This document discusses recent advances in ceramic materials used in orthopaedics. It describes different types of ceramics including bioinert ceramics like alumina and zirconia, bioactive ceramics like hydroxyapatite and bioglass, and bioresorbable ceramics like tricalcium phosphate and calcium sulphate. It provides details on the composition, properties and biomedical applications of these ceramics for uses like bone grafts, prosthesis coatings, and filling bone defects.

1. RECENT ADVANCE CERAMIC IN
ORTHOPAEDICS
Dr. Bipul Borthakur ( Prof.)
Dept. of Orthopaedics, SMCH

2. Introduction
• Biomaterial is defined as natural or synthetic substances,
capable of being tolerated permanently or temporarly by the
human body
• Ceramics are one of them
• Ceramic is synthesized , inorganic , solid, non metallic
,crystalline Materials with varying composition

3. Preparation of ceramics
• Made by mixing the fine powders of ingredient material with water and
adhesive binder
• Then squeezed into a mould to obtain desired shape then air dried to dry-
binder & finally burned out by thermal treatment
• Modern ceramics do not use these binder agents
• They use an isostatic pressure technology to fuse the ceramic under very
high pressure to form non hygroscopic and non water dependent
• Final structure depends on –
a) highest temperature reached
b) Duration of heat treatment

4. Classification
• Boadly three types-
A. Bionert
B. Bioactive
C. Bioresobable

5. Bioinert ceramics
Incorporate into bone in accordance with pattern of contact
osteogenesis
Two types- a) aluminia ceramics(Al2o3) and
b) zirconia ceramics( ZrO2)

6. Aluminia ceramics
Al2O3 molecule is most stable oxide as high energetic ion &
covalent bond between Al and O atoms.
These strong bonds protect ceramic by galvanic reactions
Aluminia ceramics are entirely hexagonal crystals
Under compressive load it shows good resistance but under tensile
force it leads to brittleness
Doesn’t show plastic deformation at room temperature before
fracture
Tensile strength is increased with higher density and smaller grain
size

7. Aluminia ceramics
• Aluminia is chemically more stable in vivo
• Better wear resistant than stainless steel or Co-Cr alloy ( in case
of bearing component of hip prosthesis)

8. Zirconia ceramics
Metal dioxide of zirconium (ZrO2)
Pure zirconia is unstable
Consists of three crystallographical phase – cubic, tetragonal and
monoclinic
Their transformation takes place under temperature , clinical
mechanical stress and humidity
To stabilize it non metallic oxide is added (MgO, CaO and Y2O3) to
form partially stabilized zirconia
Partially stabilized zirconia is mechanically stronger than alumina
Better wear resistance than stainless steel or cobalt-Cr alloy

10. Mixed oxide ceramics
• New class of ceramics
• Combined with tribiological properties of aluminia and yitrium
stabilized zirconia
• Better wear compared to aluminia ceramics in vitro
• Hip joint stimulator have been promising
• Further investigation necessary for long term performance

11. Biomedical applications of zirconia
• THR ball heads
• THR acetabular inlays
• THR condyles
• Finger joints
• Spinal spacers
• Humeral epiphysis
• Hip endoprostheses

12. Bioactive
• Act as osetoconduction
• Capability of chemical bonding with living tissue (
bonding osteogenesis)
• They are used according to their bending and
compressive strength
• Used as –
1. Bone graft substitute
2. Coating of prosthesis
3. As a spacer-
 Iliac crest

13. Bioactive
• Types –
1. Synthetic hydoxyapatite(HA)
2. Bioglass

14. Synthetic hydroxyapatite(HA)
• HA is highly crystalline hydroxylated CP salt with high degree of
hardness
• Ceramic and natural HA have a great chemical similarity
• Act as bone graft substitute and coating of femoral prosthesis
• An excellent carrier for osteoinductive growth factors and
osteogenic cells - so useful as graft extender
• It is brittle material and undergoes slow resorption and
become focus of mechanical stress
• So it is modified and combined with other materials for

16. Bioglass
• These are hard, non porous materials consisting of calcium,
phosphorous and silicon dioxide
• They bond chemically to bone
• Bonding leads to series of surface reactions and forms hydroxy-
carbonate apatite layer at glass surface
• Thus growth of osseous tissue occur
• It possess osteoconductive property
• It is brittle and prone to fracture with cyclic loading
• Incorporation of stainless steel increases its binding strength

17. Bioresorable ceramics
• Gradually absorbed in vivo and replaced by bone in the bone
tissue
• Similar to contact osteogenesis
• But interface between bioresorable ceramics and bone is not
stable as bioinert ceramics

18. Tricalcium phosphate
• TCP ceramic is similar to amorphous bone precursors
• It enhances bonding with adjacent bone of the host
• Act as bone graft substitute
• This stimulates osteoclastic resorption and osteoblastic new
bone formation within the resorbed implant
• Two forms alpha TCP and beta TCP
• Pure phase alpha TCP is made of porous granules that can
replace bone and resorobed in 24 months
• Beta TCP is an abundantly porous substance and create to
imitate the trabecular structure of cancellous bone
• its porosity facilitates activities of bone regenerating entities
• Disadvantage- due to rapid breakdown it may lead to
inflammatory reaction and volume loss

19. Calcium sulphate
• It is osteoconductive bone-void filler
• It is completely resorbed and substituted gradually as new bone remodells
• It is biocompatible, bioactive and resorbable after 12 weeks
• It combined with various antibiotics to deliver in bone and soft tissue
infections
• Indications-
1. Filling of bone cyst, benign bone lesions
2. Cavitary or segmental bone defect
3. As a graft extender in spinal fusion
4. Filling of bone graft harvesting sites