Implant with reinforced resorbable stem

Claim 2

An anchor for a bone joint implant adapted to be inserted in a cavity defined by a bone and having a given cross section for affixing the implant to the bone without substantial motion of the implant relative to the bone after affixation, the anchor comprising: a nonresorbable core sized for insertion in the cavity and having a cross section sufficiently smaller than the cross section of the cavity so that contact between the bone and the core is prevented; and a resorbable sleeve applied to the core and having a size so that it tightly engages the cavity in the bone to thereby immovably secure the anchor to the bone.

Claim 3

The anchor of claim 1 further comprising: a permanent, articulating implant component having a surface to contact the bone and a surface to interact with a cooperating surface of a joint; and a securing means for joining the articulating implant component to the core.

Claim 4

The anchor of claim 2 wherein the securing means comprises a taper lock.

Claim 5

The anchor of claim 1 wherein the core is formed of a metal alloy selected from a group consisting of titanium-6-aluminum-4-vanadium, cobalt-chromium, and stainless steel.

Claim 6

The anchor of claim 1 wherein the resorbable sleeve is formed from a material selected from a group consisting of polymers of glycolic acid, polymers of lactic acid, polyamides of α-amino acids, polyglycolic acid, polylactic acid-polyglycolic acid copolymers, polyetheretherketone (PEEK), polyorthoester, polycarbonate, calcium hydroxyapatite and tricalcium phosphate.

Claim 7

The anchor of claim 1 wherein the anchor is part of a prosthetic hip.

Claim 8

An implant for a bone joint comprising: a component defining an operative portion of the joint, the component having an interface facing generally away from the joint and adapted to be placed into intimate contact with an actual bone to which the component is to be fixed, at least part of the interface including means promoting bony ingrowth when the interface is in intimate contact with the natural bone; and an anchor connected to the component and adapted to be inserted in a cavity in the bone for orienting and immovably fixing the component to the bone immediately upon implantation, the anchor comprising: a relatively high strength, permanent core having a cross section sufficiently smaller than the cross section of the cavity so that contact between the bone and the core is prevented; an outer layer applied to the core and shaped so that the layer, upon implantation, securely engages a bone surface defining the cavity, the layer being constructed of biodegradable material so that it resorbs after a period of time and thereby vacates a portion of the cavity; and whereby, after the layer has resorbed, the core of the anchor is spaced from and out of contact with the bone surface defining the cavity so that substantially no load transference between the bone surface defining the cavity and the core takes place.

Claim 9

An implant for a bone joint comprising: a component defining an operative portion of the joint, the component having an interface facing generally away from the joint and adapted to be placed into intimate contact with an actual bone to which the component is to be fixed, at least part of the interface including means promoting bony ingrowth when the interface is in intimate contact with the natural bone; and an anchor connected to the component and adapted to be inserted in a cavity in the bone for orienting and immovably fixing the component to the bone immediately upon implantation, the anchor comprising: a relatively high strength, permanent core having a cross section sufficiently smaller than the cross section of the cavity so that contact between the bone and the core is prevented; an outer layer applied to the core and shaped so that the layer, upon implantation, securely engages a bone surface defining the cavity, the layer being constructed of biodegradable material so that it resorbs after a period of time and thereby vacates a portion of the cavity; and whereby, after the layer has resorbed, the core of the anchor is spaced from and out of contact with the bone surface defining the cavity so that substantially no load transference between the bone surface defining the cavity and the core takes place.

Claim 10

The implant of claim 7 further comprising means for removably securing the anchor to the component.

Claim 11

The implant of claim 8 wherein the securing means comprises a taper lock defined by the component and the core.

Claim 12

The implant of claim 7 wherein the component comprises a joint socket.

Claim 13

The implant of claim 7 wherein the component comprises a convex surface adapted to cooperate with a concave surface of another joint member.

Claim 14

The implant of claim 11 wherein the convex surface is defined by a ball joint member.

Claim 15

The implant of claim 12 wherein the component further includes a body connected with the ball and defining the interface.

Claim 16

The implant of claim 13 including means for detachably securing the body and the ball to each other.

Claim 17

The implant of claim 7 wherein the outer layer is removably connected to the core to enable the selection of the outer layer from a supply of differently formed outer layers and thereby fit the outer layer to the shape of the cavity.

Claim 18

An implant for a bone joint comprising: a component defining an operative portion of the joint, the component including a ball joint member, a body having an interface facing generally away from the joint and adapted to be placed into intimate contact with an actual bone to which the component is to be fixed, at least part of the interface including means promoting bony ingrowth when the interface is in intimate contact with the natural bone and means for detachably securing the ball joint member and the body to each other; and an anchor connected to the component and adapted to be inserted in a cavity in the bone for orienting and immovably fixing the component to the bone immediately upon implantation, the anchor comprising: a relatively high strength, permanent core having a cross section sufficiently smaller than the cross section of the cavity so that contact between the bone and the core is prevented; an outer layer applied to the core and shaped so that the layer, upon implantation, securely engages a bone surface defining the cavity, the layer being constructed of biodegradable material so that it resorbs after a period of time and thereby vacates a portion of the cavity; and whereby, after the layer has resorbed, the core of the anchor is spaced from and out of contact with the bone surface defining the cavity so that substantially no load transference between the bone surface defining the cavity and the core takes place.

Claim 19

An implant for a bone joint comprising: a component defining an operative portion of the joint, the component including a ball joint member, a body having an interface facing generally away from the joint and adapted to be placed into intimate contact with an actual bone to which the component is to be fixed, at least part of the interface including means promoting bony ingrowth when the interface is in intimate contact with the natural bone and means for detachably securing the ball joint member and the body to each other; and an anchor connected to the component and adapted to be inserted in a cavity in the bone for orienting and immovably fixing the component to the bone immediately upon implantation, the anchor comprising: a relatively high strength, permanent core having a cross section sufficiently smaller than the cross section of the cavity so that contact between the bone and the core is prevented; an outer layer applied to the core and shaped so that the layer, upon implantation, securely engages a bone surface defining the cavity, the layer being constructed of biodegradable material so that it resorbs after a period of time and thereby vacates a portion of the cavity; and whereby, after the layer has resorbed, the core of the anchor is spaced from and out of contact with the bone surface defining the cavity so that substantially no load transference between the bone surface defining the cavity and the core takes place.