Method and apparatus for hip femoral resurfacing tooling

Abstract

Tools and methods for implanting hip resurfacing femoral prostheses along a path defined by the axis of a shaped femoral head surface are described. The prostheses are stemless partial ball components having an outer surface shaped to conform to an acetabular socket and may be a two part design having a mating sleeve component with an internal bore adapted to receive the shaped femoral head. The tools and methods are capable of accurately implanting both one and two piece ball components and sleeves without requiring the prosthesis to have a central stem or the preparation of a stem cavity in the femoral head and neck.

1 . A tool for translating a hollow sleeve prosthesis component along a femoral head axis to install the sleeve on a prepared femoral head, the head axis being defined by a datum used to prepare the femoral head outer surface, the sleeve having a distal end with an opening into a cavity to engage the outer surface of the prepared natural femoral head and a proximal end with an aperture in the proximal end, the tool comprising:
 a distal sleeve interface for retaining and releasing the hollow sleeve by contacting the sleeve outer surface;   a guide capable of aligning the sleeve interface with the femoral head axis when engaged with the datum and guiding the interface portion to slidingly translate along the head axis when engaged; and   a handle for applying force to the sleeve interface.   
   
   
       2 . The tool as set forth in  claim 1  wherein the datum is a guide wire. 
   
   
       3 . The tool as set forth in  claim 2  wherein the guide comprises a bore through the sleeve interface configured to slidingly journal the guide wire. 
   
   
       4 . The tool as set forth in  claim 1  wherein the datum is a guide wire bore. 
   
   
       5 . The tool as set forth in  claim 4  wherein the guide comprises a pin extending from the sleeve interface configured to slidingly fit in the guide wire bore. 
   
   
       6 . The tool as set forth in  claim 1  wherein at least one surface of the the sleeve interface is tapered. 
   
   
       7 . The tool as set forth in  claim 6  wherein the sleeve interface comprises an extractor assembly that is capable of applying force to the sleeve to release the sleeve from the tool. 
   
   
       8 . The tool as set forth in  claim 7  wherein the force is applied symmetrically about a central axis of the proximal portion of the sleeve. 
   
   
       9 . The tool as set forth in  claim 6  wherein at least one surface of the the sleeve interface is partially cone shaped. 
   
   
       10 . A method of installing a femoral sleeve prosthesis to a femoral head, said method comprising the steps of:
 a.) preparing the outer surface of the femoral head about a datum to a predetermined configuration to create a prepared femoral head having a head axis defined by the datum;   b.) selecting a sleeve prosthesis, the sleeve having a distal end with an opening into a cavity, the cavity being sized and configured to engage the outer surface of the prepared femoral head, and a proximal end having an aperture;   c.) inserting the sleeve into the sleeve interface of a tool and retaining the sleeve in the sleeve interface, the tool further comprising a guide capable of aligning the sleeve interface with the head axis when engaged with the datum and guiding the interface portion to slidingly translate along the head axis when engaged with the datum, and a handle for applying force to the interface portion;   d.) engaging the guide of the tool with the datum;   e.) applying force to the tool handle to slidingly translate the tool and sleeve along the head axis to seat the sleeve cavity on the prepared femoral head surface; and   f.) releasing the sleeve from the sleeve interface, disengaging the guide from the datum and removing the tool.   
   
   
       11 . The method as set forth in  claim 10  wherein the datum is a guide wire. 
   
   
       12 . The method as set forth in  claim 11  wherein the guide comprises a bore through the sleeve interface configured to slidingly journal the guide wire and the guide is engaged with the guide wire by positioning the tool to pass the guide wire into the sleeve cavity, through the sleeve aperture and into the guide bore. 
   
   
       13 . The method as set forth in  claim 10  wherein the datum is a guide wire bore. 
   
   
       14 . The method as set forth in  claim 13  wherein the guide comprises a pin extending from the sleeve interface and configured to slidingly fit in the guide wire bore and the guide pin is engaged with the guide wire bore by passing the guide pin through the sleeve aperture and cavity when inserting the sleeve into the sleeve interface and then positioning the tool to place the guide pin into the guide wire bore. 
   
