Responsiveness of six outcome assessment instruments in total shoulder arthroplasty

To assess the responsiveness (sensitivity to change) of 6 shoulder outcome instruments.

In a prospective cohort study of 153 total shoulder arthroplasties, outcome was measured by the Short Form 36 (SF-36); Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH); Shoulder Pain and Disability Index (SPADI); American Shoulder and Elbow Surgeons questionnaire for the shoulder (ASES); and the Constant (Murley) Score (CS). Responsiveness was mainly quantified by effect sizes before and 6 months after operation. Sensitivity analysis of the effects by receiver operating characteristic (ROC) curves was performed to determine the instruments' ability to classify effects into global health change assessment categories.

Effect sizes of the self-assessment total scores were 0.71, 1.19, 2.10, and 2.13 for the SF-36, DASH, SPADI, and ASES, respectively. The clinical ASES and the CS had effect sizes of 1.87 and 2.23, respectively. The SPADI (effect size 2.12) and the CS (effect size 2.72) were most responsive for pain. For functioning, the patient ASES (effect size 2.10), the CS (effect size 1.82), and the clinical ASES (effect size 1.85) were almost equal. The SF-36 bodily pain scale and most scores of the condition-specific instruments showed a significant area under the ROC of up to 0.77.

The SPADI and/or the CS are the most suitable for short, responsive, shoulder-specific assessment. The more expensive patient ASES can be used for most responsive shoulder-function assessment. For a comprehensive measurement of health and quality of life, the DASH and/or the SF-36 should be added to the set.