The helicopter hit the ground with very little lateral movement, could that still result in spike knock? I've only seen spike knock when there is forward speed at ground contact when the skids come to a sudden stop causing the transmission to rock forward. Not-withstanding, vertical speed at ground contact probably bent the cross tubes and deformed the tub, where the tail boom connects to the main body would also be worth a close look, I bet the skins on the tail boom weren't very round any more. I'd be surprised if it was flyable after the pilot eventually woke up. Assuming the big bump when he arrived at the bottom woke him up. He sure wasn't very awake before that. Sad to see needless damage caused to a nice helicopter.