Joint prosthesis

Claim 2

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, and said second component capable of being operatively connected to said second bone, wherein the connections of said first and second components to said first and second bones, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 3

The finger joint prosthesis of claim 1 wherein said finger joint is the metacarpophalangeal joint.

Claim 4

The finger joint prosthesis of claim 2 wherein said first bone is the proximal phalanx.

Claim 5

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, and the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, wherein the connection of said second component to said second bone is such as to provide in normal use for mechanically unrestrained relative movement between said second component and said second bone longitudinally of said bone.

Claim 6

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, and the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, wherein the connection of said second component to said second bone is such as to provide in normal use for mechanically unrestrained relative movement between said second component and said second bone longitudinally of said bone.

Claim 7

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, and wherein the connections of said first and second components to said first and second bones, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 8

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, and wherein the connections of said first and second components to said first and second bones, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 9

The finger joint of claim 5 wherein the connection of said second component to said second bone is such as to prevent relative rotation between said second component and said second bone about the longitudinal axis of said second bone.

Claim 10

A finger joint prosthesis for a metacarpophalangeal joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, and the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, and wherein the connections of said first and said second components to said first and said second bones, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 11

A finger joint prosthesis for a metacarpophalangeal joint of a first bone with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said first bone, said second component capable of being operatively connected to said second bone, and the connection of said first component to said first bone being such as to provide for relative rotation between said first component and said first bone about the longitudinal axis of said first bone, and wherein the connections of said first and said second components to said first and said second bones, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 12

A finger joint prosthesis for a metacarpophalangeal joint of a proximal phalanx with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said proximal phalanx, said second component capable of being operatively connected to said second bone, and the connection of said first component to said proximal phalanx being such as to provide for relative rotation between said first component and said proximal phalanx about the longitudinal axis of said proximal phalanx, and wherein the connections of said first and said second components to said proximal phalanx and said second bone, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 13

A finger joint prosthesis for a metacarpophalangeal joint of a proximal phalanx with a second bone comprising a first component, a second component in articulatory bearing relationship with said first component, said first component capable of being operatively connected to said proximal phalanx, said second component capable of being operatively connected to said second bone, and the connection of said first component to said proximal phalanx being such as to provide for relative rotation between said first component and said proximal phalanx about the longitudinal axis of said proximal phalanx, and wherein the connections of said first and said second components to said proximal phalanx and said second bone, respectively, is such as to provide in normal use for mechanically unrestrained relative movement between each of said components and its bone longitudinally of said bone.

Claim 14

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising: a first intramedullary plug adapted to be secured to the wall of the intramedullary canal of said first bone and provided with a longitudinal bore therein; a first component comprising a bearing portion and a stem extending therefrom, with said stem being disposed within said longitudinal bore such as to provide for relative rotation between said stem and said bore about the longitudinal axis of said bore; a second component comprising a bearing portion and a stem extending therefrom for insertion with the intramedullary canal of said second bone; with said bearing portions of said first and second components being in mutual articulatory engagement; and wherein the connection of said second component to said second bone is such as to provide in normal use for mechanically unrestrained relative movement between said second component and said second bone longitudinally of said bone.

Claim 15

A finger joint prosthesis for a finger joint of a first bone with a second bone comprising: a first intramedullary plug adapted to be secured to the wall of the intramedullary canal of said first bone and provided with a longitudinal bore therein; a first component comprising a bearing portion and a stem extending therefrom, with said stem being disposed within said longitudinal bore such as to provide for relative rotation between said stem and said bore about the longitudinal axis of said bore; a second component comprising a bearing portion and a stem extending therefrom for insertion with the intramedullary canal of said second bone; with said bearing portions of said first and second components being in mutual articulatory engagement; and wherein the connection of said second component to said second bone is such as to provide in normal use for mechanically unrestrained relative movement between said second component and said second bone longitudinally of said bone.

Claim 16

The finger joint prosthesis of claim 9 wherein said finger joint is the metacarpophalangeal joint.

Claim 17

The finger joint prosthesis of claim 10 wherein said first bone is the proximal phalanx.

