Neck sparing total hip implant methods

Abstract

A femoral prosthesis. The femoral prosthesis includes an implant body having a proximal end and a distal end and a shoulder at the proximal end, the shoulder being structured and dimensioned for a tight press fit into the neck of a femur. The implant body includes a trunk at the distal end, the trunk having a wedge formed by a tapered portion extending in the direction of the distal end of the implant body. The implant body also includes a medial column extending from the shoulder toward the distal end and a lateral column extending from the shoulder toward the distal end. The wedge, the medial column, and the lateral column to provide multi-planar stability for the implant body and surface area for fixation of the implant body.

1 - 68 . (canceled) 
     
     
         69 . A method for fixating a femoral prosthesis to a proximal end of a femur comprising;
 providing an implant body comprising;   a proximal end and a distal era, the proximal end being dimensioned and configured to support a prosthetic neck, the implant body comprising:
 a trunk at the distal end, the trunk comprising;
 a wedge formed by a tapered portion extending in the direction of the distal end of the implant body, 
 a plurality of terraces disposed on the wedge, 
 a medial side member extending toward the distal end, the medial side member disposed on a medical aids of the wedge, and 
 a lateral side member extending toward the distal end, the lateral side member disposed on a lateral side of the wedge; 
 
 wherein the wedge, the medial side member, and the lateral side member provide multi-planar stability for the implant body; 
   inserting the implant body into an open neck of a femur so that the implant body is substantially straight along the longitudinal axis of the femoral neck;   pressing the implant body tightly into the femoral neck so that the wedge penetrates the spongiosa inside the femur to secure the implant body in the femur.   
     
     
         70 . The method of  claim 69 , further comprising cutting the femur along a plane perpendicular to the longitudinal axis of the femoral neck. 
     
     
         71 . The method of  claim 69 , further comprising positioning a neck sizing template on a resected surface of the femoral neck, the neck sizing template comprising:
 an outer perimeter sized to match an outer perimeter of a shoulder of the implant body;   a first aperture corresponding to one of a medial cannula disposed in the medial side member of the implant body and a lateral cannula disposed in the lateral side member of the implant body; and   a second aperture corresponding to the other one of the medial cannula and the lateral cannula.   
     
     
         72 . The method of  claim 71 , further comprising installing a first guide wire into the neck of the femur through one of the first aperture and the second aperture of the neck sizing template, the one of the first aperture and the second aperture to direct the position and angle of the first guide wire relative to the neck of the femur. 
     
     
         73 . The method of  claim 72 , further comprising forming a first channel in the femur around the first guide wire, the first channel formed using a cannulated tool, the method further comprising positioning the first guide wire through a cannula of the cannulated tool. 
     
     
         74 . The method of  claim 73 , wherein the cannulated tool is a cannulated ream. 
     
     
         75 . The method of  claim 73 , further comprising installing a second guide wire into the neck of the femur through one of the first aperture and the second aperture of the neck sizing template, the one of the first aperture and the second aperture to direct the position and angle of the second guide wire relative to the neck of the femur. 
     
     
         76 . The method of  claim 75 , further comprising forming a second channel in the femur around the second guide wire, the second channel formed using a cannulated tool, the method further comprising positioning the second guide wire through a cannula of the cannulated tool. 
     
     
         77 . The method of  claim 76 , wherein inserting the implant body into the open neck of the femur further comprises:
 positioning the first guide wire into one of the medial cannula, and the lateral cannula of the implant body;   positioning the second guide wire into the other of the medial cannula and the lateral cannula of the implant body;   aligning the medial side member with one of the first channel and the second channel, and the lateral side member with the other of the first channel and the second channel; and   sliding the implant body along the first and second guide wires to guide the implant body into the femur.   
     
     
         78 . The method of  claim 73 , further comprising positioning the neck sizing template on the resected surface of the femoral neck such that a positioning plug disposed on the neck sizing template extends into the first channel formed in the femoral neck to stabilize the neck sizing template to position one of the first aperture and the second aperture, wherein one of the first aperture and the second aperture pass through the positioning plug. 
     
     
         79 . The method of  claim 69 , further comprising fitting the implant body into the femoral neck at an angle to approximate the normal anatomy of the femur. 
     
     
         80 . The method of  claim 69 , further comprising custom shaping the implant body to a patient using magnetic resonance imaging (MRI) or computer tomography (CT) templating. 
     
