[Translated article] In vitro elution of local anaesthetics from PMMA bone cement

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Pharmacology

Background:

• Optimal pain management after total knee arthroplasty remains a challenge, with no current gold standard drug delivery system.
• Bone cement, specifically polymethylmethacrylate (PMMA), has a history of use as a drug delivery system since the 1970s, primarily for antibiotics.

Purpose of the Study:

• To characterize the elution profile of two local anesthetics: lidocaine hydrochloride and bupivacaine hydrochloride.
• To evaluate the potential of PMMA bone cement as a localized drug delivery system for post-operative pain management.

Main Methods:

• Specimens of Palacos® R+G bone cement were prepared with either lidocaine hydrochloride or bupivacaine hydrochloride.
• Specimens were immersed in phosphate-buffered saline (PBS) and sampled at various time points.
• Local anesthetic concentrations in the PBS were quantified using liquid chromatography.

Main Results:

• Lidocaine elution from PMMA bone cement reached 9.74% at 72 hours and 18.73% at 336 hours.
• Bupivacaine elution from PMMA bone cement was 2.71% at 72 hours and 2.70% at 336 hours.
• Eluted doses at 72 hours approached those used in clinical anesthetic blocks.

Conclusions:

• Local anesthetics demonstrate in vitro elution from PMMA bone cement.
• PMMA bone cement shows promise as a drug delivery vehicle for local anesthetics in orthopedic surgery.
• The study supports the investigation of PMMA bone cement for enhanced post-arthroplasty pain control.