Other

Minnesota Mining and Manufacturing Company

Joint Medical Products Corporation

Osteonics Corp.

Osteotech of Virginia

Mark R Forte

Douglas G Noiles

Alex Khowaylo

Edward B MacMahon

Ewald Schloesser

David A Sonstegard

A resurfacing type of total knee prosthesis is disclosed which also provides a posterior stabilization function over the entire range of flexion. The knee prosthesis provides primary or supplementary posterior stabilization of the reconstructed knee joint by means of a unique mechanical cam/follower mechanism, which is integrated within the medial and lateral distal condyles of the femoral component to provide functional compensation for lost, resected or incompetent posterior cruciate ligaments or to work in conjunction with surgically retained viable or questionably viable cruciate ligament structures of the reconstructed knee joint. The invention extends to prostheses including a hinge connection that defines a posterior stabilization construction separate from that defined by the condyles. One embodiment of the invention extends individually to the posterior stabilizing hinge assembly.

Mechanically linked hinged total knee prosthesis

An acetabular cup includes a plurality of bone receiving depressions on its convex exterior surface. Bone, obtained from the femoral head of the hip to be replaced, is morselized and then compressed in the bone receiving depressions. The dense bone on the exterior surface of the acetabular cup serves as a graft and acts as a new subchondral bone. The bony fixation technique may be used on other prosthesis (e.g., shoulders, and the like). Variations in size, shape, depth and distribution of the recesses can be modified to make this form of fixation applicable to all forms of bone/prosthesis fixation.

Bony fixation and support of a prosthesis

A resurfacing type of total knee prosthesis is disclosed which also provides a posterior stabilization function over the entire range of flexion. The knee prosthesis provides primary or supplementary posterior stabilization of the reconstructed knee joint by means of a unique mechanical cam/follower mechanism, which is integrated within the medial and lateral distal condyles of the femoral component to provide functional compensation for lost, resected or incompetent posterior cruciate ligaments or to work in conjunction with surgically retained viable or questionably viable cruciate ligament structures of the reconstructed knee joint. The invention extends to prostheses including a hinge means that defines a posterior stabilization means separate from that defined by the condyles. One embodiment of the invention extends individually to the posterior stabilizing hinge means.

Total knee prosthesis with resurfacing and posterior stabilization

An implant for a hip or other joint is provided. Briefly stated, a intramedullary stem is provided having flexibility which is comparable to that of the surrounding bone. A bore is disposed in the stem portion with the stem wall thickness uniform or varying from the proximal end to the distal end, depending upon the amount of flexibility desired. This flexibility therefore distributes the loading forces from the joint more uniformly over the supporting cortical bone with the result that bone degeneration from stress shielding is minimized or eliminated.

Prosthesis with flexible intramedullary stem

A posterior stabilized knee prosthesis includes a femoral component formed by medial and lateral condyles, each having an anterior portion, a distal portion and a posterior portion, an anterior patella flange interconnecting the anterior portions of the medial and lateral condyles in parallel, spaced apart relation, and a cam member connected to the lateral surface of the posterior portion of the medial condyle and to the medial surface of the posterior portion of the lateral condyle and having a convex cam surface; a tibial component including a multi-radius medial and lateral tibial plateau bearing surfaces for receiving the medial and lateral condyles for rolling and sliding movement thereon, and a follower member positioned between the medial and lateral tibial plateau bearing surfaces for receiving the cam surface for rotational and sliding movement thereon; the cam surface being in contact with the follower member for substantially the entire flexion range of the knee, with the cam surface being in congruent contact with the follower member from approximately the end of posterior rollback at approximately 25.degree.-30.degree. of flexion to full-flexion; and the cam surface being in sliding contact with the follower member to provide the posterior rollback of the convex cam surface during flexion, starting at approximately -6.degree. (hyperextension) of flexion and ending at approximately 25.degree.-30.degree. of flexion; and the cam member and follower member having heights which are not greater than the thickness of the condyles so as not to extend beyond the inner surfaces thereof.

Totally posterior stabilized knee prosthesis

An implantable prosthetic hip joint includes an acetabular shell component for securing the prosthetic joint within the acetabulum socket of a biological hip bone, and including an inner spherical surface, an open circumferential end and a plurality of apertures extending therethrough at the open circumferential end; an annular wedge retaining ring positioned within the acetabular shell component, the ring including a plurality of counter-sunk apertures therein in alignment with the apertures extending through the acetabular shell component; a hemispherical asymmetric socket insert in the acetabular shell component and including an outer spherical dome engaging the inner spherical surface of the acetabular shell component, an open circumferential end having an asymmetric lip thereat and an inner spherical surface, the outer spherical dome including a tapered surface for engagement with the wedge retaining ring; a femoral component having a femoral stem connected with the femur of a person and a femoral head connected with the femoral stem and received in the inner spherical surface of the socket insert for ball-and-socket movement therein; and a plurality of screws inserted through the apertures of the wedge retaining ring and acetabular shell component and threadedly received within the hip bone so as to force the wedge retaining ring inwardly to compress the socket insert and retain the same within the acetabular shell component in a fixed position, and loosening of these screws permits universal rotational adjustment of the socket insert in the acetabular shell component.

