Hydrogel implants for mid-foot

An implant for replacing a portion of an articulation surface of a joint, the implant comprising:

• a main portion configured for inserting into a joint, wherein the main portion comprises:
• a porous material portion having a first bone-engaging surface;
• and
• a hydrogel portion that is bonded to the porous material portion and forms an articulation surface opposite from the first bone-engaging surface;
• and
• a bone plate portion configured for securing the implant to a bone that forms the joint;
• wherein, the main portion has a leading end and a trailing end, wherein the leading end is configured for being inserted into the joint, and wherein the bone plate portion extends from the trailing end;
• wherein the bone plate portion has an extension piece that extends from the first bone-engaging surface and forms a second bone-engaging surface that is also formed of the same porous material as the porous material portion, and extends from the first bone-engaging surface in a direction opposite from the articulation surface at an angle with respect to the first bone-engaging surface, whereby a space is formed between the porous material portion and the extension piece at the trailing end;
• wherein the bone plate portion comprises a solid metal portion that fills the space and also forms all exterior surfaces of the bone plate portion except for the second bone-engaging surface;
• and
• wherein the bone plate portion has at least one screw hole for receiving a bone screw.