The tibia implant (26) has a vertical cross section and a base plate (44) which carries a sponge structure. The vertical cross section tapers downwardly in the use position. The tibia has a vertical sectional surface and a vertical knee close incision with two sectional surfaces. The sponge structure is attached on the sides of the tibia. The side faces the sectional surfaces. The sponge structure has regular lattice structures in sections. The base plate is a part of a supporting frame (34) surrounding circumferentially the sponge structure. An independent claim is included for a method for manufacturing a tibia implant.
