Ability of lower-extremity injury severity scores to predict functional outcome after limb salvage

Background: Lower-extremity injury severity scoring systems were developed to assist surgeons in decision-making regarding whether to amputate or perform limb salvage after high-energy trauma to the lower extremity. These scoring systems have been shown to not be good predictors of limb amputation or salvage. This study was performed to evaluate the clinical utility of the five commonly used lower-extremity injury severity scoring systems as predictors of final functional outcome. Methods: We analyzed data from a cohort of patients who participated in a multicenter prospective study of clinical and functional outcomes after high-energy lower-extremity trauma. Injury severity was assessed with use of the Mangled Extremity Severity Score; the Limb Salvage Index; the Predictive Salvage Index; the Nerve Injury, Ischemia, Soft-Tissue Injury, Skeletal Injury, Shock, and Age of Patient Score; and the Hannover Fracture Scale-98. Functional outcomes were measured with use of the physical and psychosocial domains of the Sickness Impact Profile at both six months and two years following hospital discharge. Four hundred and seven subjects for whom the reconstruction regimen was considered successful at six months were included in the analysis. We used partial correlation statistics and multiple linear regression models to quantify the association between injury severity scores and Sickness Impact Profile outcomes with the subjects' ages held constant. Results: The mean age of the patients was thirty-six years (interquartile range, twenty-six to forty-four years); 75.2% were male and 24.8% were female. The median Sickness Impact Profile scores were 15.2 and 6.0 points at six and twenty-four months, respectively. The analysis showed that none of the scoring systems were predictive of the Sickness Impact Profile outcomes at six or twenty-four months to any reasonable degree. Likewise, none were predictive of patient recovery between six and twenty-four months postoperatively as measured by a change in the scores in either the physical or the psychosocial domain of the Sickness Impact Profile. Conclusions: Currently available injury severity scores are not predictive of the functional recovery of patients who undergo successful limb reconstruction. Level of Evidence: Prognostic Level I. See Instructions to Authors for a complete description of levels of evidence.