Alternative materials to acrylic bone cement for delivery of depot antibiotics in orthopaedic infections

Acrylic bone cement has considerable laboratory and clinical data validating it as a delivery material for depot administration of antibiotics. However, an alternate material that does not require a secondary procedure for removal is desired. Many biodegradable materials have been evaluated as alternatives including protein-based materials (collagen, fibrin, thrombin, clotted blood), bone-graft, bone-graft substitutes and extenders (hydroxyapatite, beta-tricalcium phosphate, calcium sulfate, bioglass), and synthetic polymers (polyhanhydride, polylactide, polyglycolide, polyhydroxybutyrate-co-hydroxyvalerate, polyhydroxyalkanoate). Various forms and combinations of these materials have been investigated worldwide, characterizing their elution properties and performance in treating osteomyelitis in animal models. Many of these have had limited clinical evaluation. Outside the United States, some of these materials are used clinically. In the United States, none have been approved. None are commercially available for clinical use. Morselized cancellous bone and calcium sulfate are the two materials that have been used clinically in the United States on a physician-prescribed, hand-mixed, basis. Considering the limited clinical data that currently are available, the use of these materials still is experimental. Clinical application should be cautious, limiting the total antibiotic load. Until definitive data are available, a prudent dose would be no higher than one that would have acceptable toxicity risk if administered intravenously over 24 hours.