Patent ID: 7682540

Claim:
A method of making a hydrogel having an outer surface and a plurality of first superficial pores and a plurality of second superficial pores along at least a portion of said outer surface, said method comprising: providing a mold having an array of first projections and an array of second projections thereon for creating a plurality of first and second pores; wherein said array of first projections is configured to form the plurality of first pores, each of said first pores being defined by a first cavity extending from the outer surface of the hydrogel to a bottom surface of said first cavity; wherein said array of second projections extends from an end of at least one of the first projections, said second projections configured to form the plurality of second pores; wherein each of said second pores is defined by a second cavity extending below the bottom surface of a first cavity; casting a hydrogel in the mold; allowing the hydrogel to form while in the mold; and removing the hydrogel from the mold; wherein said first cavities and said second cavities are only located on or near the outer surface of the hydrogel; and wherein said hydrogel is adapted for long term or chronic implantation such that said hydrogel remains within a joint after implantation to augment cartilage and function as cartilage replacement.