JPH10165429A - Ceramic caput ball and caput ball stem of artificial articulation - Google Patents

Ceramic caput ball and caput ball stem of artificial articulation

Info

Publication number
JPH10165429A
JPH10165429A JP8342521A JP34252196A JPH10165429A JP H10165429 A JPH10165429 A JP H10165429A JP 8342521 A JP8342521 A JP 8342521A JP 34252196 A JP34252196 A JP 34252196A JP H10165429 A JPH10165429 A JP H10165429A
Authority
JP
Japan
Prior art keywords
tapered hole
stem
ball
ceramic
tapered
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP8342521A
Other languages
Japanese (ja)
Inventor
Kentaro Fujikawa
健太郎 藤川
Atsushi Sugimoto
淳 杉本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Priority to JP8342521A priority Critical patent/JPH10165429A/en
Publication of JPH10165429A publication Critical patent/JPH10165429A/en
Pending legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/32—Joints for the hip
    • A61F2/36—Femoral heads ; Femoral endoprostheses
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof

Landscapes

  • Health & Medical Sciences (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Cardiology (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Materials For Medical Uses (AREA)
  • Prostheses (AREA)

Abstract

PROBLEM TO BE SOLVED: To enable a highly strong and rigid stem to be used even though it has small diameter, by forming a sliding face spherical, equipping a tapered hole to be fit by a stem, and forming a ring shaped reinforcing protruding part so as to be protruded outside along the periphery of the tapered hole opening part. SOLUTION: A metallic stem 4 of an artificial articulation is formed into a long shape tapered to the end part side which does not fit with a ceramic caput ball 3 and is fixed via a bone cement into a hole part formed by bone- cutting at the proximal end of a thigh bone. An artificial socket is formed spherical inside and is fixed via a bone cement onto a dent part formed by bone cutting at a socket. A spherical sliding face 10 is equipped on the ceramic caput ball 3, a tapered hole 11 opened toward the surface opposite to the tip end of the sliding face 10 is formed in the radial direction of the sphere formed by the sliding face 10, and the tip end of the stem 4 is fit into the papered hole 11. A reinforcing protruding part 12 is formed so as to protrude outward onto the opening part periphery of the tapered hole 11.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、人工股関節あるい
は人工肩関節等の人工関節に使用されるセラミック骨頭
球、及びそれを用いた骨頭球システムに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic head ball used for an artificial joint such as an artificial hip joint or an artificial shoulder joint, and a head ball system using the same.

【０００２】[0002]

【従来の技術】図７に示すように、従来より使用されて
いる人工股関節１００は、関節摺動部を形成する骨頭球
１０１に対し、これを大腿骨近位端Ｆ側に取り付けるた
めの金属ステム１０２が固定される一方、臼蓋Ｍ側には
高密度ポリエチレン（以下、ＨＤＰという）等で構成さ
れたソケット１０３が固定され、これに上記骨頭球１０
１が受座される構造を有している。骨頭球１０１は、自
身に形成されたテーパ孔に対し、対応するテーパ面をな
すステム１０２の末端部を嵌合させることによりこれと
一体化される。ここで、骨頭球１０１の材質としては、
従来よりステンレス鋼、Ｃｏ−Ｃｒ鋼、Ｔｉ合金等の金
属が使用されているが、金属製の骨頭球１０１を用いる
と、ソケット１０３を構成するＨＤＰの摩耗を生じやす
い欠点がある。そこで、近年では、上述のような摩耗を
抑制するためにアルミナやジルコニア等のセラミック製
骨頭球が多く用いられるようになってきている。2. Description of the Related Art As shown in FIG. 7, a conventionally used artificial hip joint 100 has a metal cap for attaching a head cap ball 101 forming a joint sliding portion to a proximal end F of a femur. While the stem 102 is fixed, a socket 103 made of high-density polyethylene (hereinafter, referred to as HDP) or the like is fixed to the acetabular M side.
1 has a structure to be received. The head ball 101 is integrated with a tapered hole formed therein by fitting a distal end of a stem 102 having a corresponding tapered surface. Here, as a material of the head ball 101,
Conventionally, metals such as stainless steel, Co-Cr steel, and Ti alloy have been used. However, the use of a metal head ball 101 has a disadvantage that the HDP forming the socket 103 is liable to wear. Therefore, in recent years, ceramic head balls made of ceramics such as alumina and zirconia have been used in many cases in order to suppress the above-mentioned wear.

