Patents by Inventor Michael J. Pappas
Michael J. Pappas has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20100241237Abstract: An orthopedic joint replacement has first and second joint components that can be placed in load-bearing articulation with one another. The first joint component has first and second convex spherical condylar segments defining first and second radii. The second joint component has a spherical first concave condylar segment with a radius equal to the radius of the first convex spherical condylar segment. The second joint component also has a non-spherical second concave condylar segment. The first convex spherical condylar segment of the first joint component is in congruent contact with the first spherical concave condylar segment of the second joint component. The second spherical convex condylar segment of the first joint component is in line contact with the non-spherical concave condylar segment of the second joint component.Type: ApplicationFiled: September 21, 2009Publication date: September 23, 2010Applicant: BUECHEL-PAPPAS TRUSTInventor: Michael J. Pappas
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Patent number: 7485147Abstract: The tibial component of a prosthetic ankle joint including a tibial component, a talar component, and an intermediate sliding plastic bearing, with the tibial component including a depending peripheral wall that surrounds and is spaced from the plastic bearing and is intended to reduce rubbing of the plastic bearing against tissue which would produce wear particles that lead to the formation of bone cysts. The depending peripheral wall of the tibial component is intended to reduce such possible abrasions by at least partially shielding the plastic bearing from the surrounding tissue.Type: GrantFiled: February 3, 2005Date of Patent: February 3, 2009Inventors: Michael J. Pappas, Frederick F. Buechel
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Patent number: 7014660Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. The anterior extreme of the control arm includes a removable stop for limiting anterior movement of the bearing relative to the tibial component.Type: GrantFiled: April 9, 2003Date of Patent: March 21, 2006Assignee: Biomedical Engineering Trust IInventors: John B. Fenning, Michael J. Pappas
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Patent number: 7008454Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. Anterior and posterior extremes of the control arm include stops for limiting anterior and posterior movement of the bearing relative to the tibial component. At least one of the stops is removable relative to the control arm to facilitate implantation.Type: GrantFiled: September 24, 2003Date of Patent: March 7, 2006Assignee: Biomedical Engineering Trust IInventors: John B. Fenning, Michael J. Pappas
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Publication number: 20040204765Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. Anterior and posterior extremes of the control arm include stops for limiting anterior and posterior movement of the bearing relative to the tibial component. At least one of the stops is removable relative to the control arm to facilitate implantation.Type: ApplicationFiled: September 24, 2003Publication date: October 14, 2004Applicant: Biomedical Engineering Trust IInventors: John B. Fenning, Michael J. Pappas
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Patent number: 6797005Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion.Type: GrantFiled: August 2, 2002Date of Patent: September 28, 2004Assignee: Biomedical Engineering TrustInventor: Michael J. Pappas
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Patent number: 6764516Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.Type: GrantFiled: June 7, 2002Date of Patent: July 20, 2004Assignee: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Publication number: 20030195634Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. The anterior extreme of the control arm includes a removable stop for limiting anterior movement of the bearing relative to the tibial component.Type: ApplicationFiled: April 9, 2003Publication date: October 16, 2003Applicant: Biomedical Engineering Trust IInventors: John B. Fenning, Michael J. Pappas
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Patent number: 6548104Abstract: A physical vapor deposition apparatus and process are provided for providing a highly smooth shiny coating to a substrate. The apparatus includes a chamber with a fixture for mounting the components to be coated. The fixture is arranged such that the surfaces to be coated define a “dark side” that faces away from the source of ion bombardment. With this arrangement, heavier multiple ions will travel past the surface to be coated. Lighter single ions will be drawn more readily to the oppositely charged surface to be coated, and hence will undergo a non-linear travel path for deposition onto the component.Type: GrantFiled: March 12, 2001Date of Patent: April 15, 2003Inventor: Michael J. Pappas
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Publication number: 20030009229Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion.Type: ApplicationFiled: August 2, 2002Publication date: January 9, 2003Applicant: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Patent number: 6491726Abstract: A prosthetic replacement knee joint includes a tibial component, a femoral component, a bearing and a control arm. The tibial component has a superior bearing surface and a conical recess extending into the superior bearing surface. The bearing has an inferior surface slidably engaged with the superior surface of the tibial component and formed with a dovetailed groove therein. The bearing also has a concave superior surface. A notch extends into the posterior extreme of the bearing. The femoral component has a pair of convex arcuate condyles in articular bearing engagement with the superior surface of the bearing. The femoral component also includes a posterior notch having a minor medial-lateral width at the inferior surface of the femoral component and a major width at more superior locations on the femoral component. The control arm has a conical bearing rotatable positioned in the conical recess of the tibial component.Type: GrantFiled: February 28, 2001Date of Patent: December 10, 2002Assignee: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Patent number: 6475241Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.Type: GrantFiled: February 28, 2001Date of Patent: November 5, 2002Assignee: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Publication