A Simple Method for Measurement of Femoral Anteversion-Validation and Assessment of Reproducibility.

Abstract

To propose a simple method for measurement of femoral anteversion (AV) with a conventional fluoroscope, to evaluate the interobserver and intraobserver reliability of this method on the basis of human cadaver femurs, and to validate such method on the basis of computed tomography (CT). Fourteen human cadavers with 28 intact femurs were included in the study. Three blinded observers measured femoral AV of the specimen with a fluoroscope. The session was repeated 8 weeks later and CT of the femurs were performed. Mean AV values and the difference between single and mean AV values were calculated. Interobserver/intraobserver reliability of the proposed method was assessed. Correlation between AV values measured with fluoroscope and CT was calculated. Mean AV was 18.1° when measured with fluoroscope and 19.2° when measured with CT. Mean differences between single AV values were 2.2° with fluoroscope and 2.5° with CT. The mean maximum observer variation per specimen was 8.8°. Interobserver reliability was excellent (intraclass correlation coefficient: 0.853) and intraobserver reliability was good (intraclass correlation coefficient: 0.682). A high correlation was found between AV values measured with fluoroscope and CT (rho = 0.739, P < 0.01). The presented technique allows reliable and simple measurement of femoral AV with a conventional fluoroscope. The mean interobserver variation is comparable to what has been reported for CT. Maximum interobserver variation was <15° in all specimens. A clinical study will be necessary to prove the value of this technique for intraoperative adjustment of femoral AV according to the intact contralateral side.