According to research published in The Journal of Bone and Joint Surgery (2005) a daily dose of Vitamin C for 50 days after is effective at reducing the prevalence of Complex Regional Pain Syndrome (CRPS) after wrist fractures.
They weren't clear on the mechanism, but it looks like Vitamin C is a cheap an effective way to reduce risk.of CRPS.
These conclusions are supported by a meta-analysis of a number of similar studies in 2015, which concluded that a 50 day course of Vitamin C at 500mg per day reduced the 1 year risk of develop CRPS after wrist fracture.