Experimental study of the application of a new bone cement loaded with broad spectrum antibiotics for the treatment of bone infection.

Objectives: To evaluate the in vivo behaviour of a new bone cement loaded with antibiotics, in a rabbit bone infection model.

Material And Methods: Sixteen New Zealand rabbits divided into 4 groups were used, depending on the cement (commercial or experimental) and the antibiotic (vancomycin or linezolid) used to control a bone infection caused by Staphylococcus aureus. The commercial cement is Palacos R and the experimental cement has been achieved by adding PLGA to the solid phase of Palacos R cement. A novel histological staging method based on bone histoarchitecture has been used. This staging allows us a global vision of bone repair capacity, in the presence of modified cement, and also allows us to correlate the damage generated with the functionality of the tissue.

Results: The degree of bone destructuration found depended on the type of cement and antibiotic, and was higher in the groups with commercial cement than in the experimental group (P<.01) and in the groups with linezolid with respect to vancomycin (P=.04) The percentage of macrophages varied exclusively depending on the antibiotic used, and was higher in the vancomycin groups (P=.04).

Discussion: The development of new formulations of bone cement that release more, and more prolonged, new generation antibiotics such as linezolid, present an in vivo behaviour superior to commercial cement, respecting the bone structure. This behaviour would have a clinical implication in fighting infections by increasingly resistant germs in the treatment of prosthetic infection.