Establishment of an Accurate and Precise Alternative Intraoperative Technique for Determination of Femoral Version.

BACKGROUND

Accurate assessment of the femoral version can be challenging in the operating room. We evaluated if an observer can reliably and accurately determine when a femoral neck is parallel to the floor with a modified C-arm technique. We compared this technique to the previously reported modified Ogata-Goldsand technique for determining the intraoperative femoral version.

METHODS

To evaluate if an observer can determine when the femoral neck is level to the ground, 72 cadaveric femurs were photographed laterally at the proximal femur with the bone rotated to simulate a version ranging from -20 degrees to +20 degrees in 5-degree increments. These were arranged in a grid layout and validated through 3-fold randomization and blinding. Five investigators selected the orientation they believed to be closest to the neutral (0 degrees) femoral version. Then, 4 full-size cadavers were examined in a surgical suite. The femoral version of each full-size femoral cadaver was estimated utilizing the modified C-arm technique versus the modified Ogata-Goldsand technique, with the Kingsley and Olmsted technique used as the widely accepted standard to measure the femoral version.

RESULTS

In determining the neutral femoral neck position, observers were able to determine 0 degrees of version accurately, with the average deviation being 4.4 ± 2.4 degrees. The modified C-arm technique produced an average measurement deviating 3.2 ± 4.2 degrees from the true value. The modified Ogata-Goldsand technique had an average measurement deviation of 2.3 ± 2.6 degrees from the true angle. The modified C-arm technique had an intraclass correlation coefficient of 0.82 for different observers and 0.81 when compared to the Kingsley and Olmsted method as the standard, versus 0.72 and 0.90 for the modified Ogata-Goldsand technique.

CONCLUSIONS

Observers can accurately perceive when a femoral neck is parallel to a virtual floor, supporting the inclusion of this parameter in the modified C-arm technique. Utilization of the modified C-arm technique is comparable to the modified Ogata-Goldsand technique.

CLINICAL RELEVANCE: The relative simplicity of the modified C-arm technique versus the modified Ogata-Goldsand technique makes the modified C-arm technique a reasonable additional option for measuring intraoperative femoral version.