TABLE 3.

Summary of the metamaterials and their applications in bone implant.

Type of metamaterial		Application	Advantages and disadvantages	References
Auxetic structures	Re-entrant	Medical screw, bone-implant contact	Better tensile stiffness, good NPR effect, longer fatigue life	Kolken et al. (2021), Yao et al (2020)
	Chiral	Medical screw, bone scaffold fabrication	Better tensile stiffness, high fracture toughness, limited by chirality	Yao et al (2020)
	Rotating	Medical screw, auxetic materials fabrication	Better auxetic performance, low stability	Yao et al,(2020)
Non-auxetic	honeycomb	Bone defects repair, bone reconstruction, bone tissue engineering materials	Proper elastic modulus, high yield strength, high permeability	Garcia Garcia et al. (2018), Liu et al. (2020), Wang et al. (2021)