Apparatus for knee prosthesis

Claim 1

A modular apparatus for use in the preparation of bone surfaces and the implantation of a modular total knee prosthesis in a patient, which apparatus comprises: (a) an extendable rod having a distal end and a proximal end, means for adjusting the length of the rod, means for adjusting the lateral alignment and angular orientation of the proximal end of the rod, clamp means associated with the distal end of said rod for clamping said distal end to the ankle region of the patient's leg and combination fixing means and cutting platform associated with said proximal end of the rod for attaching said proximal end to the upper end of the patient's tibia while aligning the cutting platform close to the tibial plateau; (b) an adjustable stylus for aligning said cutting platform at the correct level for resecting the tibial plateau; (c) a modular stem/fin template for determining the peripheral size of the resected proximal tibia and including a raised cylindrical hollow tube for aligning a stem/fin punch; (d) a stem/fin punch comprising a central hollow cylindrical tube with a distal chisel edge and two fins extending radially from said tube at a predetermined angle and each having a distal chisel edge; (e) a push rod which fits into said hollow cylindrical tube of said stem/fin punch; (f) an alignment fork attached to an intramedullary rod adapted to be introduced into a medullary canal of the patient; (g) a femoral distractor comprising a handle, a rail adapted to slide onto the alignment for, a lateral arm and a medial arm, each of which has associated means for separately raising and lowering each arm; (h) a drill guide adapted to slide along the rail of the femoral distractor and having a plurality of holes for accepting locating pins; (i) a distal cutting guide comprising a flat plate having a top surface and a bottom surface and integral flanges extending from said bottom surface and each being inset from one edge of said surface, each of said flanges having a locating hole extending therethrough; (j) a modular cutting guide for guiding a saw blade to make cuts required for a femoral component prosthesis, comprising a substantially rectangular frame having a top wall and a bottom wall, each of said walls being defined by substantially parallel planar outer and inner surfaces wherein each outer surface provides a flat cutting plane and the inner surfaces define an open window within which is located an intermediate solid block having an angled top surface and an angled bottom surface, each of said angled surfaces providing a guide for making a chamfer cut, said angled top surface being spaced apart from the top inner surface of said window and said angled bottom surface being spaced apart from the bottom inner surface of said window by gaps which provide a surgeon with a clear view of the surfaces being cut; (k) a femoral sizer for determining the size of the patient's femur, comprising a body portion having locating holes, a central tubular orifice for accepting a feeler element and indicating means for indicating the depth of the feeler element within said orifice when the sizer is located on the patient's femur, thereby providing a determination of the size required for a modular cutting guide; (l) a reamer guide for correct location of a reamer for preparing a cavity to locate a femoral prosthesis peg, which reamer guide comprises a flat plate having a top surface and a bottom surface, a hole extending through the plate, a tubular bushing extending from said top surface and lined up with said hole and locating pegs extending from said bottom surface; (m) a patella resection guide comprising a scissor-type clamp having distal gripping arms, each of said arms defining a cutting surface and gripping teeth, said gripping teeth being inset below the plane of the associated cutting surface; (n) a patella handling instrument providing alternative template and clamping functions comprising a scissor-type member having a first pivotal arm with a distal end and a second pivotal arm with a distal end; the first arm having a swivable platform located at its distal end, the surface of said platform facing inwardly toward said second arm and said second arm having means to interchangeably grip and hold either;--(i) a modular patella template having holes to accept drills, or (ii) a clamp member adapted to clamp a patella prosthesis to a resected patella.