Claim 18

An articulating metacarpophalangeal joint prosthesis comprising: a first component comprising a stem for insertion within the intramedullary canal of a first bone, a neck portion at one end of said stem and a protuberant head portion on said neck portion, said head portion being of generally cylindrical shape with rounded ends and with the longitudinal axis of said head portion being perpendicular to the plane of articulation of said prosthesis; and a second component comprising a stem for insertion within the intramedullary canal of a second bone and a socket portion at one end of said stem including inside walls for defining a socket cavity bounded at one end by a concave bearing surface with which said head portion is capable of snugly fitting, said socket portion being dimensioned and configured such that the dimension of the socket cavity along the longitudinal axis of the second component is greater than the diameter of the head portion along the longitudinal axis of the first component, said socket portion including an aperture in the end thereof facing away from said second bone, said inside walls including a volar and a dorsal wall, said volar wall having a longitudinal slot, means for mechanically restraining said second component from rotating about the longitudinal axis of said second bone, said inside walls of said socket cavity extending axially of said second component from said bearing surface to the peripheral edge of said aperture such that said socket cavity communicates with said longitudinal slot of said volar wall and said aperture, said head portion of said first component capable of being received by and slidingly movable within said socket cavity generally along the longitudinal axis of the second component, with said neck portion of said first component capable of being located in said slot in said volar wall of said socket portion as said joint prosthesis is flexed, the configuration of said socket cavity being such so as to permit in normal use mechanically unrestrained relative radio-ulnar rocking of said two components when said joint prosthesis is substantially extended and also to permit mechanically unrestrained relative separation of said head portion and said concave bearing portion longitudinally of said second component.

Claim 19

An articulating metacarpophalangeal joint prosthesis comprising: a first component comprising a stem for insertion within the intramedullary canal of a first bone, a neck portion at one end of said stem and a protuberant head portion on said neck portion, said head portion being of generally cylindrical shape with rounded ends and with the longitudinal axis of said head portion being perpendicular to the plane of articulation of said prosthesis; and a second component comprising a stem for insertion within the intramedullary canal of a second bone and a socket portion at one end of said stem including inside walls for defining a socket cavity bounded at one end by a concave bearing surface with which said head portion is capable of snugly fitting, said socket portion being dimensioned and configured such that the dimension of the socket cavity along the longitudinal axis of the second component is greater than the diameter of the head portion along the longitudinal axis of the first component, said socket portion including an aperture in the end thereof facing away from said second bone, said inside walls including a volar and a dorsal wall, said volar wall having a longitudinal slot, means for mechanically restraining said second component from rotating about the longitudinal axis of said second bone, said inside walls of said socket cavity extending axially of said second component from said bearing surface to the peripheral edge of said aperture such that said socket cavity communicates with said longitudinal slot of said volar wall and said aperture, said head portion of said first component capable of being received by and slidingly movable within said socket cavity generally along the longitudinal axis of the second component, with said neck portion of said first component capable of being located in said slot in said volar wall of said socket portion as said joint prosthesis is flexed, the configuration of said socket cavity being such so as to permit in normal use mechanically unrestrained relative radio-ulnar rocking of said two components when said joint prosthesis is substantially extended and also to permit mechanically unrestrained relative separation of said head portion and said concave bearing portion longitudinally of said second component.

Claim 20

The finger joint prosthesis of claim 12 wherein said socket portion is dimensioned and configured such that said head portion is contiguous to the dorsal and volar walls of said socket portion so as to prevent rotation of said head portion relative to said socket portion about the longitudinal axis of said second bone.

Claim 21

The finger joint prosthesis of claim 12 wherein said first bone is the proximal phalanx and said second bone is the metacarpus.

Claim 22

The finger joint prosthesis of claim 14 wherein said prosthesis includes a first intramedullary plug adapted to be secured to the wall of the intramedullary canal of the proximal phalanx and provided with a longitudinal bore therein, with said stem portion of said first component being rotatably received within said longitudinal bore.

Claim 23

The finger joint prosthesis of claim 12 wherein said head portion of said first component is made of metal or metal alloy and said socket cavity is defined by the walls of a removable plastic bearing insert contained within said socket portion of said second component.

Claim 24

The finger joint prosthesis of claim 16 wherein said first bone is the proximal phalanx and said second bone is the metacarpus.

