A prospective study from the LEAP group (Bosse 2001) used five injury severity scoring systems (MESS, LSI, PSI>>) to prospectively evaluate 556 patients with lower extremity injuries. At six months from the time of injury 407 patients remained in the limb salvage group. They found that each scoring system was highly specific for amputation, but not sensitive. They concluded that a low score could be used to predict a limb salvage patient, but that a high score could not be used to predict the need for an amputation. This study was not included in the references for the CPG as it did not assess difference in outcomes, however, is relevant to the use of lower extremity injury severity scores at time of injury. While the panel agrees these scores should not be used to guide treatment, they can be useful when used in a descriptive manner and to provide a framework when discussing treatment options with the patient and family.
The same group (Ly, 2008) prospectively evaluated the same five scoring systems to predict outcome following limb salvage using the Sickness Impact Profile (SIP) at 6 months and 2 years after injury. They found that none of the scores were predictive of either the SIP at 6 and 24 months or of the change in SIP between 6 and 24 months. They concluded that these scoring systems should not be used to predict functional outcome following successful limb salvage in patients who sustain a high energy lower-extremity trauma.
A study of 155 military patients with type III open tibia fractures reported that 110 patients underwent successful limb salvage and 45 eventually required amputation. The average MESS scores for these two cohorts were 5.3 and 5.8, respectively; more importantly, MESS scores demonstrated specificity of 87.8% for predicating amputation, but a sensitivity of only 35% and positive predictive value of only 50% for scores ≥7. The authors concluded that MESS scores were neither adequately “sensitive nor accurate for predicting amputation” (Sheean 2014).
BENEFITS & HARMS:
Given that lower extremity scores have not been shown to predict outcomes or the need for amputation or limb salvage, the benefit of implementing this recommendation will be that fewer patients will receive an upfront amputation based on a high extremity specific score such as the MESS or LSI. This should reduce the number of unnecessary amputations. It is possible that a patient with a high MESS, LSI or PSI score may ultimately require an amputation due to other factors and each patient should be evaluated on a case by case basis.
Priority outcomes include preventing unnecessary amputations based on tools that have been shown to have a low sensitivity to predict need for amputation.
COST EFFECTIVENESS/RESOURCE UTILIZATION:
As an independent factor, there is no direct impact on cost effectiveness/resource utilization.
Developing a more sophisticated tool for surgeons that incorporates available patient characteristics that has a better sensitivity and specificity in identifying patients who would benefit from an immediate amputation using the body of research from the LEAP studies.
Additional Rationale References:
- Bosse, M.J., MacKenzie, E.J.,Kellam, J.F., et. al. A Prospective Evaluation of the Clinical Utility of the Lower-Extremity Injury-Severity Scores. J Bone Joint Surg Am. 2001; 83(1):3-14.
- Sheean, A.J., Krueger, C.A., Napierala, M.A., Stinner, D.J., Hsu, J.R. Evaluation of the Mangled Extremity Severity Score in Combat-Related Type III Open Tibia Fracture. J Orthop Trauma. 2014; 28(9):523-6.
*Strength of Recommendation: Moderate (upgraded) Evidence from two or more “Moderate” quality studies with consistent findings, or evidence from a single “High” quality study for recommending for or against the intervention. Also requires no or only minor concerns addressed in the EtD framework.