Bristol-myers Squibb Compnay

Zimmer Gmbh

Other

New York Society for the Relief of the Ruptured and Crippled,

John N Insall

Peter Stanley Walker

Mark Alan Heldreth

Robert A Hodorek

William Rohr

Audrey M Beckman

Jonathan Blamey

Kyoko Ohkuni

Roy Yoshikazu Hori

Vince Webster

Steve Zawadski

Michael Wadcock

Steven A Zawadzki

Albert H Burstein

Steven B Haas

Clayton R Miller

Linggawati Tanamal

James M Carr

Audrey Patmore

David J Krueger

Christopher McLean

Pascal Poilvache

Giles R Scuderi

Shawn Elliott McGinley

A femoral knee implant includes a fourth compartment of articulation. The superior posterior articulating surface is achieved by first increasing the thickness of the superior posterior condylar portion of the femoral component to widen the superior posterior edge of the posterior condyle. Second, the newly created surface at the superior posterior condyle is smoothly rounded to provide an articular surface with no sharp changes in the surface contours. In one embodiment, the fourth articular compartment of this invention is provided in a one piece femoral design. In another embodiment, it is provided as a modular addition to an existing prior art femoral component. In another embodiment, the fourth compartment is combined with a posterior stabilized (PS) TKR design that includes a tibial post and cooperating femoral cam characterized by low engagement of the cam on the spine.

Four compartment knee

An orthopaedic knee component for implanting within a proximal tibia includes a tibial tray with a proximal tibial plateau and a projection extending generally orthogonal to the tibial plateau. The tibial tray also includes a distally extending stem. A bearing is coupled with the tibial plateau and has an articular bearing surface for engagement with a femoral component. The bearing is rotationally movable between a first rotational limit and a second rotational limit about an axis extending generally orthogonal to the tibial plateau. The bearing has a backing surface engaging the tibial plateau which is sized and shaped such that the backing surface is substantially entirely supported by the tibial plateau at any position during rotational movement between the first rotation limit and the second rotational limit.

Tibial knee component with a mobile bearing

The prosthesis comprises a femoral component (2) having at least one substantially spheroidal condylar bearing surface (10,11), a tibial component (6) including a tibial platform (20), and a plastics meniscal component (7) located between the condylar bearing surface (10,11) an the tibial component (6) and being slidable on the platform (20). The meniscal component (7) is retained on a guide (23) upstanding from the platform (20). The guide (23) includes a post (24) and a cap (25) which is a snap-fit in a recess (30) in the meniscal component (7). The guide (23) is slidable in a track (32) within the meniscal component (7) so that movement of the meniscal component (7) in the anterior/posterior direction (A-P) is limited by impingement of the meniscal component (7) on the post (24) and/or on a rail member (21) projecting from the surface of the tibial platform (20). To install the prosthesis, a femur (1) is resected to provide a base for receiving the femoral component (2), which is retained in the resected femur by pins (3). The tibia (4) is resected to provide a flat base into which the tibial component (6) is fixed by a stem (5).

Prosthesis for knee replacement

The invention provides means for evaluating the fit of a knee replacement prosthesis on a resected tibial surface. A provisional instrument for this purpose includes a positioning tray having a peripheral profile corresponding to that of the tibial platform of the prosthesis, the tray having an upper surface and an under surface which is substantially flat and free from projections and the tray having a plurality of holes for receiving pins for temporarily attaching the positioning tray in a desired position on the resected tibial surface. Also disclosed is a jig for guiding, drilling and broaching operations, the jig having an aperture which is shaped to guide the broach. In addition, the invention includes a tibial broach which includes a hollow body having an upper end and a lower end and having an anvil at its upper end, an interior face and a posterior face which slopes downwardly towards a lower end, the posterior face having a series of teeth which are formed in the hollow body, such that bone cut by the teeth as the broach is driven into an intramedullary canal of a tibia passes into the hollow body.

Evaluating the fit of an orthopaedic implant

A notch/chamfer guide has chamfer and trochlear recess cutting slots and a notch, corresponding to the intercondylar box of a femoral implant, with a removable notch slot attachment. With the notch slot attachment assembled to the cutting guide adjacent the notch, blade receiving slots are defined between the notch slot attachment and the inside walls of the notch. The slots provide control to the saw blade to prevent the blade from angling away from the notch walls and making imprecise cuts. The notch slot attachment is removable to allow easy access to the notch area so that a manual instrument such as an osteotome can be used for final removal of the notch bone and to facilitate the use of an oscillating saw in the chamfer slots of the guide. A U-shaped notch is provided for cutting a trochlear recess that will lie behind the anterior portion of the implanted knee component to receive the backside of the patellar track of the implant. The outside surface of the guide, corresponding to the distal aspect of the femur, is angled so that it is parallel to the guide surface which guides the cut forming the top of the intercondylar notch. This parallel external surface of the guide acts as a visual reference such that when a saw blade being used to cut the sides of the intercondylar notch is held perpendicular to the external surface it will intersect at a right angle the cut forming the top of the intercondylar notch.

