Medullary cavity extension assembly
By designing the medullary cavity extension component, using Mohs' taper fit and lug and notch design, the problem of difficult matching of the extended handle size in the prior art is solved, achieving higher prosthesis stability and better patient recovery effect.
Patent Information
- Application Number
- CN202421473236.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-25
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-06-25
AI Technical Summary
The extended handle size of existing artificial knee prostheses is difficult to accurately match according to the patient's osteotomy amount, resulting in insufficient stability of the prosthesis and affecting the patient's recovery.
A medullary cavity extension assembly was designed, including medullary cavity extension and prosthetic extension. Through the Mohs taper fit and lug and notch design, more size choices are achieved to adapt to the osteotomy volume of different patients.
By combining different medullary cavity extensions and prosthetic extensions, it can better match the individual needs of patients, improve the stability of the prosthesis, and promote the recovery of patients.
Smart Images
Figure CN222917674U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of medical devices, and particularly relates to a medullary cavity extension assembly. Background Art
[0002] Total knee arthroplasty is a surgery that replaces the severely damaged knee joint surface that can no longer perform normal functions with an artificial prosthesis, thereby eliminating pain, correcting knee joint deformities, restoring knee joint stability and mobility, improving knee joint movement function, and enhancing the patient's quality of life.
[0003] Existing artificial knee joint prostheses include three parts: a tibial tray, a tibial spacer, and a femoral condyle prosthesis. The tibial spacer and the tibial tray are rigidly connected together through a locking mechanism and fixed inside the human tibia. The femoral condyle is fixed in the human talus, and the movement of the joint part is realized through the joint movement surface between the femoral condyle and the tibial spacer. Among them, most of the tibial tray and femoral condyle prostheses use an extension stem inserted into the medullary cavity of the tibia or talus to achieve the connection of the tibia or talus. However, due to the different heights and lesion sizes of different patients, the corresponding osteotomy amounts are also different. The standard prosthesis extension stem sizes in the prior art are difficult to accurately match according to the osteotomy degree of the patient. Therefore, the utility model proposes a medullary cavity extension assembly, which can adjust the length of the extension stem according to the osteotomy amount of the patient to better fit the patient, make the prosthesis have better stability after replacement, and be more conducive to the patient's recovery. Summary of the Utility Model
[0004] The purpose of the utility model is to provide a medullary cavity extension assembly that can better fit the length of the medullary cavity extension rod for patients.
[0005] To achieve the above purpose, the technical solution adopted by the utility model is as follows:
[0006] A medullary cavity extension assembly, comprising:
[0007] A medullary cavity extension piece, which has a table surface part, a frustum part, and an extension stem. The bottom end of the frustum part is connected to the top surface of the table surface part, the top end of the extension stem is connected to the bottom of the table surface part, and the extension stem is coaxially arranged with the frustum part;
[0008] A prosthesis extension piece, which includes a cylinder body. A boss part for cooperating with a prosthesis replacement part is arranged at the top of the cylinder body, and a tapered hole is arranged at the bottom of the cylinder body;
[0009] Wherein, the frustum part of the medullary cavity extension piece extends into the tapered hole, and the frustum part and the tapered hole are arranged in Morse taper fit.
[0010] In one embodiment, a plurality of first grooves extending along its axial direction are provided on the outer peripheral surface of the shank of the medullary cavity extender, and the plurality of first grooves are evenly distributed on the outer peripheral surface of the shank. The outer surface of the extender shank has a PPS coating.
[0011] In one embodiment, the bottom surface of the first groove is composed of a symmetrically arranged first inclined surface and a second inclined surface, and both the first inclined surface and the second inclined surface are inclined from the middle of the bottom surface of the first groove to both sides, and the height in the middle is greater than that on both sides.
[0012] In one embodiment, the coating thickness of the PPS coating is 0.2 - 0.3 mm.
[0013] In one embodiment, the medullary cavity extension assembly further includes a bushing. The bushing includes a bushing body, and a bushing hole extending axially through the bushing body is provided on the bushing body. An upper end portion of the extender shank connected to the table portion is provided with a bushing section matching the bushing hole. The bushing is sleeved on the bushing section, and a Morse taper fit connection is adopted between the bushing hole and the bushing section.
[0014] In one embodiment, at least two first lugs are provided on the top of the bushing body, and a first notch matching the first lugs is provided on the table portion of the medullary cavity extender. When the bushing is sleeved on the extender shank, the first lugs are located in the corresponding first notches.
[0015] In one embodiment, PPS coatings are provided on the lower part and the bottom surface of the bushing body, and the porosity of the PPS coating is 30% - 80%.
[0016] In one embodiment, the pore intercept of the PPS coating is 100 - 1000 μm, the surface roughness is greater than Rz800 μm, and the coating thickness is 600 - 800 μm.
