Current Clinical Diagnostic Modalities Fail to Accurately Confirm or Exclude Osteomyelitis: A Retrospective Review

Purpose: Osteomyelitis is a feared complication of diabetic foot ulcers and wounds in the presence of peripheral arterial disease (PAD). Clinically diagnosed osteomyelitis significantly increases the risk of lower extremity amputation and accounts for up to 60% of amputations in patients with diabetes. However, accurate clinical diagnosis of osteomyelitis remains controversial. We therefore retrospectively compared diagnostic imaging findings of osteomyelitis with histopathologic examination of amputated specimens.

Materials and Methods: A retrospective analysis was conducted of patients who underwent lower extremity amputations from 2011 to 2017 at a community hospital. Osteomyelitis diagnosis before amputation was determined by bone scan or magnetic resonance imaging. Both major and minor amputations were included. Amputated specimens were reviewed by pathology and evaluated for the presence of osteomyelitis.

Results: A total of 407 amputated specimens from 310 patients were evaluated. Diabetes mellitus was present in 86% and PAD 41%. A total of 45% were undergoing formal wound care before amputation. Osteomyelitis was diagnosed in 199 (49%) based on diagnostic imaging before amputation. Of these, 124 (62%) had a confirmed histopathologic diagnosis (P <0.0001). Furthermore, 81 (49%) of specimens that received a negative clinical diagnosis were positive for osteomyelitis based on histopathology (P <0.0001). Calculated accuracy was 61.9%.

Conclusions: Osteomyelitis is a deciding factor in lower extremity amputation, which in turn increases patient morbidity and mortality. Current modalities for clinical diagnosis have poor accuracy both in confirming or excluding the presence of histopathologic infection and should not be used in isolation when choosing amputation versus revascularization.