which covers the fixing section 12, the plug 4, and the fastener 5;

[0148] P8. Polish the handle 1 and the rod 3.

[0149] As in the two preparation methods mentioned above, the formation of the microporous titanium layer 2 is mainly relied on to seal and reinforce the plug 4 and the fastener 5, and the assembly process of the handle body 1 and the rod body 3 is adaptively controlled. In the first preparation method, only the handle body 1 needs to be sintered, and the preparation is relatively efficient and fast; in the second preparation method, it is necessary to assemble the rod body 3 and the fastener 5, and then participate in the sintering process of the microporous titanium layer 2, so that the fastener 5 can be sealed to effectively improve the structural integrity.

[0150] The specific implementation steps of N5 during the assembly of the femoral stem are:

[0151] N51. Insert the bone cement injection tube into the medullary cavity to inject bone cement. As the bone cement interface rises, the bone cement injection tube is simultaneously withdrawn upward to prevent bone cement from contaminating the upper medullary cavity wall interface. When the injection volume reaches the target, stop the injection and withdraw the bone cement injection tube.

[0152] N52. Insert the femoral stem to insert the insertion section 32 of the rod body 3 into the bone cement and ensure that the fixing section 12 of the stem body 1 fits the medullary cavity wall;

[0153] N53. Insert the bone cement injection tube into the large-diameter section 1021 of the injection channel 102, ensuring that the end of the bone cement injection tube abuts against the inner wall of the tapered section 1023. Then, inject bone cement through the small-diameter section 1022 to fill the gap below the fixing section 12.

[0154] N54. Observe the viewing hole 101. After the bone cement enters the viewing hole 101 through the reflux channel 103, continue injecting for a while to ensure that the gap below the fixing section 12 is completely filled.

[0155] N55. Pull out the bone cement injection tube and clean the bone cement in the viewing hole 101 into the injection channel 102 and the return channel 103;

[0156] N56. Utilize the viewing hole 101 to selectively install auxiliary accessories to achieve functions such as force sensing and monitoring;

[0157] N57. Install the ball head on the connecting section 11 of the handle body 1 and match it with the ball socket installed on the acetabulum to reposition the hip joint.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A femoral stem, characterized in that: It comprises a handle (1), a microporous titanium layer (2) and a rod (3), wherein: The handle body (1) has a connecting section (11) and a fixing section (12), the connecting section (11) is used to mount a ball head to connect to the acetabulum, and the connecting section (11) is inclined relative to the fixing section (12); The microporous titanium layer (2) is arranged on the outside of the fixing section (12), and the fixing section (12) is in contact with the bone marrow cavity; The rod body (3) is connected to the fixed section (12), and the diameter of the rod body (3) is smaller than the diameter of the fixed section (12); The fixed section (12) is provided with a viewing hole (101), an injection channel (102) and a return channel (103), wherein: One end of the viewing hole (101) is open, and the other end extends toward the rod body (3); The injection channel (102) passes through the fixed section (12), and the injection channel (102) is connected to the viewing hole (101); The return flow channel (103) is arranged opposite to the injection flow channel (102), and the return flow channel (103) is connected to the viewing hole (101) and the injection flow channel (102); Bone cement is injected into the lower side of the fixing section (12) through the injection channel (102), and gas is discharged through the return channel (103). After the gap below the fixing section (12) is filled, the bone cement flows back through the return channel (103) and enters the viewing hole (101).

2. The femoral stem according to claim 1, wherein: The injection channel (102) comprises a large diameter section (1021), a small diameter section (1022) and a tapered section (1023), wherein: The large diameter section (1021) is provided on a side of the fixed section (12) close to the connecting section (11), and is connected to the outside, the viewing hole (101) and the return flow channel (103); The small diameter section (1022) is arranged on a side of the fixed section (12) close to the rod body (3) and is connected to the outside world; The tapered section (1023) connects the large-diameter section (1021) and the small-diameter section (1022).

3. The femoral stem according to claim 2, wherein: The return flow channel (103) comprises an access section (1031), an intermediate section (1032) and a connecting section (1033), wherein: The access section (1031) is arranged opposite to the small-diameter section (1022) and is connected to the outside world; The middle section (1032) is arranged in an inclined shape, one end of the middle section (1032) is connected to the access section (1031), and the other end is connected to the large-diameter section (1021); One end of the connecting section (1033) is connected to the viewing hole (101), the other end is connected to the middle section (1032), and the side is connected to the large-diameter section (1021), and the flow cross-sectional area of ​​the connecting section (1033) is smaller than the flow cross-sectional area of ​​the middle section (1032).

