Background Subacromial decompression surgery and rotator cuff repair surgery are often used to treat shoulder pain but evidence suggests these surgeries provide limited clinical benefit and may cause harm. We developed a patient decision aid – guided by the International Patient Decision Aids Standards (IPDAS) – that presents evidence-based information on the benefits and harms of these surgeries for shoulder pain compared to non-surgical options.

Objective To evaluate whether our patient decision aid for people considering shoulder surgery influences treatment intentions, knowledge of options, attitudes towards shoulder surgery, percentage likely to make an informed choice, and decisional conflict, and whether the display of options in the decision aid influences these outcomes.

Design Online randomised controlled trial.

Methods Participants (n=425) with non-traumatic shoulder pain considering shoulder surgery were recruited online and randomised to i) a co-designed patient decision aid outlining the benefits and harms of shoulder surgery and non-surgical options (participants were further randomised to two versions of the decision aid: options side-by-side vs. top-and-bottom); and ii) information about shoulder pain from the National Health Service (NHS). Treatment intentions (as a continuous and dichotomous variable) was the primary outcome. Secondary outcomes included knowledge of options, attitudes towards shoulder surgery, percentage likely to make an informed choice, and decisional conflict. Multivariate linear and logistic regression models were used to evaluate between-group differences in outcomes. All outcomes were transformed to a 0–100 scale.

Results 409 participants (96%) had post-intervention data. Mean age was 41.3 years, 44.2% were female, and mean shoulder pain over the last week was 6.3 out of 10. At baseline, mean treatment intentions was 73.3 (where 100 indicates definitely intending to have surgery) and 90.1% intended to have shoulder surgery (score of >50/100 for treatment intentions). Post-intervention there was no between-group difference in mean treatment intentions (decision aid: 72.4 vs. control: 75.7, adjusted mean difference [MD] -0.2 on a 0–100 scale, 95% CI: -3.3 to 2.8) and percentage intending to have shoulder surgery (decision aid: 85.8% vs. control: 91.7%, adjusted Odds Ratio [OR] 0.7, 95% CI: 0.3 to 1.5). The decision aid slightly improved knowledge of options compared to the control (decision aid: 37.7 vs. control: 35.1, adjusted MD 4.4, 95% CI: 0.2 to 8.6), but there was no between-group difference in mean attitude towards shoulder surgery (decision aid: 73.0 vs. control: 75.3, adjusted MD -1.7 on a 0–100 scale, 95% CI: -4.4 to 1.0), percentage likely to make an informed choice (decision aid: 27.5% vs. control: 24.4%, adjusted OR 1.4, 95% CI: 0.9 to 2.3), and decisional conflict (decision aid: 22.6 vs. control: 22.7, adjusted MD -0.1, 95% CI: -1.9 to 1.7). The display of options did not influence any outcome.

Conclusions In this online trial, a co-designed patient decision aid had no effect on treatment intention, attitudes, informed choice, and decisional conflict, but a small effect on improving knowledge. Future research is needed to evaluate whether decision aids for people considering shoulder surgery are beneficial when used in discussions with health professionals and earlier in the decision-making journey.