DIAGNOSIS OF INFECTION IN UNUNITED FRACTURES - COMBINED IMAGING WITH INDIUM-111-LABELED LEUKOCYTES AND TC-99M METHYLENE DIPHOSPHONATE

The results of combined scintigraphy in which indium-111-labeled leuko cytes and technetium-99m methylene diphosphonate were used were compar ed with the results of cultures of open bone at 102 sites of delayed u nion or non-union, to determine the effectiveness of this combination as a preoperative indicator of osteomyelitis. There were twenty-five t rue-positive, fifty-nine true-negative, eleven false-positive, four fa lse-negative, and three indeterminate interpretations, yielding, for t he diagnosis of osteomyelitis, a sensitivity of 86 per cent, a specifi city of 84 per cent, an accuracy of 82 per cent, a positive predictive value of 69 per cent, and a negative predictive value of 94 per cent. There were few false-negative scans; false-positive results were most likely at a metaphyseal site adjacent to a joint in which there was p ost-traumatic arthropathy, at the site of a failed arthrodesis, and at the site of an unstable delayed union or non-union.