Table 4.

The ideal quality dimensions of porous internal architecture of Ti bone implants.

Quality Approach	Dimension	Description
Product-based approach	Performance	The porous microstructure should provide an environment ideal for bone ingrowth and endow the implant with a stiffness similar to natural human bone while maintaining sufficient strength.
	Features	Tailored internal architecture with specific properties, including but not limited to pore size, unit cell, porosity, elastic modulus, interconnectivity, compressive yield, and ultimate strength, as well as fatigue strength.
	Reliability	Optimised fabrication of porous Ti structures with high mechanical strength as well as a high degree of reproducibility, minimal defects, and zero failure rates (within their life expectancy).
Manufacturing-based approach	Manufacturability	The scaffold’s micro-geometry should be designed in such a way that it is easy to manufacture with high accuracy and definition.
	Conformance	The mechanical, geometrical, and dimensional characteristics should comply with medical regulations and quality standards.
	Durability	Porous Ti structures should withstand mechanical forces experienced during handling, implantation surgery, and operation thereafter in a traumatised bone microenvironment constantly under load.
User-based approach	Perceived quality	Clinicians should have access to relevant characteristics through medical reports and statistical data where implant performance can be seen.