Substantial Loss of Skeletal Muscle Mass Occurs After High Energy Trauma

The aim of this study was too quantify loss of skeletal muscle mass that occurs early after high energy trauma and determine the association with poor nutrition intake.

This prospective cohort study was completed at a midwest academic level 1 trauma center. Patients aged 18 - 55 years old with acute open fracture of the extremity/pelvis and/or two or more injured extremities treated with operative fixation were enrolled. Body composition was measured with bioelectrical impedance analysis at time of injury, 6 weeks, and 12 weeks after injury (Lean Body Mass (LBM), Skeletal Muscle Mass (SMM), Percent Body Fat (%BF)).Dietary intake was measured with the Vioscreen® survey at time of injury and at 3 months. Baseline to post-operative changes in body composition were evaluated using repeated measures generalized linear models (GLM). To determine whether body composition changes differed according to baseline protein insufficiency, subjects were grouped according to baseline protein insufficiency status (<0.8 g protein/Kg Bodyweight, y/n) and analyses were repeated with addition of a group*time interaction term to GLM models.

Twenty patients (male, n=16 (80%)), mean age 37.7 SD 12.4 years) from June 2021 - June 2022 were enrolled. Subjects lost significant LBM at 6 weeks (mean = -5.2kg SD5.6kg, p=0.0007), 12 weeks (mean = -5.3kg SD5.5 kg, p=0.0017), and 24 weeks (mean = -8.3kg SD 7.3kg, p=0.0037). and significant SMM at 6 weeks (mean= -3.0kg SD 3.3kg, p=0.0009), 12 weeks (mean = -3.1 kg SD 3.2 kg, p=0.0013) and 24 weeks (mean = -4.8kg SD 4.4kg, p= 0.0049). There was also a significant increase in %BF seen at follow-up (0.45% SD 0.16%, p<0.05). Five out of 20 subjects were protein deficient at the time of injury. Protein deficiency was not associated with loss of LBM or SMM.

This study documented significant loss of LBM and SMM and increases in %BF after high energy musculoskeletal trauma. Insufficient protein intake was not associated with greater loss of muscle mass in this small series. Level of Evidence: II.