Movement mapping as dynamic preoperative surgical planning in total hip replacement. A precondition to navigation?

The purpose of the present study was to develop and present a computer program for preoperative simulation of implant components placement in total hip alloarthroplasty, and its influence on the possible range of motion (ROM). We evaluated a computer simulation for preoperative estimation of range of motion (movement mapping) in total hip replacement. The computer program was based on Borland C++. The system had an open data port, so the data could be transferred to an Excel spreadsheet for statistical evaluation. With the developed virtual computer simulation, a practical model was established. The model showed range of motion patterns which correspond to clinical experience. ROM was best at a shaft anteversion between 20 degrees and 30 degrees. ROM had its maximum with a CCD angle of 120 degrees -130 degrees. Acetabular cup anteversion was optimal between 10 degrees and 20 degrees, and cup inclinations were optimal below 40 degrees. The presented movement mapping system seems to be a reliable option for dynamic preoperative planning, which may be a prerequisite for the use of intraoperative navigation systems.