Combat Versus Civilian Open Tibia Fractures: The Effect of Blast Mechanism on Limb Salvage

Abstract

This study compares open tibia fractures in US Navy and US Marine Corps casualties from the current conflicts with those from a civilian Level I trauma center to analyze the effect of blast mechanism on limb-salvage rates. Data from the 28,646 records in the University of California San Diego Trauma Registry from 1985 to 2006 was compared with 2,282 records from the US Navy and US Marine Corps Combat Trauma Registry Expeditionary Medical Encounter Database for the period of March 2004 to August 2007. Injuries were categorized by Gustilo-Anderson (G-A) open fracture classification. Independent variables included age, gender, mechanism of injury including blast mechanisms, shock, blood loss, prehospital time, procedures, Injury Severity Score, length of stay, and Mangled Extremity Severity Score (MESS). Dependent variables included early or late amputation and mortality. The civilian group had 850 open tibia fractures with 45 amputations; the military group had 21 amputation patients (3 bilateral) in 115 open tibia fractures. Military group patients were more severely injured, more likely have hypotension, and had a higher amputation rate for G-A IIIB and IIIC fractures then civilian group patients. Blast mechanism was seen in the majority of military group patients and was rare in the civilian group. MESS scores had poor sensitivity (0.46, 95% confidence interval: 0.29-0.64) in predicting the need for amputation in the civilian group; in the military group sensitivity was better (0.67, 95% confidence interval: 0.43-0.85), but successful limb salvage was still possible in most cases with an MESS score of ≥7 when attempted. Despite current therapy, limb salvage for G-A IIIB and IIIC grades are significantly worse for open tibia fractures as a result of blast injury when compared with typical civilian mechanisms. MESS scores do not adequately predict likelihood of limb salvage in combat or civilian open tibia fractures.