Clinical Application of Navigation in the Surgical Treatment of a Pelvic Ring Injury and Acetabular Fracture.

The purpose of this chapter is to review current evidence on indications, techniques, and outcomes of computer-navigated surgical treatment of pelvic ring injuries and acetabular fractures, particularly computer-navigated screw fixation.Iliosacral screw fixation of pelvic ring injury using navigation is attracting attention because the biomechanical stabilization of posterior pelvic ring disruption is of primary importance and is widely indicated because it does not require complete reduction of the fracture site. A cadaver study with a simulated zone II sacral fracture demonstrated a substantial compromise in the space available for iliosacral screws with displacements greater than 10 mm. It is possible to reduce the fracture fragment prior to intraoperative imaging in 2D or 3D fluoroscopic navigation. The use of 3D fluoroscopic navigation reportedly results in lower rates of iliosacral screw malpositioning than the use of the conventional technique or 2D fluoroscopic navigation. Moreover, compared with the conventional technique, it reduces radiation exposure and lowers revision rates. However, the malposition rate associated with 3D fluoroscopic navigation ranges from 0% to 31%, demonstrating that there is still room to improve the navigation performance.Conversely, complete articular surface reduction is required when treating a displaced acetabular fracture to prevent residual hip pain and subsequent osteoarthritic changes. Treating a severely displaced acetabular fracture by screw fixation is very challenging, even with the use of 3D fluoroscopic navigation, because of the difficulty in performing closed anatomical reduction. The indication for percutaneous screw fixation is limited to cases with a small articular displacement. Using 3D fluoroscopic navigation for open surgeries reportedly improves the quality of radiographic fracture reduction, limits the need for an extended approach, and lowers the complication rate.In conclusion, percutaneous screw fixation for pelvic ring injuries is widely indicated, and navigation makes these procedures safe and reliable. The indication for percutaneous screw fixation of acetabular fractures is limited to cases with a small articular displacement. Using 3D fluoroscopic navigation when performing open surgeries is reported to be useful in evaluating fracture reduction and screw position.