Hi Maika! I have found that amputation/prosthetics constitutes a very small part of the NCS exam – at the same time, it is a huge topic! If someone dives into studying amputations, it is likely that they’d end up investing way more time than is necessary for the NCS exam and that time is better spent on the bigger topics that will be a larger chunk of the NCS exam. I think the most important topic to be prepared for on the NCS exam are related to gait analysis – possible impairments that could impact gait (i.e., probable tight and weak muscles) and gait deviations related to ill-fitting prostheses.
This website has a nice overview of gait post-ampuation: http://www.oandplibrary.org/alp/chap14-01.asp
You could also review a guide like this to familiarize yourself with some terminology related to prostheses: https://now.aapmr.org/lower-limb-prosthetics/#.-overview-and-description