     
         81 . (canceled) 
     
     
         82 . The method of  claim 69 , wherein the step of providing a stem further comprises:
 providing the stem in which the medial side member of the trunk of said stem further comprises a cross-section having an outer surface that is substantially a portion of a circle;   wherein a medial side member axis runs through successive center points of the medial side member;   wherein an outer surface of the medial side member has a lateral cross-section comprising a medial side member arc having a substantially constant radius from, a center point of the medial side member;   wherein a medial cannula extends along the medial side member axis;   wherein the lateral side member further comprises a cross-section having an outer surface that is substantially a portion of a circle;   wherein a lateral side member axis extends parallel to the medial side member axis, the lateral side member axis running through successive center points of the lateral side member;   wherein an outer surface of the lateral side member has a lateral cross-section comprising a lateral side member arc having a substantially constant radius from a center point of the lateral side member; and   wherein a lateral cannula extends along the lateral side member axis; and   wherein a terminal flare is disposed at a proximal end the medial side member, the terminal flare configured contact an internal medial calcar region of the femoral bone, such that load is transferred medially from the stem component to the medial calcar region.   
     
     
         83 . The method of  claim 69 , wherein each of the plurality of terraces are aligned at an angle relative to a long axis of the implant body between 125 degrees and 160 degrees. 
     
     
         84 . The method of  claim 69 , wherein the medial side member comprises a column. 
     
     
         85 . The method of  claim 69 , wherein the lateral side member comprises a column. 
     
     
         86 . A method for fixating a femoral prosthesis to a proximal end of a femur comprising:
 providing an implant body comprising:
 a proximal end and a distal end, the proximal end being dimensioned and configured to support a prosthetic neck, the implant body comprising: 
   a shoulder at the proximal end, the shoulder being structured and dimensioned for a tight press fit into the neck of a femur; and   a trunk at the distal end, the trunk comprising;
 a wedge formed by a tapered portion extending in the direction of the distal and of the implant body, 
 a central fin extending from the wedge, 
 a medial side member extending from the shoulder toward the distal end, the medial side member disposed on a medial side of the wedge, and 
 a lateral side member extending from the shoulder toward the distal end, the lateral side member disposed on a lateral side of the wedge; 
   inserting the implant body into an open neck of a femur so that the implant body is substantially straight along the longitudinal axis of the femoral neck;   pressing the implant body tightly into the femoral neck so that the shoulder wedges into the femoral neck and increases hoop stress at the femoral neck and the retentive effect of the shoulder in the neck and so that the wedge penetrates the spongiosa inside the femur to secure the implant body in the femur.   
     
     
         87 . The method of  claim 85 , wherein the medial side member comprises a fin. 
     
     
         88 . The method of  claim 86 , wherein the lateral side member comprises a fin. 
     
     
         89 . The method of  claim 86 , wherein the trunk further comprises a plurality of central fins extending from the wedge. 
     
     
         90 . The method of  claim 83 , wherein a cross-section of the plurality of central fins is X-shaped. 
     
     
         91 . A method for fixating a femoral prosthesis to a proximal end of a femur comprising:
 providing an implant body comprising:
 a proximal end and a distal end, the proximal end being dimensioned and configured to support a prosthetic neck, the implant body comprising: 
 a shoulder at the proximal end, the shoulder being structured and dimensioned for a tight press fit into the neck of a femur; and 
 a trunk at the distal end, the trunk comprising: 
 a wedge formed by a tapered portion extending in the direction of the distal end of the implant body, 
 a medial side member extending from the shoulder toward the distal end, the medial side member disposed on a medial side of the wedge and having a C-shaped cross-section, and 
 a lateral side member extending from the shoulder toward the distal end, the lateral side member disposed on a lateral side of the wedge and having a C-shaped cross-section; 
   inserting the implant body into an open neck of a femur so that the implant body is substantially straight along the longitudinal axis of the femoral neck;   pressing the implant body tightly info the femoral neck so that the shoulder wedges into the femoral neck and increases hoop stress at the femoral neck and the retentive effect of the shoulder in the neck and so that the wedge penetrates the spongiosa inside the femur to secure the implant body in the femur.   
     
     
         92 . A method for fixating a femoral prosthesis to a proximal end of a femur comprising:
 providing an implant body having a proximal end and a distal end, the proximal end being dimensioned and configured to support a prosthetic neck, the implant body comprising a medial cannula and a lateral cannula;   installing a first guide wire into a neck of a femur;   installing a second guide wire into the neck of the femur;   positioning the first guide wire into one of the medial cannula and the lateral cannula of the implant body;   positioning the second guide wire into the other of the medial cannula and the lateral cannula of the implant body; and   sliding the implant body along the first and second guide wires to guide the implant body into the neck of the femur.