Second Ray Amputation in Diabetic Foot – Functionally Better than Proximal Foot Amputations, but Beware of Charcot Arthropathy: A Case Report and Review of Literature

INTRODUCTION: Lower limb amputations secondary to diabetic foot infection/osteomyelitis (OM) are the most common cause for non-traumatic amputations of the lower extremity. Hind/midfoot amputations are commonly done for metatarsal (MT) OM. They are, however, associated with higher complication and revision rates and often lead to below knee amputation. In comparison, distal/forefoot toe disarticulation/ray amputation (R amp) have lesser revision rates/complications and give better functional outcome. Here, we report a case of 2nd R amp with an uncommon complication. CASE REPORT: A 42-year-old male with uncontrolled diabetes and bilateral diabetic neuropathy presented with discharging sinus over plantar aspect of the left foot since 1 week. There was no evidence of underlying OM on MRI. Wound healed with soft-tissue debridement and empirical antibiotics (culture negative) for 2 weeks. Re-debridement was done for a wound gape 6 weeks later. Infection resolved with targeted antibiotics (oral ciprofloxacin and doxycycline) for Enterobacter cloacae given for 1 month. Six months later, he developed pain and swelling in the left foot following prolonged barefoot walking and possible injury with a stone. There was local redness, swelling, and a plantar sinus. MRI revealed septic arthritis of the left 2nd metatarsophalangeal (MTP) joint, OM of the 2nd MT head, and an encapsulated soft-tissue abscess. Aggressive debridement with 2nd R amp and careful separation of encapsulated abscess was done leaving behind base of 2nd MT to maintain stability of the Lisfranc joint. Wound healed primarily. Targeted antibiotics for Methicillin Susceptible Staphylococcus aureus were given for 6 weeks. Good diabetic control and avoiding bare foot walking were advised and he is infection free, fully functional, and asymptomatic at 36 months. However, he was noted to have developed valgus deformity of the midfoot secondary to Charcot osteoarthropathy of the Lisfranc joints at 36 months follow-up, involving 1st, 3rd, and 4th TMT joints. The other foot did not show any evidence of Charcot arthropathy. CONCLUSION: Recurrent wound infections with subsequent OM are a common feature of diabetic foot. R amps have better functional outcomes with preserved foot stability, shorter length of hospitalization, and associated costs as compared to hind/midfoot amputations. They may, however, develop Charcot osteoarthropathy due to the void between adjoining MTs resulting in altered forces across the Lisfranc joints. Surgeons must beware of this complication, especially following R amps and monitor these patients with serial clinical and radiographic examination.