JP2004057621A - Prosthetic hip joint - Google Patents

Prosthetic hip joint Download PDF

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Publication number
JP2004057621A
JP2004057621A JP2002222205A JP2002222205A JP2004057621A JP 2004057621 A JP2004057621 A JP 2004057621A JP 2002222205 A JP2002222205 A JP 2002222205A JP 2002222205 A JP2002222205 A JP 2002222205A JP 2004057621 A JP2004057621 A JP 2004057621A
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JP
Japan
Prior art keywords
liner
head
neck
hip joint
gripping
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
JP2002222205A
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Japanese (ja)
Inventor
Takao Hotokebuchi
佛淵　孝夫
Noriyuki Ishida
石田　典之
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.)
Kyocera Corp
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Kyocera Corp
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 Kyocera Corp filed Critical Kyocera Corp
Priority to JP2002222205A priority Critical patent/JP2004057621A/en
Publication of JP2004057621A publication Critical patent/JP2004057621A/en
Pending legal-status Critical Current

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    • 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
    • A61F2/34—Acetabular cups
    • 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

Abstract

<P>PROBLEM TO BE SOLVED: To enlarge a joint moving range while restraining a rib head bulb in a liner. <P>SOLUTION: A prosthetic hip joint 1 is composed of a stem 2, a cylindrical or truncated conical-shape neck 3 mounted at one end part of the stem 2, a rib head bulb 4 having a neck fitting hole 4a for fitting the neck 3, and a liner 6 having a semi-spherical recessed part 6a for rotatably receiving the rib head bulb 4. The depth (s) of the semi-spherical recessed part 6a of the liner 6 is made smaller than the radius (r) of the rib head bulb 4. The liner 6 is provided with a plurality of holding pieces 6b for holding the rib head bulb 4. An enlarged width part 6e having a rib head bulb abutting surface (k) is provided at the root side of the holding pieces 6b. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、機能不全に陥った人体の股関節部位を置換する人工股関節に関するものである。
