A Novel Mangled Upper Extremity Injury Assessment Score

Abstract

Managing mangled upper extremity injuries is a challenging problem because multiple tissue components including soft tissue, muscle, tendon, bone, nerves, and vessels are involved. The complexity of these injuries has hindered the development of accurate scoring systems and treatment algorithms.

Methods: Patients with mangled upper extremities presenting to a metropolitan level 1 trauma center in New York City over a 10-year period were identified. A mangled upper extremity was defined as any injury to ≥3 tissue components involving the extremity proximal to the digit.

Results: The injuries and outcomes of 76 patients were evaluated and used to create a Mangled Upper Extremity Score (MUES). One point was assigned for each of the following injury characteristics: patient age >40, fasciotomy needed, bony fixation required, bony defect present, revascularization required, crush injury mechanism, degloving or avulsion injury present, and a soft tissue defect >50 cm². The MUES correlated with the number of complications (P value = 1.96 × 10^-7) and length of hospital stay (P value = 3.95 × 10^-7). Next, a Mangled Extremity Severity Score (MESS) equivalent was calculated for each patient. There was no correlation between the MESS and the number of complications (P value = 0.92) or length of hospital stay (P value = 0.35).

Conclusions: Existing extremity scoring systems, including the MESS, are not reliable in predicting the success of limb salvage attempts or outcomes of mangled upper extremity injuries. The MUES developed in this study correlates significantly with important outcome measures including the number of hospital complications and length of hospital stay.

Fig. 1.

MUESs correlate significantly with recovery outcome measures in patients with mangled upper extremity injuries. (A–F) Patient MUESs and MESSs plotted against number of complication events, operations required, or hospital length of stay. A solid blue nonlinear regression line is provided on each graph depicting the relationship between the respective scoring system and the outcome measure of interest. The dashed red lines above and below the regression line represent the 95% confidence interval for the regression. There are significant positive correlations between the MUESs and the outcomes of interest. No significant correlation is noted between MESSs and the outcomes of interest.

Fig. 2.

MUESs are significantly higher for patients where limb salvage failed compared with patients where limb salvage was successful. (A, B) The mean MUESs and MESSs are shown for 3 groups of patients: successful salvage, failed salvage, and no salvage attempted. Additionally, the whiskers of the box plot depict the 95% confidence intervals for each group’s MUES or MESS. On the MUES graph, a dashed green line depicts the recommended MUES salvage threshold score of ≥6. The average MUES for failed salvage attempts was 5.29 compared with 3.89 when salvage was successful. On the MESS graph, a dashed orange line represents the previously published recommended MESS salvage threshold score of ≥7. MESSs did not differ significantly between patients with failed compared with successful salvage attempts. The average MESS was 7.29 for failed salvage attempts and 6.92 when salvage was successful. (C) Table (2 × 2) used to calculate sensitivity and specificity of MUES test for predicting when mangled upper extremity salvage attempts will fail. The specificity of the test is shaded in green. (D) Table (2 x 2) used to calculate sensitivity and specificity of MESS test for predicting when mangled upper extremity salvage attempts will fail. The specificity of the test is highlighted in the box shaded in red.

Fig. 3.

Higher MUESs were seen in patients with worse functional outcomes following a mangled upper extremity injury. (A–C) The mean MUESs are given for patients who had tissue necrosis, decreased passive ROM, or decreased sensation following a mangled upper extremity injury compared with patients without these postsalvage functional limitations. The whiskers of the box plots depict the 95% confidence intervals for each group’s MUES. An unpaired 2-tailed t test was performed comparing the 2 groups, and the associated P value is provided. MUESs were significantly higher in patients with decreased functional outcomes after salvage.