Predictors of amputation in high-energy forefoot and midfoot injuries

Introduction: High energy injuries to the midfoot and forefoot are highly morbid injury groups that are relatively unstudied in the literature. Patients sustaining injuries of this region are challenging to counsel at the time of injury because so little is known about the short and long term results of these injuries. The purpose of this study was to investigate injury specific factors that were predictive of amputation in patients sustaining high energy midfoot and forefoot injuries.

Patients and methods: 137 patients with 146 injured feet [minimum of two fractures located in the forefoot and midfoot, excluding phalanges, talus, calcaneus, with a high energy mechanism].

Results: 121 of 146 feet (83%) were treated operatively; 27 patients sustained 34 total surgical amputation events. 30-day amputation rate was 13.9% and 1-year amputation rate was 18.9%; 27 of 146 feet ultimately sustained amputation with 23 of 27 sustaining a below the knee amputation (BKA) and 17 of 23 (73.9%) received a BKA as their first amputation. Statistically significant predictors of amputation included the number of bones fractured in the foot (p=0.015), open injury to the plantar or dorsal surfaces of the foot, Gustilo grade, vascular injury, and complete loss of sensation to any surface of the foot (all p<0.001). Specific fracture patterns predictive of any amputation were fracture of all five metatarsals (p<0.001) and fracture of the first metatarsal (p=0.003). Presence of a dislocation or fracture of the distal tibia were not predictive of amputation. Midterm patient-reported-outcomes (N=51) demonstrated no difference in physical function for patients with and without amputations.

Conclusions: High-energy forefoot and midfoot injuries are associated with a high degree of morbidity; 1/5th of patients sustaining these injuries proceeded to amputation within 1year. Injury characteristics can be used to counsel patients regarding severity and amputation risk.