   
       15 . The method as set forth in  claim 10  wherein at least one outer surface of the sleeve is tapered. 
   
   
       16 . The method as set forth in  claim 15  whereby the sleeve is released from the sleeve interface by actuating an extractor assembly that applies force to the sleeve to release the sleeve from the tool. 
   
   
       17 . The method as set forth in  claim 16  wherein the force is applied symmetrically about a central axis of the proximal portion of the sleeve. 
   
   
       18 . The method as set forth in  claim 15  wherein at least one surface of the sleeve interface is partially cone shaped. 
   
   
       19 . The method of  claim 10  wherein bone cement is applied between the interior surface of the sleeve and the prepared femoral head surface prior to seating the sleeve cavity on the prepared femoral head surface. 
   
   
       20 . The method of  claim 10  wherein the outside of the sleeve is solid metal. 
   
   
       21 . The method of  claim 10 , wherein the sleeve is substantially composed of a metal selected from the group of titanium, titanium alloys, cobalt chrome alloys, niobium and tantalum. 
   
   
       22 . A tool for establishing a secondary datum for translating a ball prosthesis along a femoral head axis to install the ball on a prepared femoral head, the head axis being defined by a datum fixed in the femoral head and used to prepare the femoral head outer surface, the ball having a distal end with an opening into a cavity to engage the outer surface of the prepared femoral head, the tool comprising:
 an alignment jig comprising a mount, an extension connected to the mount by at least one joint, and a secondary datum location feature connected to the extension, the mount being capable of being mounted to the proximal femur adjacent the prepared femoral head, and the extension being capable of moving the secondary datum location feature, when the jig is mounted, to a position establishing a secondary datum coaxial with the datum and distant from the datum along the proximal portion of the femoral head axis.   
   
   
       23 . The tool as set forth in  claim 22  wherein the alignment jig extension further comprises at least one movable and lockable joint. 
   
   
       24 . The tool as set forth in  claim 23  wherein the alignment jig extension further comprises providing at least one translational degree of freedom between said mount and said secondary datum location feature. 
   
   
       25 . The tool as set forth in  claim 23  wherein the alignment jig extension further comprises providing at least two rotational degrees of freedom between said mount and said secondary datum location feature. 
   
   
       26 . The tool as set forth in  claim 23  wherein the alignment jig extension further comprises providing at least four degrees of freedom between said mount and said secondary datum location feature. 
   
   
       27 . The tool as set forth in  claim 23  wherein the alignment jig extension further comprises providing at least four degrees of freedom including at least two rotational degrees of freedom and at least one translational degrees of freedom between said mount and said secondary datum location feature. 
   
   
       28 . The tool as set forth in  claim 22  wherein the alignment jig further comprises an axial extension, said mount and said axial extension being connected by at least one movable and lockable joint providing at least two rotational degrees of freedom to allow the axial extension to be aligned axially parallel with the datum. 
   
   
       29 . The tool as set forth in  claim 26  wherein the alignment jig extension further comprises a radial extension incorporating said secondary datum location feature, said radial extension being capable of rotation about the axis of said axial extension to radially align with the axis of the datum and radially translate relative to the axial extension to allow the axial extension to align said secondary datum location features coaxially with said datum and establish the secondary datum when the mount is mounted to the femur and the axial extension is aligned axially parallel with the datum. 
   
   
       30 . The tool as set forth in  claim 22  wherein the alignment jig allows the distance from the prepared femoral head to the secondary datum location feature to be a sufficient length to allow the placement of a ball prosthesis centrally between the femoral head and the secondary datum. 
   
   
       31 . The tool as set forth in  claim 22  wherein the alignment jig allows the distance from the prepared femoral head to the secondary datum location feature to be at least 25 mm. 
   
