A medical implant with an external surface layer of silicone elastomer and having an open-cell structure is made by applying solid particles to the external surface layer of the implant before it is cured, curing the external surface layer with the solid particles embedded therein and then dissolving the solid particles with a solvent that does not dissolve the silicone elastomer. An implant having such an external surface layer is expected to help prevent capsular contraction, to help prevent scar formation, and to help in anchoring the implant within the body.