Association of Specific Lower Extremity Injuries With Delayed Amputation.

Introduction: Despite medical interventions to preserve viability and functionality of injured limb(s) among combat-injured service members, delayed amputations may occur. The goal of this study was to determine whether specific lower extremity (LE) injuries were associated with delayed amputations.

Methods: The Expeditionary Medical Encounter Database was queried for combat-related LE injuries between 2003 and 2015. The Abbreviated Injury Scale (AIS) was used to categorize LE injuries by severity. Injury episodes with a maximum LE AIS of 1 or amputation on the day of injury were excluded. The final sample included 2,996 service members with at least one LE injury with an AIS ≥2. The frequencies of specific LE fractures and nerve and vessel injuries were determined. Logistic regression with paired independent variables was performed to examine the impact of multiple LE injuries on the odds of delayed amputation.

Results: Delayed LE amputation was identified in 308 (10.3%) service members in the sample. The delayed and no amputation groups did not differ in age and service branch. The majority of injury episodes were blast-related and with an Injury Severity Score ≥9. The most frequent fractures were tibia (34.4%) and fibula (29.3%), but the highest rates of delayed amputation were in those with navicular (36.2%), talus (30.0%), or calcaneus (28.1%) fractures. Odds of amputation were highest among service members with the calcaneus fracture and LE nerve injury (odds ratio [OR]: 41.74; 95% confidence interval [CI], 14.70, 118.55; p < 0.001), calcaneal fracture and LE vessel injury (OR: 17.99; 95% CI: 10.53, 30.74; p < 0.001), and calcaneus and tibia fractures (OR: 15.12; 95% CI: 9.54, 23.96; p < 0.001) combinations.

Conclusions: Odds of delayed amputation increased substantially with specific injury combinations. These findings may guide clinical decision-making in the acute care period.