Claim 25

The finger joint prosthesis of claim 16 wherein said plastic bearing insert is provided with lip means at the end of said insert facing away from said second bone, with said lip means reducing the size of said aperture so as to prevent dislocation of said prosthesis as a result of abnormal relative radio-ulnar rocking of said two components or abnormal relative separation of said two components longitudinally of said second component.

Claim 26

The finger joint prosthesis of claim 12 wherein said head portion of said first component is capable of freely sliding through said aperture to enter said socket cavity.

Claim 27

An articulating metacarpophalangeal joint prosthesis wherein the first bone is the proximal phalanx and the second bone is the metacarpus comprising: a first component comprising a stem for insertion within the intramedullary canal of a first bone, a neck portion at one end of said stem and a protuberant head portion on said neck portion, with said head portion being of generally cylindrical shape with rounded ends and with the longitudinal axis of said head portion being perpendicular to the plane of articulation of said prosthesis; and a second component comprising a stem for insertion within the intramedullary canal of a second bone and a socket portion at one end of said stem having walls defining a socket cavity bounded at one end by a concave bearing surface with which said head portion is capable of snugly fitting, the dimension of the socket cavity along the longitudinal axis of the second component being greater than the diameter of the head portion, with said socket cavity extending longitudinally from said bearing surface to an aperture in the end of said socket portion facing away from said second bone, with the volar wall of said socket portion being provided with a longitudinal slot communicating with said socket cavity and said aperture, with said head portion of said first component being received by and slidingly movable within said socket cavity generally along the longitudinal axis of the second component, with said neck portion of said first component being located in said slot in said volar wall of said socket portion as said joint prosthesis is flexed, and with said second component being mechanically restrained from rotating about the longitudinal axis of said second bone, whereby the shape of said socket cavity is such as to permit in normal use mechanically unrestrained relative radio-ulnar rocking of said two components when said joint prosthesis is substantially extended and mechanically unrestrained relative separation of said two components longitudinally of said second component, and is also such as to prevent, by the contact of said head portion against the dorsal and volar walls of said socket portion, rotation of said head portion of said first component relative to said socket portion of said second component about the longitudinal axis of said second bone, wherein said prosthesis includes a first intramedullary plug adapted to be secured to the wall of the intramedullary canal of the proximal phalanx and provided with a longitudinal bore therein, with said stem portion of said first component being rotatably received within said longitudinal bore, and wherein said prosthesis includes a second intramedullary plug adapted to be secured to the wall of the intramedullary canal of the metacarpus and provided with a longitudinal bore therein, with said stem portions of said first and second components both being longitudinally slidably received in said bores in said first and second intramedullary plugs, respectively.

Claim 28

An articulating metacarpophalangeal joint prosthesis wherein the first bone is the proximal phalanx and the second bone is the metacarpus comprising: a first component comprising a stem for insertion within the intramedullary canal of a first bone, a neck portion at one end of said stem and a protuberant head portion on said neck portion, with said head portion being of generally cylindrical shape with rounded ends and with the longitudinal axis of said head portion being perpendicular to the plane of articulation of said prosthesis; and a second component comprising a stem for insertion within the intramedullary canal of a second bone and a socket portion at one end of said stem having walls defining a socket cavity bounded at one end by a concave bearing surface with which said head portion is capable of snugly fitting, the dimension of the socket cavity along the longitudinal axis of the second component being greater than the diameter of the head portion, with said socket cavity extending longitudinally from said bearing surface to an aperture in the end of said socket portion facing away from said second bone, with the volar wall of said socket portion being provided with a longitudinal slot communicating with said socket cavity and said aperture, with said head portion of said first component being received by and slidingly movable within said socket cavity generally along the longitudinal axis of the second component, with said neck portion of said first component being located in said slot in said volar wall of said socket portion as said joint prosthesis is flexed, and with said second component being mechanically restrained from rotating about the longitudinal axis of said second bone, whereby the shape of said socket cavity is such as to permit in normal use mechanically unrestrained relative radio-ulnar rocking of said two components when said joint prosthesis is substantially extended and mechanically unrestrained relative separation of said two components longitudinally of said second component, and is also such as to prevent, by the contact of said head portion against the dorsal and volar walls of said socket portion, rotation of said head portion of said first component relative to said socket portion of said second component about the longitudinal axis of said second bone, wherein said prosthesis includes a first intramedullary plug adapted to be secured to the wall of the intramedullary canal of the proximal phalanx and provided with a longitudinal bore therein, with said stem portion of said first component being rotatably received within said longitudinal bore, and wherein said prosthesis includes a second intramedullary plug adapted to be secured to the wall of the intramedullary canal of the metacarpus and provided with a longitudinal bore therein, with said stem portions of said first and second components both being longitudinally slidably received in said bores in said first and second intramedullary plugs, respectively.

