After Group Health introduced video “decision aids” for people with knee and hip arthritis, rates of knee and hip replacement surgeries dropped sharply: By 38 and 26 percent, respectively, over six months. Costs of caring for those patients also declined: By 12 percent to 21 percent, according to a new article. Decision aids are balanced sources of information, used in shared decision making, which present evidence-based pros and cons of treatment options.