First, a music video to watch while you contemplate the things set forth in this thread: http://www.youtube.com/watch?v=aLzrRAs8fdc...feature=related
With the possible exception of Twilight 2000 I don't believe that I've ever encountered any RPG or RPG-style video game that handles injury in a fully realistic manner. It is always very quick and easy to make a full recovery from serious injuries such as gunshot wounds, stab wounds, or broken legs. This is because it's probably a fair statement that the majority of gamers would rather have their character get quickly back into the action of the game instead of leaving play due to a limb permanently lost or having to take a year off for physical therapy to get back to the level of physical ability he or she used to be at. The gaming fast track recovery can be represented by anything from Cure Light Wounds to picking up and immediately using a first aid kit with your feet in a FPS to Jagged Alliance 2's healing taking place in terms of hours or days rather than months.
At the same time, though, quick and simple recovery from injury really does end up circumventing a bunch of pretty interesting real world issues. In the first place, it kind of eliminates the idea of logistical strain created on a group of people due to needing to care for lots of wounded. So in a game or RPG that is emphasizing strategy on various levels you lose that level of logistical strategy that tracking the long term injuries of casualties could create. Secondly, it eliminates the possibility to have an interesting medical system in your game, if you're interested in that sort of thing. If long term injury were handled in a detailed and realistic manner you could determine things like whether or not a bone was damaged, whether or not infection has set in, the sorts of procedures that would be required in a certain situation to stabilize someone, and perhaps even the details of field hospital management. Perhaps these things don't necessarily appeal to the general public as a whole as much as heroic firefights do, but I must not be the only person who thinks this sort of thing could be interesting to think about in the context of a RPG.
In light of this, I'd propose the idea that more detailed or realistic injury systems in RPGs could be implemented if the gameplay changed so that instead of each player having only one character, each player would have a roster of characters ready to go, kind of like the Paranoia "six pack". The characters in the roster would all be related or somehow linked to each other such that if one of them died or had to return home either permanently or for an extended period of time due to serious injuries the next character in the lineup would step up in the first character's place. So for example if we were playing some kind of medieval campaign I might have a roster of a knight, the knight's brother, and then maybe the knight's brother's faithful squire, or something like that. As each character got taken out of action as a player I could quickly and painlessly just switch to the next character sheet. This would eliminate the problems associated with someone's one and only character being out of action for a long time upon being injured and would in so doing enable more detail devoted to injury, healing, and logistics.