Notch/chamfer guide

A set of instruments and a surgical technique facilitate precise orientation of the femoral implant. Precision is aided by decoupling the determination of A/P placement, valgus angle, and external rotation into three discrete steps. In this way, a surgeon's full concentration can be directed to each element of placement and fine adjustments can readily be made to each. An Epicondylar Guide is configured to ease referencing external rotation from the epicondyles. The narrow elongated guide is easily alignable with the epicondyles when it is placed on the flat distal cut. A Posterior Reference/Rotation Guide can be attached to the Epicondylar Guide to check the rotation relative to the intact posterior condyles to confirm the epicondylar setting. A slot in the guide guides a saw blade to cut a corresponding slot in the distal femur. An A/P Cutting Guide has a fin that fits in the slot cut in the distal femur. With the A/P Cutting Guide engaging the slot and resting on the flat distal cut, external rotation is fixed and the A/P Cutting Guide can only move in the A/P direction. By moving the guide in the A/P direction, fine adjustments in the flexion and extension gaps can be made. Once A/P placement is set, the anterior and posterior cuts are made through slots in the guide. In an alternative embodiment, the Epicondylar Guide defines a linear track attached to the distal femur and the A/P Cutting Guide includes a slot configured to engage the linear track.

Apparatus and method for knee implantation

A condylar replacement knee prosthesis has a tibial platform adapted for attachment to a resected tibia, a femoral component adapted for attachment to a resected femur and a plastics meniscal component interposed between the femoral and tibial components. The upper surface of the meniscal component is shaped to correspond with bearing surfaces of the femoral component. The meniscal component is guided for sliding movement in an anterior-posterior direction on the tibial component and for limited rotational movement, the rotational movement being centred about an axis which is displaced medially from the anterior-posterior centre line of the tibial component.

Prostheses for knee replacement

A femoral prosthesis is disclosed comprising a bicondylar femoral component (41), a tibial component (72) and at least one meniscal component (42) interposed between the femoral and tibial components, the femoral component including a pair of condylar surfaces (46) separated by a patella bearing surface (44) which in use provides a normal anatomical patella lever arm, the condylar surfaces being shaped for substantial conformity with corresponding tibial bearing surfaces (47) of the meniscal component or components over the entire range of normal flexion.

Knee prosthesis with femoral, tibial conformity

A tibial knee component includes reference marks to which a surgeon can reference the location of the point of contact between the tibial component and a femoral knee component. In one embodiment of the invention, the femoral component also includes reference marks to aid the surgeon in determining the contact point and to aid in orienting the knee in specific predetermined degrees of flexion.

Knee position indicator

A patella cutting clamp comprises a pair of jaw members joined together in scissors-like relation for pivotal movement relative to each other about a pivot axis intermediate their ends. Each jaw member has a handle portion extending in one direction from the pivot axis and a jaw portion extending in the other direction. The jaw portions have edges facing each other that are shaped for engagement with opposite borders of a patella. Teeth along the patella-gripping edges grip and hold the patella firmly. Saw guide slots in the jaw portions lying in a common plane guide the saw when the saw cut is made. A patella elevator member is attached to the jaw members for movement along the pivot axis and has a platform portion adapted to engage the anterior aspect of the patella. A mechanism is provided for establishing and maintaining a predetermined position of the elevator member relative to the jaw members and thereby positioning the patella at a predetermined position relative to the saw guide slots. Another mechanism holds the jaw members in an adjusted position relative to each other with the jaw portions engaging and holding the patella.

Patella cutting clamp

A box-like recess between the condylar portions of the femoral component has a transverse convexly curved cam follower portion at the posterior extremity of a superior wall which engages a concave cam surface at the inferior portion of the posterior surface of a tibial post that extends up from the plateau surface of the tibial component into the recess. The camming action between the cam follower and cam surface forces the zones of contact between the condylar portions of the femoral component and concavities in the tibial component posteriorly as the leg approaches full flexion, thereby increasing the range of flexion without interference between posterior surfaces of the femur and the tibial component and preventing anterior dislocation of the femur. The plateau of the tibial component slopes inferiorly and posteriorly, also to increase the range of flexion without interference.

Posteriorly stabilized total knee joint prosthesis

A knee joint prosthesis comprises a femoral component having laterally spaced-apart condylar portions shaped to match generally the shapes of the condylar surfaces of the femur and a tibial component having a plate-like platform portion which includes laterally spaced-apart concavities in the external surface, each of which receives and supports one of the condylar portions of the femoral component in all positions of the leg. The femoral component has a box-like intercondylar portion interconnecting the condylar portions and defining an intercondylar recess which receives a post that extends upwardly from the tibial component. At and near full extension of the leg, any tendency for posterial dislocation of the femur results in engagement between the anterior surfaces of the post and recess to prevent posterial dislocation of the femoral component relative to the tibial component. At leg flexions approaching full flexure, the posterior surface of the recess engages the posterior surface of the post in the event of a tendency toward anterial dislocation of the femur, thereby preventing anterial dislocation. Large antero-posterior movements and dislocation are prevented in all leg positions by engagement between surfaces of the post and recess. The post and recess are shaped and dimensioned to permit essentially normal rotation and lateral angulation of the prosthetic joint in all positions.

Growing community of inventors

New York, NY, United States of America

John N Insall