A prospective evaluation of the clinical utility of the lower-extremity injury-severity scores

Background: High-energy trauma to the lower extremity presents challenges with regard to reconstruction and rehabilitation. Failed efforts at limb salvage are associated with increased patient mortality and high hospital costs. Lower-extremity injury-severity scoring systems were developed to assist the surgical team with the initial decision to amputate or salvage a limb. The purpose of the present study was to prospectively evaluate the clinical utility of five lower-extremity injury-severity scoring systems. Methods: Five hundred and fifty-six high-energy lower-extremity injuries were prospectively evaluated with use of five injury-severity scoring systems for lower-extremity trauma designed to assist in the decision-making process for the care of patients with such injuries. Four hundred and seven limbs remained in the salvage pathway six months after the injury. The sensitivity, specificity, and area under the receiver operating characteristic curve were calculated for the Mangled Extremity Severity Score (MESS); the Limb Salvage Index (LSI); the Predictive Salvage index (PSI); the Nerve injury Ischemia, Soft-Tissue Injury, Skeletal Injury, Shock, and Age of Patient Score (NISSSA); and the Hannover Fracture Scale-97 (HFS-97) for ischemic and nonischemic limbs. The scores were analyzed in two ways: including and excluding limbs that required immediate amputation. Results: The analysis did not validate the clinical utility of any of the lower-extremity injury-severity scores. The high specificity of the scores in all of the patient subgroups did confirm that low scores could be used to predict limb-salvage potential. The converse, however, was not true. The low sensitivity of the indices failed to support the validity of the scores as predictors of amputation. Conclusions: Lower-extremity injury-severity scores at or above the amputation threshold should be cautiously used by a surgeon who must decide the fate of a lower extremity with a high-energy injury.