Griff, your not alone man.
When I was 19 (about 8 years ago) I also got in a bad@ss car wreck. While my injures pail in comparison to yours (I walked away with a shattered rotator cuff) I to lift and live in pain. And yes PK's are just a part of life some times. While Tylenol can be toxic in the liver and is included in most PK's there are many other meds that contain less or no Tylenol in them. I personally I take pure oxycodone (percocet) because it doesn't contain any Tylenol.
So if your going to be using these drugs long term there are defiantly other options you can discuss with your doctor if this is of concern for you. It sure as hell was for me, Fcuk Acetaminophen!! There are much better ways to destroy your liver IMO!!! lol