Claim 29

A finger joint prosthesis comprising: a proximal intramedullary plug adapted to be secured to the wall of the intramedullary canal of the proximal bone and provided with a longitudinal bore therein; a distal intramedullary plug adapted to be secured to the wall of the intramedullary canal of the distal bone and provided with a longitudinal bore therein; a proximal component comprising a bearing portion and a steam extending therefrom; and a distal component comprising a bearing portion and a stem extending therefrom, with said stems of said proximal and distal components being in normal use received for mechanically unrestrained longitudinal sliding movement in said bores in said proximal and distal intrameduallary plugs, respectively, and with said bearing portions of said proximal and distal components being in mutual articulatory engagement.

Claim 30

A finger joint prosthesis comprising: a proximal intramedullary plug adapted to be secured to the wall of the intramedullary canal of the proximal bone and provided with a longitudinal bore therein; a distal intramedullary plug adapted to be secured to the wall of the intramedullary canal of the distal bone and provided with a longitudinal bore therein; a proximal component comprising a bearing portion and a steam extending therefrom; and a distal component comprising a bearing portion and a stem extending therefrom, with said stems of said proximal and distal components being in normal use received for mechanically unrestrained longitudinal sliding movement in said bores in said proximal and distal intrameduallary plugs, respectively, and with said bearing portions of said proximal and distal components being in mutual articulatory engagement.

Claim 31

The finger joint prosthesis of claim 21 wherein said finger joint is the metacarpophalangeal joint, said proximal bone is the metacarpus and said distal bone is the proximal phalanx.

Claim 32

The finger joint prosthesis of claim 22 wherein said prosthesis contains means to prevent rotation of at least one of said components relative to the intramedullary plug receiving it about the longitudinal axis of the bone to which said plug is secured.

Claim 33

The finger joint prosthesis of claim 23 wherein rotation of only one of said components relative to the intramedullary plug receiving it about the longitudinal axis of the bone to which said plug is secured is prevented.

Claim 34

The finger joint of claim 24 wherein said rotation preventing means comprises one or more longitudinal fins projecting from the exterior of the stem of the component whose rotation is prevented and corresponding longitudinal slots to receive said fins in the wall of the longitudinal bore in the intramedullary plug with which said component is slidingly engaged.

Claim 35

The finger joint prosthesis of any of claims 24 or 25 wherein rotation of said proximal component relative to said proximal intramedullary plug about the longitudinal axis of the metacarpus is prevented.

Claim 36

The finger joint prosthesis of any of claims 21 or 22 wherein said proximal and distal intramedullary plugs both terminate, at their distal and proximal ends, respectively, with flanges adapted to seat against the cortical surfaces of said proximal and distal bones, respectively, and to distribute upon said surfaces a substantial portion of compressive forces exerted in use upon said prosthesis.

Claim 37

The finger joint prosthesis of claim 27 wherein each of said intramedullary plugs is tapered so as to have decreasing cross-sectional area with increasing distance from the flange-terminated end of said plug.

Claim 38

The finger joint prosthesis of claim 21 wherein said intramedullary plugs are made of plastic and said stems of said proximal and distal components are made of metal or metal alloy.

Claim 39

The finger joint prosthesis of claim 29 wherein the bearing portion of one of said components presents a convex metal or metal alloy bearing surface to the other component, and the bearing portion of said other component includes a removable plastic bearing insert which presents a concave bearing surface to, and contacts in use, said convex bearing surface.

Claim 40

The finger joint prosthesis of claim 30 wherein said finger joint is the metacarpophalangeal joint, said proximal bone is the metacarpus, said distal bone is the proximal phalanx, and said convex bearing surface is presented by the bearing portion of said distal component.