JPH0415051A - Artificial born head for articulatio coxae - Google Patents

Abstract

PURPOSE:To suppress the damage and breakage of a jaw part even in the case of adding a large load, advantageously make the jaw part slender, and consequently increase the freedom of design and the movable range of the feet of a living body by work-hardening the part, of the jaw part, at least fitting to a microcephalic part to make it stronger than a trunk part. CONSTITUTION:Almost a trunk part 1 is inserted to a hole formed in the femoral region of a living body and bonded to the thigh-bone through a binder such as cement, and it has a hollow form internally having a long hole. A jaw part 2 is a branched part obliquely protruding from one end of the proximal part 11 of the trunk 1. A microcephalic part 3 is engaged with the acetabulum of the pelvis of the living body or a socket provided on the acetabulum to ensure smooth joint function, and has a form close to a sphere. The trunk part 1, the jaw part 2 and the microcephalic part 3 are formed with austenitic stainless steel. In the jaw part 2, the part fitting to hole 30 of the microcephalic part 3 is work-hardened stronger than the proximal part 11 of the trunk part 11, and even if a considerable load is worked thereon, the damage and breakage of the jaw part 2 is suppressed, and the jaw part 2 can be made slender while ensuring the strength and durability of the jaw part 2.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a prosthetic head for a hip joint.

[Prior Art] As we move toward an aging society, opportunities for bone replacement are increasing, and in view of this situation, artificial femoral heads for hip joints have been provided in recent years. This artificial femoral head is interposed between the femur and pelvis of the living body. This artificial femoral head is used when the hip joint has lost its function due to osteoarthritis, hip joints, bone fractures, etc.

By the way, in recent years, as an artificial femoral head for the hip joint, JP-A-60-
lJ, columnar 9 as disclosed in Publication No. 41963
One known structure consists of seven parts, a branch-like neck part that projects obliquely from one end of the trunk, and a small head that fits into the tip of the neck part. With such an artificial hip joint head, delicate adjustments can be made by appropriately changing the combination of the trunk and the small head.
Improves compatibility with the cow body.

The present invention is an improvement on the conventional artificial hip joint head described above, and its object is to provide an artificial hip joint head that can further improve durability. .

[Means for Solving the Problems] The artificial hip joint head according to the present invention includes a pillar-shaped trunk made of metal and engaged with the femur, and a branch-shaped trunk made of metal and protruding at an angle from one end of the trunk. and a small head into which at least the distal end of the neck fits and engages with a socket installed in the acetabulum or the acetabulum, and the small head fits into at least the small head of the neck. This part is characterized by being work hardened and stronger than the trunk.

The trunk is the part that engages the femur. The 7th part is anchored by a distal part that is placed at a distance from the neck and a proximal part that connects to the neck. Usually, most or all of the trunk is attached to the femur. cement is inserted into the hole formed in
It is attached to the femur with a bonding agent such as ・.

The neck is a branch-like part that protrudes from one end of the trunk at an angle. The cross-sectional area of the neck is set to be smaller than the cross-sectional area of the proximal part. Although it depends on the living body, the cross section of the neck can be, for example, 50 to 115 mm2. The trunk and neck are usually solid, or may be hollow if the necessary strength can be achieved.

The small head engages with the pelvis as the tip of the neck engages (1).
It is something that The capitula engages a socket located in the pelvic crotch or cuff. The small head can have a shape that approximates a sphere, for example. A fitting part, for example, a hole, into which the tip of the neck fits is formed in the small head.

The 9 parts and the neck are made of metal. The metal is selected in consideration of compatibility with living organisms, strength, corrosion resistance, etc. As the metal, for example, steel, copper alloy, titanium, titanium alloy, etc. can be used, and in this case, low alloy, medium alloy, or high alloy may be used.

Specifically, austenitic stainless steel (e.g. 5U
S304LN, 5US316LN, etc.), cobalt-chromium-molybdenum alloy, and ausformed steel can be used.