   
       32 . A tool kit for translating a ball prosthesis along a femoral head axis to install the ball on a prepared femoral head, the head axis being defined by a datum fixed in the femoral head and used to prepare the femoral head outer surface, the ball having a distal end with an opening into a cavity to engage the outer surface of the prepared natural femoral head, the kit comprising:
 an alignment jig capable of being mounted to the proximal femur adjacent the prepared femoral head, locating on the datum when mounted and creating a secondary datum coaxial with the datum and proximally distant from the prepared femoral head along the femoral head axis; and   a prosthesis holding tool having a first distal ball interface for retaining and releasing a first ball prosthesis of a first diameter by contacting the first ball outer surface, a proximal guide capable of aligning the ball interface with the head axis when engaged with said secondary datum and guiding the ball interface to slidingly translate along the head axis when engaged, and a handle for applying force to the ball interface.   
   
   
       33 . A kit according to  claim 32  further comprising a second prosthesis holding tool having a distal ball interface for retaining and releasing a second ball prosthesis of a second diameter different from said first diameter of said first ball prosthesis by contacting the second ball outer surface. 
   
   
       34 . A method of installing a femoral ball prosthesis to a femoral head, said method comprising the steps of:
 a.) preparing the outer surface of the femoral head about a datum to a predetermined configuration to create a prepared femoral head having a head axis defined by the datum;   b.) mounting an alignment jig to the proximal femur adjacent the prepared femoral head, and using the alignment jig to locate on the datum when mounted and create a secondary datum coaxial with the datum and proximally distant from the prepared femoral head along the femoral head axis;   c.) selecting a ball prosthesis, the ball prosthesis having a distal end with an opening into a cavity, the cavity being sized and configured to engage the outer surface of the prepared femoral head;   d.) inserting the ball prosthesis into the ball interface of a prosthesis holding tool and retaining the ball in the ball interface, the tool further comprising a proximal guide and a handle;   e.) engaging the guide of the prosthesis holding tool with the secondary datum, the guide, upon engagement, aligning the ball interface with the head axis;   f.) applying force to the tool handle to slidingly translate the tool and ball prosthesis along the head axis to seat the ball prosthesis cavity on the prepared femoral head surface; and   g.) releasing the ball prosthesis from the ball interface, retracting the tool and removing the alignment jig and the prosthesis holding tool.   
   
   
       35 . A tool for establishing a secondary datum for the purpose of translating a ball prosthesis along a femoral head axis to install the ball on a prepared femoral head, the head axis being defined by a datum fixed in the femoral head and used to prepare the femoral head outer surface, the ball having a distal end with an opening into a cavity to engage the outer surface of the prepared natural femoral head, the tool comprising:
 an axis alignment jig comprising a proximal datum location feature having an axis, a distal secondary datum fixture, and an intermediate extension connected to the datum location feature and the secondary datum fixture, the datum location feature being capable of mounting to the datum adjacent the prepared femoral head, locating the location feature axis co-axially with the head axis and positioning the jig relative to the datum, the extension being capable of locating the secondary datum fixture, when the jig is mounted to the datum, to a position distally remote from the prepared femoral head for establishing a secondary datum in the proximal femur with an axis intersecting the femoral head axis, and the secondary datum fixture being capable, when the jig is mounted to the datum, of providing a guide for establishing a secondary datum in the proximal femur with an axis intersecting the femoral head axis.   
   
   
       36 . The tool as set forth in  claim 30  wherein the datum is a guide wire. 
   
   
       37 . The tool as set forth in  claim 31  wherein the proximal datum location feature comprises a bore through the feature configured to slidingly journal the guide wire in order to locate the datum and position the jig relative to the datum. 
   
   
       38 . The tool as set forth in  claim 30  wherein the datum is a guide wire bore. 
   
   
       39 . The tool as set forth in  claim 33  wherein the proximal datum location feature comprises a pin configured to slidingly fit in the guide wire bore in order to locate the datum and position the jig relative to the datum. 
   
   
       40 . The tool as set forth in  claim 30  wherein the secondary datum fixture guide is a slot oriented toward the axis of the datum location feature. 
   
