Concurrent criterion-related validity and reliability of a clinical test to measure femoral anteversion.

STUDY
DESIGN: Clinical measurement, criterion standard.
OBJECTIVES: To determine if the clinical measure of femoral anteversion is comparable to measures obtained from magnetic resonance imaging (MRI). An additional purpose of this study was to assess the intertester and intratester reliability of the clinical test.
BACKGROUND: Femoral anteversion is commonly assessed as part of the physical examination; however, limited and inconsistent data exist on the validity and reliability of the clinical test.
METHODS: Eighteen healthy adults (9 males, 9 females; mean +/- SD age, 25.4 +/- 3.3 years; body mass index, 22.9 +/- 3.4 kg/m2) participated. Each underwent 3 data collection sessions: (1) MRI to measure femoral anteversion, (2) clinical testing of femoral anteversion, measured independently by 2 physical therapists, and (3) repeated clinical testing. Validity and reliability were assessed using intraclass correlation coefficient (ICC2,3) and standard error of measurement (SEM).
RESULTS: Moderate agreement was found between the clinical test and MRI measures of femoral anteversion (ICCs of 0.69 and 0.67 for examiners 1 and 2, respectively). The SEM was similar for both examiners (5.8 degrees and 6.0 degrees ). Both intra tester (ICCs of 0.88 and 0.90 for examiners 1 and 2, respectively) and intertester (ICC = 0.83) reliability was found to be substantial.
CONCLUSIONS: In persons with a low body mass index, the clinical test to assess femoral anteversion was shown to exhibit substantial reliability, but only moderate agreement with MRI measurements. When performing the clinical test, one can be 95% confident that the true value of femoral anteversion will fall within 11.8 degrees of the clinically measured value. This relatively wide confidence interval calls into question the clinical utility of the clinical test for assessing femoral anteversion.