The composition of austenitic stainless steel is, for example, carbon 0.08% or less and silicon 0.40 to 0.2% by weight.
0%, mankan 3.00-3.50%, phosphorus 0.03%
Below, sulfur is 0.01% or less, nickel is 9.0 to 10%.
0%, chromium 20-22%, molybdenum 2.0-3.0
%, the remainder FC1 can be an unavoidable impurity. The small head can also be formed of the above-mentioned metal, and in this case, it is preferable that the neck and the small head are made of the same material in order to suppress corrosion of the battery caused by dissimilar metals.

Now, in the artificial hip joint head of the present invention, at least the portion of the neck that fits into the small head is work-hardened and is made stronger than the trunk. Methods for work-hardening and strengthening include methods for partially swaging and covering the neck using a swaging machine, press forging means for partially forging the neck using a press forging die, and rotating a roll die. Let me do it
A rotary forging means for rotary forging covering the neck part, or a means for casting a casting material such as shot into the neck part may be adopted depending on the case.

Such measures should only be applied in a cold state. The swaging process refers to a process in which the material is pressed in a direction perpendicular to its axis to reduce its cross-sectional area and stretch it in the H-axis direction.

According to the swaging process and forging method described above, in the unlikely event that
Even if microporosity exists inside the neck, strengthening can be expected in this sense by crushing the porosity.

In manufacturing the artificial hip joint head of the present invention, for example, first, there is a step of forming an artificial femoral head or an artificial femoral head material having a portion that will become the neck portion and a portion that will become the 7 portions, and a step that will become the neck portion of the artificial femoral head. The steps of partially reinforcing the portion with the above-mentioned reinforcing means to form the neck can be carried out in sequence. The artificial femoral head 1 or the artificial femoral head material 1 in a state before the neck is strengthened may be a forged product, a VI manufactured product, or a machined product. In addition, in the case of J, (j, after work hardening, heat treatment can be performed as appropriate to adjust the material quality and structure of the work hardened part, and cutting 7J11 pieces can be performed as appropriate = j method sub-adjustment. The heat treatment atmosphere may be, for example, a protective atmosphere such as vacuum or inert gas.

The humidity and time of the heat treatment are appropriately selected depending on the required strength, quantity, etc.

The artificial femoral head for the groin (n1) of the present invention depends on the type of living body, the required strength, etc. [The hardness of the neck is 1-IV32]
0 or more (hardness of base material [-1200 to 260>), static tensile strength is 10Q l/mm2 or more, yield strength is 100kC
It can be expressed as l/mm2 or more.

When reducing the cross-sectional area of the neck when strengthening the neck, the area reduction rate can be 15% or more, particularly 25%.
~60%.

[Function] At least the distal end of the neck fits into the small head, so stress concentration tends to occur in the boundary area between the neck and the small head during biological movement, or the hip joint prosthesis of the present invention In the femoral head,
The part of the neck that fits into the small head is work-hardened and is stronger than the 9th part, so 10 scratches on the neck can be suppressed.

[Example] Examples of the artificial femoral head according to the present invention will be described.

The small head and neck of the artificial femoral head according to this example are assembled ("J
' Figure 1 shows the state before G-pulling, and Figures 2 and 3 show the assembled state.

The artificial femoral head according to this embodiment has a columnar 97 part 1 and a neck part 2.
and a small head 3.

9 part 1 is to be engaged with the femur. Executive 1 is
A distal part 10 provided at a position away from the neck 2, a proximal part 11 with a slightly large cross-sectional area connected to the neck 2, and an intermediate part 12 between the distal part 10 and the proximal part 11. It is formed by. Most of the trunk 1 is inserted into a hole formed in the femur of the living body, and is bonded to the femur using a bonding agent such as Cement 1. The d33 part 1 is hollow with a long hole inside.

The neck 2 is a branch-like part that protrudes obliquely from the proximal part 11 of the 99 part 1.The cross-sectional area of the neck 2 is The area is also set small and decreases toward the tip of the neck 2.The cross-sectional area of the neck 2 depends on the part of the cross section.
- Approximately 115 mm2.

