This research seeks to develop a novel computer assisted and robotic tool that will enable less and minimally invasive surgical techniques for orthopaedic surgery while at the same time provide more precise bone shaping. The clinical focus will be on Joint Arthroplasty i.e., total knee and hip replacement procedures. The Miniature Bone Attached Robotic System (MBARS) is a miniature parallel robotic device that is attached to the operated bone and actively shapes it according to a patient specific pre-operative plan to fit an implant. As MBARS is rigidly attached to the operated bone, the two become a one rigid body eliminating the need to compute relative motions from individually tracked entities, which results in greater precision. After a one time registration of the robot.s location to the patient specific computer bone model, the robot actively mills the bone (just like a CNC machine) resulting in a precise bone surface to which the implant may be attached. Additionally, with the aid of a computer, more intricate designs that integrate more effectively with the anatomy can be implanted.