Abstract
Anti-vehicle mines (AV) and Improvised Explosive Devices (IEDs) remain the most prevalent threat to Coalition troops operating in Iraq and Afghanistan. Detonation of these devices results in rapid deflection of the vehicle floor resulting in severe injuries to calcaneus. Anecdotally referred to as a ‘deck-slap’ injury, there have been no studies evaluating the pattern of injury or the effect of these potentially devastating injuries since World War II. Therefore the aim of this study is to determine the pattern of injury, medical management and functional outcome of UK Service Personnel sustaining calcaneal injuries from under-vehicle explosions.
From Jan 2006 – Dec 2008, utilising a prospectively collected trauma registry (Joint Theatre Trauma Registry, JTTR), the records of all UK Service Personnel sustaining a fractured calcaneus from a vehicle explosion were identified for in depth review. For each patient, demographic data, New Injury Severity Score (NISS), and associated injuries were recorded. In addition, the pattern of calcaneal fracture, the method of stabilisation, local complications and need for amputation was noted. Functional recovery was related to the ability of the casualty to return to military duties.
Forty calcaneal fractures (30 patients) were identified in this study. Mean follow-up was 33.2 months. The median NISS was 17, with the lower extremity the most severely injured body region in 90% of cases. Nine (30%) had an associated spinal injury. The overall amputation rate was 45% (18/40); 11 limbs (28%) were amputated primarily, with a further 3 amputated on return to the UK. Four (10%) casualties required a delayed amputation for chronic pain (mean 19.5 months). Of the 29 calcaneal fractures salvaged at the field hospital, wound infection developed in 11 (38%). At final follow-up, only 2 (6%) were able to return to full military duty with 23 (76%) only fit for sedentary work or unfit any military duty.
Calcaneal injuries following under-vehicle explosions are commonly associated with significant polytrauma, of which the lower limb injury is the most severe. Spinal injuries were frequently associated with this injury pattern and it is recommended that radiological evaluation of the spine be performed on all patients presenting with calcaneal injuries from this injury mechanism. The severity of the hindfoot injury witnessed is reflected by the high infection rate and amputation rate seen in this cohort of patients. Given the high physical demands of a young, active military population, only a small proportion of casualties were able to return to pre-injury duties. We believe that the key to the reduction in the injury burden to the soldier lies in the primary prevention of this injury. Work is currently on going to develop experimental and numerical models of this injury in order to drive future mitigation strategies.
