Design and Development of an Elevating/Articulating Manual Wheelchair Legrest

The function of elevating legrests is to reposition a wheelchair user to increase circulation and to redistribute pressure thereby increasing comfort and minimizing the risk of pressure sores. Three categories of wheelchair users can benefit from elevating legrests; those who cannot sense discomfort in their lower extremities (spinal cord injuries), those that lack the physical strength to reposition themselves (muscular dystrophy), and those that lack the coordination to reposition themselves (cerebral palsy). Elevating legrests that rotate about a fixed point lower than the center of the knee will shorten the effective leg length, push against the foot and cause torque at the user’s hip. Raising the center of rotation to coincide with the knee has the undesirable effect of interfering with transfers to and from the wheelchair. To match the motion of the leg, an elevating legrest having a center of rotation below the axis of the knee must articulate (lengthen) when being raised. Currently available articulating designs generally require outside assistance to operate [1, 2] or potentially impede wheelchair transfers. The goal of our work was to design, construct and evaluate a user-operated, elevating legrest that accurately follows the natural motion of the user’s leg.