[Navigation-assisted nailing of femoral shaft fractures--experimental and clinical results].

AIM

The aim of the study was to evaluate the application of a navigation system (Brainlab) to control length and torsion intraoperatively while nailing a femoral shaft fracture.

METHOD

At first the system was tested with 10 fractured synthetic bones. The postoperatively reached length and torsion were measured and the difference to the envisioned values statistically evaluated. Clinically we used the navigation system for patients with complex femoral shaft fractures. We always performed a preoperative computed tomography of the opposite leg to analyse the axis and fixed the fractured leg on these parameters using the navigation system. We noticed as improvement opportunities, the duration of the operative steps and the radiation exposure. The operative result was radiologically controlled and the torsion and length differences to the intraoperative measurement evaluated. Furthermore, we analysed the duration of the operation steps including the additional radiation exposure.

RESULTS

There were no technical problems during operations on the synthetic bones. The accuracy was with +/- 5 degrees or +/- 2 mm good enough to use the already approved system clinically. The navigation system was used for 17 operations. All navigation-assisted operations were completed successfully. It took an average time of 32 min to install the navigation system and required an additional X-ray time of 44 sec. The average postoperative rotational deviation was 5.5 degrees . The average difference in length was 2 mm.

CONCLUSION

The application of a navigation system for repositioning of femoral shaft axes and controlling the length and torsion while nailing complex femoral shaft fractures is associated with some additional work. Nevertheless, in our study a relevant rotational deviation can be avoided by using the navigation system. To prove the advantage of the navigation system over the conventional technique, clinical studies with larger number of cases are necessary.