- See:
Characteristics of Metals and Implants:
- Discussion:
- titanium is often selected as a materalial for metal plates or femoral stem implants due to its lower modulus of
elasticity (as compared to other alloys);
- advantages:
- resistance to
fatigue is execellent;
- it is easily worked, and 1/16
plates are radiolucent;
-
yield strength:
- metals ranked according to yeild strength (highest to lowest);
- cast
cobalt chrome > titanium > wrought
cobalt chrome,
stainless steel;
- resistance to corrosion:
- by itself titanium would have a high potential for oxidative corrosion;
- the titanium dioxide layer which coats the outer metal layer provide a major barrier to corrosion;
- disadvantages: this metal has an extremely
low modulus of elasticity & low tensile strength;
- titanium
plates and implants, therefore, have to be bulkier than
stainless steel in order to provide same rigidity;
- Corrosion:
- it is the most inert of metals;
- resistance of titanium to corrosion in a chloride environment is excellent;
- titanium and its alloys form oxide passivation layers more rapidly than do substances that contain chromium, such as cobalt-chromium
alloy and
stainless steel;
- while an active metal like titanium forms its oxide passivation layer spontaneously in any environment that contains oxygen, strength
of adhesion of the oxide layer to the underlying titanium metal is not as great as that of chromium oxide layer to its metal substrate;
- in addition, chromium oxide passivation film is more dense than titanium oxide layer;
- Wear of Modular Titanium Stems
- known drawbacks of using titanium as a bearing include its poor resistance to wear, notch sensitivity, and reports that it is more
susceptible to abrasive wear by particles of debris;
Serum titanium levels in individuals undergoing intramedullary femoral nailing with a titanium implant.
The advantages of titanium alloy over stainless steel plates for IF of fractures: an experimental study in dogs. HK Uhthoff. et al. JBJS 1981. 63-B. p 427-434.
Aseptic loosening in THR secondary to osteolysis induced by wear debris from titanium alloy modular femoral heads. AV Lombardi Jr. et al. JBJS Vol 71-A. 1989. p 1337-1342.
Metallic wear in failed titanium alloy total hip replacements: A histological and quantitative analysis. HJ Agins. JBJS 1988. 70-A. p 347-356.
-
comparison of mechanical properties of titanium vs stainless steel
Stainless Steel Titanium Alloy
Hardness 30 Rc 35 Rc
Yield Strength 790 MPa 900 MPa
Ultimate Tensile Strength 960 MPa 960 MPa
Modulus of Elasticity 200 GPa 110 GPA
(from HK Uhthoff. et al. JBJS 1981. 63-B. p 427-434.)
