Instrumentation for use in orthopaedic surgery

In combination, a set of instruments for establishing and verifying a rotational alignment angle and a predetermined valgus angle for a knee joint during total knee arthroplasty and for assisting a surgeon in choosing the proper prosthetic components and ensuring a proper soft tissue balance for the knee joint prior to resection of the distal femur, the knee joint including a femur and tibia interconnected by soft tissue, the combination including;

• an angular alignment guide, said angular alignment guide including means for establishing rotational alignment guide marks on the distal end of the femur, said guide marks relating to the preferred rotational angle for a knee joint;
• a tensor apparatus for placement between the femur and tibia of the knee joint, said tensor apparatus including means for tensioning the soft tissues interconnecting the femur and tibia;
• and
• measurement means connectable to the tensor apparatus for indicating to a surgeon the proper size of prosthetic components compatible with the knee joint and for indicating to the surgeon the space between the tibia and femur, wherein said measurement means includes a femoral sizing guide which is slidably accommodated within the tensor and includes an arm adapted for contacting an anterior surface of the femur when the knee joint is positioned in flexion, the measurement means further including a flexion polymer thickness guide which is positioned in overlying relationship to the femoral sizing guide and includes indicia thereon relating to the size of the space between the femur and the tibia when the knee joint is positioned in flexion, wherein the measurement means further includes an extension polymer thickness guide which is carried by the tensor when the knee joint is positioned in extension and includes indicia thereon which relates to the size of the space between the femur and tibia when the knee joint is positioned in extension.

A method of establishing and verifying a rotational alignment angle and a predetermined valgus angle for a knee joint during total knee arthroplasty and for assisting a surgeon in choosing the proper prosthetic components and ensuring a proper soft tissue balance for the knee joint prior to resection of the distal femur, the knee joint including a femur and tibia interconnected by soft tissue, the method comprising the steps of:

• a) surgically exposing a knee joint and placing the knee joint in a flexion position, the joint including a proximal tibia and a distal femur, the distal femur including posterior condyles;
• b) providing a rotational alignment guide and inserting said rotational alignment guide into the femur and aligning the rotational alignment guide with known anatomical landmarks;
• c) providing a saw blade and guiding said saw blade within slots formed in the rotational alignment guide for resecting the posterior condyles so that the surface formed is substantially parallel to the tibia;
• d) providing a tensioner device and inserting said tensioner device between the tibia and femur and manipulating the tensioner device until a predetermined amount of force is applied to the tensioner device to separate the femur and the tibia;
• e) providing a femoral sizing guide and placing said femoral sizing guide onto the tensioner device until a portion of the femoral sizing guide contacts the femur, the femoral sizing guide includes a plurality of indicia thereon for indicating the size of a femoral component required for the femur;
• f) providing a flexion poly thickness guide and placing said flexion poly thickness guide onto the tensioner device, the flexion poly thickness guide including indicia thereon for indicating the size of a space between the femur and the tibia with the knee joint in flexion;
• g) obtaining a reading from the femoral sizing guide;
• h) obtaining a reading from the flexion poly thickness guide;
• i) positioning the knee joint in an extended position,
• j) inserting the tensioner device between the tibia and femur and manipulating the tensioner device until a predetermined amount of force is applied to the tensioner device to separate the femur and the tibia;
• k) providing an extension poly thickness guide and placing said extension poly thickness guide onto the tensioner device, the extension poly thickness guide including indicia thereon for indicating the size of a space between the femur and the tibia with the knee joint in extension;
• l) obtaining a reading from the extension poly thickness guide;
• and
• m) subtracting the reading obtained from the extension poly thickness guide from the reading obtained from the flexion poly thickness guide to obtain a difference, wherein the difference indicates a variance to be factored into the amount of femur to be resected to accommodate a prosthetic component.