【０００３】[0003]

【発明が解決しようとする課題】ところで、上記セラミ
ック骨頭球は、実用上は十分な強度を有しており良好に
使用されているが、金属製の骨頭球と比較すれば強度が
やや小さい問題がある。そして、ステムを嵌合した場合
のセラミック骨頭球の強度は、骨頭球の直径が小さくな
ると減少することも知られており、限界破壊強度のさら
に高いセラミック骨頭球の開発が望まれている。また、
ステム嵌合時のセラミック骨頭球の強度は、該ステムと
の嵌合部分における接触面積が大きければさらに高めら
れることが知られているが、ステムに対する骨頭球の嵌
合位置を調整するために、骨頭球側のテーパ孔の深さを
小さくする必要がある場合には、上記接触面積が減少す
ることから、この観点からの骨頭球の強度向上は期待で
きない。By the way, the above-mentioned ceramic skull ball has a sufficient strength in practical use and is used well. However, the strength of the skull ball is slightly lower than that of a metal skull ball. There is. It is also known that the strength of the ceramic head sphere when the stem is fitted thereto decreases as the diameter of the head sphere decreases, and it is desired to develop a ceramic head sphere having a higher critical fracture strength. Also,
It is known that the strength of the ceramic head ball at the time of fitting the stem is further increased if the contact area at the fitting portion with the stem is larger, but in order to adjust the fitting position of the head ball with respect to the stem, If it is necessary to reduce the depth of the tapered hole on the side of the head, the contact area is reduced, so that improvement in the strength of the head from this viewpoint cannot be expected.

【０００４】さらに、このようなセラミック骨頭球に対
して嵌合される金属ステムの材質は、ステンレス鋼、Ｃ
ｏ−Ｃｒ鋼、Ｔｉ合金等さまざまなものが使用されてい
るが、その材質の違いにより骨頭球の強度に差が生じる
こともある。具体的には、ステンレス鋼やＣｏ−Ｃｒ鋼
等の剛性の高い金属でステムを構成するよりも、Ｔｉ合
金のように多少剛性の低い材質で構成した場合のほう
が、ステム嵌合時の骨頭球の強度はより高くなる傾向に
あることが知られている。しかしながら、ステム自体の
強度を高めるためには剛性のより高い材質を用いること
が望ましいわけであり、結果としてステムの強度向上を
追求すれば、さらなる骨頭球の強度向上については断念
せざるを得なくなるディレンマが生ずる。Further, the material of the metal stem fitted to such a ceramic head ball is stainless steel, C
Various materials such as o-Cr steel and Ti alloy have been used, but the difference in the material may cause a difference in the strength of the caput ball. Specifically, a head made of a somewhat less rigid material, such as a Ti alloy, is better when the stem is made of a rigid material such as stainless steel or Co-Cr steel than when the stem is fitted. Is known to tend to be higher. However, in order to increase the strength of the stem itself, it is desirable to use a material having higher rigidity, and as a result, if the strength of the stem is pursued, it is necessary to abandon the further improvement of the strength of the headcap. A dilemma occurs.

【０００５】本発明の課題は、小径でも高強度で剛性の
高いステムの使用が可能であり、また十分な強度を確保
しつつステムに対する嵌合位置の変更を自由に行うこと
ができる人工関節のセラミック骨頭球と、それを用いた
骨頭球システムを提供することにある。An object of the present invention is to provide an artificial joint which can use a high-strength and high-rigidity stem even with a small diameter, and can freely change a fitting position with respect to the stem while securing sufficient strength. An object of the present invention is to provide a ceramic head ball and a head ball system using the same.

【０００６】[0006]

【課題を解決するための手段及び作用・効果】上述の課
題を解決するために本発明のセラミック骨頭球は、摺動
面が球面状に形成されるとともにステムを嵌合するため
のテーパ孔を有し、そのテーパ孔の開口部周縁に沿って
外側に突出するように、環状の補強突出部が形成された
ことを特徴とする。このような補強突出部の形成によ
り、ステムはテーパ孔の内周面に加えて該補強突出部の
内周面とも接触して嵌合部分の接触面積が増大するた
め、ステム嵌合時における骨頭球の強度が高められる。
これにより、小径の骨頭球でも十分な強度が確保され、
剛性の高い材質のステムも問題なく使用できる。このよ
うな強度向上の効果は、直径が２４mm以下の小型の骨頭
球において特に顕著に達成することができる。また、テ
ーパ孔の深さを小さくした場合でも、補強突出部の長さ
を増大させることで、ステムと骨頭球との嵌合部分の接
触面積を十分に確保できるので、骨頭球の十分な強度を
確保しつつステムに対するその嵌合位置を自由に調整す
ることができる。In order to solve the above problems, the ceramic head ball of the present invention has a spherical sliding surface and a tapered hole for fitting a stem. An annular reinforcing protrusion is formed so as to protrude outward along the periphery of the opening of the tapered hole. Due to the formation of such a reinforcing projection, the stem comes into contact with the inner peripheral surface of the reinforcing projection in addition to the inner peripheral surface of the tapered hole, and the contact area of the fitting portion increases. The strength of the sphere is increased.
As a result, sufficient strength is secured even with a small diameter head cap,
Stems of high rigidity can be used without any problems. Such an effect of improving strength can be particularly remarkably achieved in a small head ball having a diameter of 24 mm or less. In addition, even when the depth of the tapered hole is reduced, by increasing the length of the reinforcing protrusion, a sufficient contact area of the fitting portion between the stem and the head can be ensured. , And the fitting position with respect to the stem can be freely adjusted.

