Method and instrumentation for performing minimally invasive hip arthroplasty
A broaching instrument and method using a segmented broach head. First and second broach segments are laterally engageable with each other in vivo, and are aligned with each other on a common longitudinal axis when so engaged. The method involves making a small anterior incision adjacent a patient's femur, inserting the broach segments sequentially through the anterior incision, interconnecting the plurality of broach segments in vivo, connecting the broach handle to the broach segments, and broaching the proximal medullary canal with the assembled multi-part broach instrument.
1 . A broach instrument for preparing the proximal medullary canal of a femur for receiving a hip stem implant, comprising:
a first broach segment defining a longitudinal axis; and
a second broach segment laterally engageable with said first broach segment in vivo, said second broach segment being aligned with said first broach segment on said longitudinal axis when engaged therewith.
2 . The instrument of claim 1 , further comprising auxiliary means for applying an axial force to said broach segments.
3 . The instrument of claim 2 , wherein said broach segments each have a longitudinal bore therein, and wherein said means for applying an axial force includes a core shaft extending through said longitudinal bores.
4 . The instrument of claim 3 , further comprising a broach handle having a bore therein for said core shaft, said core shaft being rotatably mounted in said broach handle.
5 . The instrument of claim 4 , wherein said core shaft is axially restrained by said broach handle and has a threaded fastener portion on its distal end, and wherein the distalmost one of said broach segments includes a mating threaded fastener portion for engaging said core shaft and cooperating therewith to create a compression force on said broach segments when said core shaft is rotated in one direction.
6 . The instrument of claim 4 , wherein said core shaft threadedly engages said broach handle and has an unthreaded distal end for engaging the distalmost one of said broach segments to create a tension force on said broach segments when said core shaft is rotated in one direction.
7 . The instrument of claim 4 , wherein said broach handle has an offset portion with a bore extending therethrough for said core shaft, and wherein said core shaft is a flexible shaft.
8 . The instrument of claim 1 , wherein said first and second broach segments include laterally engageable mating dovetail connectors.
9 . A method of preparing the proximal medullary canal of a patient's femur for receiving a hip stem implant, comprising:
providing a multi-part broach instrument including a broach handle and a segmented broach head having a plurality of broach segments;
making an anterior incision adjacent a patient's femur;
inserting said broach segments sequentially through said anterior incision;
interconnecting said plurality of broach segments in vivo;
connecting said broach handle to said broach segments; and
broaching said proximal medullary canal with the assembled multi-part broach instrument.
10 . The method of claim 9 , wherein a compression force is applied to said interconnected broach segments with an auxiliary mechanism.
11 . The method of claim 10 , wherein said auxiliary mechanism is a core shaft extending through a bore in said broach handle and a bore in each of said broach segments.
12 . The instrument of claim 11 , wherein said core shaft is axially restrained by said broach handle and has a threaded fastener portion on its distal end, and wherein the distalmost one of said broach segments includes a mating threaded fastener portion for engaging said core shaft and cooperating therewith to create a compression force on said broach segments when said core shaft is rotated in one direction.
13 . The method of claim 9 , wherein a tension force is applied to said interconnected broach segments with an auxiliary mechanism.
14 . The method of claim 13 , wherein said auxiliary mechanism is a core shaft extending through a bore in said broach handle and a bore in each of said broach segments.
15 . The instrument of claim 14 , wherein said core shaft threadedly engages said broach handle and has an unthreaded distal end for engaging the distalmost one of said broach segments to create a tension force on said broach segments when said core shaft is rotated in one direction.
16 . The instrument of claim 9 , wherein said broach segments are laterally engageable segments.
17 . The instrument of claim 16 , wherein said broach segments include mating dovetail connectors.