Bone Cement
Bone cement
Component - Powder - Pre-polymerized PMMA
Barium Sulphate (opacifier)
Liquid- Mono Methyl-metha-acrylate (MMA Monomer )
N-dimethyl-p-toludine, which acts as an accelerator (accelerator )
Hydroquinone , which acts as an inhibitor
Colour e.g. Chlorophyll
What factors influence its properties ?
Porosity -vacuum mixing improve fatigue strength.
Antibiotics
Methods of applications .
Digital
syringe application
vacuum mixing and delivery
pressurisation
viscosity
use of stem centralizer and cement restrictor
Bone bed preparation
Bone reaming ,
Brushing
Pulse Lavage
Cementing Techniques
First Generation tecnique
hand mixing of cement in bowels
canal irrigated and suctioned before digital application of cement
cancellous bone left in situ
Second Generation technique
all cancellous bone removed
distal cement restrictor applied
irrigation , packing and drying of femoral canal done then cement application using cement gun in a retrograde fashion
Third Generation Technique
cement preparation using vacuum-centrifugation technique
canal irrigation with pulsatile lavage and packed with adrenaline soaked swabs
cement insertion in retrograde fashion, then cement pressurized.
then used proximal and distal cement centralizers.
Risks
Hypotensive episodes
Cardiac arrests
Arrythmia
Hypoxaemia
Delayed sciatic nerve entrapment due to cement extrusion
adhesion and stricture of ileum during cement polymerization
promotes local inflammation and results in peri-prosthetic osteolysis (activated macrophages express cytokines inculding IL-1,6,TNF -alpha )
Comments
Post a Comment