Purpose: This prospective study was performed to compare the accuracy of femoral version measurements following repair of femoral shaft fractures using computed tomography (CT) scanograms with 10 % of the standard dose of ionizing radiation versus standard-dose scanograms.
Methods: CT scanogram protocols that used 90 and 10 % of the usual dose of ionizing radiation were developed. Ten patients with comminuted femoral shaft fractures repaired with either an intramedullary (IM) nail or plate were imaged with both high- and low-dose CT scanograms. Postoperative version of both femurs was measured and compared between the two dose scans using the Bonesetter application. This was a prospective blinded controlled study at a level 1 trauma centre. Statistical analysis was performed, including standard deviation (SD) and paired t test. Significance was set at p < 0.05.
Results: Comparison of femoral version measurements between the 90 and 10 % dose scanograms on the native and repaired sides were insignificant (p = 0.870 and p = 0.737, respectively). The difference between native and repaired femurs had an average error of 2.0 ± 1.1° for both the high- and low-dose scans and was insignificant (p = 0.742).
Conclusions: Reducing the dose of ionizing radiation in a CT scanogram by 90 % has no significant effect on the accuracy of femoral version measurement. This simple change can significantly reduce patient radiation exposure while accurately measuring femoral version and length.
Keywords: Anteversion; CT scanogram; Femoral version; Femur fracture; Intramedullary nail.