Partially Porous Tibial Component

Abstract

A method for removing a stem portion of an orthopedic implant from a bone comprises exposing an implanted orthopedic implant having a body portion, a stem portion interconnected to the body and a porous metal section forming an interconnection between the body and the stem portion. A cutting tool is mounted on a holder connected to an exposed surface of the orthopedic implant. The porous section is aligned with the cutting tool mounted on the holder. The entire porous section is cut by moving the cutting tool therethrough in a direction transverse to the stem portion axis. The implant body portion is then removed and then the stem portion is removed from the bone. The cutting tool may be a saw or chisel which may be mounted on a guide fixed to the body portion.

16 . A tibial implant comprising:
 a baseplate;   a keel extending from the baseplate in a first direction; and   a plurality of pegs each extending from the baseplate in the first direction and each having a first section adjacent to the baseplate, a second section extending from the first section, and a free end extending from the second section,   wherein the first section of each of the pegs has a porous outer surface,   wherein the second section of each of the pegs has a solid outer surface, and   wherein the free end of each of the pegs tapers to a point.   
     
     
         17 . The tibial implant of  claim 16 , wherein each of the pegs includes an edge along which the second section intersects the free end. 
     
     
         18 . The tibial implant of  claim 16 ,
 wherein the keel includes a pair of flanges defining intersecting first and second planes and an additional flange defining a third plane bisecting the keel,   wherein either one of or both the first plane extends between a first pair of the pegs and the second plane extends between a second pair of the pegs, and   wherein the first pair of the pegs lie on a first side of the third plane and the second pair of the pegs lie on a second side of the third plane.   
     
     
         19 . The tibial implant of  claim 16 , wherein the keel includes a proximal keel portion adjacent to the baseplate and a distal keel portion extending from the proximal keel portion, and wherein the proximal keel portion includes a porous outer surface and the distal keel portion is solid. 
     
     
         20 . The tibial implant of  claim 16 , wherein each of the pegs has a non-circular cross-section. 
     
     
         21 . The tibial implant of  claim 16 ,
 wherein the baseplate includes a solid baseplate portion and a porous baseplate portion extending from the solid baseplate portion in the first direction and extending to an outer rim of the solid baseplate portion in directions transverse to the first direction,   wherein the keel has a non-circular keel cross-section at a portion of the keel adjacent to the baseplate,   wherein each of the pegs has a non-circular peg cross-section at a portion of each of the respective pegs adjacent to the baseplate, and   wherein the porous baseplate portion abuts the non-circular keel cross-section and the non-circular peg cross-sections.   
     
     
         22 . The tibial implant of  claim 16 , wherein the second section has a uniform cross-section along a thickness of the second section. 
     
     
         23 . The tibial implant of  claim 16 , wherein outer diameters of the first section and the second section are aligned. 
     
     
         24 . The tibial implant of  claim 16 , wherein the porous outer surface is produced by additive manufacturing and thereby has a randomized pore structure. 
     
     
         25 . The tibial implant of  claim 16 , wherein each of the pegs defines a longitudinal axis passing through its respective point. 
     
     
         26 . The tibial implant of  claim 16 , wherein both the second end and the free end of each of the pegs are solid. 
     
     
         27 . The tibial implant of  claim 16 , wherein the first section includes a solid core, and wherein the porous outer surface of the first section surrounds the solid core. 
     
     
         28 . An orthopedic implant kit comprising:
 the tibial implant of  claim 16 ; and   a femoral component.   
     
     
         29 . A tibial implant comprising:
 a baseplate including a solid baseplate portion and a porous baseplate portion extending from the solid baseplate portion in a first direction and extending to an outer rim of the solid baseplate portion in directions transverse to the first direction;   a keel extending from the porous baseplate portion in the first direction and including a pair of flanges defining intersecting first and second planes and an additional flange defining a third plane bisecting the keel; and   a plurality of pegs each extending from the porous baseplate portion in the first direction and each having a first section adjacent to the baseplate, a second section extending from the first section, and a free end extending from the second section,   wherein either one of or both the first plane extends between a first pair of the pegs and the second plane extends between a second pair of the pegs,   wherein the first pair of the pegs lie on a first side of the third plane and the second pair of the pegs lie on a second side of the third plane,   wherein the first section of each of the pegs has a porous outer surface,   wherein the second section of each of the pegs has a solid outer surface, and   wherein the free end of each of the pegs tapers to a point.   
     
     
         30 . The tibial implant of  claim 29 , wherein each of the pegs includes an edge along which the second section intersects the free end. 
     
     
         31 . The tibial implant of  claim 29 , wherein the keel includes a proximal keel portion adjacent to the baseplate and a distal keel portion extending from the proximal keel portion, and wherein the proximal keel portion includes a porous outer surface and the distal keel portion is solid. 
     
     
         32 . The tibial implant of  claim 29 , wherein each of the pegs has a non-circular cross-section. 
     
     
         33 . The tibial implant of  claim 32 , wherein the porous baseplate portion abuts the flanges of the keel and the non-circular cross-sections of the pegs. 
     
     
         34 . The tibial implant of  claim 29 , wherein the second section has a uniform cross-section. 
     
     
         35 . The tibial implant of  claim 29 , wherein the porous baseplate portion and the porous outer surface are produced by additive manufacturing and thereby have randomized pore structures. 
     
     
         36 . A tibial implant comprising:
 a baseplate including a solid bearing support portion and a porous bone-contacting portion extending from the bearing support portion, the porous bone-contacting portion having pore structures of differing shapes;   a keel including a pair of flanges extending from the baseplate and defining intersecting planes and further including an additional flange extending away from the pair of flanges within a bisecting plane bisecting the keel; and   four spikes extending away from the bone-contacting portion of the baseplate at locations spaced about the keel, each of the spikes having a non-tapering section and a tapering section extending from the non-tapering section and tapering to a point,   wherein the non-tapering sections of each of the spikes includes a porous outer surface adjacent the bone-contacting portion of the baseplate and the tapering sections of each of the spikes are solid,   wherein a first pair of the spikes extend away from a first side of the bone-contacting portion of the baseplate and a second pair of the spikes extend away from a second side of the bone-contacting portion opposite the first side of the bone-contacting portion of the baseplate, the first and the second sides defining the entirety of the bone-contacting portion of the baseplate, and   wherein the first pair of the spikes is spaced apart a greater distance than the second pair of the spikes.   
     
     
         37 . The tibial implant of  36 , wherein the first pair of the spikes lie on one side of a transverse plane transverse to the bisecting plane and the second pair of the spikes lie on the opposite side of the transverse plane. 
     
     
         38 . The tibial implant of  claim 36 , wherein each of the spikes includes four free ends and four filets, each of the free ends being connected to two adjacent ones of the free ends by respective ones of the filets, and wherein the free ends taper towards the point.