【０００２】
【従来の技術】
人工股関節は一般的に、大腿骨髄腔内に挿入固定するステムと、該ステムの一方端部に設けたネックと、該ネックを嵌合する骨頭球と、該骨頭球を回動自在に受容する球状凹部を備えたライナーとからなる。
【０００３】
このような人工股関節では、ステムのネックがライナーと当たるところまでが関節可動域となり、これを超えて動こうとする荷重が加わった場合、骨頭球がライナーの半球状凹部から脱臼してしまう恐れがある。
【０００４】
関節可動域を大きくする試みとしては、ライナーにおける球状凹部の深さを比較的浅くするとともに、骨頭球を拘束する力を維持するため２つの把持片を有するものが提案されている。この２つの把持片は側面視で矩形状をなし、可動域を大きくする必要のない（例えば、体の横方向）方向の側に位置される。
【０００５】
【発明が解決しようとする課題】
しかしながら、より広い関節可動域を有する人工股関節が望まれていたにもかかわらず、上記従来技術の人工股関節は、ライナーにおける球状凹部の深さが骨頭球の半径よりも深かった。そのため、関節可動域が十分大きなものではなかった。
【０００６】
これは、骨頭球をライナー内に拘束するためには、ライナーにおける球状凹部の深さを骨頭球の半径よりも深くする必要があると考えられていたためであった。
【０００７】
【課題を解決するための手段】
上記課題を解決するため請求項１の人工股関節は、大腿骨髄腔内に挿入固定するステムと、このステムの一方端部に設けた円柱状または截頭円錐状のネックと、該ネックを嵌合するネック嵌合穴を備えた骨頭球と、該骨頭球を回動自在に受容する半球状凹部を備えたライナーとからなる人工股関節であって、前記ライナーの半球状凹部の深さを前記骨頭球の半径よりも浅くするとともに、前記ライナーに前記骨頭球を把持する複数の把持片を設け、且つ該把持片の根元側に骨頭球当接面を備える拡幅部を設けたことを特徴とする。
かかる構成によれば、半球状凹部の深さを骨頭球の半径よりも深くしたことにより関節可動域を非常に広くできる。
また、前記ライナーに前記骨頭球を把持する複数の把持片を設け、該把持片の根元側に拡幅部を設けたことにより、把持片と骨頭球との当接面積を広くすることができる。これは、骨頭球が回動してネックが把持片の根元部に当接するときに断面形状が円形であるネックとは干渉しない部分を拡幅部となし、この拡幅部を骨頭球との当接部として利用するものである。
これにより、把持片の機械的強度を補強するとともに、ライナーが骨頭球を保持する力を大きくできるので、半球状凹部の深さを骨頭球の半径よりも深くした場合でも、ライナーが骨頭球を安定的に保持することができる。
請求項２の人工股関節は、前記骨頭球が回動した際に前記拡幅部に備える骨頭球当接面の側縁が前記ネックと線接触することを特徴とする。
かかる構成によれば、前記拡幅部に備える骨頭球当接面の側縁が前記ネックと線接触するので応力を分散することができる。これにより、把持片の強度をさらに補強することができる。
加えて、把持片と骨頭球との当接面積をより大きくすることができる。
【０００８】
また、請求項３の人工股関節は、前記半球状凹部の深さをｓ、前記骨頭球の半径をｒ、前記ネック嵌合穴の開口径をＭとしたときに、ｒ−ｓ≧Ｍ／２の関係式を満たすことを特徴とする。
【０００９】
かかる構成によれば、把持片を設けていない方向において、少なくとも略１８０°の関節可動域を実現することができる。
【００１０】
また、請求項４の人工股関節は前記ライナーにおいて、前記把持片間の前記半球状凹部の開口縁を非面取縁としたことを特徴とする。
【００１１】
かかる構成によれば、ライナーと骨頭球との当接面積を大きくして、ライナーが骨頭球を保持する力をより大きくすることができる。
【００１２】
次に、請求項５の人工股関節は、腰骨の臼蓋に固定されて前記ライナーを保持するシェルを設け、前記シェルに前記把持片を保持する把持片保持部を設けたことを特徴とする。
【００１３】
