Assessing Femoral Rotation: A Survey Comparison of Techniques.

Abstract

To compare 3 common techniques for assessing femoral malrotation through a response analysis. Ten intact human cadaveric pelvis-to-knee specimens were used to create a fracture model. A mobile C-arm x-ray system was used to capture images of an intact control femur and a contralateral test femur on each specimen. A midshaft femoral osteotomy was created on the test femur and it was then internally and externally rotated in 5-degree intervals up to 20 degrees. Images were obtained and stored at each increment of malrotation. Eight surveys of 20-paired images each were generated and presented for surgeon review. Accuracy of predicting femoral malrotation using the true lateral technique (TLT), neck horizontal angle (NHA) method, and lesser trochanter profile (LTP) was measured. Eighty-five surgeons completed a survey with 80 surgeons (94%) acknowledging the use of a described fluoroscopic method for assisting with rotational alignment. Surgeons correctly accepted a fracture rotated less than 20 degrees and rejected a fracture rotated 20 degrees or more 63% of the time. The ability to correctly identify 20 degrees of malrotation varied per technique used to assess rotation. With the LTP and NHA method, 67% of surgeons responded correctly. Surgeons performed significantly worse when using the TLT with only 53% providing correct responses (P < 0.0001). Surgeons using described fluoroscopic methods to identify acceptable rotation in femoral shaft fractures are correct 63% of the time. The LTP and NHA techniques are equally reliable and more effective than the TLT at detecting clinically significant femoral malrotation.