Extremity injuries comprise the majority of battlefield injuries and contribute the most to long-term disability of servicemembers. The purpose of this study was to better define the contribution of muscle deficits and volumetric muscle loss (VML) to the designation of long-term disability in order to better understand their effect on outcomes for limb-salvage patients. Medically retired servicemembers who sustained a combat-related type III open tibia fracture (Orthopedic cohort) were reviewed for results of their medical evaluation leading to discharge from military service. A cohort of battlefield-injured servicemembers (including those with nonorthopedic injuries) who were medically retired because of various injuries (General cohort) was also examined. Muscle conditions accounted for 65% of the disability of patients in the Orthopedic cohort. Among the General cohort, 92% of the muscle conditions were identified as VML. VML is a condition that contributes significantly to long-term disability, and the development of therapies addressing VML has the potential to fill a significant void in orthopedic care.