[0017] In one embodiment, the porosity of the PPS coating at the bottom of the bushing body gradually increases in a gradient from the center to the outside, and the porosity of the PPS coating on the side wall of the bushing body gradually increases from the bottom to the top.
[0018] In one embodiment, at least two second lugs are provided at the bottom of the column body of the prosthesis extender, and a second notch matching the second lugs is provided on the table portion of the medullary cavity extender. When the medullary cavity extender and the prosthesis extender are assembled, the second lugs are located in the corresponding second notches.
[0019] Adopting the above technical solution, the beneficial effect of the present utility model is that the medullary cavity extension assembly provided by the present utility model includes a medullary cavity extension piece and a prosthesis extension piece. Through the combination of the medullary cavity extension piece and the prosthesis extension piece, more size options can be available, and thus the most suitable size can be selected according to the actual situation of the patient. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The schematic diagram showing the use of the medullary cavity extension assembly in cooperation with the proximal femur replacement.
[0021] Figure 2 Showing Figure 1 exploded view of
[0022] Figure 3 The schematic diagram showing the non-cemented medullary cavity extension piece.
[0023] Figure 4 The bottom view showing the non-cemented medullary cavity extension piece.
[0024] Figure 5 The schematic diagram showing the cemented medullary cavity extension piece.
[0025] Figure 6 The bottom view showing the cemented medullary cavity extension piece.
[0026] Figure 7 The schematic diagram showing the bushing in one view direction.
[0027] Figure 8 The schematic diagram showing the bushing in another view direction.
[0028] Figure 9 The schematic diagram showing the use of the medullary cavity extension assembly in cooperation with the proximal tibia replacement.
[0029] Figure 10 The schematic diagram showing the use of the medullary cavity extension assembly in cooperation with the distal femur replacement. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] The preferred embodiments of the present utility model will be described in detail below with reference to the accompanying drawings, so as to more clearly understand the purpose, features and advantages of the present utility model. It should be understood that the embodiments shown in the drawings are not limitations on the scope of the present utility model, but only to illustrate the essential spirit of the technical solution of the present utility model.
[0031] In the following description, for the purpose of illustrating various disclosed embodiments, certain specific details are set forth to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments can be practiced without one or more of these specific details. In other instances, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail so as not to unnecessarily obscure the description of the embodiments.
[0032] Unless the context requires otherwise, throughout the specification and claims, the word "comprising" and its variants such as "comprises" and "having" shall be understood in an open, inclusive sense, i.e., shall be interpreted as "including, but not limited to".
[0033] References to "one embodiment" or "an embodiment" throughout the specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" at various places throughout the specification are not necessarily all referring to the same embodiment. Additionally, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.
[0034] As used in this specification and the appended claims, the singular forms "a" and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally used in its inclusive sense of "and / or" unless the context clearly dictates otherwise.
[0035] In the following description, for the purpose of clearly showing the structure and working mode of the present utility model, many directional terms will be used for description. However, words such as "front", "rear", "left", "right", "outer", "inner", "outward", "inward", "up", "down", etc. should be understood as convenient terms and should not be understood as limiting terms.
[0036] Furthermore, terms such as "horizontal", "vertical", "hanging", etc. do not imply that the components are absolutely horizontal or hanging, but may be slightly inclined. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.
[0037] In the description of the present application, it should also be noted that, unless otherwise clearly specified and limited, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.
[0038] As Figure 1 and Figure 2 shown, the figure shows a schematic diagram of the use of a medullary cavity extension assembly in cooperation with a proximal femoral replacement 4. The medullary cavity extension assembly includes a medullary cavity extension member 1 and a prosthesis extension member 2. The medullary cavity extension member 1 has a table surface portion 11, a frustum portion 12, and an extension stem 13. The bottom of the frustum portion 12 is connected to the top surface of the table surface portion 11. The frustum portion 12 has a Morse taper, and its bottom radius is greater than its top radius, so that the frustum portion 12 can be connected and assembled with the prosthesis extension member 2 by Morse taper fitting. The top end of the extension stem 13 is connected to the bottom of the table surface portion 11, and the extension stem 13 is coaxially arranged with the frustum portion 12.
