Bone Cement

  • The most widely used bone cement- acrylic bone cement i.e. polymethylmethaacrylate (PMMA).
  • Two components- a liquid & a powder
  • Liquid component: Methylmethaacrylate(MMA) monomer, N,N -dimethyl-p-toluidine ( as accelerator), Hydroquinone (prevent premature polymerization)
  • Powder component: PMMA microspheres (prepolymerized), Barium sulphate/Zirconium oxide (for radio-opacification), Dibenzoyl peroxide (Initiator of polymerization)
  • Some other components in Powder may be used: Tri-n -butylborane ( as Initiator), 2,5-dimethylhexane-2,5-hydroperoxide (as an accelerator), chlorophyll dye, ethanol, ascorbic acid, antibiotics, & dyes.
  • Calcium phosphate cements: two components- Calcium orthophosphate and a liquid phase; these together form a paste & later harden.
  • INDICATIONS:  1. Arthroplasty, 2. Kyphoplasty & Vertebroplasty, 3. For control of Infection as antibiotic cement beads, 4. Filling of Gap after tumor resection as in GCT, 5. Ca-phosphate in vertebral augmentation & osteoporotic fractures, unstable fractures, skull reconstruction & maxillofacial deformities, 6. Ca-sulfate in periodontal disease & maxillary sinus augmentation
  • Process of Curing: 4 stages: Mixing, Sticky/Waiting, Working, & Hardening
    Hand mixing- more porosity, can compromise mechanical properties &
    Vacuum mixing- less porous & homogenous radio-opacifier particle mixing; also reduces exposure of surgical staffs to MMA monomer vapor.
  • Complications:  To patients: Cardiopulmonary- Hypotension, Hypoxia due to toxic effects of MMA monomer/Anaphylaxis. Death & Pulmonary Infarction if embolization of PMMA when injected in liquid state e.g. during vertebral augmentation.
    To surgical staffs:- Hypersensitivity, Asthmatic reactions, Local neurological symptoms, irritations & skin reactions.