CN111759548A

CN111759548A - Artificial hip joint femoral stem prosthesis

Info

Publication number: CN111759548A
Application number: CN202010708706.9A
Authority: CN
Inventors: 张国强; 王岩
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-07-22
Filing date: 2020-07-22
Publication date: 2020-10-13
Anticipated expiration: 2040-07-22
Also published as: CN111759548B

Abstract

The invention discloses an artificial hip joint femoral stem prosthesis, which comprises a femoral stem cone, a femoral neck and a femoral stem which are sequentially connected; the femoral stem includes: the femoral stem proximal end, the femoral stem body and the femoral stem distal end are integrally formed; the proximal end of the femoral stem is divided into the inner side of the proximal end of the femoral stem and the outer side of the proximal end of the femoral stem according to the angle of the central angle of the cross section of the proximal end of the femoral stem, wherein the central angle corresponding to the inner side of the proximal end of the femoral stem is 120 degrees; the taper of the inner side of the proximal end of the femoral stem is gradually reduced along the proximal to distal direction of the femoral stem; the taper of the outer side of the proximal end of the femoral stem is constant; the far end of the femoral stem is of a cylindrical structure or a conical structure. The artificial hip joint femoral stem prosthesis can adjust the femoral anteversion angle to a normal anatomical position in the case of combining femoral anteversion angle variation and narrow medullary cavity, has good implantation effect and simple operation, and is easy to popularize and use in a large scale.

Description

Artificial hip joint femoral stem prosthesis

Technical Field

The invention belongs to the technical field of artificial prosthesis replacement, and particularly relates to an artificial hip joint femoral stem prosthesis.

Background

In total hip replacement surgery, it is desirable to achieve safe and stable movement of the hip joint by achieving a good joint anteversion of the acetabulum and femur.

In the actual operation process, the placement of the acetabulum side prosthesis needs to be compatible with the coverage of the host bone. In cases of acetabular fracture, acetabular rotation osteotomy, developmental acetabular retroversion, and the like, prostheses often need to be placed off-center or even retroversion. The variation of the anteversion angle of the femur itself is large, and particularly, the patients with hip joint dysplasia are in the majority.

It follows that there is a great need for femoral anteversion adjustment in total hip arthroplasty. Due to the problem of matching the femoral stem with the femoral medullary cavity, the range of changing the anteversion angle of the existing single wedge-shaped or double wedge-shaped femoral stem is very limited.

In order to meet the requirement of adjusting the anteversion angle on the femoral side as much as possible, the following three main implementation schemes are available:

first, cement-type femoral stems. The anteversion angle can be adjusted because the cement shank itself does not need to match the medullary cavity morphology.

However, cement-type femoral stems exist such as: high failure rate in long term fixation, osteonecrosis caused by heat generated in operation, potential abrasion particles, difficult repair and the like. Therefore, the cement type femoral stem is not applied well.

Second, a one-piece conical prismatic femoral stem, which is mainly represented by Wagner cone (Zimmer), is known. The femoral stem is integrally designed in a conical shape, and the circular cross section of the femoral stem is convenient for implanting the femoral stem in different forward inclination directions.

However, the conical appearance of the femoral stem can bring positive and negative effects in practical application: on the one hand, the femoral medullary cavity can be well matched and filled (fit-and-fill) in the implantation process; on the other hand, there is a risk of further subsidence after the operation. Furthermore, in cases of high dislocation hip dysplasia, a trochanteric osteotomy is often required; the femoral stem has limited stem length, and therefore has insufficient anti-rotation capability for the osteotomy end, and requires the use of additional instruments such as steel plates or split-binding of the osteotomy pieces to the osteotomy end. Increasing the complexity and difficulty of the procedure, as well as increasing the cost.

Third, a modular prosthesis. Depending on the location of the assembly interface, including cervical assembly prostheses, for example: kinectiv (Zimmer), Profemur (Wright), etc.; and a cuff-assembled prosthesis, such as: s-rom (Depuy), etc. The former adjusts the anteversion angle by selecting neck components with different anteversion directions; the latter can realize the free rotation between the handle and the sleeve, and adjust the anteversion angle in a wider range, thereby having wider application.

