Practical applications of antibiotic-loaded bone cement for treatment of infected joint replacements.
ABSTRACT The use of antibiotic-loaded bone cement is an accepted treatment method for infected joint arthroplasties. It is helpful to separate the use of antibiotic-loaded bone cement as a method of prophylaxis as compared with the treatment of an established infection. A low dose of antibiotic-loaded bone cement (< or = 1 g of antibiotic per batch of cement) should be used for prophylaxis, and high-dose antibiotic-loaded bone cement (> 1 g antibiotic per batch of cement) is indicated for treatment. The only commercially available antibiotic-loaded bone cement products are low dose, with the use of tobramycin or gentamicin as an antibiotic selection. High-dose antibiotic-loaded bone cement requires hand mixing by the surgeon to facilitate the use of high dosages and choices of multiple antibiotics. Treatment of infected hip and knee arthroplasties with high-dose antibiotic-loaded bone cement is aided by the use of spacers of various shapes and sizes. These spacers, whether they are static or articulating (mobile), are meant to provide local delivery of antibiotics, stabilization of soft tissues, facilitation of an easier reimplantation, and improved clinical outcomes.
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ABSTRACT: Background Tissue distribution after local delivery has been quantified over a period of 5 hours on 7-T MRI in a rabbit model using gadolinium-labeled diethylenetriamine pentaacetic acid (Gd-DTPA) as an antimicrobial surrogate; however, it is unknown how the Gd-DTPA load in a local depot will affect the duration of high-concentration Gd-DTPA in local tissues after surgical débridement. Questions/purposes We determined whether the Gd-DTPA load in bone cement affected its local tissue distribution over a period of 1 month after local delivery. Methods A 1-cm3 soft tissue dead space was created in the quadriceps of seven rabbits and filled with gadolinium-loaded bone cement. At 7, 14, and 33 days, the volume of tissue with a Gd-DTPA concentration of more than 14 μg/mL was calculated from T1-weighted images using 7-T MRI. Differences in volumes of distribution were analyzed with ANOVA. Results The volume of tissue with more than 14 μg/mL Gd-DTPA was much larger from higher gadolinium loads on Day 7 (p = 0.02) (2121 mm3 for 10 g and 665 mm3 for 1 g) and smaller with time for the 10-g formulation (2121 mm3 on Day 7 and 1241 mm3 on Day 14). Conclusions Volume of distribution and duration of Gd-DTPA after local delivery increased with increasing load in the cement and decreased with time. Clinical Relevance For local delivery, high antimicrobial concentrations would be expected in greater volumes of tissue, for longer durations, when higher antimicrobial loads are used.Clinical Orthopaedics and Related Research 11/2014; 472(11). · 2.88 Impact Factor