Abstract
Introduction
Antibiotic-loaded acrylic cement (ALAC) is employed in the treatment or prevention of infected total hip arthroplasty (THA). We have administered vancomycin (VCM) as the ALAC for the treatment of THAs with methicillin-resistant Staphylococcus aureus, or for the prevention of THAs with high risks. This study aimed to evaluate the serum concentration of VCM from ALAC in THA or cement beads.
Methods
Between December 2013 and February 2014, 16 hips (16 patients) underwent application of the ALAC including VCM at our institution. Two hips were used for the treatment of infection, in the first stage of two-staged revision THAs (i.e., cement beads). Two hips were used for the both treatment and prevention of infection, in one-staged revision THAs. Twelve hips were used for the prevention of infection, in aseptic revision THAs or primary THAs with high risks. Patients were classified into two groups depending on the VCM concentration of ALAC, as follows: high-dose group (2 hips), average 4.4% (3.8–5.0%); low-dose group (14 hips), average 1.6% (1.3–2.5%). The amount of VCM placed as ALAC into the hip was calculated by using the remaining ALAC. The serum concentration of VCM was evaluated at 1 day, 4 days, 7 days, and 28 days after surgery. Statistical analysis was performed by using the t-test, and the differences were considered significant when the p value was <0.05.
Results
Average amount of VCM placed as ALAC was 3.5 g (3.1–4.0 g) and 0.9 g (0.3–2.0 g) in the high- and low-dose groups, respectively. The average serum concentration of VCM (μg/mL) was 2.5 and 1.1 on day 1, 2.8 and 1.2 on day 4, 2.3 and 1.1 on day 7, and 1.9 and 1.0 on day 28, in the high- and low-dose groups, respectively. There were significant differences in the high- and low-dose groups on all days.
Conclusions
Although the serum concentration of VCM in the high-dose group is significantly increased compared to that in the low-dose group, it is always under the effective blood concentration (5–10 μg/mL) and seem to be clinically safe. Further, we confirmed the continuous effect of ALAC, including VCM, because they were detected at 28 days. However, careful continued follow-up and further evaluation will be required.
