An implantable medical device and method of implanting a medical device, the device including a housing surrounding an operative component and a resiliently deformable fixation member. The fixation member includes a ring shaped annulus circumscribing the housing and a plurality of elongated struts having a proximal end affixed to the housing and a distal end affixed to the annulus. The fixation member may be comprised of a hydrogel such that it may be in a smaller, dehydrated form during implantation, and then may absorb fluid to expand to a larger, hydrated form after insertion to engage the surrounding tissue.