The introduction of a foreign material will determine host response with
local, systemic, remote effect
]
Stress Shielding =
Stainless Steel
Cobalt-Based alloy
Titanium and its alloy
Oxidized Zirconium-Niobium Alloy (Oxinium)
Porous Tantalum =
Other method, 3D printing of porous Ti
Ti Microstructure
Ti has low wear resistance. Improved by surface modification.
Nitinol
Two way =
Cooled below Mf Bent Heated above Af freely take Austenitic shape
Need training for 20-30 cycles
Load change it into martensite. SIM = stress induced martensite
Stress straini curve
Factor =
Concern =
Polymeric =
PMMA (Polymethyl Methacrylate) = bone filler
UHMWPE (Ultra High Molecular Weight Polyethylene) = bearing
Oxidative chain scission (gamma radiation in air) Cross-linking
Osteolysis
Ceramic. Inert = Al2O3, ZrO2
Bioactive = Ca-based, bioglass
Usage =
Alumina
Zirconia
Ca-Based
Bioglass – mineral-rich structure to bond the bone
Surface modification = sintered fibers, sintered beads, plasma spray coating
Failure = - Long-term stability
- Wear (osteolysis) - Fracture
- Infection - Dislocation
- Stress shielding - Post-surgical care
Location = articulating surface Implant – bone interface
Implant junction Bone – cement interface
Damage = abrasive wear (fine wear), delamination wear (large particle),
fatigue fracture, wear
Knee
Shoulder
THA Revision
Revision prosthesis = Calcar, Arcos, and Custom
Remove cement = using ultra drive, cement remover
Atherosclerosis =
Treatment stent
How to make stent safer?
1. Inhibition of neointima formation
2. Promotion of endothelial coverage
Treatment =
1. Balloon angioplasty
2. Stenting
Inflate by balloon
Stainless Steel 316L
CoCr alloy
Nitinol alloy
Drug eluting
Fe as biodegradable
Magnesium
Failure
Biodegradable material for stent
Scaffold = structure
Bioactives =
1. Chemical
2. Extracellular matrix
a. Growth factor
3. Gene theraphy
b. Supplement
4. Mechanical loading
c. Hormones
d. Vitamins
e. Amino acid
Ethics
Consideration
Cellular response
(Bio)chemical modification of titanium surface
Interfacial processes following implantation of Ti
(Bio)chemical modification of titanium surface
Self-assembled monolayers
Regenerative medicine
Gait shows multidirectional movement
Reduce polyethylene wear
Zirconic on conventional polyethylene
Ceramic on ceramic
Highly X linked Polyethylene = good result
Can be added with vitamin E to reduce wear.
Metal particle = nano size, more dangerous
Polyethylene particle = macro
Large head = stable
Small head = less wear
Player for body response
Monocyte macrophage foreign body giant cell
Nautrophilic granulocyte, or polymorphonuclear phagocyte (PMN) : aggresive
Monocyte / macrophage / dendritic cell
Non adhesive surface
Tissue integrating surface
Contact killing surface
Antimicrobial releasing coating
Ideal multifunctional coating
Surface antibacterial activity testing
Antimicrobial coating
Honey!
