Risk and adverse events related to lower-limb exoskeletons

Since the marketing clearance from the U.S. Food and Drug Administration (FDA), powered lower-limb exoskeletons have been proposed as a promising tool in gait assistance and rehabilitation. However, previous studies often overlooked the potential risk and adverse events related to the device. Without a clear understanding and comprehensive knowledge of adverse events and the risks users face, it is difficult to evaluate the risk-to-benefit ratio of powered exoskeletons. We reviewed all publically available exoskeleton-related adverse events, and compared the result to the risks that were identified by the FDA. Results showed that bone fracture is a serious risk that was not considered in previous literatures. Additionally, skin and soft tissue damage is common across subjects, studies, and devices. It was often treated as an incidental minor event and overlooked. We encourage more effort at keeping the safety of exoskeleton users in future studies.