Effect of patient decision aid was influenced by presurgical evaluation among patients with osteoarthritis of the knee

Background: Decision aids help patients make total joint arthroplasty decisions, but presurgical evaluation might influence the effects of a decision aid. We compared the effects of a decision aid among patients considering total knee arthroplasty at 2 surgical screening clinics with different evaluation processes. Methods: We performed a subgroup analysis of a randomized controlled trial. Patients were recruited from 2 surgical screening clinics: an academic clinic providing 20-minute physician consultations and a community clinic providing 45-minute physiotherapist/nurse consultations with education. We compared the effects of decision quality, decisional conflict and surgery rate using Cochran-MantelHaenszel chi(2) tests and the Breslow-Day test. Results: We evaluated 242 patients: 123 from the academic clinic (61 who used the decision aid and 62 controls) and 119 from the community clinic (59 who used the decision aid and 60 controls). Results suggested a between-site difference in the effect of the decision aid on the patients' decision quality (p = 0.09): at the academic site, patients who used the decision aid were more likely to make better-quality decisions than controls (54% v. 35%, p = 0.044), but not at the community site (47% v. 51%, p = 0.71). Fewer patients who used decision aids at the academic site than at the community site experienced decisional conflict (p = 0.007) (33% v. 52%, p = 0.05 at the academic site and 40% v. 24%, p = 0.08 at the community site). The effect of the decision aid on surgery rates did not differ between sites (p = 0.65). Conclusion: The decision aid had a greater effect at the academic site than at the community site, which provided longer consultations with more verbal education. Hence, decision aids might be of greater value when more extensive total knee arthroplasty presurgical assessment and counselling are either impractical or unavailable.