Ligament balancing femoral trial

An instrument system for setting ligament tension between a distal femur and a proximal tibia during total knee arthroplasty, comprising

• a rod for mounting in an intramedullary canal of a distal femur, the rod having an extension portion extending outwardly of the distal femur along a first axis;
• a first drive element mounted on the rod portion extending from the distal femur and rotatable about a second axis parallel to and offset from the first axis;
• a body rotatably mounted on the extension portion of the rod for rotation about the first axis, the body having a second drive element engaging the first drive element whereby rotation of the first drive element about the second axis rotates the body with respect to the first axis, the body further comprising a third drive element extending about a third axis offset from the first and second axis;
• a ligament tensioning element mounted on the body for movement with respect thereto, the ligament tensioning element having a foot for engaging a posterior condyle of a femur and having a fourth drive element extending generally parallel to and spaced from the third drive element;
• and
• a fifth drive element engaging both the third and fourth drive elements for moving the ligament tensioning element with respect to the body along the third axis.