Joint Prosthesis with Positionable Head

Abstract

A prosthesis assembly in one embodiment includes a stem configured to be implanted in a bone and including a first coupling portion, a head having a bearing surface configured to mate with at least one of a natural opposing joint component and a prosthetic opposing joint component, the head further having a second coupling portion, a coupler including a third coupling portion and a fourth coupling portion, the third coupling portion configured to couple with the second coupling portion, and an insert including (i) a fifth coupling portion configured to couple with the fourth coupling portion in any of a plurality of rotational orientations in combination with any of a plurality of roll angles and any of a plurality of pitch angles, and (ii) a sixth coupling portion configured to couple with the first coupling portion only when the insert assumes a predetermined rotational orientation with respect to the stem.

1 - 7 . (canceled) 
     
     
         8 . A prosthesis assembly kit, comprising:
 at least one stem configured to be implanted in a bone, the at least one stem including a keyed stem coupling portion;   a plurality of heads, each of the plurality of heads having a bearing surface configured to mate with at least one of a natural opposing joint component and a prosthetic opposing joint component, each of the plurality of heads further having a head coupling portion;   at least one first coupler including an upper coupling portion and a lower coupling portion, the upper coupling portion configured to couple with the head coupling portion of each of the plurality of heads; and   at least one insert including (i) a non-keyed insert coupling portion configured to couple with the lower coupling portion of each of the at least one first couplers in any of a plurality of rotational orientations in combination with any of a plurality of roll angles and any of a plurality of pitch angles, and (ii) a keyed insert coupling portion configured to couple with the keyed stem coupling portion of each of the at least one stems.   
     
     
         9 . The prosthesis assembly kit of  claim 8 , wherein the at least one stem comprises a plurality of stems, each of the plurality of stems having a length that is different from the length of each of the other of the plurality of stems. 
     
     
         10 . The prosthesis assembly kit of  claim 8 , wherein each of the plurality of heads has a bearing surface that is of a size different from the size of each of the other of the plurality of heads. 
     
     
         11 . The prosthesis assembly kit of  claim 8 , further comprising:
 at least one second coupler including a first coupling portion and a second coupling portion, the first coupling portion configured to couple with the head coupling portion of each of the plurality of heads, and the second coupler configured to couple with the keyed stem coupling portion of each of the at least one stems.   
     
     
         12 . The prosthesis assembly of  claim 11 , wherein:
 the keyed stem coupling portion and the keyed insert coupling portion are configured to provide a Morse taper coupling when coupled;   the head coupling portion of each of the plurality of heads and the upper coupling portion of the at least one first coupler are configured to provide a Morse taper coupling when coupled;   the head coupling portion of each of the plurality of heads and the first coupling portion are configured to provide a Morse taper coupling when coupled; and   the keyed stem coupling portion and the second coupling portion are configured to provide a Morse taper coupling when coupled.   
     
     
         13 . The prosthesis assembly of  claim 12 , wherein:
 the keyed stem coupling portion and the keyed insert coupling portion are configured to provide a Morse taper coupling of a first angle when coupled;   the head coupling portion of each of the plurality of heads and the upper coupling portion of the at least one first coupler are configured to provide a Morse taper coupling of a second angle when coupled;   the head coupling portion of each of the plurality of heads and the first coupling portion are configured to provide a Morse taper coupling of the second angle when coupled; and   the keyed stem coupling portion and the second coupling portion are configured to provide a Morse taper coupling of the first angle when coupled, wherein, the first angle is larger than the second angle.   
     
     
         14 . The prosthesis assembly kit of  claim 8 , further comprising a removal tool, the removal tool including a longitudinal axis and comprising:
 a base portion;   a pair of elongate wedge members extending in a first direction away from the base portion along the longitudinal axis; and   an impacting handle extending in a second direction away from the base portion along the longitudinal axis.   
     
     
         15 . A method of forming a prosthesis comprising:
 implanting a stem in a bone, the stem including a first coupling portion;   determining a desired orientation of a head with respect to the stem;   coupling the head with a first coupling portion of a coupler;   coupling a second coupling portion of the coupler with an insert at a selected orientation based upon the determination;   aligning a key member of the coupled insert with the implanted stem; and   coupling the aligned insert with the implanted stem such that the head is in the desired orientation with respect to the stem.   
     
     
         16 . The method of  claim 15 , wherein coupling the second coupling portion of the coupler with an insert comprises:
 coupling the second coupling portion of the coupler with the insert at a selected orientation based upon the location of the key member of the insert.   
     
     
         17 . The method of  claim 16 , wherein coupling the second coupling portion of the coupler with an insert comprises:
 orienting a longitudinal axis of the coupler with respect to a longitudinal axis of the insert based upon the location of the key member of the insert and the desired orientation of the head with respect to the stem;   contacting a tapered wall portion which extends about a periphery of a receptacle with a round portion of the oriented coupler; and   impacting the tapered wall portion with the round portion of the oriented coupler.   
     
     
         18 . The method of  claim 16 , further comprising:
 positioning a portion of a removal tool adjacent to opposing portions of a previously implanted coupler;   applying force to the underside of a previously implanted head with the removal tool; and   decoupling a previously implanted insert from the implanted stem using the removal tool.   
     
     
         19 . The method of  claim 16 , further comprising:
 threading a portion of a decoupler into a threaded portion of a previously implanted insert; and   decoupling the previously implanted insert from the implanted stem using the decoupler.   
     
     
         20 . The method of  claim 19 , wherein decoupling the previously implanted insert comprises:
 impacting a flange on the decoupler.