かかる構成によれば、シェルの外表面積を大きくして骨とシェルとの固定力を大きくすることができる。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態を図により説明する。
【００１５】
図１乃至３に示すように、本人工股関節１は、大腿骨髄腔内に挿入固定するステム２と、このステム２の一方端部に設けた円柱状または截頭円錐状のネック３と、該ネック３を嵌合するネック嵌合穴４ａを備えた骨頭球４と、この骨頭球４を回動自在に受容する半球状凹部６ａと該骨頭球４を把持する複数の把持片６ｂとを備えたライナー６とからなる。
【００１６】
そして、図１（ｂ）に示すように、前記ライナー６における半球状凹部６ａの深さｓは、前記骨頭球４の半径ｒより小さく形成されている。
【００１７】
前記ライナー６は、前記半球状凹部６ａの深さｓ方向に対し略反対方向に突出して前記骨頭球４を把持する複数の把持片６ｂを備える。
【００１８】
この把持片６ｂに前記半球状凹部６ａと略同一球面を形成する骨頭球当接面６ｃを設けてある。さらに、前記把持片６ｂは、その根元側に骨頭球当接面６ｃ［図２（ｃ）参照］を備える拡幅部６ｅを設けてある。
この人工股関節１によれば、半球状凹部６ａの深さｓを骨頭球４の半径ｒよりも深くしたことにより関節可動域を非常に広くできる。
また、断面形状が円形であるネック３とは干渉しない部分［図２（ｃ）中の部分ｋ］を利用して、前記把持片６ｂの根元側に拡幅部６ｅを設けることで把持片６ｂと骨頭球４との当接面積を大きくしてある。
これにより、把持片６ｂの機械的強度を補強するとともに、ライナー６が骨頭球４を保持する力を大きくできるので、半球状凹部６ａの深さｓを骨頭球４の半径ｒよりも深くした場合でも、ライナー６が骨頭球４を安定的に保持することができる。
なお、前記骨頭球４が回動した際に前記骨頭球当接面ｋを備える拡幅部６ｅの側縁ｊとネック３とが線接触することが好ましい［図２（ｃ）参照］。
この場合、把持片６ｂへのネック３からの応力を分散することができる。これにより、把持片６ｂの強度をさらに補強することができる。加えて、把持片６ｅと骨頭球４との当接面積をより大きくすることができる。
【００１９】
また、上記人工股関節１は、前記半球状凹部６ａの深さをｓ、前記骨頭球４の半径をｒ、前記ネック嵌合穴４ａの開口径をＭとしたときに［図１（ｂ）参照］、ｒ−ｓ≧Ｍ／２の関係式を満たすことが好ましい。
【００２０】
例えばｒ−ｓ＝Ｍ／２のときに、図１（ｃ）に示すように、把持片６ｂを設けていない方向において前記半球状凹部６ａの開口縁６ｄとネック３とが当接するところまでネック３を回動させたときに、ネック３の軸と前記開口縁６ｄを含む平面がほぼ平行となる。したがって、前記の関係式を満たす場合には、少なくとも略１８０°の関節可動域を実現することができる。
また、図２に示すように、前記ライナー６は、前記半球状凹部６ａの開口縁６ｄが前記骨頭球４と当接するように、前記把持片６ｂ間の開口縁６ｄを非面取縁（ピン角縁）としている。
従来の人工股関節では、ネックとの摺動磨耗を防止する目的で、半球状凹部の開口縁に斜めの面取り面を形成していたが、面取りした分だけ、ライナーが骨頭球を保持する力が低下する。
しかし、前記人工股関節１によれば、骨頭球４を回動自在に受容する半球状凹部６ａの深さｓを前記骨頭球４の半径ｒより浅くしたことにより関節可動域が非常に広い。したがって、ネック３と前記開口縁６ｄが当接摺動することが少ない。そこで、前記半球状凹部６ａの開口縁６ｄが前記骨頭球４と当接するように、前記把持片６ｂ間の開口縁６ｄを非面取縁とした。これにより、半球状凹部６ａの壁面における骨頭球４との当接面積が大きくなり、ライナー６が骨頭球４を保持する力がより大きくなる。
なお、人工股関節１は、把持片６ｂの前記拡幅部６ｅと非面取縁とした開口縁６ｄのうち、どちらか一方のみを備えたものであってもよい。
【００２１】
次に、人工股関節１はシェル５を備えたものであってもよい。図３に示すように、シェル５は、前記ライナー６の把持片６ｂを保持する把持片保持部５ｂを備える。
【００２２】
従来の人工股関節は、ライナーの開口端部外側にリングを嵌合し、ライナーに備える把持片の外方への変形を抑制していたが、本人工股関節１では、ライナー６の半球状凹部６ａの深さｓを前記骨頭球４の半径ｒより浅くした形状であるので、ライナー６における半球状凹部６ａの開口側からリングを装着することができない。
【００２３】
そこで、シェル５に前記把持片保持部５ｂを形成し、把持片６ｂの外方への変形を抑制している。この把持片保持部５ｂは、シェル５の半球状外表面５ｃの面積を広くするので、骨とシェル５との固定力を増加させることができる。
