Foot and ankle injuries are severely disabling for military personnel who are conditioned to undertake impact activities. Following injury, performance and patient-reported outcomes have been shown to improve for amputees compared to limb-salvage military patients. A novel custom-made ankle foot orthosis may provide improved outcomes for limb-salvage patients. Initial results with the orthosis demonstrate improved performance and patient-reported outcomes at 2-year follow-up and a reduction in the number of personnel pursuing amputation. The orthosis, however, does not work for all foot and ankle injuries. This work sought to define the indications for prescription and create a clinical decision tool to facilitate evidence-based prescription.

The outcomes for UK military personnel with complex foot and ankle injuries who underwent rehabilitation prior to the introduction of the orthosis were investigated. Over 50% of the cohort underwent amputation with improved performance outcomes for amputees compared to limb-salvage patients. Following the introduction of the orthosis, a reduction in amputation and improvement in physical performance measures were seen. Patients with a pain-specialist diagnosis of chronic pain did not benefit from prescription of the orthosis, whereas patients with primarily a nerve injury diagnosis did.

Using injury characteristics alone, however, was found to be unable to predict outcome for all injured personnel. Therefore, biomechanical measures were examined. Gait analysis of patients prior to prescription of an orthotic was conducted. Patients with a negative symmetry index of more than 20% for power generation at pre-swing were found to benefit from prescription of the orthosis in the absence of an ipsilateral injury.

This is the most complete investigation of UK personnel prescribed a novel orthosis following foot and ankle injury. This analysis facilitated the production of a clinical decision tool. The tool now requires validation and can be used to counsel foot and ankle injury patients on whether they may benefit from prescription of this orthosis.