【０００７】上記セラミック骨頭球の材質は特に限定さ
れないが、例えばＡｌ2Ｏ3、ＺｒＯ2、Ｓｉ3Ｎ4、Ｓｉ
Ｃ等を主成分とするセラミックを使用することができ
る。例えば、Ａｌ2Ｏ3を主成分とするセラミックにより
構成する場合、より高強度の骨頭球を得るためには、Ａ
ｌ2Ｏ3の純度は９９．５重量％以上とすることが望まし
い。また、ＺｒＯ2を主成分とするセラミックを使用す
る場合、より高強度の骨頭球を得るためには、ＺｒＯ2
の含有率が９０重量％以上、望ましくは９２重量％以上
であり、さらに安定化成分としてＹ2Ｏ3を２〜４mol
％、望ましくは２〜３mol％の範囲で含有するものを使
用するのがよい。The material of the ceramic head ball is not particularly limited. For example, Al 2 O 3 , ZrO 2 , Si 3 N 4 , Si
A ceramic containing C or the like as a main component can be used. For example, in the case of using a ceramic mainly composed of Al 2 O 3 , in order to obtain a higher-strength head cap, A
It is desirable that the purity of l 2 O 3 be 99.5% by weight or more. Further, when using a ceramic containing ZrO 2 as a main component, in order to obtain a higher strength headcap, ZrO 2
Is 90% by weight or more, preferably 92% by weight or more, and 2 to 4 mol of Y 2 O 3 as a stabilizing component.
%, Preferably in the range of 2 to 3 mol%.

【０００８】なお、補強突出部の内周面とテーパ孔の内
周面とが、一体のテーパ面を形成するように構成するこ
とができる。この場合、ステムの外面をこれに対応する
テーパ面に形成することで、ステム外面と上記骨頭球側
のテーパ面との間の接触面積がさらに増大し、骨頭球の
強度が一層高められる。The inner peripheral surface of the reinforcing projection and the inner peripheral surface of the tapered hole may be configured to form an integral tapered surface. In this case, by forming the outer surface of the stem as a corresponding tapered surface, the contact area between the outer surface of the stem and the tapered surface on the side of the head is further increased, and the strength of the head is further increased.

【０００９】次に、補強突出部は、テーパ孔の軸に沿う
断面においてその外周面が、その外周面と前述の摺動面
との接続点を通るように該摺動面に対して引いた接線と
一致するか、又はそれよりもテーパ孔の軸側に位置する
ものとなるように形成することができる。このように形
成された補強突出部は、摺動面との接続部に凹曲率部を
形成しないので、ステム嵌合時の骨頭球の強度がさらに
高められる。Next, the reinforcing projection is pulled with respect to the sliding surface so that the outer peripheral surface thereof passes through a connection point between the outer peripheral surface and the sliding surface in a cross section along the axis of the tapered hole. It can be formed so as to coincide with the tangent line or to be located on the axial side of the tapered hole. Since the reinforcing protrusion formed in this manner does not form a concave curvature at the connection with the sliding surface, the strength of the headcap at the time of fitting the stem is further increased.

【００１０】上記セラミック骨頭球においては、摺動面
をテーパ孔側に延長して得られる仮想的な球面とテーパ
孔の内周面との交線を含む平面を境界として、該境界か
ら補強突出部の開口縁までの高さＱと、テーパー孔の内
周面のうちそのテーパ面をなす部分のテーパ孔底部側端
縁から上記境界までの、該テーパ孔の深さ方向に沿う距
離Ｌとの比Ｑ／Ｌを０．１〜１に設定することが望まし
い。Ｑ／Ｌが０．１未満になると、補強突出部形成に伴
う骨頭球の強度向上の効果が十分に得られなくなる。ま
た、Ｑ／Ｌが１を超えて大きくなると補強突出部が不必
要に長くなり、該補強突出部の破壊が生じやすくなっ
て、強度は却って低下する。なお、Ｑ／Ｌは、より望ま
しくは０．３〜１の範囲で調整するのがよい。[0010] In the above-mentioned ceramic head ball, a reinforcing surface protrudes from the boundary with a plane including an intersection line between an imaginary spherical surface obtained by extending the sliding surface toward the tapered hole and the inner peripheral surface of the tapered hole. And the distance L along the depth direction of the tapered hole from the tapered hole bottom side edge of the portion forming the tapered surface of the inner peripheral surface of the tapered hole to the above boundary. It is desirable to set the ratio Q / L to 0.1 to 1. If the Q / L is less than 0.1, the effect of improving the strength of the head of the head due to the formation of the reinforcing protrusion cannot be sufficiently obtained. Further, when Q / L exceeds 1 and becomes large, the reinforcement protrusion becomes unnecessarily long, and the reinforcement protrusion is easily broken, and the strength is rather reduced. The Q / L is more preferably adjusted in the range of 0.3 to 1.

