Accuracy of measurement of femoral anteversion in femoral shaft fractures using a computer imaging software: a cadaveric study.

INTRODUCTION

Rotational malalignment after intramedullary nailing of femoral fractures remains an unresolved problem. Various techniques have been described to address this problem, with limited success. In this cadaveric study, we describe the determination of the femoral anteversion (FAV) angle utilizing a new imaging software program which allows us to generate and manipulate reformatted virtual images from standard DICOM (Digital Imaging and Communications in Medicine) images.

MATERIALS AND METHODS

Eleven intact femoral specimens were scanned by CT before and after fracture induction in standardized fashion. The obtained DICOM image datasets were uploaded to the new software tool. From this, we obtained reformatted virtual fracture fragment images, which enabled us to reconstruct the femoral anatomy and determine FAV measurements. We then compared FAV measurements before and after fracture induction to determine if there were any statistically significant differences.

RESULTS

Fracture induction generated 5 AO type A and 6 AO type B fractures. In the specimens prior to fracture induction, we were able to determine the mean FAV to be 17.94° ± 4.48°. Additionally, analysis of the fractured femoral specimens revealed the new mean FAV to be 16.26° ± 4.83°. Statistical analysis of these two measurement groups did not demonstrate statistical significance. When a sub-analysis was performed of the FAV measurements between the two different AO fracture types, there also were no statistically significant differences.

DISCUSSION

Through new imaging software that allows us to reformat standard DICOM images and generate virtual fracture fragments, we were able to determine the appropriate FAV. We feel that this technique can potentially be integrated into the imaging algorithm for femoral shaft fractures in the future, and can potentially optimize clinical outcomes by allowing the orthopaedic surgeon to determine precisely the appropriate native FAV.