An implantable medical device includes a first component including a first material, a second component including a second material, and a fiber matrix including a plurality of fibers. The fiber matrix joins the first component to the second component. The fiber matrix includes a first a first portion connected to the first component, and a second portion connected to the second component. The first portion of the fiber matrix is interpenetrated with, and mechanically fixed to, the first material. The first portion of the fiber matrix directly contacts the first material.