Abstract 41

ANTIBIOTIC AND ITS EFFECT ON ACRYLIC BONE CEMENT

PELLETIER, MH; Okamoto, K; Walsh, WR

Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Hospital, Sydney, NSW, Australia

The limited availability of bone cement containing antibiotics leads to surgeons adding varying amounts during mixing. The aim of this study is to determine the effects of antibiotics on commercially available bone cements.

Two PMMA bone cements were evaluated in this study; Simplex (Stryker, Ireland), and VersaBond (Smith & Nephew,USA). Three groups were tested; 1) PMMA (No Antibiotic), 2) PMMA with 1g Flucloxacillin and 1g of Vancomycin (5 wt%), and 3) PMMA with 3g Flucloxacillin and 3g Vancomycin (15 wt%). Cement specimens were prepared according to ASTM F451-99a; Standard Specification for Acrylic Bone Cement. The cement dowels were tested in uni-axial compression and scanned using Micro CT to assess compressive strength, porosity, and Euler characteristics.

The addition of antibiotics had an overall negative effect on the compressive properties of both cements. When compared to the unaltered mix; the compressive properties of VersaBond were effected at both antibiotic levels, while Simplex was effected only at the higher dose. When comparing both antibiotic loaded conditions no differences were seen. This is interesting as the high dose was three times the low dose. Porosity was increased with the addition of antibiotic. The Euler characteristics showed isolated solids with VersaBond and isolated pores with Simplex. Micro CT images between cement types were very different.

The increased porosity seen could aid in elution characteristics, and there was little difference in mechanical properties between the loaded and highly loaded states. These two results provide some support for increasing the amount of antibiotic used in arthroplasty.

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