Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1992-11-05
1994-11-01
Isabella, David
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
623 21, A61F 232, A61F 242
Patent
active
053604490
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an artificial joint mechanism for use in reconstructing joints such as wrists, finger joints, etc., and is designed for use between fixtures anchored in the bone and/or tissue on each side of the joint.
BACKGROUND OF THE INVENTION
Previously known joint mechanisms for finger joints and wrists, for instance, generally comprise a pad of resilient material which has been secured in suitable manner between fixtures anchored in the bone and/or tissue on each side of the natural joint which has been removed--see for instance U.S. Pat. application Ser. No. 406,586 filed Sep. 13, 1989 by Per-Ingvar Branemark and issued on Nov. 5, 1991 as U.S. Pat. No. 5,062,851 entitled Anchoring Element For Supporting a Joint Mechanism of a Finer or Other Reconstructed Joint.
However, in practice such a resilient pad has proved to have certain limitations both as to general strength and also since it lacks certain joint functions--controllable bending, lateral movement, particularly in the case of wrists, effective "locking" when under load, e.g. when the palm of the hand is used as support, etc.
SUMMARY OF THE INVENTION
The object of the invention is to eliminate the above-mentioned difficulties and drawbacks in the type of artificial joint mechanisms described above and to achieve a joint mechanism which is simple in design but still permits stable bending positions and lateral movement, and is also vastly superior to previously known constructions from the point of view of wear.
This is solved according to the invention primarily in that it comprises a male part with at least one joint pin protruding from a base plate and having a substantially arc-shaped joint surface, like a sector of a cylinder, and a female part with a recess corresponding to the joint pin and having a substantially arc-shaped defining surface, like a sector of a cylinder, for contact with said joint surface in the male part.
According to a preferred embodiment of the invention the joint surface of the male part comprises two part surfaces separated by a central recess, said part surfaces being aligned with each other along the centre line of the base plate and extending from said recess towards the short sides of the base plate.
Suitably each part joint surface is provided with a first joint portion located close to the recess, running substantially parallel to the base plate and then continuing into a second joint portion running with slightly downward inclination towards the short sides of the base plate.
The first part joint surfaces in the male part thus cooperate with the recess in the female part, acting as a joint at bending movements, while the desired lateral movement is achieved by cooperation of the second, inclined joint portions in the male part with the recess in the female part.
According to another embodiment of the invention-the second joint portions of the part join surfaces may, depending on anatomical criteria, have different angles of inclination (.alpha.and .beta.) in relation to the base plate.
The angles of inclination between the base plate and the second joint portions may suitably lie between 0.degree. and 50.degree. . The joint portions are arc-shaped and suitably define a sector angle of between 10.degree. and 350.degree..
According to yet another embodiment of the invention the second joint portions of the male part may have a different, optional profile, and be arranged to cooperate with differently profiled recesses in the female part.
According to the invention the male part and the female part are secured against displacement along their cooperating surfaces. This is suitably achieved by means of bosses protruding from the joint surfaces or contact surfaces of the male and/or female parts and arranged to cooperate with corresponding recesses in respective parts or by the lateral ends of either the male or the female part being arranged to grip the short ends of the male or female part.
According to another embodiment of the invention the actual bending movemen
REFERENCES:
patent: 3991425 (1976-11-01), Martin et al.
patent: 4216549 (1980-08-01), Hillberry et al.
patent: 4301553 (1981-11-01), Noiles
patent: 4383337 (1983-05-01), Volz et al.
patent: 4714473 (1987-12-01), Bloebaum
patent: 4784661 (1988-11-01), Beckenbaugh et al.
patent: 4944758 (1990-07-01), Bekki et al.
patent: 5007933 (1991-04-01), Sidelootham et al.
patent: 5152794 (1992-10-01), Dividson
Isabella David
Medevelop AB
LandOfFree
Artificial joint mechanism for reconstructing human joints does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Artificial joint mechanism for reconstructing human joints, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Artificial joint mechanism for reconstructing human joints will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1799977