【００１１】次に、本発明の骨頭球システムは、上述の
セラミック骨頭球と、そのセラミック骨頭球のテーパ孔
に嵌合するとともに、Ｔｉ、Ｔｉ合金、ステンレス鋼、
Ｃｏ−Ｃｒ合金のいずれかにより構成された金属ステム
とを含むことを特徴とする。ステムを上記金属で構成す
ることで、生体親和性と耐久性とに優れた人工関節が実
現される。特に、ステンレス鋼及びＣｏ−Ｃｒ合金は剛
性が高いためステムの強度を著しく高めることができ、
またそのステムが嵌合するセラミック骨頭球には前述の
補強突出部が形成されていることから、骨頭球側の強度
も高水準なものとなる。Next, the head sphere system of the present invention fits into the above-mentioned head sphere and the tapered hole of the head sphere, and includes Ti, Ti alloy, stainless steel,
And a metal stem made of any one of Co-Cr alloys. By configuring the stem with the above-described metal, an artificial joint excellent in biocompatibility and durability can be realized. In particular, since stainless steel and Co-Cr alloy have high rigidity, the strength of the stem can be significantly increased,
Further, since the above-mentioned reinforcing protrusion is formed on the ceramic head sphere to which the stem is fitted, the strength of the head sphere is also high.

【００１２】なお、上記本発明のセラミック骨頭球及び
骨頭球システムは、人工股関節に最も好適に使用できる
他、人工肩関節に適用することも可能である。[0012] The above-mentioned ceramic head ball and head system of the present invention can be most suitably used for an artificial hip joint, and can also be applied to an artificial shoulder joint.

【００１３】[0013]

【発明の実施の形態】以下、本発明の実施の形態を図面
に示す実施例により説明する。図１は、本発明の骨頭球
システムを用いた人工股関節の一例を模式的に示してい
る。すなわち、人工股関節１は、セラミック骨頭球３
と、一端側がこれに嵌合する金属ステム４とからなる骨
頭球システム２と、臼蓋Ｍ側に固定されてセラミック骨
頭球３を受座するＨＤＰ製のソケット５とを備えてい
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to examples shown in the drawings. FIG. 1 schematically shows an example of a hip prosthesis using the caput ball system of the present invention. That is, the artificial hip joint 1 comprises the ceramic head ball 3
And a head stem system 2 composed of a metal stem 4 fitted at one end thereof, and an HDP socket 5 fixed to the acetabular M side for receiving the ceramic head head ball 3.

【００１４】金属ステム４はＴｉ、Ｔｉ合金、ステンレ
ス鋼、Ｃｏ−Ｃｒ合金のいずれかにより構成され、セラ
ミック骨頭球３と嵌合しない端部側が、先細りとなる長
尺形状に形成され、大腿骨Ｆの近位端に骨切りにより形
成された孔部Ｗ内において骨セメント層７を介して固定
されている。一方、ソケット５は内面が球面状に形成さ
れ、臼蓋Ｍに骨切りにより形成された凹部Ｖに対し、骨
セメント層６を介して固着されている。The metal stem 4 is made of any one of Ti, Ti alloy, stainless steel, and Co-Cr alloy, and the end side of the metal stem 4 which does not fit the ceramic head ball 3 is formed in a tapered long shape, and the femur is formed. F is fixed via a bone cement layer 7 in a hole W formed by osteotomy at the proximal end. On the other hand, the socket 5 has an inner surface formed in a spherical shape, and is fixed via a bone cement layer 6 to a concave portion V formed by osteotomy in the acetabulum M.

【００１５】次に、セラミック骨頭球３は、例えばＡｌ
2Ｏ3、ＺｒＯ2、Ｓｉ3Ｎ4、ＳｉＣ等を主成分とするセ
ラミック焼成体、例えばＡｌ2Ｏ3を９９．５重量％以上
含有するＡｌ2Ｏ3系セラミック焼成体、あるいはＺｒＯ
2を９０重量％以上、望ましくは９２重量％以上含有
し、さらに安定化成分としてＹ2Ｏ3を２〜４mol％、望
ましくは２〜３mol％の範囲で含有するＺｒＯ2系セラミ
ック焼成体により構成されている。Next, the ceramic head ball 3 is made of, for example, Al.
2 O 3, ZrO 2, Si 3 N 4, a ceramic sintered body mainly composed of SiC or the like, for example, Al 2 O 3 based ceramic sintered body Al 2 O 3 containing 99.5 wt%, or ZrO
2 90 wt% or more, preferably contains more than 92 wt%, further 2～4Mol% of Y 2 O 3 as a stabilizing component, preferably composed of a ZrO 2 based ceramic sintered body containing in the range of 2～3Mol% Have been.

【００１６】図２に示すように、セラミック骨頭球３は
球面状の摺動面１０を有するとともに、該摺動面１０の
先端とは反対側においてその表面に開口するテーパ孔１
１が、該摺動面１０の形成する球の半径方向に形成され
て、ここにステム４の端部が嵌合している。そして、そ
のテーパ孔１１の開口部周縁には、これに沿って外側に
突出するように環状の補強突出部１２が形成されてお
り、該補強突出部１２の内周面とテーパ孔１１の内周面
とは一体のテーパ面をなしている。一方、テーパ孔１１
に嵌合するステム４の端部外面はこれに対応するテーパ
面とされている。なお、テーパ孔１１の底部には拡径部
１１ａが形成されている。この拡径部１１ａは、ステム
４の嵌合に伴う応力集中を緩和するための逃がし部とし
て機能しうる。As shown in FIG. 2, the ceramic head ball 3 has a spherical sliding surface 10 and a tapered hole 1 opened in the surface of the sliding surface 10 on the side opposite to the tip of the sliding surface 10.
1 is formed in the radial direction of the sphere formed by the sliding surface 10, and the end of the stem 4 is fitted therein. An annular reinforcing protrusion 12 is formed at the periphery of the opening of the tapered hole 11 so as to protrude outward along the opening. The inner peripheral surface of the reinforcing protrusion 12 and the inside of the tapered hole 11 are formed. The peripheral surface forms an integral tapered surface. On the other hand, the tapered hole 11
The outer surface of the end portion of the stem 4 that fits with the tapered surface is a tapered surface corresponding to this. In addition, an enlarged diameter portion 11 a is formed at the bottom of the tapered hole 11. The enlarged diameter portion 11a can function as a relief portion for relieving stress concentration due to fitting of the stem 4.

