This document discusses bone cement, providing its history, composition, polymerization process, and techniques for use. Bone cement is composed of PMMA powder and methyl methacrylate liquid that undergo radical polymerization to form polymers. Proper bone cementing techniques like pulsatile lavage, vacuum mixing, and pressurization improve cement quality and fixation. Additives like antibiotics and opacifiers are used but can affect cement properties. Occupational and patient hazards like cement implantation syndrome require prevention through management of vapor exposure and embolic risks.

1. Bone Cement
By
Ihab El-Desouky (M.D.)
Asst. Prof. Orthopaedics & Traumatology
Pelvis and Joints Reconstruction Unit
Kasr Al-Ainy School pf Medicine
Cairo University- Egypt

2. BONE CEMENT
Definitions:
Cement: Synthetic, self-curing organic or
inorganic material used to fill up a cavity or
to create a mechanical fixation.
Bone cement: A bio-material cement
obtained by mixing a powder and a liquid
& can be molded and implanted as a paste
with the ability to set within the body.
It is a filler (grout) and not a glue

3. BONE CEMENT
History:
1936: Kulzer Co.: heat-curing PMMA (at 100 ⁰C)
1943: Kulzer & Degussa Co.: Cold -curing PMMA
(room temperature)—close cranial defects.
Birth Of PMMA Bone Cement

4. BONE CEMENT
History
Early 1950s: Judet & Judet: PMMA femoral head
prosthesis (Plexiglass) but failed
In 1958: Sir John Charnley: Succeeded
“Bone Cement On Acrylic Basis”
Used PMMA to anchor
prosthesis .

5. Components Of Bone Cement
Powder:
Polymers
Polymethyl methacrylate
(PMMA)
Initiator
Benzoyl Peroxide (BPO)
Radio-opacifier:
Barium Sulfate
Zirconia
Antibiotics (heat stable)
e.g.: gentamycin, vancomycin
tobramycin
Liquid
Monomer
Methyl methacrylate (polymerizable)
Activator (accelerator):
N-Dimethyl-p-Toluidine (DmpT)
Inhibitor (stabilizer)
Hydroquinone

6. Polymerization Process:
Powder + Liquid = Reaction
Powder dissolves in liquid (PMMA mixed with monomers)
AND
Initiator (BPO)reacts with activator (DmpT)--- Free Radicals
(Radical Polymerization)

7. Radical Polymerization
Bonding of monomers
+PMMA-- longerpolymers
chains of variable MW
By Time:
-Depletion of free radicals
(polymerization stops)
-Viscosity of the dough
increases+ residual
monomers.
-Release of heat: Exothermic
reaction
in vitro: 70-80 ⁰C BUT
In vivo : 40-45 ⁰C
Why?

8. Radical Polymerization
Exothermic Reaction: Polymerization shrinkage:
In vivo: early shrinkage is
compensated by air & water
uptake by cement

9. Radical Polymerization
Fate of residual monomers Phases of
polymerization in
surgical procedures:
Four phases
1-Mixing.
2-Waiting.
3-Working.
4-Hardening (setting)

10. Handling Of The Bone Cement:

11. Handling Of Bone Cement

12. Handling Of The Bone Cement
In general, all bone cements have dough, working and
setting TIMES:
Dough Time: Beginning of mixing till cement is not
stick to gloved fingers (includes mixing and waiting phases)
Up to 3 minutes
Working Time: End of dough time till the cement is
too stiff to manipulate (includes working phase)
5-8 minutes
Setting Time: Dough + working times
8-10 minutes

13. Types of Bone Cement: (viscosity)
Low viscosity: Long waiting (sticky) phase (3
min) then viscosity rapidly increases during short
working phase ( 2 min long)
Medium viscosity: Long waiting phase (3 min)
but viscosity slowly increases during working and
setting.
High viscosity: Short waiting phase (1 ½ to 2
min), long working phase with constant viscosity

14. Factors affecting cement preparation

15. Generations Of Cementing

16. Technique of better bone cementing:
Pulsatile lavage
(Bone bed preparation)
-Pulsatile lavage is equally
important to pressurization.
-Pulsatile lavage improves cement
penetration+ reduces the risk of
embolic complications during cement
pressurization.

17. Technique of better bone cementing:
Distal Cement Restrictor: allow formation of
closed space for cement pressurization
Should be appropriate size to close the canal

18. Technique of better bone cementing:
Vacuum Mixing:
Reduces Porosity and air inclusion &Increases cement
homogeneity----Increases mechanical strength of cement
Decrease exposure of surgical team to monomer fumes.

19. Technique of better bone cementing:
Pressurization: more cement inter-digitation

20. Technique of better bone cementing:
Stem centralizer(s): uniform cement mantle &
allow for controlled stem subsidence

21. Technique of better bone cementing:
Stem Design:
Collar-less :
allow stem subsidence by cement shrinkage (creep)
Polished :
no shear during insertion or subsidence.
Tapered :
wedged inside the cement in stem travel during
subsidence so –-- compression forces (not shear)

22. Properties of Bone Cement
Visco-elastic material
1-Creep
- Gradual Deformation of
material under constant load
-Cement creep is reflected as
Volume reduction

23. Properties of Bone Cement
Stress relaxation
Decrease of material stress under condition of
constant strain
Effect of loading:
Compression> Tension> Shear

24. Additives To Bone Cement:
(Opacifiers ,Antibiotics )
1-Opacifiers:
Barium sulphate or Zirconium dioxide
For: monitoring & detection of failures
Radiographic assessment of quality of
cementing:
Barrack grading:

25. Additives to Bone Cement:
Antibiotics: Antibiotics Loaded Acrylic Cement (ALAC)
Bone cement acts a delivery system for local antibiotics .

26. Additives to Bone Cement:
Antibiotics: Antibiotics Loaded Acrylic Cement (ALAC)
Low dose< 2 gram Antibiotic per 40 gram cement
High dose> 3.6 gram --- per 40 gram cement

27. Additives to Bone Cement:
Antibiotics: Antibiotics Loaded Acrylic Cement (ALAC)

28. Hazards Of Bone Cementing
Occupational hazards : on Surgical team
1-Excessive vapor– respiratory irritation
2-High vapor concentration---headache,
drowsiness and even loss of
consciousness.
3-Skin irritation and burns if exposed to
liquid.
4-Contact lenses (soft) penetration by
vapor---pitting

29. Hazards Of Bone Cementing
Patient Hazards : Bone Cement implantation
Syndrome(BCIS)
Hypoxia, hypotension, loss of consciousness and even
cardiac arrest
At time of: cementing, prosthesis insertion, joint
reduction, or deflation of tourniquet in stemmed total
knee.
Etiology: (theories)
1-Monomer liquid absorption into circulation
2-Emblosim: exothermic reaction expand medullary B.V.–
embolism of fat , marrow , air or cement particles.
3-Anapylxis and complement activation

30. Hazards Of Bone Cementing
Bone Cement implantation Syndrome(BCIS)
Prevention:
Management:

31. Take Home Messages
Bone cementing technique: results and
complications.
A stem: respects the natural properties of
the bone cement
Antibiotics loaded cement : dose and use.
Complications: strict technique to avoid its
occurrence. Thank you