Crippling injuries

[Chalkarts]

Are there rules that I'm missing for broken limbs?

I was thinking about having a BBEG, instead of killing a PC he's incapacitated, doing terrible things to a limb, causing maybe Dex damage for a Leg or Str damage for an arm?

Are there any RAW for broken limbs and recovery from them?

[sithlordnergal]

Page 227 of the DMG, it details lingering injuries, how to get them, and how to heal them. You'll probably want to change the Broken Bones as any amount of magical healing technically heals them.

[Kane0]

You could just say 'you now have one less hand/eye/leg', since things like peg legs, ersatz eyes, Regenerate and the armorer artificer give you ways around that.