前記シェル５は予め整形された臼蓋内に骨セメントやスクリュー等の手段で固定される。このシェル５は生体為害性のない金属材料、例えば、ステンレス、チタン、コバルトクロム合金などからなる。
前記ライナー６は、高分子材料、例えば、高分子ポリエチレンからなる。このライナー６はシェル５内に嵌合する。前記シェル５に係合用の小突起５ａが形成され、該小突起５ａが前記ライナー６の対向部位にくい込むことで両者は結合する。
また、図２に示すように前記ライナー６の把持片６ｂには、縦方向の複数の溝７が形成されている。この溝７には、シェル５の把持片保持部５ｂにおける対応部分に形成された小突起８が嵌合する。これにより、ライナー６の向きを微調整することができる。
【００２４】
また、別の実施形態として、前記ライナー６において、前記把持片６ｂを高分子材料より構成するとともに前記半球状凹部６ａの内面をセラミック材料で構成することにより、ライナー６の強度を低下させることなく、耐摩耗性を向上させることができる。
以上、本発明の実施形態を例示したが、本発明は上記実施例に限定されるものでなく、発明の目的を逸脱しない限り任意の形態とすることができることは云うまでもない。
【００２５】
【発明の効果】
以上のように本発明によれば、大腿骨髄腔内に挿入固定するステムと、このステムの一方端部に設けた円柱状または截頭円錐状のネックと、該ネックを嵌合するネック嵌合穴を備えた骨頭球と、該骨頭球を回動自在に受容する半球状凹部を備えたライナーとからなる人工股関節であって、前記ライナーの半球状凹部の深さを前記骨頭球の半径よりも浅くするとともに、前記ライナーに前記骨頭球を把持する複数の把持片を設け、且つ該把持片の根元側に骨頭球当接面を備える拡幅部を設けたことにより、関節可動域を非常に広くでき、また、把持片と骨頭球との当接面積を広くすることができる。これは、骨頭球が回動してネックが把持片の根元部に当接するときに、断面形状が円形であるネックとは干渉しない部分を拡幅部となし、骨頭球との当接部として利用するものである。
これにより、把持片の機械的強度を補強するとともに、ライナーが骨頭球を保持する力を大きくできるので、半球状凹部の深さを骨頭球の半径よりも深くした場合でも、ライナーが骨頭球を安定的に保持することができる。
また、前記把持片の拡幅部を、前記骨頭球が回動した際に前記拡幅部に備える骨頭球当接面の側縁が前記ネックと線接触するようにした場合、把持片へのネックからの応力を分散することができる。これにより、把持片の強度をさらに補強することができる。加えて、把持片と骨頭球との当接面積をより大きくすることができる。
【００２６】
また、前記半球状凹部の深さをｓ、前記骨頭球の半径をｒ、前記ネック嵌合穴の開口径をＭとしたときに、ｒ−ｓ≧Ｍ／２の関係式を満たすようにした場合、把持片を設けていない方向において、少なくとも略１８０°の関節可動域を実現することができる。
【００２７】
また、前記ライナーにおいて、前記把持片間の前記半球状凹部の開口縁を非面取縁とした場合、ライナーと骨頭球との当接面積を大きくして、ライナーが骨頭球を保持する力をより大きくすることができる。
【００２８】
さらに、腰骨の臼蓋に固定されて前記ライナーを保持するシェルを設け、前記シェルに前記把持片を保持する把持片保持部を設けた場合、シェルの外表面積を大きくして骨とシェルとの固定力を大きくすることができる。
【００２９】
【図面の簡単な説明】
【図１】（ａ）（ｂ）は本発明実施形態の人工股関節の要部破断正面図である。
【図２】図１の人工股関節を構成するライナーを示し、（ｂ）は底面図、（ａ）は（ｂ）のＡ−Ａ線断面図、（ｃ）は（ｂ）のＣ−Ｃ線断面図である。
【図３】図１の人工股関節を構成するシェルを示し、（ａ）は断面図、（ｂ）は側面図である。
【符号の説明】
１　人工股関節
２　ステム
３　ネック
４　骨頭球
４ａ　ネック嵌合穴
５　シェル
５ｂ　把持片保持部
５ｃ　半球状外表面
６　ライナー
６ａ　半球状凹部
６ｂ　把持片
６ｃ　骨頭球当接面
６ｄ　開口縁
６ｅ　拡幅部
ｓ　　（半球状凹部６ａの）深さ
ｒ　　（骨頭球４の）半径
Ｍ　　（ネック嵌合穴４ａの）開口径
ｊ　　（骨頭球当接面ｋの）側縁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an artificial hip joint for replacing a hip joint site of a dysfunctional human body.