[0039] The extension stem 13 can be divided into a cemented type and a non-cemented type, which are suitable for different surgical occasions and provide more choices. Refer to Figure 3 and Figure 4 , Figure 3 The non-cemented type medullary cavity extension member is shown. A plurality of first grooves 131 extending along its axial direction are provided on the outer peripheral surface of the stem body of the extension stem 13. These first grooves 131 are evenly distributed on the outer peripheral surface of the stem body. The design of the first grooves 131 provides effective anti-rotation performance, facilitates the installation of the prosthesis, and reduces more stress shielding. Preferably, refer to Figure 4 , the bottom surface of the first groove 131 is composed of a symmetrically arranged first inclined surface 1311 and a second inclined surface 1312. The first inclined surface 1311 and the second inclined surface 1312 are both inclined from the middle of the bottom surface of the first groove 131 to both sides, and the height of the middle is greater than that of both sides. The first groove 131 designed in this way can have better anti-rotation performance and reduce more stress shielding. Another preferably, the distal end of the extension stem 13 is designed with a bullet-like shape. The distal end portion thereof is a spherical segment structure, and a tapered transition connection is provided between the spherical segment and the stem body. The bullet-like shape has a certain guiding property on the one hand, which can make it more convenient to install the prosthesis, and on the other hand, it can reduce the contact stress at the distal end and reduce the pain at the distal end.
[0040] Another preferably, the outer surface of the extension stem 13 has a PPS coating (not shown in the figure), and the coating thickness is 0.2 - 0.3 mm. The PPS coating can be effectively bio-fixed, which can further improve the stability of the medullary cavity extension member 1 in the medullary cavity.
[0041] Refer to Figure 5 and Figure 6 , Figure 5Shown is a cement-type medullary cavity extender. A plurality of second grooves 132 extending along its axial direction are provided on the outer peripheral surface of the shank body of the extension shank 13. These second grooves 132 are evenly distributed on the outer peripheral surface of the shank body. The design of the second grooves 132 provides effective anti-rotation performance, facilitates the installation of the prosthesis, and reduces more stress shielding. The second grooves 132 are arc-shaped grooves with equal depth to facilitate the injection and fixation of bone cement.
[0042] The cement-type medullary cavity extender can also be used in conjunction with a bushing. Specifically, refer to Figure 4 - Figure 8 , an adapter section 1313 that mates with the bushing 3 is provided at the upper end of the extension shank 13 where it is connected to the table surface portion 11. The adapter section 1313 is a circular smooth rod portion without the second grooves 132. The bushing 3 includes a bushing body 31. The bushing body 31 has a bushing hole 32 that axially penetrates the bushing body 31. The size of the bushing hole 32 is set to match the size of the adapter section 1313 of the extension shank 13. Preferably, a Morse taper fit connection is adopted between the bushing hole 32 and the adapter section 1313 to facilitate the mating and assembly between the bushing 3 and the extension shank 13. At least two first lugs 33 are provided at the top of the bushing body 31. The table surface portion 11 of the medullary cavity extender 1 is provided with first notches 111 that are matched with the first lugs 33. Each first notch 111 corresponds to a first lug 33. When the bushing 3 is sleeved on the extension shank 13, the first lugs 33 extend into the corresponding notches to play an anti-rotation role for the bushing 3. The bushing can effectively transfer the stress between the prosthesis and the bone, avoid stress shielding absorption, and can reduce the prosthesis bone cement stress to the lowest level, thereby avoiding prosthesis fracture and loosening; it can also prevent bone fragments from entering the prosthesis bone connection and causing osteolysis, playing a barrier role. Additionally, biomechanically, the bushing 3 also increases the torsional stiffness and the average maximum torque at failure. Furthermore, the bushing 3 can be designed with multiple diameters, and the most suitable size can be selected according to the actual situation of the patient.
[0043] Preferably, PPS coatings 34 are provided on the lower part and the bottom surface of the bushing body 31. The PPS coatings 34 can effectively grow together with tendon soft tissues and can be effectively bio-fixed. The porosity of the PPS coatings 34 is 30% - 80%. The porosity is smaller in the places where more bone is in contact, and the porosity gradually increases in a gradient from the bottom center outwards. The porosity on the side wall increases from the bottom upwards. The pore intercept is 100 - 1000 μm, the surface roughness is greater than Rz800 μm, and the average coating thickness is 600 - 800 μm. The smaller the porosity in the places where more bone is, the faster the bone ingrowth efficiency and the better the effect.
