Cold treatment for sprained ankle. A woman's foot, seen at top, has been placed in a pressurised cold water jacket (Jobst cryo/temp machine) designed to relieve a sprained ankle. The jobst cryo/temp machine (lower frame) works like an ice-pack but applies higher pressure and allows fine control of temperature. The green inflatable jacket contains cold water pumped in at high pressure and maintained at a precise temperature. Sprained ankle is caused by tearing of a muscle, ligament or tendon in the ankle. The injury typically produces swelling and bruising after the initial pain subsides, and may take weeks to heal completely.