Differentiation between bone infarction and acute osteomyelitis in children with sickle-cell disease with use of sequential radionuclide bone-marrow and bone scans.

BACKGROUND: The differentiation of bone infarction from acute osteomyelitis in patients with sickle-cell disease is challenging, as the clinical presentations of the two conditions are similar and imaging and laboratory studies are of limited value. METHODS: A combination of radionuclide bone-marrow and bone scans was performed sequentially within a twenty-four-hour period (with one exception) to aid in the differentiation between bone infarction and osteomyelitis in seventy-nine consecutive episodes of acute bone pain in children with sickle-cell disease. RESULTS: Seventy cases of bone infarction were diagnosed on the basis of decreased uptake on the bone-marrow scan and abnormal uptake on the bone scan at the site of pain. Antibiotic administration was discontinued in sixty-six of the seventy cases after the imaging results were obtained, and the bone pain resolved. In four of the seventy-nine cases, there was normal uptake on the bone-marrow scan and abnormal uptake on the bone scan at the site of pain, findings that were suggestive of acute osteomyelitis. In three of these cases, osteomyelitis was proven by culture, and the symptoms in all four resolved with antibiotic treatment. In five of the seventy-nine cases, the bone-marrow and bone scans were normal and thought to indicate neither osteomyelitis nor bone infarction; in all of these cases, the symptoms resolved without the use of antibiotics. CONCLUSIONS: These findings suggest that osteomyelitis can be differentiated from bone infarction in children with sickle-cell anemia and acute bone pain by a combination of sequential bone-marrow and bone scintigraphy.

Relation of surface area to in vitro elution characteristics of vancomycin-impregnated polymethylmethacrylate spacers.

To study the relationship between surface area and antibiotic elution from antibiotic-impregnated polymethylmethacrylate (PMMA) spacers, a standard block spacer made of vancomycin (4 g) and 40 g of PMMA was compared with two unique spacer designs, the "donut" and "fenestrated." The spacers were incubated in phosphate-buffered saline, which was changed daily, and a microbiologic assay was used to measure the antibiotic activity of the eluates. The donut and fenestrated spacers had 12% and 40% more surface area than the standard spacer, respectively. There was no significant difference, however, in daily elution levels of antibiotic between the donut spacer and the standard spacer. The fenestrated spacer displayed significantly better elution than either the standard or donut spacers, with an average of 20% more antibiotic eluted on any given day.