Centrifugation of antibiotic impregnated bone cement

Antibiotic impregnated bone cement is commonly used in orthopedic procedures to prevent infection. The mechanical properties of the cement can affect surgical outcomes. Centrifugation is a technique used to enhance cement strength by reducing air inclusions. However, the impact of this process on antibiotic distribution remains unclear. Prior research has shown that centrifugation improves cement homogeneity. It was already known that air bubbles can compromise the structural integrity of bone cement. The role of centrifugation in preserving antibiotic concentration is not well established. This gap motivated further investigation into the effects of centrifugation on antibiotic distribution. No prior work had resolved the question of whether centrifugation alters the spatial distribution of antibiotics in cement.

This study aimed to evaluate the impact of centrifugation on antibiotic distribution in bone cement. Specifically, the researchers focused on tobramycin and cefamandole impregnated cement. The objective was to determine whether centrifugation disrupts the uniformity of antibiotic concentration. The motivation for this study stemmed from the need to optimize cement preparation techniques. Centrifugation is known to reduce air bubbles, but its effect on antibiotic distribution is uncertain. The researchers wanted to assess whether centrifugation alters the spatial profile of antibiotics. They also sought to identify any residual air inclusions after centrifugation. The study aimed to provide evidence to guide clinical practice in cement preparation.

The researchers used Surgical Simplex P polymethylmethacrylate impregnated with tobramycin and cefamandole. The cement was mixed and prepared according to the manufacturer's instructions. Centrifugation was performed using standard techniques recommended by the manufacturer. A control group of hand-mixed cement was also prepared for comparison. The concentration of antibiotics was assessed using a zone of inhibition bioassay. The bioassay measured antibiotic levels at different points along the cement column. The presence of air inclusions was visually evaluated after centrifugation. The top 1 cm of the centrifuged cement column was analyzed separately for residual air.

The study found no significant difference in antibiotic distribution between centrifuged and hand-mixed cement. Both tobramycin and cefamandole showed similar concentration profiles along the cement column. Centrifugation reduced the number of large air inclusions in the cement. However, a notable number of air bubbles remained at the top of the centrifugation gradient. The zone of inhibition bioassay confirmed uniform antibiotic distribution in centrifuged samples. The researchers observed that the top 1 cm of the centrifuged column contained the highest concentration of air. This layer also showed a slight decrease in antibiotic concentration compared to the lower portion. The results suggest that centrifugation does not compromise antibiotic distribution but leaves residual air at the top.

The authors concluded that centrifugation of antibiotic impregnated bone cement does not disturb the overall distribution of antibiotics. The technique may be used without affecting the uniformity of antibiotic concentration. The study suggests that centrifugation reduces large air inclusions but leaves some at the top of the column. The authors recommend discarding the top 1 cm of the centrifuged cement to remove residual air. This step may improve the mechanical properties of the cement. The findings support the use of centrifugation in clinical settings for antibiotic impregnated cement. The results align with the hypothesis that centrifugation preserves antibiotic distribution. The study provides evidence to guide best practices in cement preparation.