An apparatus for evaluating motions of a joint is provided that is designed for determining stability of an anatomical joint. The apparatus includes a support frame, a fixation assembly for securing a first body segment of a joint, and a displacement assembly mounted to the support frame. The fixation assembly includes an axis of rotation moveable relative to the support frame. The displacement assembly includes a first frame pivotably mounted to the support frame and rotatably connected to a first end of the fixation assembly, and a second frame pivotably mounted to the support frame and rotatably connected to a second end of the fixation assembly.