Does the Duncan-Ely test predict abnormal activity of the rectus femoris in stroke survivors with a stiff knee gait?

Abstract

ObjectiveTo determine the diagnostic value of the Duncan-Ely test in predicting abnormal rectus femoris activity during gait in stroke survivors walking with a stiff knee gait.DesignCross-sectional diagnostic study.SubjectsA total of 95 patients with chronic stroke.MethodsDuring physical examination, the Duncan- Ely test was performed and scored. Surface electromyography of the rectus femoris was then recorded during dynamic gait. To determine the diagnostic value, the results of the Duncan-Ely test and surface electromyography recordings (gold standard) were compared.ResultsThe Duncan-Ely test had a sensitivity of 73%, a specificity of 29%, a positive predictive value of 60%, and a negative predictive value of 42%. The area under the curve was 0.488 (95% CI 0.355– 0.621, p = 0.862), showing that the Duncan-Ely test is not better than random guessing.ConclusionThe Duncan-Ely test has no predictive value for determining abnormal activity of the rectus femoris during gait. Using this test can lead to incorrect identification of abnormal rectus femoris activity, which might hamper the selection of optimal treatment options. We recommend stopping use of the Duncan-Ely test to predict rectus femoris overactivity during swing, and instead use surface electromyography.LAY ABSTRACTAfter stroke, some patients have difficulty bending their knee when they swing their leg forwards. This can be the result of the rectus femoris muscle being too active. It is important to know whether this is the case. If the rectus femoris is too active, we can select a treatment option that aims to reduce its activity. Healthcare professionals often use the Duncan-Ely test, to test for overactivity of the rectus femoris. However, it is not known whether this test is reliable. This study therefore compared the Duncan-Ely test with a measurement in which the activity of the rectus femoris was recorded during walking. No correlation was found between the score of the Duncan-Ely test and the activity of the rectus femoris during walking. We conclude that healthcare professionals should no longer use the Duncan-Ely test to assess overactivity of the rectus femoris, but should replace it with surface electromyography.