Outcome of minor amputations at the diabetic foot in relation to bone histopathology: a clinical audit

Objective: to assess the clinical course of minor amputations at the diabetic foot in relation to bone histopathology at the affected site, and at the osteotomy site.

Methods: A total of 54 toes or metatarsal bones were amputated by general surgeons. Amputation level and mode of wound closure (primary wound closure) was left at the surgeons' discretion. The subjects were 45 diabetic patients, suffering from critical foot ischaemia (n = 27), polyneuropathy (n = 41) and chronic hemodialysis because of endstage renal failure (n = 4).

Results: Histopathology revealed osteomyelitis (n = 34), gangrene (n = 8), gout arthritis (n = 1), bone necrosis (n = 2), normal bone tissue or myelofibrosis (n = 9). The osteotomy site was located in healthy bone in 20 amputation specimens (Group A), and was affected by osteomyelitis in the remaining 34 specimens (Group B). Primary healing was observed in 11 wounds in Group A versus 3 wounds in Group B (p = 0.003). Further amputations were required in 3 cases in Group A (12 cases in Group B, n. s.). In 25 cases with critical foot ischaemia and osteomyelitis at the osteotomy site, primary healing was observed in only 1 (4 %) of the wounds, versus primary healing in 7 (77 %) of the 9 wounds without foot ischaemia and without osteomyelitis at the osteotomy site (p < 0.0001).

Conclusions: Under conditions of routine general surgery, osteomyelitic bone tissue will not always be fully resected by minor amputation procedures. Better pre-operative infection staging using MR imaging instead of radiography could prove advantageous.