Apparatus is provided for placement at an anatomical site, including an orthopedic implant, which has front and rear ends, a top and bottom, right and left sides, and a central part connecting the sides. A distance between the top and the bottom is (a) greater at a first location at one of the sides than at a second location opposite the first location at the other side, and (b) greater at a third location at the front end than at a fourth location opposite the third location at the rear end. At least a portion of the implant is a porous matrix, which is shaped to define pores that extend through the porous matrix in at least each of: (a) a front-to-rear direction, (b) a left-to-right direction, and (c) a top-to-bottom direction.
