Alteration of Masquelet's induced membrane characteristics by different kinds of antibiotic enriched bone cement in a critical size defect model in the XXXX 's femur.

@entity801 @entity2176 @entity79 @entity10521 @entity35 @entity3402
UNASSIGNED: The Masquelet technique for the treatment of large bone defects consists of a 2-stage procedure. In the first stage, a polymethylmethacrylate (PMMA) cement spacer is inserted into the bony defect of a @entity35 's femur and over a period of 2-4 weeks a membrane forms that encapsulates the defect/spacer. In a second operation the membrane is opened, the PMMA spacer is removed and the resulting cavity is filled with autologous bone. Different kinds of bone cements are available, with or without supplemental antibiotics. Both might influence the development and the characteristics of the induced membrane which might affect the @entity79 response. Hence, this comparative study was performed to elucidate the effect of different bone cements with or without supplemental antibiotics on the development of an induced membrane in a critical size femur defect model in @entity35 . A total of 72 male SD @entity35 received a 10mm critical size defect of the femur which was stabilised by a plate osteosynthesis and filled with either Palacos+ @entity801 , @entity10521 @entity801 + @entity2176 , @entity10521 + @entity801 + @entity3402 or @entity10521 Spacem. The induced membranes were analysed after two, four and six weeks (wks) after insertion of the cement spacers (n=6/group). Paraffin embedded histological sections of the membrane were microscopically analysed for membrane thickness, elastic fibres, vascularisation and proliferation by an independent observer blinded to the group setup. The thickness of the induced membrane increased significantly from 2 wks (553 m) to 6 wks (774 m) in group Palacos+ @entity801 whereas membrane thickness decreased significantly in groups @entity10521 + @entity801 + @entity3402 (682-329 m) and @entity10521 Spacem (916 m to 371 m). The comparison between the groups revealed significantly increased membrane thickness in group Palacos+ @entity801 and @entity10521 @entity801 + @entity2176 in comparison to group @entity10521 + @entity801 + @entity3402 six weeks after induction. However, the fraction of elastic fibres was significantly increased in groups @entity10521 + @entity801 + @entity3402 (71%, 80%) and @entity10521 Spacem (82%, 81%) after 2 and 4 weeks in comparison to the groups Palacos+ @entity801 (56%, 57%) and @entity10521 @entity801 + @entity2176 (63%, 69%). Those differences however were partly diminished after 6 wks. The ratio of immature (vWF+) to more mature (CD31+) blood vessels increased significantly in groups Palacos+ @entity801 and @entity10521 @entity801 + @entity2176 whereas no significant alterations were noted in groups @entity10521 + @entity801 + @entity3402 and @entity10521 Spacem. For the first time we demonstrated that thickness and proportion of elastic fibres in induced membranes were influenced by the type of cement and the kind of supplemental antibiotics being used. Whether these alterations of the induced membrane have an effect on @entity79 remains to be proven in future studies.
