There is a lot less exposure in ortho, due to the smaller exposure times. We usually don't need to film what we're doing, we can get away with just taking several images. For trauma, spine, long bone osteotomies you need fluoroscopy, but there is rarely a need for that in arthroscopy (barring hip), total joints and many things in foot & ankle and hand. Most basic trauma cases usually end up with a fluoro time of 2-10 seconds, compared to peripheral vascular with several minutes of fluoro time per case, although there are certainly instances where you get more rads (difficult reductions, interlocking screws etc).