However, in either of the above-described assembled prostheses, the assembled interfaces present a potential problem. The micromotion of the assembly interface can generate metal abrasive dust, so that local foreign body reaction is caused; in addition, both have mechanical complications such as interfacial fracture.

Therefore, there is a high necessity for a femoral stem prosthesis that can adjust the anteversion angle without being limited to the femoral medullary canal morphology, which is applied to the artificial total hip replacement surgery.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an artificial hip joint femoral stem prosthesis.

According to one aspect of the invention, an artificial hip joint femoral stem prosthesis is provided, which comprises a femoral stem cone, a femoral neck and a femoral stem which are connected in sequence;

the femoral stem includes: the femoral stem proximal end, the femoral stem body and the femoral stem distal end are integrally formed;

the proximal end of the femoral stem is divided into the inner side of the proximal end of the femoral stem and the outer side of the proximal end of the femoral stem according to the angle of the central angle of the cross section of the proximal end of the femoral stem, wherein the central angle corresponding to the inner side of the proximal end of the femoral stem is 120 degrees;

the taper of the inner side of the proximal end of the femoral stem is gradually reduced along the proximal to distal direction of the femoral stem;

the taper of the outer side of the proximal end of the femoral stem is constant;

the far end of the femoral stem is of a cylindrical structure or a conical structure.

According to an embodiment of the invention, the taper of the inner side of the proximal end of the femoral stem decreases from 10 ° to 5 ° in the proximal to distal direction of the femoral stem.

According to another embodiment of the invention, the taper of the proximal outer side of the femoral stem is 5 °.

According to a further embodiment of the invention, the outer surface of the proximal outer side of the femoral stem is grit blasted.

According to a further embodiment of the invention, two fin-shaped protrusions are provided on the outer surface outside the proximal end of the femoral stem.

According to yet another embodiment of the invention, the distal end of the femoral stem is tapered at 2 ° when the distal end of the femoral stem is tapered.

According to a further embodiment of the invention, the outer surface of the distal end of the femoral stem is provided with a ridge.

According to another embodiment of the present invention, the distal tip of the femoral stem has a tuning fork shape.

According to another embodiment of the invention, the surface of the proximal end of the femoral stem is coated with a porous titanium metal coating, a tantalum metal coating or a titanium gunite + hydroxyapatite coating.

According to another embodiment of the present invention, the outer surface of the proximal inner side of the femoral stem is treated with a stepped microstructure.

The artificial hip joint femoral stem prosthesis provided by the invention adopts an integrally formed structure, so that potential risks such as stem interface fracture, metal abrasive dust, local foreign body reaction and the like caused by a matched interface are avoided; the step-shaped microstructure processing on the inner side of the near end converts the shearing stress between the prosthesis and the bone interface into the compressive stress, and improves the initial stability; the porous coating on the proximal surface has good friction coefficient, porosity and osteoinductivity, promotes bone ingrowth and provides long-term stability.

The femoral stem is creatively provided with a gradual taper area at the inner side of the proximal end of the femoral stem, so that the sinking risk caused by the integral conical design of the traditional femoral stem prosthesis is greatly reduced; on the other hand, the rotation angle in the femoral bone marrow cavity can be adjusted on the basis of reducing the bone destruction as much as possible. More importantly, compared with the proximal triangular sleeve component of the sleeve assembled prosthesis, the gradual taper area is more inclined to the outer side, so that the damage to the bone on the inner side of the proximal end is less, the implantation is easier, and the phenomenon similar to overhung of the sleeve on the proximal femur can be avoided. The latter causes excessive lengthening of the limb, with the risk of vascular nerve damage. This also indirectly reduces the potential for making a trochanteric osteotomy, since this design facilitates implantation into the medullary cavity. This design provides sufficient shank length to effect a stable intramedullary nail osteotomy even with a trochanteric osteotomy if necessary, and in addition, the edges of the distal protruding surface of the shank may embed into the bone, further providing rotational stability.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is an elevation view of one embodiment of an artificial hip stem prosthesis provided in accordance with the present invention;

FIG. 2 illustrates a rear view of one embodiment of an artificial hip stem prosthesis provided in accordance with the present invention;

FIG. 3 illustrates a side view of one embodiment of an artificial hip femoral stem prosthesis provided in accordance with the present invention;

FIG. 4 is a schematic cross-sectional view of the femoral stem proximal end of the artificial hip femoral stem prosthesis shown in FIG. 3 at three selected locations A-A, B-B, C-C;

fig. 5 is a schematic structural diagram of another embodiment of the artificial hip femoral stem prosthesis according to the present invention.