【００１７】また、上記摺動面１０をテーパ孔１１側に
延長して得られる仮想的な球面ＶＳとテーパ孔１１の内
周面との交線Ｉを含む平面を境界Ｂとして、該境界Ｂか
ら補強突出部１２の開口縁までの高さ（以下、単に「補
強突出部１２の高さ」という）Ｑと、テーパー孔１１の
内周面のうちそのテーパ面をなす部分のテーパ孔底部側
端縁から上記境界Ｂまでの、該テーパ孔１１の深さ方向
に沿う距離（以下、単に「テーパ孔１１の深さ」とい
う）Ｌとの比Ｑ／Ｌは、０．１〜１、望ましくは０．３
〜１の範囲で設定されている。一方、テーパ孔１１の深
さＬは、摺動面１０が形成する球の直径をＤとすれば、
該テーパ孔１１に嵌合したステム４の先端部が、その軸
方向において前述の仮想的な球面ＶＳからＤ／３以上、
望ましくはＤ／２以上隔たって位置するように調整され
ている。さらに、図３に示すように、テーパ孔１１のテ
ーパ角θ1は、２．５＜θ1≦６．５°の範囲で調整さ
れ、ステム４の外面のテーパ角θ2は２．５≦θ1＜６．
５°の範囲でθ1よりも若干小さくなるように設定され
ている。A plane including an intersection line I between an imaginary spherical surface VS obtained by extending the sliding surface 10 toward the tapered hole 11 and the inner peripheral surface of the tapered hole 11 is defined as a boundary B. (Hereinafter, simply referred to as the “height of the reinforcing projection 12”) Q, and the tapered hole bottom side of a portion of the inner peripheral surface of the tapered hole 11 that forms the tapered surface. The ratio Q / L of the distance from the edge to the boundary B along the depth direction of the tapered hole 11 (hereinafter, simply referred to as the “depth of the tapered hole 11”) L is preferably 0.1 to 1. Is 0.3
-1 is set. On the other hand, if the diameter L of the sphere formed by the sliding surface 10 is D, the depth L of the tapered hole 11 is
The tip of the stem 4 fitted into the tapered hole 11 is D / 3 or more from the above-mentioned virtual spherical surface VS in the axial direction.
Desirably, it is adjusted so as to be located at a distance of D / 2 or more. Further, as shown in FIG. 3, the taper angle θ1 of the tapered hole 11 is adjusted in the range of 2.5 <θ1 ≦ 6.5 °, and the taper angle θ2 of the outer surface of the stem 4 is 2.5 ≦ θ1 <6. .
It is set to be slightly smaller than θ1 in the range of 5 °.

【００１８】上述のようなセラミック骨頭球３において
は、補強突出部１２が形成されることで、テーパ孔１１
の内周面が実質的にその軸方向に延長されることとな
り、ステム４と骨頭球３との嵌合面積（すなわち、ステ
ム４の外面とテーパ孔１１及び補強突出部１２の内周面
との接触面積）が増大して、骨頭球３の強度、具体的に
は、嵌合状態となったステム４に対し軸方向の押込み力
がさらに作用した場合の強度が高められる。このような
強度向上の効果は、骨頭球３の直径Ｄが２４mm以下であ
る場合に特に著しい。なお、強度が高められる要因とし
ては、嵌合面積の増大により、上記押込み力が嵌合面全
体に分散され、応力集中が生じにくくなることが考えら
れる。In the ceramic head ball 3 as described above, the reinforcing protrusion 12 is formed so that the tapered hole 11 is formed.
The inner peripheral surface of the stem 4 is substantially extended in the axial direction, and the fitting area between the stem 4 and the head 3 (that is, the outer peripheral surface of the stem 4 and the inner peripheral surface of the tapered hole 11 and the reinforcing projection 12) The contact area of the head 3 increases, and more specifically, the strength when the axial pushing force further acts on the stem 4 in the fitted state. Such an effect of improving the strength is particularly remarkable when the diameter D of the head 3 is 24 mm or less. It is conceivable that the strength is increased because the pushing force is dispersed over the entire fitting surface due to an increase in the fitting area, so that stress concentration hardly occurs.

