In cemented total hip arthroplasty, vacuum mixing of polymethylmethacrylate bone cement is performed primarily to achieve which effect?
- A Increase the peak polymerisation temperature to improve interdigitation
- B Reduce cement porosity, thereby improving fatigue strength of the mantle ✓
- C Accelerate curing time so the component can be inserted earlier
- D Increase elution of antibiotics from the cured cement
Correct answer: B. Reduce cement porosity, thereby improving fatigue strength of the mantle
Explanation
Vacuum mixing removes entrapped air bubbles generated during monomer polymerisation. Lower porosity significantly improves the fatigue life of the cement mantle, reducing fatigue failure and loosening. It also slightly lowers the exothermic temperature and reduces monomer fumes, but these are secondary effects. Antibiotic elution depends on cement composition and porosity is not deliberately increased for it.
Reference: Miller's Review of Orthopaedics, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.