Reliability of the Scapula Reposition Test in Subjects with Rotator Cuff Tendinopathy and Scapular Dyskinesis

The Scapula Reposition Test (SRT) is proposed to determine if a relationship exists between scapular dyskinesis and shoulder pathology. The purpose of this study was to evaluate intra-rater and inter-rater reliability of the SRT in subjects with rotator cuff tendinopathy and scapular dyskinesis. In addition, we compared subjective strength findings from the test to an objective measure made by dynamometry. The SRT was independently and randomly performed by two physical therapists in 42 subjects. The percent agreement, Cohen's kappa (κ), maximum attainable κ, prevalence and bias indexes, and prevalence-adjusted-bias-adjusted kappa were used as intra- and inter-rater reliability estimates. Finally, the point-biserial correlation coefficient (r_pb) was used for correlation analysis of objective and subjective strength findings. A moderate intra-rater (κ = 0.43; CI 95%, 0.14 to 0.73; p = 0.004) and poor inter-rater (κ = 0.08; CI 95%, -0.22 to 0.38; p = 0.61) agreement was found. Subjective strength changes during SRT and dynamometry were poorly correlated (r_pb = 0.137; CI 95%, -0.175 to 0.423; p = 0.389). The SRT cannot be recommended for clinical practice. More studies evaluating its reliability are needed as well as further research on the capability of a rater to manually detect strength changes.