Poster 3: Three-dimensional scapular attitudes measured with the optotrak probing system: a reliability study on 30 shoulders

Abstract

Objective: To evaluate the intra- and intersessions reliability of 3-dimensional scapular attitudes measured with a new method. Design: Test-retest. Setting: 2 sessions with the same protocol repeated by the same evaluator. Participants: 15 healthy subjects (30 shoulders). Interventions: 3-dimensional scapular attitudes were measured at 70° of flexion, 90° of abduction, and arm at rest, using the Optotrak probing system. 3 trials were recorded for each position. For each trial, the posterolateral tip of the acromion, the inferior angle, and the edge of the spine of the scapula were digitized. Main Outcome Measure: 3-dimensional scapular attitudes in external and internal rotation, anterior and posterior tilting, and anterior and posterior transverse rotation planes. Results: The intrasession reliability at 70° of flexion and 90° of abduction was excellent, as indicated by intraclass correlation coefficients (ICCs), which ranged from .87 to .99, and standard errors (SEs) of measurement, which varied from 0.4° to 1.7°. The intersessions reliability was poorer, with ICCs ranging from .37 to .56, and SEs of measurement varying from 2.7° to 4.7°. Conclusion: For studies that look at the effect of rehabilitation interventions on 3-dimensional scapular attitudes, findings should be interpreted in light of the magnitude of measurement errors.