Citation

Ramasamy MA, Hill AM, Phillip R, Gibb IE, Bull AMJ, Clasper JC. J. Orthop. Trauma 2013; 27(1): 49-55.

Affiliation

*Imperial Blast Biomechanics and Biophysics Group, Imperial College London, London, United Kingdom †Academic Department of Military Surgery and Trauma, Royal Centre for Defence, Medicine, Birmingham Research Park, Vincent Drive, Birmingham, United Kingdom ‡Defence Medical Rehabilitation Centre, Headley Court, Epsom, Surrey, United Kingdom §Centre for Defence Imaging, Fort Blockhouse, Gosport, Hants, United Kingdom.

Copyright

(Copyright © 2013, Lippincott Williams and Wilkins)

DOI

10.1097/BOT.0b013e3182519664

PMID

22561744

Abstract

OBJECTIVES:: Due to the absence of clinical blast data, automotive injury data using the abbreviated injury score (AIS) has been extrapolated to define current North Atlantic Treaty Organisation (NATO) injury thresholds for anti-vehicle mine tests. We hypothesized that AIS, being a marker of fatality rather than disability, would be a worse predictor of poor clinical outcome compared with the lower limb-specific foot and ankle severity score (FASS). METHODS:: Using a prospectively collected trauma database, we identified UK Service Personnel sustaining lower leg injuries from under-vehicle explosions from January 2006 to December 2008. A full review of all medical documentation was performed to determine patient demographics and the severity of lower leg injury, as assessed by AIS and FASS. Clinical endpoints were defined as (1) need for amputation or (2) poor clinical outcome (defined as amputation or ongoing clinical problems). Statistical models were developed to explore the relationship between the scoring systems and clinical endpoints. RESULTS:: Sixty-three UK casualties (89 limbs) were identified with a lower limb injury after under-vehicle explosion. The mean age of the casualty was 26.0 years. At 33.6 months follow-up, 29.1% (26 of 89) required an amputation and 74.6% (67 of 89) having a poor clinical outcome. Only 9 (14%) casualties were deemed medically fit to return to full military duty. Receiver operating characteristic analysis revealed that both AIS = 2 and FASS = 4 could predict the risk of amputation, with FASS = 4 demonstrating greater specificity (43% vs. 20%) and greater positive predictive value (72% vs. 34%). In predicting poor clinical outcome, FASS was significantly superior to AIS. Probit analysis revealed that a relationship could not be developed between AIS and the probability of a poor clinical outcome. CONCLUSIONS:: Our study clearly demonstrates that AIS is not a predictor of long-term clinical outcome and that FASS would be a better quantitative measure of lower limb injury severity.

Language: en