Diagnostic accuracy of the flexion-rotation test and cut-off value in acute whiplash-associated disorders: A secondary analysis of a cross-sectional study1

Background

Headache is common in people with whiplash-associated disorders (WAD). Upper-cervical structures may be involved in the presence of headache, and the flexion-rotation test (FRT) has been widely studied to assess cervicogenic headaches.

Objectives

To evaluate the diagnostic accuracy of the FRT for the presence of headache in people with WAD, and its cut-off value.

Methods

In this secondary analysis from a previously published study 47 people with WAD were consecutively recruited, 28 with and 19 without headache. FRT was assessed by a single blinded evaluator, with production of headache during the test as the reference standard. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were assessed through cross-tabulation. The cut-off value was calculated based on the Youden's Index. The positivity of the test was defined based on: a) range of motion (ROM) <32°; and ROM <32° combined with headache provocation.

Results

Differences between groups were significant for both most and least restricted sides of FRT in terms of ROM (p < 0.001). For the most restricted side, moderate sensitivity and specificity was found (82.1 % [95 %CI = 68.4 %, 95.8 %] and 63.2 % [95 %CI = 40.8 %, 85.6 %], respectively) when only ROM was considered. When headache provocation was included, sensitivity and specificity were 78.6 % (95 %CI = 63.1 %, 93.7 %) and 68.4 % (95 %CI = 47.5 %, 88.5 %), respectively. A cut-off value of 31.5° was found.

Conclusion

Moderate diagnostic accuracy through both ways of assessing the FRT was found for this test to detect the presence of whiplash-associated headache from upper cervical origin. The FRT may be considered positive if ROM is less than 31.5°.