Cold application (cryotherapy
) is the simplest and most commonly used method for treatment of acute musculoskeletal injury. Among chiropractic practitioners it is the most often utilized (94.5%) passive adjunctive therapy.1
The pathophysiological effects of cold have been well documented. Studies have shown that cold applications can reduce the metabolic rate of a tissue, decrease pain and swelling, and reduce muscle spasm.2
Most health care practitioners are taught to use ice therapy for treatment of bruises, strains, sprains, or muscle tears and most are familiar with the rest, ice, compression, and elevation (RICE) principle following acute soft tissue injury, yet there is little agreement in the literature on the optimum application technique for such care.
Cryotherapy has wide uses ranging from immediate care and rehabilitation
to uses as a surgical adjunct to cryosurgery.2
For the purpose of this paper, cryotherapy will be restricted to its uses in acute and rehabilitative care. Several papers reviewing the available literature have been published on the efficacy of cryotherapy.3-11
The purpose of this paper is to present the findings of these and other studies as to the length, duration, frequency, mode of application, and contraindication of ice for acute soft tissue injury.
Cold therapy can be used to control pain and edema.2,6,9,11
Cold cannot reverse edema once it has developed, however, if applied soon enough after injury can prevent it from occurring. Cold diminishes secondary hypoxic injury, so there is less free protein in the tissues decreasing the tissue oncotic pressure leading to tissue swelling. This is done in two ways: by decreasing metabolism (see later) and by lowering permeability. Decreased metabolism results in decreased secondary hypoxic injury and therefore less tissue debris. With less tissue debris, there is less free protein and a lower oncontic tissue pressure. It should be noted that there is some confusion concerning edema and inflammation. Edema is a sign of inflammation and using ice to control it is helpful, however, cold can also diminish the inflammatory response if used to try to remove the swelling once it has occurred and is not recommended for this use.2
Cold has an analgesic effect for musculoskeletal pain although the mechanism is not well understood. Studies have shown that cold has an effect on nerve conduction velocity and can raise pain threshold and tolerance.13, 14
Another important effect of cold application is decreased metabolism.2,6,9,11
Cold reduces cellular energy needs reducing the tissue requirements for oxygen. A body temperature kept at a subnormal level will require less blood. A lower metabolism will give an injured organ a better chance at survival. Cold therapy has been used in reduction of muscle spasm.2, 6,9, 11
Pain can lead to reflex muscular spasm, which are neurological in origin involving both gamma and alpha motor neurons. Cold applications help decrease gamma motor spasm and pain which allows the muscle to relax.22. Application:Length:
This is a major point of contention among authors. Method of application and body part treated seem to add to the confusion. After a literature review in 1977, McMaster3
concluded that cold should be applied for at least 20 minutes and preferably 30 minutes to ensure the lowering of deep tissue temperature to effect a beneficial change at the site of injury. In 1996, Swenson et al.5
reviewed the literature and found a consensus of treatment at 20-30 minute repeated every 2 hours, for up to 48 -72 hours during the acute inflammatory phase In 2000, MacAuley10
did a systematic search of a convenience sample of 45 sports medicine textbooks and concluded that there is little consistency among the textbooks on how ice should be applied, but by his own admission these were general textbooks and did not include specialist text on cryotherapy. MacAuley9
also published a literature review in 2001 and found a consensus of repeated applications of 10 minutes per session but did not include a conclusion for frequency and length of treatment. Many of the reviewed articles used ice massage
as mode of application, which requires less time for cooling. Knight and Londeree5,15
concluded in their study that the duration time can be extended to at least 45 minutes without any increased risk of frost-bite or other severe complications. Duration:
The length of time that intermittent applications of cold packs is determined by the severity of the injury and the body part to be iced, however, the sooner after injury cryotherapy is initiated, the more beneficial the reduction in metabolism will be.2, 5, 11
The consensus among authors is for 12 to 72 hours post injury.Methods of Application:
NOTE: Most searches found a consensus of 10-15o C (50-59o F) as the optimum temperature range for reduction of cell metabolism without causing cell damage.9,10,11Ice packs.
Crushed, shaved, or chipped ice usually in a plastic bag applied directly to the injured area.2
Several authors agree that some form of protection be used to prevent frostbite.5,9,16
suggest, since ice pack temperature is 0 o C (32 o F) and frostbite risk is at -25 o C (-13 o F), that ice packs can be applied directly to the skin to maximize the effectiveness of the cold application. Most agree that ice packs are the most efficient for ice therapy. Cold-gel packs.
A gelatinous substance enclosed in a vinyl cover containing water, and antifreeze (such as salt). Since gel pack are chilled to far below 0 o C (32 o F), they may cause frostbite.2Chemical cold packs.
These consist of two chemical substances, one in a small vinyl bag within a larger bag. Squeezing the smaller bag until it ruptures and spills its contents into the larger causes a chemical reaction producing the cold. They are ideally utilized for emergency use, however they do not adequately lower the body temperature to therapeutic levels.2 Ice immersion.
A container is filled with ice and water, and the body part is immersed in it. Immersion is recommended for extremities.2 Ice massage.
A cube of ice is rubbed over and around the underlying muscle fiber until numb. Most suggest the cube be prepared in an 8-10 ounce paper cup and applied with constant circular motion around the site to prevent frostbite.17
This search did not yield any studies advising length of time, however, studies have shown ice massage to decrease muscle temperatures much sooner than ice bag treatment.16,173. Precaution: Frostbite.
The risk of freezing the skin seems to be minor above -10 o C (14 o F), whereas the risk is pronounced below -25 o C (-13 o F).18
Although frostbite has been classified by degree20,21
, it may be more usefully classified as superficial or deep. (20, 22) Superficial frostbite affects the skin and subcutaneous tissues; deep frostbite also affects bones, joints and tendons. Factors other than temperature are involved with frostbite. The length of application, body part involved, and the method of cooling are some other considerations. Since the temperature of an ice pack is 0 o C (32 o F), the chance of causing frostbite is lessened, however the length of time is still a consideration.5
Gel packs are chilled to far below 0 o C (32 o F) and should be used with caution. The body part involved is also a factor: fatty tissue does not cool as fast as lean.23Nerve palsy.
Nerve palsy is more likely to occur in areas where large nerves are situated directly beneath the skin. Injury can occur if cooled to below 10 o C (50 o F). Care must also be taken with the application of compression in conjunction with cold therapy. Most of the reports of nerve palsy also included varying levels of compression. Although nerve palsy is a concern it is considered rare.2,4-6,9,24 4. Contraindication:
Cold Hypersensitivity and persons with vasospastic disorders are contraindicated for ice therapy. Cold sensitive patients may risk local burns or systemic complications with ice therapy.5
Vasospastic disorders are conditions in which the vessels of the extremities do not dilate properly.2
Conditions such as Raynaud’s Phenomenon are regarded as absolute contraindications.2,4,5 Conclusion
Ice therapy is indicated for soft tissue trauma and rehabilitation. Crushed ice in a bag is applied directly to the skin (thorough a towel or directly) for 20-30 minutes per session immediately after injury for a period of up to 72 hours post injury.