Review Question - QID 211880

A 60-year-old patient with a history of type 2 diabetes presents to your office with complaints of foot pain and non-healing ulceration which has been present for months, without a rapidly changing appearance. White blood cell count is 15,000/µL. CRP and ESR are 75 mg/L and 120 mm/hr, respectively. On exam, there is no obvious deformity to the foot but sensation is diminished diffusely. Erythema and swelling are noted, which do not improve with elevation of the foot. There is an ulcer over the plantar surface of the midfoot which appears to probe to bone with minimal drainage. What is the most likely diagnosis?