The same or similar reference numbers in the drawings identify the same or similar elements.

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.

Referring to fig. 1 to 3, the present invention provides an artificial hip stem prosthesis. The femoral stem prosthesis comprises a femoral stem cone 10, a femoral neck 20 and a femoral stem 30 which are connected in sequence. To avoid the problems of interface fretting, metal swarf, etc. that can occur with assembled interfaces, the femoral stem taper 10, the femoral neck 20, and the femoral stem 30 are integrally formed.

The femoral stem 30 includes: a proximal femoral stem end 31, a body femoral stem 32 and a distal femoral stem end 33 are integrally formed.

The proximal femoral stem end 31 is divided into a proximal femoral stem end inner side and a proximal femoral stem end outer side according to the angle of the central angle of the cross section of the proximal femoral stem end 31. Wherein, the central angle corresponding to the inner side of the proximal end of the femoral stem is 120 degrees. It will be appreciated that the central angle corresponding to 240 is just outside the proximal end of the femoral stem.

In order to promote bone growth, it is preferable that the surface of the proximal end 31 of the femoral stem is coated with a porous titanium metal coating, a tantalum metal coating, or a titanium gunite + hydroxyapatite coating. Different coatings have different porosity, pore size, etc. parameters in order to obtain the best bone ingrowth effect. If a porous titanium metal coating is adopted, the porosity is 55-70%, and the pore diameter is 300-640 μm. If tantalum metal coating is adopted, the porosity is 80%, and the pore diameter is 550 μm. If titanium guniting and hydroxyapatite are adopted for coating, particularly 330 mu m titanium and 50 mu m hydroxyapatite are adopted, and the surface roughness is between 21 and 28 mu m.

Further, in order to convert the shear stress between the prosthesis-bone interface into compressive stress and improve the initial stability, it is preferable to perform a step-shaped microstructure treatment on the 120 ° taper gradient region inside the proximal end 31 of the femoral stem.

In order to make it easier for the femoral stem 30 to adjust the anteversion angle and to implant in the medullary cavity, the taper of the inner side of the proximal end of the femoral stem decreases in the proximal to distal direction of the femoral stem 30. More preferably, the taper of the inner side of the proximal end of the femoral stem decreases from 10 ° to 5 ° in the proximal to distal direction of the femoral stem 30.

Referring to fig. 3 and 4, three cross-sections, a-A, B-B, C-C, are first taken along the proximal end 31 of the femoral stem shown in fig. 3, in the proximal-to-distal direction of the femoral stem 30. Taking section a-a in fig. 4 as an example, the side of the central angle corresponding to 120 ° is the inner side of the proximal end 31 of the femoral stem, and the other side is the outer side of the proximal end 31 of the femoral stem. Section B-B and section C-C are the same.

As can be seen in fig. 4, the curvature of the inner side of the proximal end of the femoral stem varies in different cross-sections, and thus it can be seen that the taper of the inner side of the proximal end of the femoral stem varies and decreases in the proximal-to-distal direction along the femoral stem 30. In different cross-sectional views, the radian of the outer side of the proximal end of the femoral stem is the same, i.e. the taper of the outer side of the proximal end of the femoral stem is constant. Preferably, the taper of the outer side of the proximal end of the femoral stem is 5 degrees.

