-Max chain over 28 - 300
-No mistakes - 700
-Completed with 225 left - 500
-3 COOLs earned - 500
This operation is a pain when you don't know what to do, but once you do it's not much of a problem. Try to remember to hit the skip button as you're diving into the patient so you don't get interrupted when you're about to align the ulna back into place.
Start by draining the blood pools. Remember that one of them has a minor wound beneath it which can be treated quickly with the antibiotic gel. After that's done, you'll extract the bone fragments. You can do this very fast since it's almost impossible to botch. I'd recommend getting them from right to left but it's up to you. Moving the ulna back into place is very frustrating when you don't know exactly how you should place it, as you'll constantly keep getting misses. But basically what you want to do is grab it from the tip and move it so that it's pointing towards the broken bone on the bottom. Not the one on the right, but the leftmost one. There's no need to do this quickly. Just make sure that when you let go of the forceps it is pointing in the right direction, otherwise you'll get a miss.
When that's out of the way, it's time to reform the broken bone with the fragments you picked up. Because you're going for the XS, this means that you're going to want to memorize exactly where and how each bone fragment goes. This can be done either through sheer repetition or by carefully watching the video. It's your choice. I'm not going to describe in detail where and how to place each piece as that would be too tedious. It's much faster and helpful if you just watch their placement in the video. The order in which you originally picked up the fragments dictates the order in which they'll be given to you when it comes time to reform the bone, so my recommendation is to always pick the fragments in the same order. That way you'll know where each one goes ahead of time.
The main thing here is that you don't want to have to think about where to place the fragments. You must know through memorization. Remember that you don't have to rotate them to an exact position. The game gives you a little bit of slack in that regard. As a general rule, after you've placed a piece and before you grab the next one, remember to rotate your wrist back to the neutral position. You don't want to get caught with a piece on your hand and unable to rotate your wrist further. If you want to go one step ahead, though, anticipate the direction in which you'll rotate the next piece before you grab it, and rotate your wrist towards the OTHER direction. That way when you do grab it and rotate it, your wrist will be in the neutral position, giving you greater control.
After you've successfully placed all the available pieces, there will still be one missing. It's always hiding in the same place, so there's no need to use the ultrasound to find it. Simply make an incision with the scalpel in that general area, grab it, and place it. This last one is easy since there's no two places where you can put it. Unless you decide to place it on top of another one, but why would you do that? In any case, gel over both bones quickly and several times. After you do that, there's a slight lull where nothing's happening but you still have control of your tools. It isn't necessary, but this is a good time to inject some stabilizer. It's better than doing nothing, anyway.
Now once you're out of the patient, be very careful. This last part is critical. It's absolutely essential that you get COOLs in both the final suture and the bandage. If you don't, you will not get the XS. There's no reason to rush, and it could very well mean you have to do everything all over again, so unless you're some kind of legendary surgeon, take it slow. As always, the suture is lenient and thus easy. As always, try to do many quick passes that are wider than the actual opening. The bandage can be easily botched, so wait until the gel completely disappears so your view isn't blocked, and apply it slowly. You can afford to lose a few seconds, but you cannot afford to miss the COOL on this one.