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Today's Forecast: Temperatures Dropping inside the Knee Joint

It borders on common sense. Ice is an effective first aid choice for many ailments--bumps, bruises, and even insect bites. Now it makes "scientific sense" how cold treatments play a major role in helping patients get better, faster after orthopedic surgery.

Called cryotherapy, cold treatments are believed to help ease pain, swelling, and inflammation after surgery. Cryotherapy even helps patients improve faster using fewer painkillers. Past studies have proven that patients given cold treatments after knee surgery generally recover more quickly, gaining joint movement faster and finding it easier to get up and walk.

However, these studies have only shown a drop in temperature on the skin's surface. This is the first human study to show how applying cryotherapy after knee surgery can lower the temperature inside the knee joint.

Seventeen patients had knee surgery. After surgery, a special cooling wrap was placed over each patient's sore knee. Twelve patients began their cold treatments immediately after surgery. The other five waited one hour.  

The researchers measured the temperature inside the knee joint with a special probe. Readings were taken hourly after surgery. After one hour, the people who used cold treatment immediately after surgery showed a marked drop in knee temperature. The other patients' knee temperatures went up. Remarkably, there was over 7 degrees of difference between the two groups after one hour.

The second group started their cold treatments after waiting one hour. Even though their knee temperature had gone up at first, starting cold treatment one hour after surgery caused a marked drop in temperature, about 4 degrees.

The researchers didn't study how well or how quickly the patients healed. Yet their findings suggest that cooling the inside of the joint after knee surgery must be a major reason cryotherapy works.

References: Stephanie S. Martin, MD, et al. Cryotherapy: An Effective Modality for Decreasing Intraarticular Temperature after Knee Arthroscopy. In The American Journal of Sports Medicine. May/June 2001. Vol. 29. No. 3. Pp. 288-291.

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