Studies on the development of lower-limb exoskeletons began in the 1960s. However, these robotic devices' technological progress has been plodding, despite being studied for a long time. Therefore, the purpose of this article is to document a systematic review of the trends in the application of components that are part of the development of exoskeletons applied to the rehabilitation of lower-limbs. The objective is to provide the researcher with a structured matrix that integrates these components related to lower-limb exoskeletons development. As methods, it used different databases and specialized search engines that helped collect research from 2016 to 2020. The process of filtering and selecting the reviewed research was carried out, leaving 90 selected. Finally, it is concluded that there is still room for improvement and continue development of lower-limb exoskeletons that contribute to the rehabilitation process and are closer to the human lower-limb's real functioning.