PUTTING ICE ON A LIGAMENT INJURY
Ross Hauser, M.D.

ICE SLOWS METABOLISM!
The cells that make up ligaments, tendons, and organs are extremely temperature-sensitive. The metabolic rate at which these cells function is directly proportional to the temperature in their environment. Cooling tissue will decrease that cell's metabolism.

It is obvious that ligaments require improved circulation to the area in order to heal after an injury, since the blood supply to ligaments is normally so poor. Yet ice is arguably the most widely used therapeutic agent in medicine today, which most definitely decreases circulation. Ice is often the first line of treatment for traumatic injuries, but are there any side effects?

The Research on Ice
In one landmark study done at the University of Hawaii, Dr. Sherwin Ho and associates, put a commercially-available ice wrap on one knee for 20 minutes, and on the opposite knee a wrap was placed at room temperature. The knees were then injected with dye and scanned for blood flow. The study showed that all iced knees demonstrated a decrease in arterial and soft tissue blood flow, as well as decreased bone uptake of the dye, which is a reflection of changes in both the bone blood flow and metabolic rate.

The authors go on to conclude that these findings provide a scientific rationale for the use of ice in limiting further hemorrhage and cell injury after traumatic musculoskeletal injuries and surgical procedures.

See the thinking in modern medicine? The last statement would only apply if swelling were occurring in a closed space, as in "compartment syndrome," which only occurs in muscles (and only those with a lot of damage) and never occurs in ligaments. The last statement would, therefore, not apply around the knee which is full of ligaments.

Dr. Ho had already published articles in 1990 on the negative effects of ice, where he showed that as little as five minutes of icing a knee can decrease both blood flow to the soft tissues and skeletal metabolism. He found that icing a knee for 25 minutes decreases blood flow and skeletal metabolism another 400 percent! Healing is hindered by a decrease in blood flow and metabolism to the area. Icing increases the chance of incomplete healing by decreasing blood flow to the injured ligaments and tendons. This increases the chance of re-injury or the development of chronic pain.

Did you ever wonder why almost all athletic trainers and therapists ice a limb for 20 minutes? Why not 15 or 30? It does not matter if you are in France, Idaho, or Germany, they all ice for 20 minutes. In 1980, at the American Orthopedic Society meeting for Sports Medicine in Big Sky, Montana, and then again in American Journal of Sports Medicine, physicians from the Louisiana State University School of Medicine reported on five athletes who obtained nerve palsies (nerve injuries usually to the peroneal nerve that moves the foot up) from too much ice around the knee. The conclusion of the article was, "Applying ice for more than 30 minutes, and preferably for not more than 20 minutes, should be strictly avoided."

Dr. William McMaster of the University of California at Irvine, a well-known researcher on the use of ice therapy and its use in athletics cautions its use because "Cold application or ice has been shown to depress the excitability of free nerve endings and peripheral nerve fibers, increasing pain threshold. This effect is of great value in acute treatment; however, its judicious use can contribute to serious injury. The loss of protective pain sensibility after local icing is probably a contraindication to athletic participation. Additional effects of cold application include: decrease in blood flow, decrease in inflammatory response, and decrease in local edema protection."

Remember that ice decreases cell metabolism. When a nerve is exposed to ice, it is unable to accurately sense pain. This is bad for an athlete who has an injury. His body feels good with the ice, so he returns to competing only to intensify the injury. Dr. McMaster feels so strongly that if an athlete uses ice for this anesthetic effect that it is a contraindication for the athlete going back into the game. He notes, "Specifically, in dealing with athletic injuries, the application of cold, in light of its known effects on tissue, may be contraindicated during intense physical activity. The alteration in extensibility of collagen tissues after application of cold may interfere with normal function and predispose to additional injury. The anesthetic effects of cold may be dangerous due to masking of pain, an important protective mechanism. The athlete, for instance, with anesthesia in a partially injured ligament can no longer protect himself against exceeding of the limits of that structure, as mediated by a painful response to stress."

Collagen tissue, which makes up ligaments, is normally extensible and exhibits primarily elastic properties, when it is stressed it can stretch a little. However, when a ligament is cooled, it becomes stiffer and more prone to injury because it cannot stretch when it is stressed.