Reliability, agreement, and diagnostic accuracy of the Modified Lateral Scapular Slide test

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BackgroundThe Lateral Scapular Slide Test is a static test used in clinical settings to assess medio-lateral inferior angle displacement and scapular asymmetry at three different degrees of shoulder abduction. However, there is no evidence in the literature about the reliability and diagnostic accuracy of a modified LSST (arm elevation in the scapular plane with loading) in a symptomatic population. ObjectiveTo assess the intra- and inter-rater reliability, agreement, and diagnostic accuracy of the MLSST ​ (Modified Lateral Scapular Slide Test) in subjects with and without shoulder symptoms. A new test position is examined, in which the arm is held in 90° of elevation in the scapular plane with 1 kg load. DesignWithin day intra- and inter-rater reliability, agreement, and diagnostic accuracy study. MethodParticipants included 25 (42 ± 2.7 years) subjects with shoulder symptoms and 25 (40 ± 2.1 years) asymptomatic control subjects. Two raters, blinded to each other's outcomes, measured the distance between the inferior scapular angle and T7 at arms by the side, hands on hips and 90° of arm elevation in the scapular plane with 1 kg load. Measurements were performed twice, bilaterally. Intraclass correlation coefficient (ICC), minimal detectable change (MDC95%) and diagnostic accuracy were calculated. ResultsThe ICCs for intra- and inter-rater reliability were good to high in both shoulders of symptomatic and asymptomatic groups. The MDC95% in the symptomatic group ranged between 0.67 and 1.40 cm in the symptomatic shoulder and 0.72–1.16 cm in the asymptomatic shoulder. The asymptomatic group presented a MDC95% ranging between 0.63 and 1.52 cm in the dominant and 0.60–1.41 cm in the non dominant shoulder. Positive and negative likelihood ratios ranged between 0.67–5.50 and 0.81–1.11, respectively. ConclusionThe MLSST had good reliability and agreement properties to assess scapular position in both groups. However, no test position had clinical utility as a diagnostic criterion for shoulder pathology.