Intraobserver reliability of 4 physiologic movements of the shoulder in subjects with and without symptoms
Objective: To assess intraobserver reliability of 4 physiologic movements of the shoulder. Design: Test-retest analyses. Blinded data entry. Setting: Outpatient department in National Health Service teaching hospital. Participants: Forty-five asymptomatic volunteers and 45 subjects with shoulder symptoms. Interventions: Not applicable. Main Outcome Measures: Intraclass correlation coefficients (ICC), 95% confidence intervals, and standard error (SE) of measurements for bilateral measurements of shoulder flexion and abduction (gravity dependent inclinometer), shoulder external rotation (tape measure), and shoulder internal rotation (visual estimation). Results: For subjects without symptoms, single measure ICC results ranged from .85 to .96; SE of measurement results for the angular movements ranged from 2.1° to 2.8° and for the linear measurements 1.1 to 1.6cm. For subjects with symptoms, single measure ICC results ranged from .82 to .98; SE of measurement results for the angular movements ranged from 1.5° to 13.3° and for the linear measurements 1.3 to 1.6cm. Conclusions: With the exception of painful shoulder flexion in the group of subjects with symptoms, the single-measure ICC results were very good to excellent and the highest SE of measurement values were 5.3° for the angular measurements and 1.6cm for the linear measurements. For clinicians involved in the management of subjects with shoulder symptoms, the SE of measurement results provide guidance as to the error associated with the individual measurements. Using the SE of measurement results, a clinician may determine if a clinically important change, be it negative or positive, has occurred as a result of any intervention offered.