The stepped microstructure processing can effectively convert the shearing force between the femoral stem 30 and the medullary cavity into the compressive stress, so as to improve the initial stability, and the gradual taper design of the proximal end 31 of the femoral stem reduces the sinking risk brought by the overall conical design of the traditional femoral stem prosthesis (such as Wagner cone). In addition, the gradual taper area of the proximal end 30 of the femoral stem is more outside than the traditional triangular sleeve (such as S-rom), so that the damage to the bone is less, the implantation of the femoral stem prosthesis is more convenient, and the rotation angle of the femoral stem prosthesis in the femoral medullary cavity can be flexibly adjusted. In addition, thanks to the convenience of implantation, the femoral stem can be implanted deeper in a femoral medullary cavity relative to the triangular sleeve, so that the excessive extension of limbs is avoided, and the possibility of bone cutting under the tuberosity is reduced.

To facilitate implantation and further reduce costs, the outer surface of the femoral stem may be grit blasted only on the outside of the proximal end.

In addition, to further increase the anti-rotation ability of the proximal femoral stem end 30 after implantation, it is preferable to provide two fin-shaped protrusions on the outer surface of the proximal outer side of the femoral stem. More preferably, the two fin-shaped protrusions are symmetrically arranged.

The distal end 33 of the femoral stem has a cylindrical or conical configuration.

When the distal femoral stem end 33 is tapered, it is preferred that the distal femoral stem end 33 be tapered at 2. It will be appreciated that the overall structure of the femoral stem 30 is tapered inwardly in the proximal to distal direction along the femoral stem 30 to facilitate the implantation procedure.

Preferably, the outer surface of the distal femoral stem end 33 is provided with a ridge. The rotational stability of the distal femoral stem end 33 can be significantly improved by the occlusion of these ridges with cortical bone. As the number of fins increases, the anti-rotation stability of the distal femoral stem end 33 also increases. However, since the number of the ribs is preferably 8, which is uniformly distributed on the outer surface of the distal end 33 of the femoral stem, the excessive ribs increase the production cost. More preferably, the height of the rib is between 1mm and 1.25mm, for example: 1mm, 1.15mm or 1.25 mm.

In addition, in order to reduce the rigidity of the femoral stem 30 and the incidence of thigh pain, the tip of the distal femoral stem end 33 has a tuning fork shape, i.e., the tip of the distal femoral stem end 33 is provided with a slot.

The artificial hip joint femoral stem prosthesis provided by the invention can be highly matched with the femoral medullary cavity in shape, the anteversion angle is adjustable, the implantation is convenient and fast, the anti-rotation capability is strong, the postoperative risk is low, and the large-scale popularization and use are easy.

Although the present invention has been described in detail with respect to the exemplary embodiments and advantages thereof, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims. For other examples, one of ordinary skill in the art will readily appreciate that the order of the process steps may be varied while maintaining the scope of the present invention.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. The artificial hip joint femoral stem prosthesis is characterized by comprising a femoral stem cone, a femoral neck and a femoral stem which are sequentially connected;

2. The femoral stem prosthesis of claim 1, wherein the taper of the inner side of the proximal end of the femoral stem decreases from 10 ° to 5 ° in the proximal-to-distal direction of the femoral stem.

3. The femoral stem prosthesis of claim 1, wherein the taper of the proximal outer side of the femoral stem is 5 °.

4. The femoral stem prosthesis of claim 1, wherein the outer surface of the proximal outer side of the femoral stem is grit blasted.

5. The femoral stem prosthesis of claim 4, wherein two fin-shaped protrusions are provided on the outer surface outside the proximal end of the femoral stem.

6. The femoral stem prosthesis of claim 1, wherein the distal femoral stem end is tapered at 2 ° when the distal femoral stem end is tapered.

7. The femoral stem prosthesis of claim 1, wherein the outer surface of the distal end of the femoral stem is provided with a ridge.

8. The femoral stem prosthesis of claim 1, wherein the distal tip of the femoral stem has a tuning fork configuration.

9. The femoral stem prosthesis of claim 1, wherein the surface of the proximal end of the femoral stem is coated with a porous titanium metal coating, a tantalum metal coating, or a titanium gunite + hydroxyapatite coating.

10. The femoral stem prosthesis of claim 1, wherein the outer surface of the proximal inner side of the femoral stem is treated with a stepped microstructure.