[0002]
[Prior art]
A hip prosthesis generally includes a stem inserted into and fixed in the femoral medullary cavity, a neck provided at one end of the stem, a head ball for fitting the neck, and the head head rotatably received. And a liner having a spherical concave portion.
[0003]
In such a hip prosthesis, the area where the neck of the stem hits the liner becomes the range of motion of the joint, and if a load is applied to move beyond this, the head may be dislocated from the hemispherical recess of the liner. There is.
[0004]
As an attempt to increase the range of motion of the joint, a proposal has been made in which the depth of the spherical concave portion in the liner is relatively shallow, and which has two gripping pieces in order to maintain a force for restraining the headcap. The two gripping pieces have a rectangular shape in a side view, and are located on the side in a direction that does not need to have a large movable range (for example, in the lateral direction of the body).
[0005]
[Problems to be solved by the invention]
However, despite the desire for a hip prosthesis having a wider range of motion, the prior art hip prosthesis described above had a spherical recess in the liner that was deeper than the radius of the headcap. Therefore, the range of motion of the joint was not sufficiently large.
[0006]
This was because it was considered that the depth of the spherical recess in the liner had to be greater than the radius of the head ball in order to restrain the head head ball in the liner.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the artificial hip joint according to the first aspect of the present invention has a stem inserted and fixed in a femoral medullary cavity, a columnar or frustoconical neck provided at one end of the stem, and the neck is fitted. And a liner having a hemispherical recess for rotatably receiving the head ball, wherein the depth of the hemispherical recess of the liner is It is characterized in that it is shallower than the radius of the sphere, a plurality of gripping pieces are provided on the liner for gripping the head ball, and a widened portion having a head contact surface is provided on the base side of the holding piece. .
According to such a configuration, the movable range of the joint can be extremely widened by making the depth of the hemispherical concave portion larger than the radius of the headcap sphere.
Also, by providing a plurality of gripping pieces for gripping the head ball on the liner and providing a widened portion on the base side of the gripping piece, it is possible to increase the contact area between the holding piece and the head bone. This is because the part that does not interfere with the neck having a circular cross section when the neck abuts on the base of the gripping piece when the head turns and the neck abuts on the base of the gripping piece is the widened part. It is used as a part.
This reinforces the mechanical strength of the gripping pieces and increases the force with which the liner holds the head sphere, so that even when the depth of the hemispherical recess is made deeper than the radius of the head sphere, the liner holds the head sphere. It can be stably held.
The hip joint according to a second aspect is characterized in that a side edge of a head contacting surface provided in the widening portion makes line contact with the neck when the head turning is rotated.
According to this configuration, since the side edge of the head contacting surface provided in the widening portion is in line contact with the neck, stress can be dispersed. Thereby, the strength of the holding piece can be further reinforced.
In addition, the contact area between the grasping piece and the head cap can be increased.
[0008]
The artificial hip joint according to a third aspect of the present invention provides a hip joint, where s is the depth of the hemispherical recess, r is the radius of the head cap, and M is the opening diameter of the neck fitting hole. Is satisfied.
[0009]
According to such a configuration, a joint movable range of at least approximately 180 ° can be realized in the direction in which the gripping pieces are not provided.
[0010]
In the artificial hip joint according to a fourth aspect, in the liner, an opening edge of the hemispherical concave portion between the grip pieces is a non-chamfered edge.
[0011]
According to this configuration, the contact area between the liner and the head can be increased, and the force with which the liner holds the head can be increased.
[0012]
Next, the artificial hip joint according to claim 5 is characterized in that a shell fixed to the acetabulum of the hip bone and holding the liner is provided, and a gripping piece holding portion for holding the gripping piece is provided in the shell.
[0013]
According to such a configuration, it is possible to increase the outer surface area of the shell and increase the fixing force between the bone and the shell.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
As shown in FIGS. 1 to 3, the present artificial hip joint 1 includes a stem 2 inserted and fixed in a femoral medullary cavity, a columnar or frustoconical neck 3 provided at one end of the stem 2, A head ball 4 having a neck fitting hole 4a for fitting the neck 3; a hemispherical recess 6a for rotatably receiving the head ball 4; and a plurality of gripping pieces 6b for gripping the head ball 4 And a liner 6.
