The C-arm is routinely used introperatively to control the anatomic structures during osteotomies and during reposition and nailing of the femoral neck fractures. Fluoroscopic navigation has been introduced in spinal surgery and it is a widely accepted tool for pedicel screws. It has been proven that fluoroscopic imaging in two planes shows an adequate reproduction of the 3-dimensional anatomy and enables a realistic acquisition for computer-assisted navigation. This experience with the Medtronic system is now adapted for application as the „Viking System“ for total knee replacement using the Genesis II knee arthroplasty. After experimental cadaver studies and critical evaluation the system was tested the first time in our clinic during live surgery. In the first series of 40 Genesis II TKR we could establish a high degree of accuracy and reproducibility with the fluoroscopic navigation. Several advantages using the fluoroscopic navigation can be shown:
The navigation offers an online documentation at each step during surgery These data give a good background for further studies Fluoroscopic assisted navigation needs only very short radiation exposure Fluoroscopic imaging is superior to virtual pixels in other systems There is no limitation to use fluoroscopic navigation in case of severe destruction of the knee or in case of severe contracture of the ipsilateral hip or ankle joint The intraoperative and postoperative controls show a deviation of the alignment of less than 2 degrees. During the study we could find a reduction of the time of surgery. The examination of additional laxity tests at various degrees of flexion with the trial implants in situ give an assessment of the ligament stability. Fluoroscopic assisted navigation may be used during the routine TKR to be prepared for the difficult case and to avoid malalignment in the routine TKR. Further investigation i. e. in a prospective study may reveal the advantage of navigation in correlation to the clinical outcome and the survival rates of the TKR.
