Hey guys, just wanted to mention that I've managed to pretty much kick a pretty bad case of dorsal wrist impingement in my left wrist that left me unable to even do pushups, and I attribute it almost entirely to first knuckle pushups.
I've seen a lost of people on here complain about wrist pain during different exercises in different places, and as someone who's now had dorsal impingement, forearm splints, and elbow tendonitis, I cannot stress how important prehab is.
What gave me dorsal impingement six months ago was doing straddle press handstands, with apparently poorly-prepared wrists. I'd done them fine before, but I dropped them in a workout without having done them for a few weeks, and something went wrong. I stopped training for months, due to wanting to rest it and being demoralized in general (I couldn't lift myself off the floor with that hand, the slightest pressure on my palm triggered pain, and handstands, which I love, were out of the question). It didn't go away. But after I started doing first knuckle pushups (mainly just in a PU position and raising my knuckles with as much weight as they would take, not actually doing a PU) to strengthen the weak ROM, magic has been worked. I don't know if it's completely better, but I want to give it a few more weeks and not push it, but I can at least do pushups and even tumble with a Tiger's Paw on, and I haven't felt pain (which would only happen when my wrist was pushed into unhappy flexion) for a month or two, even though I've started training again. I now do rice bucket exercises and three types of wrist pushups twice daily to try to fully slay the beast.
Success!
I just wanted to share.