【００１９】ここで、ステム４はテーパ孔１１に対し、
これを押し広げる方向に力を作用させながら進入するの
で、テーパ孔１１の底部（先端）にはいわゆる開口型の
引張応力が作用することとなる。この場合、その引張応
力の大きさは、上記開口方向に作用する力のモーメント
にほぼ比例して増大すると考えられ、これが大きくなる
ほど骨頭球３には破壊が生じやすくなるといえる。そし
て、テーパ孔１１のテーパ角θ1がステム４の外面のテ
ーパ角θ2よりもよりも小さくなっていると、ステム４
は補強突出部１２の開口部側から先に接触し、テーパ孔
１１の底部から比較的隔たった位置に応力が集中しやす
くなる。その結果、上記開口方向の力のモーメントが増
大するので、骨頭球３の強度向上の観点からは不利とな
る。しかしながら、上述のようにθ1＞θ2となるように
設定すれば、テーパ孔１１への挿入に伴い、ステム４は
テーパ孔１１の内周面に対し底部に近い側から先に当接
することから、前述の力のモーメントは比較的小さく抑
さえられ、骨頭球３の強度を向上させる上で都合がよ
い。なお、このような効果を高めるためには、上記角度
の差θ1−θ2を１°を超えない範囲内で設定することが
望ましい。Here, the stem 4 is inserted into the tapered hole 11.
Since it enters while applying a force in the direction in which it is spread, so-called open-type tensile stress acts on the bottom (tip) of the tapered hole 11. In this case, it is considered that the magnitude of the tensile stress increases almost in proportion to the moment of the force acting in the opening direction, and it can be said that the greater the magnitude of the tensile stress, the more likely the head ball 3 is to be broken. If the taper angle θ1 of the tapered hole 11 is smaller than the taper angle θ2 of the outer surface of the stem 4, the stem 4
Contacts the opening from the opening side of the reinforcing protrusion 12, and the stress is easily concentrated at a position relatively separated from the bottom of the tapered hole 11. As a result, the moment of the force in the opening direction increases, which is disadvantageous from the viewpoint of improving the strength of the head ball 3. However, if it is set so that θ1> θ2 as described above, the stem 4 comes into contact with the inner peripheral surface of the tapered hole 11 first from the side closer to the bottom with the insertion into the tapered hole 11, so that The above-mentioned moment of force is suppressed relatively small, which is convenient for improving the strength of the head ball 3. In order to enhance such an effect, it is desirable to set the angle difference θ1−θ2 within a range not exceeding 1 °.

【００２０】なお、補強突出部１２は、図４に示すよう
に、テーパ孔１１の軸に沿う断面においてその外周面１
２ａが、その外周面１２ａと前述の摺動面１０との接続
点Ｃを通るように該摺動面１０に対して引いた接線Ｔと
ほぼ一致するものとなるように形成することができる。
この場合、補強突出部１２の外周面１２ａの断面外形線
はほぼ直線状のものとなる。一方、図５に示すように、
補強突出部１２の外周面１２ａは、上記接線Ｔよりもテ
ーパ孔１１の軸側に位置するものとなるように形成して
もよい。なお、図５においては、補強突出部１２の外周
面１２ａの断面外形線は、外向きの大きな曲率（例えば
Ｒが５０〜１００mm程度）を有するものとされている。
このように形成された補強突出部１２は、摺動面１０と
の接続部に凹曲率部を形成しないので、ステム嵌合時の
骨頭球の強度がさらに高められる。As shown in FIG. 4, the reinforcing projection 12 has an outer peripheral surface 1 in a cross section along the axis of the tapered hole 11.
2a can be formed so as to substantially coincide with a tangent line T drawn to the sliding surface 10 so as to pass through a connection point C between the outer peripheral surface 12a and the sliding surface 10 described above.
In this case, the cross-sectional outline of the outer peripheral surface 12a of the reinforcing protrusion 12 is substantially straight. On the other hand, as shown in FIG.
The outer peripheral surface 12a of the reinforcing protrusion 12 may be formed so as to be located on the axis side of the tapered hole 11 with respect to the tangent T. In FIG. 5, the cross-sectional outline of the outer peripheral surface 12a of the reinforcing projection 12 has a large outward curvature (for example, R is about 50 to 100 mm).
Since the reinforcing projection 12 formed in this manner does not form a concave curvature portion at a connection portion with the sliding surface 10, the strength of the headcap at the time of fitting the stem is further increased.

【００２１】[0021]

