Spherical kinematic joint
First Claim
1. An improved spherical joint prosthesis for providing three degrees of rotational movement between two bones, comprising:
- a first component for engaging one of said two bones and providing internally a first seat;
a second component for engaging the other of said two bones and including a neck and a spherical head;
a bearing insert comprising a generally semi-hemispherically shaped primary bearing segment having a forward portion and a separate generally annularly shaped, radially split collar having a rearward portion, said primary bearing segment and said collar cooperatively providing internally a second seat having an opening for receiving said head;
said forward and rearward portions provided respectively with complementarily shaped mating means, said mating means form said primary bearing segment and said collar into a sub-assembly whereupon engagement of said complementarily shaped mating means allows said collar to expand radially outwardly permitting said head to be inserted through said opening and once said head is received in said second seat said collar is able to contract radially inwardly without separation from said primary segment prior to and during assembly with said first and second component;
said bearing insert and said first component provided with cooperative retaining means for retaining said bearing insert within said first seat upon insertion of said bearing insert into said first component; and
upon said head being received within said second seat with said neck extending through said opening, said bearing insert for being received and retained within said first seat with said first component confining said head within said second seat whereby said rotational movement between said two bones is permitted, said bearing insert providing an overlap angle for preventing dislocation of said head from said bearing insert during said rotational movement.
1 Assignment
0 Petitions
Accused Products
Abstract
An improved spherical kinematic joint which allows ease and convenience of assembly and disassembly, particularly assembly, by providing a plurality of substantially physically distinct bearing inserts in a sub-assembly such that the bearing inserts are effectively a unitary structure for the purpose of assembly and disassembly but which bearing segments expand easily with low manual force during assembly and disassembly of the various bearing insert embodiments from the head and/or cavity or spherical seat in another joint element or member, such as for example in the prosthetic joint embodiments, an acetabular cup. Further, such ease of assembly and disassembly can be accomplished while retaining great dislocation and separation resistance and can be accomplished in a manner which does not introduce significant axial play.
204 Citations
11 Claims
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1. An improved spherical joint prosthesis for providing three degrees of rotational movement between two bones, comprising:
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a first component for engaging one of said two bones and providing internally a first seat; a second component for engaging the other of said two bones and including a neck and a spherical head; a bearing insert comprising a generally semi-hemispherically shaped primary bearing segment having a forward portion and a separate generally annularly shaped, radially split collar having a rearward portion, said primary bearing segment and said collar cooperatively providing internally a second seat having an opening for receiving said head;
said forward and rearward portions provided respectively with complementarily shaped mating means, said mating means form said primary bearing segment and said collar into a sub-assembly whereupon engagement of said complementarily shaped mating means allows said collar to expand radially outwardly permitting said head to be inserted through said opening and once said head is received in said second seat said collar is able to contract radially inwardly without separation from said primary segment prior to and during assembly with said first and second component;said bearing insert and said first component provided with cooperative retaining means for retaining said bearing insert within said first seat upon insertion of said bearing insert into said first component; and upon said head being received within said second seat with said neck extending through said opening, said bearing insert for being received and retained within said first seat with said first component confining said head within said second seat whereby said rotational movement between said two bones is permitted, said bearing insert providing an overlap angle for preventing dislocation of said head from said bearing insert during said rotational movement. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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2. An improved spherical hip joint prosthesis for receiving and retaining a spherical head having a neck during three degrees of relative rotational movement between said prosthesis and said spherical head, comprising:
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a first component for engaging a hip bone and providing internally a first seat; a bearing insert comprising a primary bearing segment having a forward portion and a separate generally annularly shaped, radially split collar having a rearward portion, said primary bearing segment and said collar cooperatively providing internally a second seat having an opening for receiving said spherical head;
said forward and rearward portions provided respectively with complementarily shaped mating means, said mating means forms said primary bearing segment and said collar into a sub-assembly whereupon engagement of said complementarily shaped mating means allows said collar to expand radially outwardly permitting said head to be inserted through said opening and once said head is received in said second seat, said collar is able to contract radially inwardly without separation from said primary segment prior to and during assembly with said first and second components;said bearing insert and said first component provided with cooperative retaining means for retaining said bearing insert within said first seat upon insertion of said bearing insert into said first component; and upon said head being received within said second seat with said neck extending through said opening, said bearing insert for being received and retained within said first seat with said first component confining said head within said second seat whereby said rotational movement between said two bones is permitted, said bearing insert providing an overlap angle for preventing dislocation of said head from said bearing insert during said rotational movement.
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Specification