The scapular dyskinesis test: Reliability, agreement, and predictive value in patients with subacromial impingement syndrome

Study design: Prospective cohort.

Introduction: Assessment of scapular dysfunction is considered important in the clinical evaluation and treatment of patients with symptoms of subacromial impingement. However, sparse research has been conducted into the reliability and predictive value of clinical tests with which to identify scapular dyskinesis.

Purpose of the study: To evaluate intrarater and interrater reliability and predictive value of the Scapular Dyskinesis Test (SDT) in patients with subacromial impingement syndrome.

Methods: Forty-five patients with subacromial impingement syndrome were included. The presence of scapular dyskinesis was classified by 2 raters using the SDT. Intrarater and interrater reliabilities were examined and compared. Patients with and without scapular dyskinesis were compared in terms of Oxford Shoulder Score and EQ-5D-5L scores at baseline and 3 months, as well rating of overall improvement in shoulder condition.

Results: SDT could not be performed in 5 patients, leaving 40 patients for further analysis. Kappa with squared weights was 0.64 for rater A and 0.86 for rater B; the intrarater agreement was 88% for A and 96% for B. For interrater comparison, the Kappa value was 0.59 and agreement 86%. No statically significant differences in Oxford Shoulder Score and EQ-5D-5L baseline and change scores or overall improvement in shoulder condition at 3 months were observed between patients with or without scapular dyskinesis.

Conclusions: Intrarater and interrater reliability and agreement of the SDT were determined. The findings that functional impairment and outcomes did not differ between patients with or without the presences of scapular dyskinesis may question the clinical value of the SDT in patients with subacromial impingement syndrome.

Level of evidence: 1b.