【実施例】以下、本発明の実施例について説明する。Ａ
ｌ2Ｏ3造粒粉をプレス成形して所定形状に加工すること
によりグリーン成形体を作り、これを焼成後さらに表面
研磨を施すことにより、図２（実施例、、）及び
図５（実施例）に示す各形状のＡｌ2Ｏ3系セラミック
骨頭球３を作製した。なお、焼成体のＡｌ2Ｏ3純度の分
析値は９９．５重量％であった。一方、ＺｒＯ2及びＹ2
Ｏ3の混合造粒粉を用いることにより、図２（実施例
、、）及び図５（実施例）に示す各形状のＺｒ
Ｏ2系セラミック骨頭球３も同様にして作製した。焼成
体の組成の分析値は、ＺｒＯ2が９３．２重量％、Ｙ2Ｏ
3が４．７重量％であった。ここで、各試料とも骨頭球
の直径を２２mm、テーパ孔１１の深さＬを９mm、テーパ
孔１１内周面のテーパ角θ1を６°、補強突出部１２の
開口径を１０．５mmφに設定した。また、補強突出部の
高さＱを各種値に設定することで、Ｑ／Ｌを０．０９〜
１．２の範囲で変化させた。なお、比較のため、両材質
ともに、補強突出部１２を形成しない骨頭球も作製した
（比較例、）。Embodiments of the present invention will be described below. A
The l 2 O 3 granulated powder was press-molded to make a green body by processing into a predetermined shape by performing further surface polishing after firing this, FIG. 2 (Example ,,) and 5 (Embodiment Al 2 O 3 -based ceramic head spheres 3 having the respective shapes shown in Examples) were produced. The analysis value of the purity of Al 2 O 3 of the fired body was 99.5% by weight. On the other hand, ZrO 2 and Y 2
By using the mixed granulated powder of O 3 , the Zr of each shape shown in FIG. 2 (Example), and FIG.
The O 2 ceramic head ball 3 was produced in the same manner. The analysis value of the composition of the fired body was as follows: 93.2% by weight of ZrO 2 , Y 2 O
3 was 4.7% by weight. Here, in each sample, the diameter of the head ball was set to 22 mm, the depth L of the tapered hole 11 was set to 9 mm, the taper angle θ1 of the inner peripheral surface of the tapered hole 11 was set to 6 °, and the opening diameter of the reinforcing protrusion 12 was set to 10.5 mmφ. did. Further, by setting the height Q of the reinforcing protrusion to various values, the Q / L is set to 0.09 to 0.09.
It was changed in the range of 1.2. For comparison, head spheres that did not form the reinforcing protrusions 12 were also produced for both materials (Comparative Example).

【００２２】上記各セラミック骨頭球３のテーパ孔１１
に対し、Ｔｉ合金（Ａｌ：５．５〜６．５重量％、Ｖ：
３．５〜４．５、Ｔｉ：残部（ただし不可避不純物を含
む））（表１）、ステンレス鋼（Ｍｎ：２重量％以下、
Ｃｒ：１９〜２１重量％、Ｎｉ：１９〜２１重量％、Ｍ
ｏ：３．５〜４．５重量％、Ｃｏ：１９〜２１重量％、
Ｆｅ：残部（ただし不可避不純物を含む））及びＣｏ−
Ｃｒ合金（Ｃｒ：２６〜３０重量％、Ｍｏ：５〜７重量
％、Ｃｏ：残部（ただし不可避不純物を含む））の各材
質のステム（先端径１１mm、テーパ角５．８°）４を嵌
合させ、図６に示すように、その状態で円錐形の受け面
を有するブロック２１により骨頭球３の摺動面１０を銅
リング２０で受けながら、圧縮試験機を用いてステム４
の軸方向に荷重を付加し、骨頭球３に破壊が生じ始める
荷重を、該骨頭球３の圧縮破壊強度値とした。結果を表
１〜表３に示す。The tapered hole 11 of each of the ceramic heads 3
With respect to Ti alloy (Al: 5.5 to 6.5% by weight, V:
3.5 to 4.5, Ti: balance (but including unavoidable impurities) (Table 1), stainless steel (Mn: 2% by weight or less,
Cr: 19 to 21% by weight, Ni: 19 to 21% by weight, M
o: 3.5 to 4.5% by weight, Co: 19 to 21% by weight,
Fe: balance (but including unavoidable impurities) and Co-
Fit a stem (tip diameter 11 mm, taper angle 5.8 °) 4 of each material of a Cr alloy (Cr: 26 to 30% by weight, Mo: 5 to 7% by weight, Co: Remaining (including unavoidable impurities)) As shown in FIG. 6, the sliding surface 10 of the head 3 is received by the copper ring 20 by the block 21 having the conical receiving surface in this state.
Was applied in the axial direction, and the load at which destruction of the head 3 began to occur was defined as the compressive fracture strength value of the head 3. The results are shown in Tables 1 to 3.

【００２３】[0023]

【表１】 [Table 1]

【００２４】[0024]

【表２】 [Table 2]

【００２５】[0025]

【表３】 [Table 3]

【００２６】すなわち、補強突出部１２を有する実施例
のセラミック骨頭球は、これを有さない比較例の骨頭球
よりも強度に優れていることがわかる。そして、Ｑ／Ｌ
を０．３前後に設定することで強度は一層高くなり、骨
頭球形状が図５に示すものである場合にはさらに高強度
となることもわかる。That is, it can be seen that the ceramic head ball of the embodiment having the reinforcing projections 12 is superior in strength to the head ball of the comparative example having no reinforcing protrusion. And Q / L
Is set to about 0.3, the strength is further increased, and it can be seen that the strength becomes even higher when the shape of the head sphere is as shown in FIG.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明のセラミック骨頭球を使用した人工股関
節の一例を示す正面部分断面図。FIG. 1 is a front partial sectional view showing an example of an artificial hip joint using a ceramic head ball of the present invention.

