I'm starting up a Dark Sun game and also created a recent thread (the one to which Garthanos thought he was responding, I imagine) about the Injury Deck. These are the house rule implementation thereof I came up with:
INJURY DECK: When a PC is reduced to 0 hit points or fewer during an encounter that PC accrues an injury. Make a saving throw after the encounter is complete. On a successful roll, the PC suffers a minor injury. On a failed roll, the PC suffers a major injury. Injuries function similarly to the disease track. All injuries begin at Stage 1. Stage 0 represents recovery from the injury, and Stage 3 represents character death.
Injury Progression: Once you’re injured, make an Endurance check after each extended rest to see if you improve, worsen, or maintain your current condition. An injury specifies two target Endurance DCs: a lower DC (easy DC for level) to maintain and a higher DC (medium DC for level) to improve.
Maintain: If the check result beats the lower DC but doesn’t beat the higher one, your condition remains the same.
Improve: If the check result beats the higher DC, your condition improves—move one step to the left on the injury track.
Worsen: If the check result doesn’t beat either DC, your condition worsens—move one step to the right on the injury track.
Cure: When you reach the left edge of the track, you are cured and stop making Endurance checks.
Final State: When you reach the right edge of the track, the final state of the injury takes effect, and the character dies.
Heal Skill: An ally can use a Heal check in place of your Endurance check to help you recover from a disease, as described in the Player’s Handbook.
In addition, the Profit from Setbacks variant is in use.
Profit from Setbacks: Some characters thrive on challenges. Some players like to overcome steep obstacles. If your campaign caters to that sort of activity, consider using this option to allow characters to turn their wounds into opportunities.
Once per encounter per injury, if an injured character meets the trigger described in the text below for his or her injury location, he or she can attempt to turn the pain of the injury into a momentary advantage.
The character makes a check as a free action using the indicated ability against an easy DC of the character’s level. On a success, the character benefits from the positive effect. On a failure, the character suffers the negative effect. Even if a character has multiple injuries, he or she can use this option only once per turn.