Precise Intra-operative Assessment of Rotation in Femoral Fracture Nailing

Background: A novel modification of an existing technique was developed to allow precise fluoroscopic assessment of rotational alignment of the fractured femur during intramedullary nailing. It is hypothesized that this will reduce the incidence of rotational malalignment which is reported to occur in 20-30 % of femoral fractures managed with intramedullary nails. The neck lateral technique has been described to assess the rotational alignment of the femur, however, observation error renders it increasingly inaccurate with C arm obliquity or hip flexion. Method: The neck lateral technique was modified with a calculation to correct for the observation error that occurs with obliquity of the C arm to the femur. This was tested on an adjustable radiopaque sawbone model in a blinded fashion. Results: When tested on the sawbone at random settings of anteversion between 0o and 60° the mean error was 2.1° (std error 1.8o). Conclusion: Femoral anteversion can be accurately assessed intra-operatively with fluoroscopy by measuring the femoral neck lateral with consideration of hip flexion and the obliquity of the X-ray tube. Corresponding Author