【図２】その骨頭球システムの正面断面図。FIG. 2 is a front sectional view of the caput ball system.

【図３】テーパ孔及びステムの、テーパ角度の望ましい
大小関係を示す模式図。FIG. 3 is a schematic diagram showing a desirable magnitude relationship of a taper angle between a tapered hole and a stem.

【図４】セラミック骨頭球の変形例を示す正面断面図。FIG. 4 is a front sectional view showing a modified example of a ceramic head ball.

【図５】同じく別の変形例を示す正面断面図。FIG. 5 is a front sectional view showing another modified example.

【図６】セラミック骨頭球の圧縮破壊強度試験方法を示
す説明図。FIG. 6 is an explanatory view showing a method for testing the compressive fracture strength of a ceramic head ball.

【図７】従来型の人工股関節を示す正面部分断面図。FIG. 7 is a front partial sectional view showing a conventional hip prosthesis.

【符号の説明】[Explanation of symbols]

１ 人工股関節（人工関節） ２ 骨頭球システム ３ セラミック骨頭球 ４ ステム １１ テーパ孔 １２ 補強突出部 Reference Signs List 1 artificial hip joint (artificial joint) 2 head ball system 3 ceramic head ball 4 stem 11 tapered hole 12 reinforcing protrusion

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 摺動面が球面状に形成されるとともにス
テムを嵌合するためのテーパ孔を有し、そのテーパ孔の
開口部周縁に沿って外側に突出するように、環状の補強
突出部が形成されたことを特徴とする人工関節のセラミ
ック骨頭球。An annular reinforcing projection is formed so that a sliding surface is formed in a spherical shape and has a tapered hole for fitting a stem, and projects outward along a peripheral edge of an opening of the tapered hole. A ceramic head ball of an artificial joint, wherein a portion is formed. 【請求項２】 前記補強突出部の内周面と前記テーパ孔
の内周面とは、一体のテーパ面を形成している請求項１
記載のセラミック骨頭球。2. An inner peripheral surface of the reinforcing projection and an inner peripheral surface of the tapered hole form an integral tapered surface.
A ceramic head ball as described. 【請求項３】 前記補強突出部は、前記テーパ孔の軸を
含む面による断面においてその外周面が、当該外周面と
前記摺動面との接続点を通るように前記摺動面に対して
引いた接線と一致するか、又はそれよりも前記テーパ孔
の軸側に位置するものとなるように形成されている請求
項１又は２に記載のセラミック骨頭球。3. The sliding protrusion is configured such that an outer peripheral surface thereof passes through a connection point between the outer peripheral surface and the sliding surface in a cross section of the surface including the axis of the tapered hole with respect to the sliding surface. The ceramic head ball according to claim 1, wherein the ceramic head ball is formed so as to coincide with a drawn tangent line or to be located on an axial side of the tapered hole. 【請求項４】 前記摺動面を前記テーパ孔側に延長して
得られる仮想的な球面と前記テーパ孔の内周面との交線
を含む平面を境界として、該境界から前記補強突出部の
開口縁までの高さＱと、前記テーパー孔の内周面のうち
そのテーパ面をなす部分のテーパ孔底部側端縁から前記
境界までの、該テーパ孔の深さ方向に沿う距離Ｌとの比
Ｑ／Ｌが０．１〜１に設定されている請求項１ないし３
のいずれかに記載のセラミック骨頭球。4. The reinforcing projection from a boundary including a plane including an intersection of an imaginary spherical surface obtained by extending the sliding surface toward the tapered hole and an inner peripheral surface of the tapered hole. And the distance L along the depth direction of the tapered hole from the tapered hole bottom side edge of the portion forming the tapered surface of the inner peripheral surface of the tapered hole to the boundary. The ratio Q / L is set to 0.1-1.
The ceramic head ball according to any one of the above. 【請求項５】 請求項１ないし４のいずれかに記載のセ
ラミック骨頭球と、 そのセラミック骨頭球の前記テーパ孔に嵌合するととも
に、Ｔｉ、Ｔｉ合金、ステンレス鋼、Ｃｏ−Ｃｒ合金の
いずれかにより構成された金属ステムとを含むことを特
徴とする人工関節の骨頭球システム。5. A ceramic head ball according to claim 1, which is fitted in said tapered hole of said ceramic head ball, and is any one of Ti, Ti alloy, stainless steel and Co-Cr alloy. And a metal stem formed by the artificial joint.
JP8342521A 1996-12-06 1996-12-06 Ceramic caput ball and caput ball stem of artificial articulation Pending JPH10165429A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8342521A JPH10165429A (en) 1996-12-06 1996-12-06 Ceramic caput ball and caput ball stem of artificial articulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8342521A JPH10165429A (en) 1996-12-06 1996-12-06 Ceramic caput ball and caput ball stem of artificial articulation

Publications (1)

Publication Number Publication Date
JPH10165429A true JPH10165429A (en) 1998-06-23

Family

ID=18354396

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8342521A Pending JPH10165429A (en) 1996-12-06 1996-12-06 Ceramic caput ball and caput ball stem of artificial articulation

Country Status (1)

Country Link
JP (1) JPH10165429A (en)

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