[Manual addition of antibiotics to industrial bone cement mixes : Investigations of the dry mix in the cement cartridge during manual admixture to polymer-active substance mixtures].

Abstract

Background: Periprosthetic infection (PPI) is a rare but serious complication. An elementary component of the therapy of PPI is the use of bone cement with the addition of antibiotics. For targeted therapy, manual mixing of antibiotics with industrially produced bone cement mixtures is often necessary. Possible problems resulting from manual mixing have not been described sufficiently so far.

Objectives: Therefore, the aim of the present study was to describe the influence of the additional homogenisation by dry mixing of a polymer-active substance mixture on the quality of manually added cement.

Material and methods: In the laboratory-based study, four cement samples were prepared using different methods for manual addition and homogenisation of antibiotics (vancomycin). The reference control was Copal® G + V (Heraeus Medical GmbH, Wehrheim, Germany), to which the vancomycin (V) had already been industrially added. The samples were then examined for mechanical, microbiological and microscopic parameters.

Results: In the mechanical and microbiological results, no statistically significant differences were found between the manually added mixtures and the reference. After dry mixing of the polymer powder, the inner surface of the mixing cartridges used showed signs of scratching in the microscopic examination and showed indications of abrasion during mixing.

Conclusion: The manual addition of antibiotics to industrially produced bone cement should be reserved for selected indications if the bone cement mixtures produced by industry are not sufficient.