Set a Break wrong and you'll hobble for life. Keep a Splint handy and fix yourself up the right way or you'll regret it for the rest of your days.
Broken Bones can be cured with a Splint, or cured by time (~28 hours).
Scout's movement speed gets slow and Hunger decreases 3,5x more.
Misc. Notes Edit
Oddly, despite the description saying that not properly treating a broken bone will cause long-term ill effects, the player can simply wait for the break to heal naturally without using a Splint and have no issues with movement or stats afterwards. It's likely flavor text.