Really sorry to hear about your accident. I have never used fenders on a motorized bike. Several years ago I had what could have easily been a fatal accident on a motorized bike. It didn't have fenders, but it had one of those clamp on chainstay mounted chain tensioners. I was riding in a bike lane, inches away from traffic going 50 mph plus. That tensioner got pulled into the rear spokes, locking up the rear wheel. I went down hard. I had several injuries, none as bad as yours. A couple of broken bones and a lot of soft tissue damage, muscles, tendons, ligaments, etc. I was VERY lucky. I went down on the sidewalk side instead of in the street, where I would have been hit by a car/truck. A few years later, I built another motorized bike, but this time I used an engine mounted tensioner and a clamshell rear sprocket mount. Yes it cost more, but I never crashed on it.