Prosthesis with interlocking fixation and providing reduction of stress shielding
OwnerFrederick F. Buechel, Michael J. Pappasinventors
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Abstract
A prosthesis including a load receiving surface for receiving a load applied to the prosthesis, a first surface provided with interlocking means for interlocking fixation of a first bone portion and for transferring a portion of the applied load to the first bone portion, and a second surface which is smooth to cause an increase in the portion of the applied load applied to the first bone portion to increase the stress produced therein thereby substantially reducing stress shielding in the first bone portion and resorption of bone therein.
Claims17
A joint prosthesis for a bone having a resected proximal end, said prosthesis comprising a stem for mounting in the bone, said stem having opposed proximal and distal ends and an exterior surface extending therebetween, said exterior surface including an anterior face, a posterior face, a medial face and a lateral face, proximal areas of at least the anterior and posterior faces being provided with interlocking means for bone ingrowth interlocking fixation to the bone, remaining portions of said anterior and posterior faces being substantially smooth for preventing bone ingrowth interlocking fixation to the bone, such that the interlocking means on the anterior and posterior faces defines a distal boundary adjacent the smooth portions thereof, said interlocking means being disposed such that the distance between the distal boundary of the interlocking means and the medial face of the stem increases at further distances from the proximal end of the stem, whereby the disposition of the interlocking means is operative to transfer loads to portions of the bone adjacent the resected proximal end of the bone for preventing stress shielding thereof.
A joint prosthesis comprising:
- a stem having opposed proximal and distal ends, opposed anterior and posterior faces and opposed lateral and medial faces;
- a collar disposed on the proximal end of said stem, said collar including anterior and posterior collar portions extending respectively outwardly anteriorly and posteriorly of said stem, said collar having a pair of access slots extending generally in a lateral to medial direction a predetermined distance inwardly into said anterior and posterior collar portions, said slots providing access to bone resection means to facilitate resectioning of prosthesis-bone fixation interfaces between said stem and a bone in which said prosthesis is implanted;
- and
- said stem including a proximal portion provided with interlocking means for bone ingrowth interlocking fixation to said bone, said interlocking means defining a distal boundary spaced from said proximal end, proximal areas of at least the anterior and posterior faces being provided with interlocking means and with portions of said prosthesis adjacent the distal boundary being smooth for preventing bone ingrowth interlocking fixation, the interlocking means being disposed such that the distance between the boundary and the medial face increases at further distances from the proximal end.
Dependencies are inferred from the claim text.