Diagnostic Accuracy of Clinical Tests for the Indirect Assessment of Hip Abductor Muscle Strength in Community-Dwelling Older Women

Abstract Objective The objective of this study was to determine the accuracy of 3 clinical tests (lateral step [LS], tandem gait [TG], and single-leg stance [SS]) in identifying older women with reduced hip abductor muscle strength and to determine the post-test probability of each test and of their combination in changing the certainty of diagnosis. Methods In this cross-sectional study, a total of 123 older women received clinical testing to obtain the variables LS height, time for TG execution, percentage of errors in TG, and time of permanence on SS and were tested for isometric hip abductor peak torque using an isokinetic dynamometer. Only the dominant lower limb was evaluated. Multiple linear regression analysis with adjustment was performed to determine the association among variables, followed by the receiver operating characteristic curve to identify clinical variables that can discriminate older women with reduced abductor muscle strength. Post-test probability was then calculated based on the receiver operating characteristic curve data. Results Although the 4 clinical variables showed correlation with abductor peak torque, only LS and TG time were able to discriminate reduced abductor muscle strength with low accuracy (area under the curve was between 0.5 and 0.7). However, the combination of LS and TG time increased post-test probability from 47% (prevalence of weakness in the population) to 76% when both tests were positive and reduced it from 47% to 18% when both tests were negative. Conclusion The combination of the LS test and TG time is useful for the indirect assessment of hip abductor strength in community-dwelling older women. Impact Hip abductor muscle strength is extremely important for function in older women. This study presents clinicians with simple, fast, and inexpensive methods for assessing hip abductor muscle strength.