Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1989-12-27
1992-07-28
Isabella, David
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
A61F 234
Patent
active
051337630
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention in the first place concerns a joint prosthesis, in particular a hip-joint prosthesis, at least consisting of an organ comprising a ball and an organ comprising a cup-shaped element for reception of said ball wherein the cup-shaped element at least consists of a first and a second part which are connected with each other and wherein the sphere-sector surface-shaped part of the contact surface between both parts of the cup-shaped element and the ball in the complete prosthesis equals to a solid angle of at most 180 degrees, of which the top coincides the heart of the ball.
BACKGROUND OF THE INVENTION
In the above given description of a joint-prosthesis is indicated that the applied ball may in no case be completely enclosed in the cup-shaped element. For that reason the sphere-sector surface-shaped part of the contact surface has been limited to at the most the surface of a half ball.
In the European patent application 0 053 794 a cup-shaped element is described, for use in a joint prosthesis as indicated above, whereby in the upper-inner edge of the cup-shaped element a recess is present for taking up a ring. The cup-shaped element is manufactured from a ceramic material while the ring is made of a plastic deformable material. The ring serves to protect both the ball and the cup of said prosthesis in case of occurrence of sub-luxation.
In some occasions however, depending on the condition of the patient, a certain hampering of luxation is necessary allthough luxation should remain possible in order to prevent damage to the bone material in which the cup is fixed using the usual cementing procedures or with mechanical means.
SUMMARY OF THE INVENTION
The present invention has as a goal to provide a joint prosthesis of the type described in which the cup-shaped element has such a form that luxation is prevented to a large extent, allthough principally luxation may still occur in cases of extreme mechanical load which otherwise would lead to damage of the bone parts to which the elements of such prosthesis are connected.
According to the invention the joint prosthesis, in particular a hip joint prosthesis is for that purpose characterized in that of the cup-shaped element said first part and said second part contain click-joint elements which can cooperate by forming a click-joint which allows free mutual rotation of both mentioned parts after connection thereof and wherein said second part consists of a ring of appropriate form which can be interchangeably connected with a recess in the inner-upper edge of the first part of said cup-shaped element while the inner side of the ring and the inner side of the first part of the cup-shaped element connect without difference of level and the height of the ring is greater than the depth of the recess over at least part of its circumference.
By applying click-joint elements to the second and first parts, which are shaped in such way that after connection of the first to the second part a mutual rotation of both parts is allowed, an optimal positioning of the second part within the first part can be achieved.
The application of the click-joint elements implies that it will have to be possible to elastically deform preferably at least one of the click-joint elements. For that reason at least one of the click-joint elements or that part of the organ of which the element is a part, will in general be made of synthetic material.
As the second part in the joint prosthesis of the organ containing a cup-shaped element is a part with a special form for prevention of luxation, the second part of the hip joint prosthesis can, after fitting of the complete hip joint prosthesis organ, be rotated in such way that in accordance with the on the spot established farthest positions an optimal position of the second part is reached. After this mentioned optimal position has been reached the second part can be further maintained in this position.
In particular seperately working means are provided for the mutual fixation of the said second part
REFERENCES:
patent: 4241463 (1980-12-01), Khovaylo
patent: 4623352 (1986-11-01), Oh
patent: 4624674 (1986-11-01), Pappas et al.
patent: 4770658 (1988-09-01), Geremakis
patent: 4784663 (1988-11-01), Kenna
patent: 4813959 (1989-03-01), Cremascoli
Isabella David
Jaskiewicz Edmund M.
LandOfFree
Joint prosthesis does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Joint prosthesis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Joint prosthesis will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1684853