Implantable acetabular prosthetic hip joint with universal adjustability

A system of three femoral components with the same distal diameter, for a hip joint prosthesis, includes an intramedullary stem for each femoral component, each stem having a distal end, a proximal end, a lateral side extending between the distal and proximal ends, and a medial side extending between the distal and proximal ends opposite to the lateral side, the medial side at a proximal portion of the stem having a concave curvature; a neck mounted to the proximal end of each stem; a femoral ball component mounted at the proximal end of each neck, each femoral ball component having an articular center; the medial sides at the proximal portions of all of the stems substantially being in exact alignment only when the intramedullary stems are offset in the lengthwise direction from each other, thereby permitting a consistent fit within a given femur and achieving different positions of the articular centers of the femoral ball components, since the medial sides at the proximal ends of all of the stems are given distal diameter have the same radius of curvature, and with the stems incorporating the same proximal-medial radius of curvature for a given distal diameter reflecting consecutive larger proximal-transverse stem widths for addressing a consistent, light mechanical press-fit into femurs of different physiological sizes.

Femoral component of a hip joint prosthesis

An implantable prosthetic hip joint includes an acetabular shell component for securing the prosthetic joint within the acetabulum socket of a biological hip bone, and including an inner spherical surface, an open circumferential end and a plurality of apertures extending therethrough at the open circumferential end; an annular wedge retaining ring positioned within the acetabular shell component, the ring including a plurality of counter-sunk apertures therein in alignment with the apertures extending through the acetabular shell component; a hemispherical asymmetric socket insert in the acetabular shell component and including an outer spherical dome engaging the inner spherical surface of the acetabular shell component, an open circumferential end having an asymmetric lip thereat and an inner spherical surface, the outer spherical dome including a tapered surface for engagement with the wedge retaining ring; a femoral component having a femoral stem connected with the femur of a person and a femoral head connected with the femoral stem and received in the inner spherical surface of the socket insert for ball-and-socket movement therein; and a plurality of screws inserted through the apertures of the wedge retaining ring and acetabular shell component and threadedly received within the hip bone so as to force the wedge retaining ring inwardly to compress the socket insert and retain the same within the acetabular shell component in a fixed position, and loosening of these screws permits universal rotational adjustment of the socket insert in the acetabular shell comoponent.

An implant for a hip or other joint is provided. Briefly stated, an intramedullary stem is provided having flexibility which is comparable to that of the surrounding bone. A bore is disposed in the stem portion with the stem wall thickness uniform or varying from the proximal end to the distal end, depending upon the amount of flexibility desired. This flexibility therefore distributes the loading forces from the joint more uniformly over the supporting cortical bone with the result that bone degeneration from stress shielding is minimized or eliminated.

An implantable prosthetic hip joint includes a spherical acetabular shell articulating within the acetabulum socket of a pelvis and including a spherical shell portion defining an inner spherical surface, and a skirt portion extending downwardly therefrom; a femoral head including a femoral head and a stem secured to the femur of the person; a hemispherical bearing insert mounted in the spherical shell portion for receiving the femoral head for ball-and-socket movement therein; a retractable split annular rim positioned below the bearing insert and including a central opening which permits passage of the femoral head therethrough, and an inner ring surface, the rim including concentric threads along the outer surface thereof which releasably mate with concentric threads along the inner surface of the skirt portion to secure the rim in a first position spaced from the bearing insert and a second position at least substantially in contact with the bearing insert, with an annular recess being defined between the bearing insert and the split rim when the split rim is secured in the first position; and a split spring ring which retains the femoral head in the bearing insert, and includes an annular inner arcuate surface biased into engagement with the femoral head and being movable in the annular recess when the split rim is secured in the first position and being held by the inner ring surface when the split rim is secured in the second position.

Bipolar femoral implant

A prosthetic knee joint is provided having an extended position, an intermediate position, and a flexed position. The motion of the joint includes a minor segment from the extended position to the intermediate position, and a major segment from the intermediate position to the flexed position. The center of pressure between the femoral component and the tibial component moves rearward on the tibia during the minor segment. During the major segment, the joint flexes about an axis of rotation with the bearing surfaces on the femoral and tibial components being in congruent engagement. The distal surface of the femoral component includes two rails for engagement with a patellar prosthesis. The contour of the rails is either a straight line or a concave curve to provide line contact between the rails and the patellar prosthesis. In certain embodiments, the patellar prosthesis has a saddle-shaped surface so that the prosthesis and each of the rails can make contact over an area extending along the length of the rail.

Prosthetic joint

Knee and patellar prosthesis

An acetabular cup assembly includes a metal shell component and a plastic bearing insert capable of assembly interoperatively, the metal shell component first being secured in position within an acetabulum and then the plastic bearing insert being receivable within the shell component, first at a preliminary axial position for ascertainment of the circumferential position of the bearing insert and the orientation of the bearing face of the bearing insert relative to the shell component and then at a fully-seated axial position wherein the bearing insert is permanently captured in the shell component, the bearing insert being readily withdrawn from the preliminary axial position for circumferential repositioning to attain appropriate orientation of the bearing face prior to capturing the bearing insert within the shell component.

Acetabular cup assembly with selective bearing face orientation

A patellar flange for a knee joint prosthesis comprising a curved base and a pair of condylar runners, one of said condylar runners being attached to each lateral side of the base and extending outwardly anteriorly therefrom diverging from each other and converging to the base superiorly and a femoral knee joint prosthesis containing the flange.

Patellar flange and femoral knee-joint prosthesis

A combination of tools and methods used to prepare a socket in a femur for receiving a femoral prosthesis including a rasp having a cutting portion and a pilot post portion, a handle assembly with a chuck for releasably engaging the pilot post portion to facilitate working the rasp into a femur, and a cutter device adapted to be journaled on the pilot post and power driven to surface the calcar adjacent the socket. After a socket is formed in the femur by use of a rasp and handle assembly, the rasp is left in the socket, the handle assembly is removed, and the cutter is journaled over the pilot post and rotated by a drive apparatus.

Growing community of inventors

Pine Brook, NJ, United States of America

Mark R Forte