To provide an implant prosthesis for repairing a defect in an existing or latent tissue or muscular wall.

The implant prosthesis includes an implant body portion 22 made of a biologically fitted material configured and disposed to cover at least part of the defect of the tissue or muscular wall; at least one tether 24 extended from the body portion 22 and configured and disposed to extend passing through the defect of the tissue or muscular wall when the body portion 22 is positioned on the defect; and an indicator 60 disposed in the at least one tether 24 in a prescribed place to indicate the position of the body portion 22 relative to a reference place.