[0016]
Then, as shown in FIG. 1B, the depth s of the hemispherical concave portion 6a in the liner 6 is formed smaller than the radius r of the head ball 4.
[0017]
The liner 6 includes a plurality of gripping pieces 6 b that project in a direction substantially opposite to the depth s direction of the hemispherical concave portion 6 a and grip the head ball 4.
[0018]
The grasping piece 6b is provided with a head cap sphere contacting surface 6c which forms a substantially identical spherical surface with the hemispherical concave portion 6a. Further, the gripping piece 6b is provided with a widened portion 6e provided with a head cap abutting surface 6c (see FIG. 2C) on the base side.
According to the artificial hip joint 1, since the depth s of the hemispherical concave portion 6 a is made larger than the radius r of the head ball 4, the movable range of the joint can be greatly increased.
Further, by using a portion [part k in FIG. 2 (c)] that does not interfere with the neck 3 having a circular cross-sectional shape, a widened portion 6e is provided at the base side of the gripping piece 6b, so that the gripping piece 6b The contact area with the head ball 4 is increased.
Thereby, the mechanical strength of the gripping piece 6b is reinforced, and the force of the liner 6 for holding the head sphere 4 can be increased. Therefore, when the depth s of the hemispherical concave portion 6a is made larger than the radius r of the head sphere 4 However, the liner 6 can stably hold the head 4.
When the head ball 4 rotates, it is preferable that the side edge j of the widened portion 6e having the head head contact surface k and the neck 3 come into line contact [see FIG. 2 (c)].
In this case, the stress from the neck 3 to the gripping piece 6b can be dispersed. Thereby, the strength of the gripping piece 6b can be further reinforced. In addition, the contact area between the gripping piece 6e and the head ball 4 can be further increased.
[0019]
In addition, the artificial hip joint 1 has a depth s of the hemispherical concave portion 6a, a radius r of the caput sphere 4, and an opening diameter M of the neck fitting hole 4a [see FIG. ], It is preferable to satisfy the relational expression of r−s ≧ M / 2.
[0020]
For example, when r−s = M / 2, as shown in FIG. 1C, the neck is brought into contact with the opening edge 6 d of the hemispherical recess 6 a and the neck 3 in the direction in which the gripping piece 6 b is not provided. When the pivot 3 is rotated, the plane including the axis of the neck 3 and the opening edge 6d becomes substantially parallel. Therefore, when the above relational expression is satisfied, a joint movable range of at least approximately 180 ° can be realized.
As shown in FIG. 2, the liner 6 has a non-chamfered edge (pin) between the gripping pieces 6b so that the opening edge 6d of the hemispherical recess 6a abuts on the head ball 4. Corner edge).
In conventional hip prostheses, a slanted chamfered surface was formed at the opening edge of the hemispherical concave portion in order to prevent sliding wear with the neck. descend.
However, according to the artificial hip joint 1, the movable range of the joint is very wide because the depth s of the hemispherical concave portion 6 a that rotatably receives the head 4 is made smaller than the radius r of the head 4. Therefore, the neck 3 and the opening edge 6d are less likely to abut and slide. Therefore, the opening edge 6d between the gripping pieces 6b is made a non-chamfered edge so that the opening edge 6d of the hemispherical concave portion 6a abuts on the head ball 4. Thereby, the contact area between the hemispherical concave portion 6a and the wall of the head 4 is increased, and the force of the liner 6 holding the head 4 is further increased.
The artificial hip joint 1 may include only one of the widened portion 6e of the gripping piece 6b and the opening edge 6d which is a non-chamfered edge.
[0021]
Next, the artificial hip joint 1 may be provided with a shell 5. As shown in FIG. 3, the shell 5 includes a gripping piece holder 5b that holds the gripping piece 6b of the liner 6.
