Abstract: A clamp device, cutting guide, and clamp slider used together in preparation to cutting of the distal end of the femur bone during total knee replacement surgery. The clamp device includes an upper arm and a lower arm rotatably secured to one another in a scissor-like manner. A curved movable component is rotatably secured to the proximal end of the lower arm. The clamp device is positioned around a portion of the distal end of the femur bone so that the distal end of the upper arm grasps a posterior ridge of the femur bone and the movable component of the lower arm is positioned along the contour of the deepest part of the trochlear groove, thereby defining a plane through the deepest part of the trochlear groove of the femur bone. Next, a clamp slider is removably secured to a cutting guide so that channels defined in the clamp slider and cutting guide are substantially aligned with one another.