Canal sizer and associated method

Abstract

An instrument for measuring the medullary canal of a long bone in order to determine the proper size for a stem centralizer is provided. The instrument includes an elongated central portion defining opposed first and second ends and a contact portion. The contact portion extends from the first end or the second end of the elongated central portion. The contact portion has a contact area for contact with the medullary canal and defines a relief area for providing clearance between the instrument and the medullary canal.

1 . An instrument for measuring the medullary canal of a long bone in order to determine the proper size for a stem centralizer, said instrument comprising:
 an elongated central portion defining opposed first and second ends; and   an arcuate contact portion extending from the first end of said elongated central portion, said contact portion having a contact area including an outer periphery, having a circumference, for contact with the medullary canal and defining a relief area for providing clearance between the instrument and the medullary canal, wherein the relief area is recessed from the outer periphery of the contact area, such that the relief area interrupts the outer periphery of the contact area, and the relief area does not extend around the entire circumference of the outer periphery; wherein said contact portion comprises a plurality of contact areas for contact with the medullary canal and defines a plurality of relief areas for providing clearance between the instrument and the medullary canal and said contact portion has 2 to 6 contact areas for contact with the medullary canal and has 2 to 6 relief areas.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . The instrument of  claim 1 , wherein said contact portion has 4 equally spaced apart contact areas for contact with the medullary canal and has 4 equally spaced apart relief areas. 
     
     
         6 . The instrument of  claim 1 , wherein said elongated central portion is generally cylindrical. 
     
     
         7 . The instrument of  claim 1 , wherein said contact portion is generally pear shaped. 
     
     
         8 . The instrument of  claim 1 , wherein said elongated central portion includes a plurality of spaced apart marks corresponding to at least one of a metric dimension and an inch dimension. 
     
     
         9 . An instrument for measuring the medullary canal of a long bone in order to determine the proper size for a stem centralizer, said instrument comprising:
 an elongated central portion defining opposed first and second ends;   a first arcuate contact portion extending from the first end of said elongated central portion, said first contact portion having a contact area including an outer periphery, having a circumference, for contact with the medullary canal and defining a relief area for providing clearance between the instrument and the medullary canal, wherein the relief area is recessed from the outer periphery of the contact area, such that the relief area interrupts the outer periphery of the contact area, and the relief area does not extend around the entire circumference of the outer periphery, wherein said contact portion comprises a plurality of contact areas for contact with the medullary canal and defines a plurality of relief areas for providing clearance between the instrument and the medullary canal and said contact portion has 2 to 6 contact areas for contact with the medullary canal and has 2 to 6 relief areas; and   a second arcuate contact portion extending from the second end of said elongated central portion, said second contact portion having a contact area including an outer periphery, having a circumference, for contact with the medullary canal and defining a relief area for providing clearance between the instrument and the medullary canal, and the relief area does not extend around the entire circumference of the outer periphery, wherein said contact portion comprises a plurality of contact areas for contact with the medullary canal and defines a plurality of relief areas for providing clearance between the instrument and the medullary canal and said contact portion has 2 to 6 contact areas for contact with the medullary canal and has 2 to 6 relief areas.   
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The instrument of  claim 9 , wherein at least one of said first contact portion and said second contact portion has 4 equally spaced apart contact areas for contact with the medullary canal and has 4 equally spaced apart relief areas. 
     
     
         13 . The instrument of  claim 9 , wherein said elongated central portion is generally cylindrical. 
     
     
         14 . The instrument of  claim 9 , wherein at least one of said first contact portion and said second contact portion is generally pear shaped. 
     
     
         15 . The instrument of  claim 9 , wherein said elongated central portion includes a plurality of spaced apart marks corresponding to at least one of a metric dimension and an inch dimension. 
     
     
         16 . A kit for use in performing total hip arthroplasty, said kit comprising:
 a plurality of instruments, each of said plurality of instruments adapted for measuring the medullary canal of a femur, each of said plurality of instruments including an elongated central portion defining opposed first and second ends, and an arcuate contact portion extending from the first end of the elongated central portion, the contact portion having a contact area including an outer periphery, having a circumference, for contact with the medullary canal and defining a relief area for providing clearance between the instrument and the medullary canal canal, wherein the relief area is recessed from the outer periphery of the contact area, such that the relief area interrupts the outer periphery of the contact area, and the relief area does not extend around the entire circumference of the outer periphery, wherein said contact portion comprises a plurality of contact areas for contact with the medullary canal and defines a plurality of relief areas for providing clearance between the instrument and the medullary canal and said contact portion has 2 to 6 contact areas for contact with the medullary canal and has 2 to 6 relief areas;   a hip stem for implantation into the medullary canal; and   a plurality of stem centralizers for cooperation with said hip stem and for implantation into the medullary canal, each of said plurality of stem centralizers corresponding to one of the contact portions of said plurality of instruments.   
     
     
         17 . The kit of  claim 16 , wherein each of said instruments further comprise a second contact portion extending from the second end of said elongated central portion, said second contact portion having a contact area for contact with the medullary canal and defining a relief area for providing clearance between the instrument and the medullary canal. 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . The kit of  claim 16 , wherein the elongated central portion of each of said instruments includes a plurality of spaced apart marks corresponding to at least one of a metric dimension and an inch dimension. 
     
     
         21 . (canceled)