Effect of Ultrasound Frequency and Treatment Duration on Antibiotic Elution from Polymethylmethacrylate Bone Cement

Abstract

Introduction. The objective of this study was to evaluate the effect of
ultrasound frequency and treatment duration on antibiotic-impregnated
polymethylmethacrylate (PMMA) antibiotic elution rates and
mechanical strength.
Methods.xTwo batches of PMMA were prepared: one with five grams
of vancomycin powder and one without. Each batch was divided
into two frequency groups: kHz and MHz. Each frequency group
was divided into two duration groups: two minutes and ten minutes.
Elution samples were measured daily using flow injection analysis.
After one week of elution, ultrasound treatments were done daily until
each group’s average concentration fell below those of non-ultrasound
control groups. After elution testing, compression testing determined
mechanical properties. Paired t-tests were used to compare daily
elution amounts to baseline values. Univariate ANOVAs were used to
test for effects of both frequency and treatment duration on antibiotic
elution amounts and on mechanical properties.
Results. All ultrasound treatments resulted in significant increases
in antibiotic elution. Frequency and duration had significant effects of
increasing antibiotic elution (p < 0.001). The kHz group produced significantly
greater antibiotic elution than the MHz group (p < 0.001).
The 10-minute duration produced significantly greater antibiotic
elution than the two-minute duration (both p < 0.001). Frequency
and duration did not have significant effects on yield stress (p = 0.841
and p = 0.179, respectively). Frequency had a significant effect (p =
0.024) on modulus, but duration did not (p = 0.136).
Conclusions. Ultrasound frequency and treatment duration significantly
affect antibiotic elution from PMMA which may be helpful for
treatment of periprosthetic joint infections during revision arthroplasty.
Kans J Med 2019;12(2):45-49.