Evaluation of diabetic foot osteomyelitis using probe to bone test and magnetic resonance imaging and their impact on surgical intervention

ObjectivesTo evaluate the role of probe to bone test (PTB) and magnetic resonance imaging (MRI) in assessing the surgical intervention in diabetic foot.Study design102 diabetic patients were included; 42 males and 60 females, mean age was 52 ± 6, all patients were subjected to PTB test followed by MRI, the presence of osteomyelitis was assessed in relation to histopathological examination.ResultsWe had 80 (75.5%) feet of osteomyelitis, PTB test was true positive in 66 (82.5%), false negative in eight and false positive in 6 feet. MRI was true positive in 78, false positive in three and false negative in two feet. Other MRI finding include abscess in 37, tenosynovitis in 69, neuropathic changes in 20 feet, and all cases had cellulites. Sensitivity, specificity, PPV and NPV were 82.5%, 76.9%, 91.7%, and 58.8% for PTB test and 97.5%, 88.5%, 96.3% and 92% for MRI respectively.ConclusionPTB test is a simple, minimally invasive, low cost test and can be done at outpatient clinic. Its sensitivity and specificity are good when compared to those of MRI, but when we need to diagnose associated soft tissue infection and planning the surgical management MRI was the image of choice.