One of the most serious complications of diabetic foot (DF) is osteomyelitis, and early detection is important. To assess the validity of thermography to screen for osteomyelitis, we investigated thermographic findings in patients with both DF and osteomyelitis. The subjects were 18 diabetic patients with 20 occurrences of DF who visited a dermatology department at a hospital in Tokyo and underwent evaluation by magnetic resonance imaging (MRI) and thermography between June 2010 and July 2012. Osteomyelitis was identified by MRI. Thermographs were taken of the wounds and legs after bed rest of more than 15？minutes. Two wound management researchers evaluated the range of increased skin temperature. There were three types of distribution of increased skin temperature: the periwound, ankle, and knee patterns. Fisher’s exact test revealed that the ankle pattern was significantly more common in the group with osteomyelitis than in the group without osteomyelitis ( ). The positive predictive value was 100%, and the negative predictive value was 71.4%. Our results suggest that an area of increased skin temperature extending to the ankle can be a sign of osteomyelitis. Thermography might therefore be useful for screening for osteomyelitis in patients with DF. 1. Introduction Diabetic foot (DF) is defined as infection, ulceration, and/or destruction of deep tissue associated with neurological abnormalities and various degrees of peripheral vascular disease in the lower limb [1]. The prevalence of foot ulcers is 4% to 10% in patients with diabetes mellitus (DM) [2]. DF severely affects a patient’s physical condition, long-term prognosis [3, 4], and quality of life [5, 6]. Therefore, early healing of DF is important. One of the most serious complications of DF is osteomyelitis, and its diagnosis and treatment (surgery and/or long-term antibiotics) have been long-standing controversies [7–9]. Therefore, early detection of osteomyelitis is important. Although swelling and warmth are associated with osteomyelitis, it is difficult to diagnose the presence of osteomyelitis in DF by physical examination because the plantar skin has an especially thick layer of stratum corneum. Furthermore, inflammatory pain may occasionally be overlooked in diabetic patients due to sensory disturbance. Although biopsy or magnetic resonance imaging (MRI) is the gold standard for diagnosing osteomyelitis [7–9], it is accompanied by disadvantages such as invasiveness, a high cost, and non-real-time diagnosis. One of the possible tools for detecting inflammation or infection in DF is
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