Accurate alignment and perfect ligament balancing are crucial to give long lasting satisfactory results to patient undergoing knee or hip replacements. Incorrect alignment can lead to abnormal wear, early mechanical loosening of new implanted prosthesis and pattelofemoral problems. The manual surgical technique involves bone cut and soft tissue balancing. During the surgery bone cuts are typically performed with reference to anatomical landmarks and available implant geometry which can give an error of +/- 3 Degree in all three axis of joint. A functional joint replacement has to be well aligned, which implies that it should be along the mechanical axis and in correct axial and rotational planes of the joint.