[0022]
In the conventional artificial hip joint, a ring was fitted to the outside of the open end of the liner to suppress the outward deformation of the gripping pieces provided on the liner. Is smaller than the radius r of the caput sphere 4, the ring cannot be mounted from the opening side of the hemispherical recess 6a in the liner 6.
[0023]
Therefore, the gripping piece holding portion 5b is formed on the shell 5 to suppress outward deformation of the gripping piece 6b. Since the gripping piece holding portion 5b increases the area of the hemispherical outer surface 5c of the shell 5, the fixing force between the bone and the shell 5 can be increased.
The shell 5 is fixed in a preformed acetabular lid by means such as bone cement or a screw. The shell 5 is made of a metal material having no harm to the living body, for example, stainless steel, titanium, cobalt chromium alloy, or the like.
The liner 6 is made of a polymer material, for example, a polymer polyethylene. This liner 6 fits inside the shell 5. A small projection 5a for engagement is formed on the shell 5, and the small projection 5a is inserted into the opposed portion of the liner 6 to join the two.
As shown in FIG. 2, a plurality of vertical grooves 7 are formed in the gripping piece 6b of the liner 6. A small projection 8 formed at a corresponding portion of the gripping piece holding portion 5b of the shell 5 is fitted into the groove 7. Thereby, the direction of the liner 6 can be finely adjusted.
[0024]
Further, as another embodiment, in the liner 6, the holding piece 6b is made of a polymer material and the inner surface of the hemispherical recess 6a is made of a ceramic material, so that the strength of the liner 6 is not reduced. , The abrasion resistance can be improved.
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can take any form without departing from the object of the invention.
[0025]
【The invention's effect】
As described above, according to the present invention, a stem to be inserted and fixed in the femoral medullary cavity, a columnar or frustoconical neck provided at one end of the stem, and a neck fitting to fit the neck An artificial hip joint comprising a head ball having a hole and a liner having a hemispherical recess for rotatably receiving the head ball, wherein the depth of the hemispherical recess of the liner is larger than the radius of the head ball. In addition, the liner is provided with a plurality of gripping pieces for gripping the head ball, and a widening portion having a head contact surface is provided at the base side of the gripping piece, so that the range of motion of the joint is greatly increased. The contact area between the gripping piece and the headcap can be increased. This is because when the head is rotated and the neck comes into contact with the base of the gripping piece, the part that does not interfere with the neck having a circular cross-section is the widened part and used as the contact part with the head. Is what you do.
This reinforces the mechanical strength of the gripping pieces and increases the force with which the liner holds the head sphere, so that even when the depth of the hemispherical recess is made deeper than the radius of the head sphere, the liner holds the head sphere. It can be stably held.
Further, the widened portion of the gripping piece, when the side edge of the head cap abutment surface provided in the widened portion is line-contacted with the neck when the head ball is rotated, from the neck to the gripping piece Can be dispersed. Thereby, the strength of the holding piece can be further reinforced. In addition, the contact area between the grasping piece and the head cap can be increased.
[0026]
Further, when the depth of the hemispherical recess is s, the radius of the head ball is r, and the opening diameter of the neck fitting hole is M, the relational expression of rs ≧ M / 2 is satisfied. In this case, it is possible to realize a joint movable range of at least approximately 180 ° in the direction in which the grip pieces are not provided.
[0027]
Further, in the liner, when the opening edge of the hemispherical concave portion between the gripping pieces is a non-chamfered edge, the contact area between the liner and the headcap is increased, and the force of the liner holding the headcap is increased. Can be larger.
[0028]
Further, when a shell fixed to the acetabulum of the lumbar bone and holding the liner is provided, and a gripping piece holding portion for holding the gripping piece is provided in the shell, the outer surface area of the shell is increased, and The fixing force can be increased.
[0029]
[Brief description of the drawings]
FIGS. 1 (a) and 1 (b) are fragmentary front views of an artificial hip joint according to an embodiment of the present invention.
2A and 2B show a liner constituting the hip joint prosthesis of FIG. 1, wherein FIG. 2B is a bottom view, FIG. 2A is a cross-sectional view taken along line AA of FIG. It is sectional drawing.