The small head 3 engages with the socket 1 of the living body's pelvis or the socket 1 interposed in the shoe opening, thereby ensuring smooth joint performance. The small head 3 has a shape similar to a sphere. The small head 3 has a bottomed hole 3 that fits the tip of the neck or a taper.
0 is formed.

In this embodiment, the trunk 1, neck 2, and small head 3 are made of Austety 1~ series stainless steel in consideration of suitability to the cow's body, strength, etc. The composition of Ausde Inu 1~ series stainless steel is 0.04% carbon and 0.3% silicon in weight%.
3%, mankan 3.26%, phosphorus 0.014%, sulfur 0.007%, nickel 9320%, chromium 21.22
%, molybdenum 2.42%, remainder) e, unavoidable impurities.

Now, in the artificial femoral head of this embodiment, the small head 3 is located in the neck 2.
The part that fits and covers the hole 30 of [J, proximal part 1 of trunk 1 which is work hardened] is strengthened. As a means for strengthening, a swaging machine was used to partially swage the neck 2 at room temperature to work harden it. Specifically 4J.

Insert the part that will become the ter 1 part between the molds of the swaging machine, narrow the mold so that the distance between the molds is about 8.8 mm, and reduce the cross-sectional area of the neck part 2. and stretched in the axial direction.

As a result, the neck portion 2 is work-hardened. In this example, the area reduction rate of the neck 2 is 35%. In this example, after swaging, the surface layer of the neck 2 was cut to adjust its dimensions.

Person in this example] In the case of a bifemoral head, the surface hardness of the neck 2 is Hv 320 or more (base material hardness T + V 220 to 250).
), static tensile strength is 100 kg/mrn2 or more, and yield strength is 100 kg/mrn2 or more.

Now, when using the femoral head on a person in this example), Figures 2 and 3
As shown in the figure, the tip of the neck 2 is fitted into the hole 30 of the small head 3 and covered. With such a structure, when the living body moves, the neck 2
Stress is concentrated in the boundary area between the small head 3 and the small head 3, that is, the part X shown in FIG. In this regard, in the artificial bone Ufl of this embodiment, the portion that fits into the ulterior head 3 of the neck 2 is
Since it is stronger than the proximal part 1 of the 9-part hardened neck part, damage to the neck part 2 can be suppressed even if a considerable amount of force is applied to the front. Therefore, while ensuring the strength and durability of the neck part 2, it is necessary to make the n part 2 thinner (there is a certain amount of time required to make the n part 2 thinner), and to increase the degree of freedom in the design and the range of movement of the legs of the living body. It is.

[Test Example] Next, a test example will be explained. In this test, a round bar (average M Hv 2
38) was used. The round bar has a diameter of 10mrT1.11mm
and 2 scales. Then, using a swaging machine 9 equipped with a mold 90 shown in FIG.
and a mold 90, and the swaging machine 9 was operated to partially swage about half the length of the round bar W. In the swaging process in this example,
The molds 90 were tightened so that the distance between the molds 90 was about 3.5 mm. Therefore, in the case of a round bar with a diameter of 1"1 mm, the area reduction rate is 40%, and in the case of a round bar with a diameter of IQ mm, the area reduction rate is 28%. The processed portion of the round bar W was cut at the cut surface W13, and the processed portion was set in a tensile testing machine to conduct a tensile test.

The results of the tensile test are shown in Table 1. As shown in Table 1, the tensile strength of the 11 mm diameter round bar swaged to 8.5 mm is 116 kCI/mm2, the yield strength is 113 kQ/mm2T, and the elongation is 17.
It was 0%. , Also, a round bar with a diameter of 1Qmm is 3.5m long.
The tensile strength is 1 in the part where swage 7Jl +
08kQ/mm2, and the yield strength is 101 kg/mm2
The elongation was 18°7%. In addition, as shown in Table 1 for unswaged round bars, the tensile strength is 80 kQ/mm.
', the yield strength is 49 kg/mm2, and the elongation is 5
It was 3%. In addition, the round bar W was remelted and solidified again to form an AsCa5t bar, and the Δ5Cast bar was similarly tested without swaging.
The tensile strength is 50kQ/mm2, and the yield strength is 31
kg/mm2, and the elongation was 25%.

