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

BACKGROUND: The 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. OBJECTIVE: To 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. DESIGN: Within day intra- and inter-rater reliability, agreement, and diagnostic accuracy study. METHOD: Participants 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. RESULTS: The 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. CONCLUSION: The 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.