Cold therapy, also known as cryotherapy is thought to help joints that are closer to the surface of the skin. The knee doesn't have much soft tissue, fat, or muscle covering the joint. The cold can get down into the joint easier.

Large muscles and at least one layer of fat cover the hip. It's always been thought unlikely that the cooling action would reach deep into the hip joint.

However a new study from Japan may prove this idea wrong. They used cryotherapy with a group of 23 total hip replacement patients. The group was compared to another group who had a hip replacement but without cold therapy afterwards.

The researchers report good success with the cold therapy. Patients got pain relief faster. They used fewer pain meds. They could begin rehab sooner. Based on this study, the use of cold after hip surgery may become more popular in the months and years ahead.