   
       41 . The tool as set forth in  claim 30  wherein the secondary datum fixture guide is a bore with an opening oriented perpendicular to the axis of the datum location feature. 
   
   
       42 . A tool for translating a ball prosthesis toward a femoral head axis to install the ball on a prepared femoral head by locating on a secondary datum in the proximal femur with an axis intersecting the femoral head axis, the head axis being defined by a datum fixed in the femoral head and used to prepare the femoral head outer surface, the ball having a distal end with an opening into a cavity to engage the outer surface of the prepared natural femoral head, the tool comprising:
 a prosthesis holding tool having a distal ball interface for retaining and releasing the ball prosthesis by contacting the ball outer surface, a guide capable of guiding the ball interface to slidingly translate toward the head axis when engaged on the secondary datum, an intermediate extension connected to the ball interface and the guide, and a handle for applying force to the ball interface.   
   
   
       43 . The tool as set forth in  claim 37  wherein the guide is a slot with an opening oriented toward the head axis when engaged on the secondary datum. 
   
   
       44 . A tool kit for translating a ball prosthesis toward a femoral head axis to install the ball on a prepared femoral head by creating and locating on a secondary datum in the proximal femur with an axis intersecting the femoral head axis, the head axis being defined by a datum fixed in the femoral head and used to prepare the femoral head outer surface, the ball having an end with an opening into a cavity to engage the outer surface of the prepared natural femoral head, the tool kit comprising:
 an axis alignment jig comprising a proximal datum location feature having an axis, a distal secondary datum fixture, and an intermediate extension connected to the datum location feature and the secondary datum fixture, the datum location feature being capable of mounting to the datum adjacent the prepared femoral head, locating the location feature axis co-axially with the head axis and positioning the jig relative to the datum, the extension being capable of locating the secondary datum fixture, when the jig is mounted to the datum, to a position distally remote from the prepared femoral head for establishing a secondary datum in the proximal femur with an axis intersecting the femoral head axis, and the secondary datum fixture being capable, when the jig is mounted to the datum, of providing a guide for establishing a secondary datum in the proximal femur with an axis intersecting the femoral head axis; and   a prosthesis holding tool having a ball interface for retaining and releasing the ball-prosthesis by contacting the ball outer surface, a distal guide capable of guiding the ball interface to slidingly translate toward the head axis when engaged on the secondary datum, an intermediate extension connected to the ball interface and the guide, and a handle for applying force to the ball interface.   
   
   
       45 . A method of installing a femoral ball prosthesis to a femoral head, said method comprising the steps of:
 a.) preparing the outer surface of the femoral head about a datum to a predetermined configuration to create a prepared femoral head having a head axis defined by the datum;   b.) mounting an axis alignment jig to the datum, the axis alignment jig comprising a proximal datum location feature having an axis, a distal secondary datum fixture, and an intermediate extension connected to the datum location feature and the secondary datum fixture, the datum location feature locating the datum axis and positioning the jig relative to the datum so that the extension locates the secondary datum fixture to a position distally remote from the prepared femoral head, the secondary datum fixture being capable of providing a guide for establishing a secondary datum in the proximal femur with an axis intersecting the femoral head axis,   c.) installing a secondary datum, under at least partial guidance from the secondary datum fixture, to position the secondary datum in the proximal femur so that the secondary datum has an axis intersecting the femoral head axis;   d.) selecting a ball prosthesis, the ball prosthesis having a distal end with an opening into a cavity, the cavity being sized and configured to engage the outer surface of the prepared femoral head;   e.) inserting the ball prosthesis into the ball interface of a prosthesis holding tool and retaining the ball in the ball interface, the tool further comprising a distal guide and a handle;   d.) engaging the guide of the tool with the secondary datum, the guide, upon engagement, aligning the ball interface with the head axis;   e.) applying force to the tool handle to slidingly translate the tool and ball prosthesis toward the head axis to seat the ball prosthesis cavity on the prepared femoral head surface; and   f.) releasing the ball prosthesis from the ball interface, and removing the alignment jig and the prosthesis holding tool.