Fixed bearing joint endoprosthesis
AssigneeBiomedical Engineering Trust I
InventorMichael J. Pappas
Life of this patent
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Abstract
Joint endoprostheses, disclosed in the context of a total knee prosthesis, incorporate a first element for rigid connection to a first bone, the first element having an articulating surface; a second element for rigid connection to a second bone, the second element having a bearing surface which engages the articulating surface; wherein the engagement of the articulation surface with the bearing surface at any degree of relative rotation therebetween is reflected by a substantially constant contact configuration, the relative rotation of the device being accompanied by displacement of the bones toward and away from each other.
Claims10
A prosthesis for permitting articulation of adjacent bones, said prosthesis comprising:
- a first element for rigid connection to a first bone, said first element having an articulating surface defined by a compound surface of revolution having a primary load bearing section;
- a second element for rigid connection to a second bone, said second element having a central longitudinal axis and having a bearing surface for engagement with said articulating surface, said bearing surface of said second element being a Helicoid surface defined by rotating and translating said compound surface of revolution around and along the central longitudinal axis of said second element;
- and
- wherein said articulation of said adjacent bones includes flexion, extension and relative rotation, wherein at any position of relative rotation the engagement of said articulating surface and said bearing surface defines a contact configuration which is substantially constant for all degrees of relative rotation of said first and second elements and wherein all of the contact of said bearing surface for all said degrees of relative rotation is with said compound surface of revolution, said relative rotation being accompanied by displacement of said bones toward and away from each other.
A prosthesis for permitting articulation of adjacent bones, comprising:
- a first element for rigid connection to a first bone, said first element having an articulating surface;
- a second element for rigid connection to a second bone, said second element having a central longitudinal axis and having a bearing surface formed on said second element for engagement with said articulating surface;
- and
- wherein the bearing surface of said second element is a Helicoid surface defined by the simultaneous translation and rotation of a generating surface around and along the central longitudinal axis of said second element.
Dependencies are inferred from the claim text.