[0044] Refer again to Figure 1 and Figure 2, the prosthesis extender 2 includes a cylindrical column 21. At the top of the column 21, there is a boss portion 22 for Morse taper fit with the proximal femur replacement 4. At the bottom of the column 21, there is a taper hole (invisible in the view direction in the figure) for Morse taper fit with the frustum portion 12. At the bottom of the column 21, there are at least two second lugs 23. On the table portion 11 of the medullary cavity extender 1, there are second notches 112 arranged to match the second lugs 23. Each second notch 112 corresponds to a second lug 23. When the medullary cavity extender 1 and the prosthesis extender 2 are assembled, the second lugs 23 extend into the corresponding second notches 112 to play an anti-rotation role for the prosthesis extender 2. Similarly, between the prosthesis extender 2 and the proximal femur replacement 4, the anti-rotation purpose is also achieved through the cooperation of lugs and notches. Specifically, at the bottom of the proximal femur replacement 4, there are at least two third lugs 41. On the upper part of the prosthesis extender 2, there are third notches 24 arranged to match the third lugs 41. Each third notch 24 corresponds to a third lug 41. When the prosthesis extender 2 and the proximal femur replacement 4 are assembled, the third lugs 41 extend into the corresponding third notches 24 to play an anti-rotation role for the prosthesis extender 2. Since the medullary cavity extender 1, the prosthesis extender 2, and the proximal femur replacement 4 all use Morse taper fit and the cooperation of lugs and notches to achieve connection and anti-rotation, it is convenient for the assembly and use of this medullary cavity extension assembly during the operation. When this medullary cavity extension assembly is actually applied, the medullary cavity extender 1 and the prosthesis extender 2 with corresponding sizes can be selected according to the osteotomy amount of the patient. More sizes can be combined through the combination of the medullary cavity extender 1 and the prosthesis extender 2, and then the most suitable size for the patient can be selected.
[0045] See Figure 9 and Figure 10 , this medullary cavity extension assembly can also be applied to other tumor prostheses. Such as Figure 9 shows a schematic diagram of the assembly connection of this medullary cavity extension assembly with the proximal tibia replacement 5, Figure 10 shows a schematic diagram of the assembly connection of this medullary cavity extension assembly with the distal femur replacement 6.
[0046] The preferred embodiments of the present invention have been described in detail above. However, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention. These equivalent forms also fall within the scope defined by the appended claims of this application.
Claims
1. A medullary cavity lengthening component, characterized in that: include: A medullary cavity extension piece, the medullary cavity extension piece having a table portion, a truncated table portion and an extension handle, the bottom end of the truncated table portion is connected to the top surface of the table portion, the top end of the extension handle is connected to the bottom of the table portion, and the extension handle is coaxially arranged with the truncated table portion; A prosthesis extension piece, the prosthesis extension piece comprises a column, the top of the column is provided with a boss portion that matches with the prosthesis replacement piece, and the bottom of the column is provided with a tapered hole; The truncated cone portion of the medullary cavity extension piece extends into the tapered hole, and the truncated cone portion and the tapered hole are matched with a Morse taper.
2. The medullary cavity lengthening assembly according to claim 1, characterized in that: A plurality of first grooves extending along the axial direction are arranged on the outer peripheral surface of the handle of the extension handle of the medullary cavity extension piece. The plurality of first grooves are evenly distributed on the outer peripheral surface of the handle. The outer surface of the extension handle has a PPS coating.
3. The medullary cavity lengthening assembly according to claim 2, characterized in that: The bottom surface of the first groove is composed of a first inclined surface and a second inclined surface that are symmetrically arranged, and the first inclined surface and the second inclined surface are both inclined from the middle of the bottom surface of the first groove to both sides, and the height of the middle is greater than that of the two sides.
4. The medullary cavity lengthening assembly according to claim 2, characterized in that: The coating thickness of the PPS coating is 0.2-0.3 mm.
5. The medullary cavity lengthening assembly according to claim 1, characterized in that: The medullary cavity extension component also includes a sleeve, which includes a sleeve body. The sleeve body has a sleeve hole that penetrates the sleeve body along its axial direction. The upper end of the extension handle connected to the table portion is provided with a sleeve segment that matches the sleeve hole. The sleeve is sleeved on the sleeve segment, and the sleeve hole and the sleeve segment are connected by a Morse taper fit.
6. The medullary cavity lengthening assembly according to claim 5, characterized in that: At least two first lugs are arranged on the top of the sleeve body, and the table portion of the medullary cavity extension piece is provided with first notches matching the first lugs, each first notch corresponds to one first lug, and when the sleeve is sleeved on the extension handle, the first lug is located in the corresponding first notch.
7. The medullary cavity lengthening assembly according to claim 5, characterized in that: The lower part and the bottom surface of the sleeve body are both provided with a PPS coating, and the porosity of the PPS coating is 30%-80%.
8. The medullary cavity lengthening assembly according to claim 7, characterized in that: The pore intercept of the PPS coating is 100-1000 μm, the surface roughness is greater than Rz800 μm, and the coating thickness is 600-800 μm.
9. The medullary cavity lengthening assembly according to claim 7, characterized in that: The porosity of the PPS coating at the bottom of the sleeve body increases gradually from the center to the outside, and the porosity of the PPS coating on the side wall of the sleeve body increases gradually from the bottom to the top.
10. The medullary cavity lengthening assembly according to claim 1, characterized in that: The bottom of the column of the prosthesis extension is provided with at least two second lugs, and the table portion of the medullary cavity extension is provided with a second notch matched with the second lug. When the medullary cavity extension is assembled with the prosthesis extension, the second lug is located in the corresponding second notch.