Introduction: The military population is at high-risk for injury with by painful sprains,
especially of the ankle. The referenced treatment method for pain is the cryotherapy,
consisting in applying cold-packs to the injured ankle several times a day. However, another
pain treatment has been developed and is commonly used by high-level sports teams and
rheumatologists but its efficacy has never been assessed within a military population, i.e.
the hyperbaric CO2 cryotherapy, also called the neurocryostimulation.

Research design: This study was carried out on a French multicenter basis, the study
consisting in a randomized controlled superiority trial and open-label prospective analysis
in the treatment of 40-year-old military patients or younger suffering from acute ankle
sprains. Two groups were made: patients were treated either by neurocryostimulation or by the
referenced cryotherapy (cold-packs). The care protocol for both groups consisted in six
supervised 30 minute-sessions within a period of three consecutive days.

Hypothesis: Neurocryostimulation is more effective in the treatment of pain severity
resulting from an ankle sprain than the referenced treatment by cold-packs. Moreover, we
theorized that the total consumption of paracetamol and the number of days of temporary
inaptitude and of work exemption were lower in patients treated by neurocryostimulation.

Outcomes:

For each session, pain severity is assessed on a 100-mm Visual Analog Scale at the beginning
and at the end of session 20 minutes later after a four-step walk.