4. The femoral stem according to claim 3, wherein: It also includes a plug (4), the plug (4) including a plug (41) and a positioning protrusion (42) of an integrated structure, the return flow channel (103) also includes a process hole (1034), the process hole (1034) is opened in the shape of the plug (4), wherein, The process hole (1034) is opened on a side of the middle section (1032) away from the connecting section (1033), and the process hole (1034) is connected to the access section (1031), the middle section (1032) and the outside world; The plug (41) and the positioning protrusion (42) are arranged in the process hole (1034), the plug (41) and the process hole (1034) are interference fit, and the positioning protrusion (42) protrudes relative to the plug (41).

5. The femoral stem according to claim 4, wherein: The surface of the fixing section (12) is frosted, and the microporous titanium layer (2) is coated on the fixing section (12); The microporous titanium layer (2) is formed by sintering spherical powdered titanium to form a spherical microporous layer structure and covers the plug (4); The porosity of the microporous titanium layer (2) is 30% to 40%, the maximum pore diameter is 0.2 mm to 0.3 mm, and the thickness is 2 to 5 mm.

6. The femoral stem according to claim 4 or 5, characterized in that: The rod body (3) comprises an inserting section (31) and an inserting section (32), wherein: The plug-in section (31) is plugged into the fixed section (12); the plug-in section (31) is provided with an embedding groove (301); a portion of the handle (1) is filled and embedded in the embedding groove (301); The length of the plug-in section (31) is less than or equal to the length of the small-diameter section (1022), and the diameter of the plug-in section (31) is less than the diameter of the insertion section (32); The insertion section (32) is connected to one end of the plug section (31) away from the fixed section (12); the diameter of the insertion section (32) is smaller than the diameter of the fixed section (12), and the end of the insertion section (32) abuts against the end surface of the fixed section (12).

7. The femoral stem according to claim 6, wherein: The insertion section (32) is provided with an annular groove (302), a guide groove (303) and an adjustment groove (304), wherein: The annular groove (302) is spaced apart from the plug-in section (31); The guide groove (303) is provided on the portion of the insertion section (32) between the annular groove (302) and the plug-in section (31), and two guide grooves (303) are provided opposite to each other, one of the guide grooves (303) connects the annular groove (302) with the small-diameter section (1022), and the other guide groove (303) connects the annular groove (302) with the access section (1031); The adjustment groove (304) is located inside the guide groove (303).

8. The femoral stem according to claim 6, wherein: It also includes a fastener (5), which includes a screw (51) and a filling block (52), wherein: The screw (51) passes through the handle body (1) and is connected to the plug-in section (31) through threaded engagement; The filling block (52) is filled in the limiting groove (501) of the screw (51).

9. A method for preparing a femoral stem as claimed in claim 4, characterized in that: The following steps are involved: S1, preparing blanks of the handle body (1) and the rod body (3); S2, opening the viewing hole (101), the injection flow channel (102), and the return flow channel (103) on the handle body (1), so that the viewing hole (101), the injection flow channel (102), and the return flow channel (103) are interconnected; S3, using a plug (4) to plug the process hole (1034) of the reflux channel (103); S4, frosting the outer surface of the fixing section (12) of the handle (1), and loosely applying spherical powdered titanium on the outer surface of the fixing section (12); S5. Sintering the spherical titanium powder at a temperature of 900° C. to 1500° C. to form the microporous titanium layer (2), wherein the microporous titanium layer (2) covers the fixing section (12) and the plug (4); S6. Grinding the handle body (1) and the rod body (3), and assembling and connecting the two.

10. A method for preparing a femoral stem as claimed in claim 8, characterized in that: The following steps are involved: P1. Preparing blanks of the handle body (1) and the rod body (3); P2. The viewing hole (101), the injection channel (102), and the return channel (103) are provided on the handle (1), so that the viewing hole (101), the injection channel (102), and the return channel (103) are interconnected; P3, using a plug (4) to plug the process hole (1034) of the reflux channel (103); P4, frosting the outer surface of the fixed section (12); P5. Assemble and connect the rod body (3) and the handle body (1), and lock and fix them using the fastener (5); P6, loosely packed spherical powdered titanium on the outer surface of the fixed section (12); P7. Sintering the spherical titanium powder at a temperature of 900° C. to 1500° C. to form the microporous titanium layer (2), wherein the microporous titanium layer (2) covers the fixing section (12), the plug (4), and the fastener (5); P8. Grinding the handle (1) and the rod (3).

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