[Principles and new concepts in computer-navigated total hip arthroplasty].

Combined component placement of cup and stem is closely correlated to stability, functionality and wear in total hip replacement (THA). Computer-navigated orthopedic surgery offers a reliable control method for a complex three-dimensional situation. Imageless navigation systems without the need of preoperative or intraoperative image acquisition and exposure to radiation have been proven to increase the accuracy of positioning the acetabular component and measure intraoperative leg length and offset changes precisely. A new development in this field is the noninvasive external femoral reference marker array system in conjunction with an imageless measurement technique. The future generation of imageless navigation systems will switch from simple measurement tasks to an integral part of the surgical process in navigated THA. The aim will be to find an optimized complementary component orientation with improved postoperative functionality and optimized range of motion without impingement.