A braided, rather than woven, three-dimensional matrix has been developed to provide mechanical support in breast reconstruction or a mastopexy procedure. The braided three-dimensional matrix may be used to assist in hernia repair procedures. The matrix is a supple, strong, and flexible material, that can increase 50% to 100% in size when stretched along the vertical plane, but only extends by about 10% to 20% in length when stretched along the horizontal plane. Although the matrix is degradable, it provides sufficient mechanical and structural support for six to twelve months following implantation to allow for repair or growth of the breast tissue or the abdominal wall. The matrix is formed of three-dimensional braided multifilament polymeric fibers plied to create yarn bundles, and wherein the matrix comprises an inter-connected, open pore structure that enables even and random distribution and in-growth of cells.