Re: Ukemi vs. Protecting your attacker
I guess the nature of the injury depends on the relative geometry between uke and nage at the point that the body fails. I tore a TFCC ligament in my wrist when I was too slow responding to an experienced partner's smooth hip rotation during a kotegaeshi.
And you don't have to use the wrist joint for this throw anyway--you can use the forearm itself (that's how I had folks do them on me while my wrist was healing), or (I'll bet) even the upper arm as the point of connection to uke's center if you do it right.