A bioabsorbable implant including an elongated metallic element comprising an alloy of more than about 70% by weight magnesium and about 2-20% by weight lithium, substantially free of rare earth metals. An implantable tissue filler includes a particulate material suspended in a carrier, comprising more than about 70% by weight magnesium and about 2-20% by weight lithium, substantially free of rare earth metals. A bioabsorbable implant includes an elongated metallic element having a core and at least two layers of alternating compositions of magnesium, iron, and alloys thereof. A bioabsorbable implant includes at least three wires including magnesium and defining a cylindrical sheath surrounding at least one core wire including iron. A bioabsorbable implant includes a plurality of intertwined magnesium alloy wires defining a strand, with an Fe-rich layer formed by vapor, chemical and/or electro-deposition defined on a surface of at least one of the wires.
