Use of Antibiotic Beads

The diabetic infecrion .is an entity encountered by countless health professionals on a daily basis and represents one of the most challenging, as well as costly, endeavors in medicine today.' As a disease that requires multidisciplinary involvement, we approach diabetes and its management with a cautious optimism, knowing the ramifications of neglecting this potentially debilitating condition. \With the help of primary care physicians, endocrinologists, infectious disease specialists, vascular tearns, and a variety of wound care modalities, the diabetic patient should be no stranger to the proverbial white coat. \7e are obligated to use the full spectrum of pharmacologic agents with this condition. The use of antibiotic impregnated beads in the management of the diabetic infection will be presented (Figures 1, 2). The use of "bone cement" has roots as early as the 1930s, during which acrylic technology was developed as a dental grout. This method relies on the synthesis of resins derived from acrylic acid, to which a monomeric Iiquid is added to create a dough-like material that is easily molded. Later this technology evolved into polymethylmethacrylate (PMMA), which was commonly used in dental applications and cranioplasty during \Morld \Mar II. Initially developed in the 1950s by Sir John Charnley, PMMA was used for orthopedic fixation of femoral head prostheses to femoral shafts in the 1960s (Figures 3, 4).' Presently, a variery of commercially available PMMA based beads are manufactured in the US and worldwide. Preparation of antibiotic beads involves a kit containing individually packaged powder and liquid, which are typically sterilized with gamma irradiation and ultrafiltration. Smith and Nephewb Palacos R cement uses ethylene oxide gas for sterilization of these separate components.' Packaged powder contains PMMA as its primary constituent, whereas the liquid vial contains the monomer subunit, methylmethacrylate. The powder will generally contain an initiator of polymerization, benzoyl peroxide, and a radio opaque substance, or opacifier, either barium sulfate or zirconium dioxide. The properties of individual bone cement are determined by additional agents that prevent premature polymerization, protect against degradation during the sterilization process, or colorizing agents such as chlorophyll or methylene blue.' PMMA has undergone intense scrutiny in regard to its mechanical properties and for its potential adverse effects after implantation. Various studies have been conducted designed to test its static and dynamic material properties, both in situ and using cadaveric specimens via tensiometery readings. Static mechanical properties include compressive, tensile, and shear and involve placing a single, axially oriented load to a cylindrical plug of the material tested. Dynamic material properties are determined using frequent application of submaximal loads, which is