Battlefield exoskeleton usability for lower-limb trauma in prolonged field care: A mixed-methods approach

Prolonged field care is increasingly important in military operations, where austere environments and delayed medical evacuations necessitate extended injury management. Tibia and fibula fractures are common, survivable battlefield injuries that demand such care. Current treatment options involve simple splints, which require the injured Service member to be carried on a litter, and exoskeletons, which are not suited for use in combat environments. The Intrepid Battlefield Exoskeleton (IBEX) was developed to address this critical gap in battlefield trauma care by stabilizing lower leg fractures and enabling independent mobility in prolonged care scenarios. This study evaluated the usability of two IBEX prototypes through sequential laboratory and field testing under two user conditions: medic and casualty. In laboratory testing, 20 participants completed a series of functional tasks with and without the IBEX and provided quantitative usability ratings and qualitative feedback via self-report measures and interviews. In field testing, 12 participants used the IBEX during a simulated mass casualty event and completed the same usability assessments. Quantitative results indicated high overall user satisfaction. Thematic analysis of qualitative feedback revealed recurring comments on usability, portability, comfort, security, and durability. Overall, results indicated moderate usability in both environments, with room to improve ease of fitting and adjustability. Findings highlight the value of a mixed-methods approach to device evaluation and underscore the importance of iterative design and testing. Ongoing work will compare the IBEX with the current standard of care and further refine the design for operational use.