Universal double offset surgical instrument

Abstract

Instruments for use in anterior approach total hip arthroplasty. Instruments according to certain embodiments of the invention connect to a shaping member such as a broach, reamer or osteotome that is used to prepare the intramedullary canal of a desired femur or other bone for total hip arthroplasty. Such an instrument according to such embodiments can be configurable to allow operation on either the left or right leg, and in doing so to provide lateral offset and anterior offset of the instrument handle relative to the shaping member so that the patient's gut, musculature or other bodily portions may be avoided while still providing desired leverage and control over the shaping member to prepare the intramedullary canal.

What is claimed is: 
     
         1 . An instrument for shaping a medullary canal of both a patient's left leg and right leg, comprising:
 (a) a handle that includes a handle longitudinal axis;   (b) a shaping member including:
 structure configured to shape bone; 
 a shaping member longitudinal axis, and 
 a connecting structure that includes an interpositional cooperation structure; 
   (c) an offset member that physically connects the handle to the shaping member, the offset member extending in an offset direction that includes a first directional component in a first direction orthogonal to the longitudinal axis of the shaping member, and a second directional component in the direction of the shaping member longitudinal axis;   (d) the offset member including:
 (i) a first opening adapted to receive the shaping member connecting structure, the first opening configured to receive the shaping member connecting structure in a manner whereby the shaping member longitudinal axis is substantially parallel to the handle longitudinal axis; 
 (ii) a second opening adapted to receive the shaping member connecting structure, the second opening configured to receive the shaping member connecting structure in a manner whereby the shaping member longitudinal axis is substantially parallel to the handle longitudinal axis; and 
   (e) a retention device or member comprising an actuator and at last one interpositional structure, the retention device or member configured to interpose the at least one interpositional structure relative to the interpositional cooperation structure of the shaping member connecting structure when the actuator is actuated.   
     
     
         2 . The instrument of  claim 1 , wherein the shaping member comprises a reference plane and the first and second openings are configured to receive the shaping member connecting structure in a manner such that the first direction orthogonal to the longitudinal axis of the shaping member bisects the angle formed by the shaping member reference plane when the shaping member is connected to the first opening and the shaping member reference plane when the shaping member is connected to the second opening. 
     
     
         3 . The instrument of  claim 1 , wherein the shaping member comprises a reference plane and the first and second openings are configured to receive the shaping member connecting structure in a manner such that when the shaping member is connected to the first opening, the shaping member reference plane is substantially orthogonal to the shaping member reference plane when the shaping member is connected to the second opening. 
     
     
         4 . The instrument of  claim 1 , wherein the shaping member is a broach. 
     
     
         5 . The instrument of  claim 1 , wherein the shaping member is a femoral shaping member for preparation of a central femoral cavity for receiving a stem of a femoral component of a prosthetic hip. 
     
     
         6 . The instrument of  claim 1 , further comprising a strike plate with a first beveled surface that corresponds to the first opening on the offset member and a second beveled surface that corresponds to the second opening on the offset member. 
     
     
         7 . The instrument of  claim 1 , wherein the offset member extends in at least two offset directions. 
     
     
         8 . The instrument of  claim 1 , wherein the offset direction includes a third directional component that is orthogonal to the first directional component, the second directional component, and the longitudinal axis of the shaping member. 
     
     
         9 . The instrument of  claim 1 , wherein the offset member includes a first abutment surface and a second abutment surface, the first abutment surface corresponding to the first opening and configured to abut a proximal surface of the shaping member, the second abutment surface corresponding to the second opening and configured to abut a proximal surface of the shaping member. 
     
     
         10 . The instrument of  claim 1 , wherein the actuator of the retention device or member includes an over-center linkage configured to lock the interpositional structure in place when interposed with the interpositional cooperation structure of the shaping member connecting structure, and wherein the interpositional structure comprises at least one pawl. 
     
     
         11 . The instrument of  claim 1 , wherein the actuator of the retention device or member includes a wedge, the interpositional structure includes at least one claw, and the wedge is configured to urge the at least one claw into interposed position with the interpositional cooperation structure of the shaping member connecting structure. 
     
     
         12 . An instrument for operating on a medullary canal for installation of a prosthetic stem component in a patient, comprising:
 a handle including an elongated shaft extending approximately in a negative z-direction;   a first offset capable of extending in a first direction that includes an x-directional component or a negative x-directional component;   a second offset extending in a second direction that includes a negative y-directional component;   the handle connected to either the first or second offset;   an insertion member extending from either the first offset or the second offset in an insertion member direction that includes a negative z-directional component;   wherein the negative y-directional component and negative z-directional components are orthogonal to each other and orthogonal to the x-directional component and the negative x-directional component, and   wherein the handle and the insertion member are positioned with respect to one another in a non-planar relationship.   
     
     
         13 . The instrument of  claim 12 , wherein one of the offsets is connected to the handle via a pivot capable of rotating relative to the handle such that one of the offsets extends in approximately an x-direction or a negative x-direction in order to configure the instrument for use with a right leg or a left leg of the patient. 
     
     
         14 . The instrument of  claim 12 , wherein the handle is configured to connect to the second offset on either a first side of the handle that faces the x direction or a second side of the handle that faces the negative x direction in order to form the first offset. 
     
     
         15 . The instrument of  claim 12 , wherein the insertion member further comprises cutting elements. 
     
     
         16 . An instrument for operating on a medullary canal for installation of a prosthetic stem component in a patient, comprising:
 a handle including an elongated shaft extending in an approximately negative z-direction;   an offset connected to the handle, the offset extending in a first direction that includes a negative y-directional component and capable of extending in a second direction that includes an x-directional component or a negative x-directional component;   a shaping member extending from the offset in a shaping member direction that includes a negative z-directional component,   wherein the negative y-directional component and negative z-directional components are orthogonal to each other and orthogonal to the x-directional component and the negative x-directional component,   wherein the handle and the shaping member are positioned with respect to one another in a non-coplanar relationship, and   wherein the shaping member further comprises cutting elements.   
     
     
         17 . The instrument of  claim 16 , wherein the offset is connected to the handle via a pivot, and the handle and pivot are capable of rotating relative to each other such that the offset extends in a direction that includes an x-directional component or a negative x-directional component in order to configure the instrument for use with a right leg or a left leg of the patient.