The effects of antipersonnel blast mines on the lower extremity

The objectives· of our study were: a) to evaluate the relative efficacy of antipersonnel mine protection offered by various de-mining footwear; b) to determine the in-situ forces and strains experienced by the lower extremity under blast conditions; c) to document the blast event, and d) medically evaluate the injury to the lower extremity that results from activation of a antipersonnel blast mine. Four fresh frozen full human cadavers were used, and four combinations of protective footwear were evaluated. The cadaver lower extremities were instrumented with a uniaxial load cell placed in the proximal tibia and strain gages applied to the distal femur. Each lower extremity was suspended with the boot heel placed directly over the landmine. High-speed video ( 1 3,500 frames per second) was used to capture the blast event and load and strain data were samRled 1 00 kHz and 50 kHz, respectively. Orthopaedic traumatologists-·examined the post blast lower extremities to assess the injuries, which ranged from an open, mangled lower extremity to a closed, minimally displaced fracture of the talus and calcaneal fracture. The results of this study suggest that practical mine protective measures may be feasible. LANDMINE INJURIES have reached epidemic proportions in third-world nations, and affect both combatants and civilians. During 1 980-1 993, the incidence of landmine related injuries doubled, resulting in an estimated 2000 deaths or injuries pE;?r month (Rutherford 1 997). By United Nations estimates, there are more than 1 00 million uncleared mines worldwide (Korver, 1 996). IRCOBI Conference Sitges (Spain), September 1999 457 In an effort to reduce the level of trauma to the lower extremity from antipersonnel mines, attempts have been made to design protective footwear. In the early 1 950's the U.S. Marine Corps developed a 6-inch sabot attachment for the combat boot, while the Army evaluated protective shanks in the 1960's. Work conducted at the US Army Natick Research, Development and Engineering Center in the 1 990's has led to the development of new antimine footwear. Antimine footwear has never been evaluated to determine its protective capability from a medical perspective. The purposes of our study were: a) to evaluate the relative protection offered by various de-mining footwear; b) to determine the in-situ forces and strains experienced by the lower extremity under blast conditions; c) to document the blast event, and d) medically evaluate the mine injury to the lower extremity that results from activation of a blast antipersonnel mine. · METHODS AND MATERIALS Four fresh frozen human cadavers (2 male and 2 female) were obtained from the willed body program and screened for hepatitis and HIV in conformance to our institutional review board's (IRB) approved protocoL The age and sex data for the subjects are listed in Table 1 . Cadavers were kept frozen at -4 °C except for instrumentation, radiography, testing and examination phases. Prior to testing, the full lower extremity of the cadavers were screened for abnormality or pre-existing injury by standard radiography, computerized axial tomography (CAT) scan (Picker PQ 5000) and magnetic resonance imaging (MRI) (GE SIGNA 5.2). Table 1 Age and sex data of cadavers used in the study.