number: 20020156535Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.Type: ApplicationFiled: June 7, 2002Publication date: October 24, 2002Applicant: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Patent number: 6344043Abstract: A set of instruments (10) is provided for use in the preparation of a natural bone of a condylar joint for receiving prosthetic components both in primary and revision surgery. To illustrate the invention and use thereof, reference is made to the preparation of a natural femur (F) in a knee joint. The set of instruments (10) includes an anterior-posterior femoral resection guide (12) having a guide aperture (36) formed therethrough, and a set of collets (14; 16; 18A; 18B) formed to detachably mount to the guide aperture (36). The set of collets (14; 16; 18A; 18B) includes a drill guide (14), a reamer sleeve (16), and a plurality of different size reamer bushings (18A; 18B).Type: GrantFiled: April 19, 2000Date of Patent: February 5, 2002Inventor: Michael J. Pappas
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Publication number: 20010034555Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.Type: ApplicationFiled: February 28, 2001Publication date: October 25, 2001Inventor: Michael J. Pappas
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Publication number: 20010034554Abstract: A prosthetic replacement knee joint includes a tibial component, a femoral component, a bearing and a control arm. The tibial component has a superior bearing surface and a conical recess extending into the superior bearing surface. The bearing has an inferior surface slidably engaged with the superior surface of the tibial component and formed with a dovetailed groove therein. The bearing also has a concave superior surface. A notch extends into the posterior extreme of the bearing. The femoral component has a pair of convex arcuate condyles in articular bearing engagement with the superior surface of the bearing. The femoral component also includes a posterior notch having a minor medial-lateral width at the inferior surface of the femoral component and a major width at more superior locations on the femoral component. The control arm has a conical bearing rotatable positioned in the conical recess of the tibial component.Type: ApplicationFiled: February 28, 2001Publication date: October 25, 2001Inventor: Michael J. Pappas
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Publication number: 20010023662Abstract: A physical vapor deposition apparatus and process are provided for providing a highly smooth shiny coating to a substrate. The apparatus includes a chamber with a fixture for mounting the components to be coated. The fixture is arranged such that the surfaces to be coated define a “dark side” that faces away from the source of ion bombardment. With this arrangement, heavier multiple ions will travel past the surface to be coated. Lighter single ions will be drawn more readily to the oppositely charged surface to be coated, and hence will undergo a non-linear travel path for deposition onto the component.Type: ApplicationFiled: March 12, 2001Publication date: September 27, 2001Inventor: Michael J. Pappas
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Patent number: 6238434Abstract: A knee joint prosthesis is provided. The prosthesis includes a femoral component for mounting to the distal end of a femur, a tibial component for mounting to the resected proximal end of the tibia and a bearing disposed between the femoral and tibial components. The tibial component includes a superior bearing surface with a recess extending distally into the bearing surface. The bearing includes an inferior bearing surface for engagement on the superior bearing surface of the tibial component. Additionally, the bearing includes a projection that is rotatably engaged in the recess of the tibial component. Rotation of the bearing relative to the tibial component is limited by a stop extending from the superior bearing surface of the tibial component. The stop is engaged in a slot formed in the inferior surface of the bearing. The slot is concentric about the rotational axis and extends through an arc consistent with the desired maximum range of rotation.Type: GrantFiled: August 5, 1999Date of Patent: May 29, 2001Assignee: Biomedical Engineering Trust IInventor: Michael J. Pappas
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Patent number: 6224632Abstract: A tibia fixturing device comprises a metal tray formed with annularly spaced recesses in its underside at a depth of at least about 1.5 mm and from which a stem depends for axial insertion into a tibia conical cavity. The stem has a circular cylindrical portion proximal the tray and a conical portion distal the tray. Fins radially extend from the stem cylindrical portion and penetrate the tibia to provide some torsional resistance. Axially extending channels are formed about the stem periphery which channels have bottom surfaces parallel to the stem axis to provide further torsional resistance. The channels are arranged to not interlock with the cement in the axial direction to permit the cement to separate first from the device during axial removal of the device from the bone. The fins have inclined edges distal the tray and inclined radial outer edges to align and center the stem to the bone cavity edge.Type: GrantFiled: September 20, 1996Date of Patent: May 1, 2001Assignee: Biomedical Engineering Trust IInventors: Michael J. Pappas, Frederick F. Buechel
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Patent number: 6206926Abstract: The prosthetic knee joint is provided for resisting valgus-varus movements. The joint includes a femoral component having a superior bone engaging surface and an inferior bearing surface. A posterior notch extends anteriorly into the posterior end of the femoral component. The prosthetic knee joint further includes a tibial component having an inferior bone engaging surface and a superior bearing surface. A plastic bearing is disposed between the femoral and tibial components. An inferior surface of the plastic bearing is in bearing engagement with the superior surface of the tibial component. A superior bearing surface of the plastic bearing is in articular bearing engagement with the bearing surface of the femoral component. The bearing includes a post projecting proximally from the superior surface. The post is slidably received in the posterior notch of the femoral component and resists valgus-varus moments imposed upon the joint.Type: GrantFiled: November 13, 1998Date of Patent: March 27, 2001Assignee: Biomedical Engineering Trust IInventor: Michael J. Pappas