Cold numbs pain and reduces swelling by constricting blood vessels. After surgery or injury, wrap an ice pack in a cloth and apply for 20 minutes, remove for 20 minutes, reapply for 20 minutes, and so on. To prevent frostbite, do not apply ice directly to the skin. Your source for cold can be as simple as a bag of frozen peas wrapped in a towel, but you can also buy easy-to-secure neoprene wraps with pockets for gel packs that you keep in the freezer. Most elaborate are electric "continuous-flow cold therapy" devices that deliver cold through pads shaped for different joints; your doctor or physical therapist may recommend such a device after surgery.
Ice helps knee injuries of all types. For hip injuries, cold can't penetrate deep into the hip joint itself, but it is still effective for hip pain stemming from problems closer to the surface, such as trochanteric bursitis (results from a single hard fall on your hip or the accumulation of minor stresses).
After injury, use ice alone for 24 to 48 hours. After that, you can continue using ice, switch to heat, or alternate. Ice increases stiffness, while heat helps restore and maintain flexibility. You may find it beneficial to use warmth before stretching and other exercise, following with ice afterward to minimize swelling. You can give yourself an ice rub by freezing water in a paper cup. Peel back the paper and cover the ice end with a cloth before applying to the area.
More Answers from Scott Martin