Foot Orthoses in the Prevention of Injury in Initial Military Training

Background: Overuse lower limb injury is common in incidence and morbidity. Many risk factors, gait related and biomechanical, have been identified, although little conclusive evidence has been found in terms of injury prevention to date. Hypothesis: Orthoses, as produced by proprietary software interpretation of plantar pressures, are able to reduce injury rates in an “at risk” military population. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Four hundred military officer trainees were assessed by means of pressure plate recording of their contact foot pressures during walking. Participants were risk assessed and randomized to receive or not receive customized orthoses using the D3D system. Both cohorts were followed up for injury through their basic training at the 7-week point. Results: The orthotic intervention group sustained 21 injuries in total (1 injury per 4666 hours of training), whereas the control group sustained 61 injuries in total (1 injury per 1600 hours of training) (P < .0001), thereby demonstrating an absolute risk reduction of 0.49 from use of the orthoses (P < .0001, chi square; confidence interval, 1.7, 2.4). Conclusion: In this military trainee population, orthoses were effective in the prevention of overuse lower limb injury. This is the first study to identify a positive preventive role of orthoses.