A Study on the Reducing of the Machining Time with Force Measurements in a MIS Robot for Total Hip Arthroplasty

Total Hip Arthroplasty is a surgical process that replaces a damaged or fractured hip joint with an artificial femoral stem and acetabular cup. It is one of the most successful operations in orthopedic surgery. However, postsurgical results depend largely on the surgeon’s skill. For a more accurate shaping of the femur as well as alignment of the inserted stem, many surgical robots for THA have been developed and commercialized. The most popular robot system for THA is ROBODOC . An earlier surgery robot showed improved results in terms of the error in the angle and in the fit of implant. However, additional surgical procedures are still required with these systems, as it uses a CT image for registration to obtain the transform between the bone coordinate and the robot coordinates. In the HWRS research group, a compact robot system known as ARTHROBOT was designed. It does not use a CT image for registration. This system uses a block-gagebased registration; therefore, CT or additional procedures are not needed. This robot is fixed to the femur with bone clamp, and the incision larger than in manual surgery. To reduce the incision size, a robot system that is fixed into the femoral cavity was designed. The performance was acceptable; however, the time required for surgery with this system is exceedingly long. In this study, a control method is suggested to reduce the time that is needed for shaping the femur. Following this, the proposed method is verified with plastic bones and bovine bones.