3A and 3B show a shell constituting the hip joint prosthesis of FIG. 1, wherein FIG. 3A is a sectional view and FIG. 3B is a side view.
[Explanation of symbols]
Reference Signs List 1 artificial hip joint 2 stem 3 neck 4 head cap sphere 4a neck fitting hole 5 shell 5b gripping piece holder 5c hemispherical outer surface 6 liner 6a hemispherical recess 6b gripping piece 6c head cap sphere contact surface 6d opening edge 6e widening portion s ( Depth r of hemispherical concave portion 6a Radius M (of head bone 4) Opening diameter j (of neck fitting hole 4a) Side edge (of head bone contact surface k)

Claims (5)

大腿骨髄腔内に挿入固定するステムと、該ステムの一方端部に設けた円柱状または截頭円錐状のネックと、該ネックを嵌合するネック嵌合穴を備えた骨頭球と、該骨頭球を回動自在に受容する半球状凹部を備えたライナーとからなる人工股関節であって、前記ライナーの半球状凹部の深さを前記骨頭球の半径よりも浅くするとともに、前記ライナーに前記骨頭球を把持する複数の把持片を設け、且つ該把持片の根元側に骨頭球当接面を備える拡幅部を設けたことを特徴とする人工股関節。A stem inserted and fixed in the femoral medullary cavity, a columnar or frustoconical neck provided at one end of the stem, a head cap ball having a neck fitting hole for fitting the neck, and the head A hip liner having a hemispherical recess for rotatably receiving a ball, wherein the hemispherical recess of the liner is made shallower than the radius of the head ball, and An artificial hip joint comprising: a plurality of gripping pieces for gripping a sphere; and a widened portion having a head contacting surface at a root side of the gripping piece. 前記骨頭球が回動した際に前記拡幅部に備える骨頭球当接面の側縁が前記ネックと線接触することを特徴とする請求項１記載の人工股関節。The artificial hip joint according to claim 1, wherein when the head ball rotates, a side edge of a head contact surface provided in the widened portion comes into line contact with the neck. 前記半球状凹部の深さをｓ、前記骨頭球の半径をｒ、前記ネック嵌合穴の開口径をＭとしたときに、ｒ−ｓ≧Ｍ／２の関係式を満たすことを特徴とする請求項１または２記載の人工股関節。When the depth of the hemispherical recess is s, the radius of the head ball is r, and the opening diameter of the neck fitting hole is M, the relational expression of rs ≧ M / 2 is satisfied. The artificial hip joint according to claim 1 or 2. 前記ライナーにおいて、前記把持片間の前記半球状凹部の開口縁を非面取縁としたことを特徴とする請求項１乃至３記載の人工股関節。4. The artificial hip joint according to claim 1, wherein an opening edge of the hemispherical concave portion between the grip pieces is a non-chamfered edge in the liner. 5. 腰骨の臼蓋に固定されて前記ライナーを保持するシェルを設け、該シェルに前記把持片を保持する把持片保持部を設けたことを特徴とする請求項１乃至４記載の人工股関節。The artificial hip joint according to any one of claims 1 to 4, wherein a shell fixed to the acetabulum of the hip bone and holding the liner is provided, and the shell is provided with a gripping piece holding portion for holding the gripping piece.
JP2002222205A 2002-07-30 2002-07-30 Prosthetic hip joint Pending JP2004057621A (en)

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JP2002222205A JP2004057621A (en) 2002-07-30 2002-07-30 Prosthetic hip joint

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007144129A (en) * 2005-09-23 2007-06-14 Benoist Girard Sas Prosthetic joints
JP2008529613A (en) * 2005-02-11 2008-08-07 ノヴァコヴスキ アンドレイ Hip prosthesis system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008529613A (en) * 2005-02-11 2008-08-07 ノヴァコヴスキ アンドレイ Hip prosthesis system
JP2007144129A (en) * 2005-09-23 2007-06-14 Benoist Girard Sas Prosthetic joints

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