Some good comments here, especially rolling and strength training.
In many years of different many different sports, I seem to be pretty good at “saving” my falls on a bike or unicycle. There will always be those times when you suddenly and unexpectly fall, and you can probably never prevent all of these (here helps strength training and protective gear), but the large majority of falls can be anticipated, even if just for a slpit second, where you then can “fall nicely”. I had a nasty UPD on my 36er a while back when a big dog stopped in my path in attack mode. I hit the disc brake way to hard and flew immediatley to the ground. However, even though I flew forward I managed to roll a little to the side, so (with glves and knee pad), only had a minor bruise to my knee and a really dirty jersey under my arm and across my back where I rolled through the gravel.
I think a lot of the practicing is then not just the roll, but also anticipating… although I use my hands to shield my face inn a bad fall, I seem to always keep my arms close in. I think the “wrong” thing to do is to land with your arms out and extended, as this puts major forces on the shoulder and joints and is a recipe for injury (same as landing with your leg extended, which is way bad for the knees). In mountain biking I have been really good at bailing without injury (e.g. jump dismounts from skinnies over 1m from the ground), and with the unicylce also, although my injury problem with the unicycle is the frequent unexpected landing on uneven ground and the stress on the ankles (had a major twist a few months ago when I dismounted the 36 in XC riding where the rooty trail was covered in leaves and I dismounted on one foot directly onto a root that was about 5cm (2 inches) high, but totally hidden be of the leaves).
Not sure if this helps so much, but through practice the conscious “planning” becomes routine and almost instinct, and in the split second you decide: is this a controlled and “planned” fall with control, a semi-controlled fall, or a no-control fall, where you just try and curl up your limps and hit the ground, let the protecters take the brunt and then roll out. Oh, for me the protectors for the hands and knees are essential to this, as otherwise you try to protect these too, and in a bad fall you simply cannot protect everything.
So: wear protectors, practice falling and visualization and consciously “thinking” abiut falling so that it then becomes routine and instinctive.
I wish you a fast recovery and return to unicyclng.