Furthermore, hardness was also investigated. The hardness distribution when a round bar with a diameter of 1"1 mm is swaged to 3.5 mm is shown in Figures 6 and 7. Figure 6 shows the hardness distribution from the surface of the swaged part. The distribution of MH hardness (load: 300CI) is shown when displacement is performed in the depth direction at intervals of .5 mm. Figure 7 shows the 1-IV hardness (1-IV hardness) of the swaged portion W10 and the unswaged portion W11. Front car 10
kq) distribution.

Further, the hardness molecule li obtained when a round bar with a diameter of 10 mm is swaged into a round bar of 5 mm is shown in Figs. ε3 and 9. FIG. 8 shows the difference in M-th V hardness (load: 300 Ω) when the swaged portion is displaced in the depth direction at intervals of Q, 5 mm from the surface layer surface. FIG. 9 shows the 1-1V hardness (Nobuko 10 kCI>) of the swaged portion W10 and the unswaged portion W11.

As is clear from FIGS. 6 and 8, in the swage-processed portion W10, the 0-polish area about 1 mm from the surface layer ITf1 is the most hardened. It is presumed that the area 0°5 mm from the surface layer is affected by the process-affected layer. Furthermore, as is clear from FIG. 7, the -1 hardness of the swaged part W10 is 350 or more, whereas
The hardness of the unswaged part (at W'11) is around 220 to 280 degrees. Also, as is clear from FIG. 9, the swaged portion W10 has a hardness of 1 (more than 320), while the unswaged portion W11 has a hardness of 1. Hv hardness 210~2
In the area where swaging was applied from test bundling of 13 or more which is close to 50 I.4. i /J111 - It is understood that it is hardened and reinforced.

In addition, when the structure of the swaged portion was observed under a microscope, it was confirmed that there was plastic flow along the length of the round bar.

[Application example] FIG. 10, 1] schematically shows an example of application.

In the example shown in FIG.
．． 1 socket i~102 is connected to CΩ]6 and a3 is engaged with the small head 3 of the artificial femoral head. Further, in the example shown in FIG. 11, the small head 3 of the artificial bone 011 is engaged with the shoe opening 101 of the base 1oo.

[Effects of the Invention] In the artificial hip joint head of the present invention, at least the part of the neck that fits into the capitula is work-hardened and strengthened more than the trunk, so even when a large weight is applied, too,
Damage and breakage of the neck are suppressed, further improving durability (
qru. Therefore, it is advantageous to make the neck of the feces thinner, and it is also advantageous to increase the degree of freedom in designing the feces and the range of movement of the legs of the living body.

[Brief explanation of drawings]

Figures 1 to 3 show embodiments of the present invention, with Figure 1 being a front view before the neck and small head are assembled, and Figure 2 being a front view after they are assembled. , FIG. 3 is a side view of the state after the set (=jU). FIGS. 4 and 5 show the form of forming and covering the trial in the test example of the present invention, and FIG. Fig. 5 is a side view of the swaged round bar. Fig. 6 and Fig. 8 are graphs showing the hardness test results. Fig. 7 9 are hardness distribution state diagrams showing the state of hardness distribution. FIGS. 10 and 11 are configuration diagrams showing application examples. In the figures, 1 is the trunk, 2 is the neck, 3 The small head is attached to the head part.

Claims (1)

[Claims] (1) A columnar trunk made of metal and engaged with the femur, a branch-shaped neck made of metal and protruding at an angle from one end of the trunk, and at least the tip of the neck fitted together. and a small head that engages with the acetabulum or a socket installed in the acetabulum, and at least the portion of the neck that fits into the small head is work-hardened and stronger than the trunk. An artificial hip joint head characterized by: