The modern "deck-slap" injury--calcaneal blast fractures from vehicle explosions.

Background: Anti-vehicle mines and improvised explosive devices remain the most prevalent threat to coalition troops operating in Iraq and Afghanistan. Detonation of these devices causes 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.

Method: From January 2006 to December 2008, using a prospectively collected trauma registry (Joint Theater Trauma Registry), 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, and associated injuries were recorded. In addition, the pattern of calcaneal fracture, the method of stabilization, local complications, and the need for amputation were noted. Functional recovery was related to the ability of the casualty to return to military duties.

Results: Forty calcaneal fractures (30 patients) were identified in this study. Mean follow-up was 33.2 months. The median New Injury Severity Score 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 United Kingdom. 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 for any military duty.

Conclusion: Calcaneal injuries following under-vehicle explosions are commonly associated with significant multiple injuries including severe lower limb injury. The frequency of associated spinal injuries mandates radiologic evaluation of the spine in all such patients. The severity of the hindfoot injury is reflected by the high infection rate and amputation rate. Only a small proportion of casualties were able to return to preinjury military duties.