Evidences and controversies about recurrence of diabetic foot osteomyelitis: a personal view and an illustrated guide for understanding

Recurrence is one of the most worrying issues when dealing with diabetic foot osteomyelitis (DFO). In accordance with expert opinion in other areas of bone infection, it is accepted that very late relapse of apparently successfully treated osteomyelitis is not uncommon. However, the physiopathology of infections in large bones secondary to hematogenous osteomyelitis, infected prostheses, and open fractures is quite different from what is seen in the feet of patients with diabetes. The anatomy of the bones, the mechanism of infection and alterations in host defenses that are frequently seen in patients with diabetes may condition the onset, clinical course, and outcomes. Apparent eradication, disappearance of inflammatory signs, wound healing, bone healing based on image studies, and no recurrences during follow-up are common terms used for defining the success of therapy for DFO. Failure of initial surgical treatment, readmission to hospital, and new episodes of infection at the same or a contiguous site are considered as recurrence of osteomyelitis. Theoretically, bacteria living in the bone could be the source of clinical recurrence, but is it possible to obtain complete healing while bacteria remain alive in the bone in the feet of patients with diabetes? Can these bacteria grow and spread from the bone to the skin after years of healing? In the author's opinion, this type of long-term recurrence of DFO has not been well documented in the medical literature. It is the aim of this illustrated guide to review the evidence and controversies regarding the recurrence of DFO.