Abstract: An adjustable prosthetic device includes: at least one socket configured to be coupled with a prosthetic foot and defining a space for receiving a residual limb of a patient; a dilatancy pouch disposed within the rigid housing and comprising a fabric material filled with a filler material; and a sealing interface disposed onto the residual limb. The pouch is disposed over the sealing interface such that the sealing interface seals the pouch between the socket and the sealing interface. When a vacuum is applied to the pouch, the pouch becomes rigid within the volume defined between the socket and the sealing interface.