Histology versus microbiology for accuracy in identification of osteomyelitis in the diabetic foot.

It is important to accurately diagnose osteomyelitis, and bone biopsy is currently considered by many to be the gold standard diagnostic test for its identification. Microbiologic studies, namely culture and sensitivity tests, are also used to identify osteomyelitis. To our knowledge, no published reports exist that compare the diagnostic characteristics of bone biopsy to microbiology with regard to making the diagnosis of osteomyelitis. For these reasons, we undertook a matched case control study to test the null hypothesis that claimed there is no difference between histology and microbiology with regard to making the diagnosis of pedal osteomyelitis in diabetic patients. The sample population consisted of consecutive diabetic patients from a tertiary care hospital who were surgically treated for foot infection with suspected osteomyelitis. Each bone specimen was hemisected, and one half sent for microbiologic testing and the other half sent for histopathologic inspection. McNemar's test for correlated proportions was used to identify whether or not a statistically significant difference existed between the diagnostic methods. A total of 44 specimens were analyzed, and our results showed that a positive microbiologic and negative histologic result was just as likely as a negative microbiologic and positive histologic result (P > .05). In conclusion, based on the results of this investigation, microbiologic testing performed as well as did histopathologic testing when it came to identifying the presence of pedal osteomyelitis in the diabetic foot.