Cryotherapy

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Definition/Description

Cryotherapy, also known as ice application, is the simplest and oldest way to treat injuries. Its worldwide use spread because of its effectiveness, convenience, low cost, and ease of transportation. Ice is believed to control pain by instigating local anaesthesia. It also decreases oedema, nerve conduction velocities, cellular metabolism, and local blood flow. The effect of the cryotherapy depends on the method, the duration, temperature of the ice, and the depth of the subcutaneous fat.

Application Methods

Application of cold pack

• Ice Packs: It is the most common method of cryotherapy. There are different types of ice used in ice packs. The most common types are ice packs made with cubed, crushed, and wetted ice. It was discovered that wetted ice is better at lowering surface temperature during treatment and maintaining the lower temperature during recovery. It is also more effective in lowering the intramuscular temperature during treatment.

* Cold Pack

• Commercial Cold Packs: Commercial cold packs, such as Col Pac and Elastic-Gel, are an efficient and commonly used method of cryotherapy. Usually filled with a petroleum distillate gel material, these cold packs are quicker to apply and reach lower temperatures than traditional ice packs.
• Vapocoolant Spray: Utilised as a superficial, cooling agent for reduction of muscle guarding and release of myofascial trigger points.
• Immersion: Simple immersion, such as an ice bath, can be utilised for full concealment of a distal extremity (e.g., foot, ankle, hand, or wrist). Cold whirlpool is a form of immersion that transfers heat via convection.

Application of ice massage

• Ice Massage: Ice massage involves applying ice directly to the skin with slow strokes in circular motion for 5-10 minutes. To achieve the desired cooling effect, move the ice about 5-7 cm/second.
• Dipstick Method: A cotton bud is soaked in cryogen, such as liquid nitrogen slush or dry ice, which is placed in a disposable container. The bud is then pressed firmly onto the lesion until a halo of ice forms around it. It is important that the size of the bud is smaller than the lesion to ensure targeted application. The freezing depth can be enhanced by applying more pressure to the lesion. This method is cost-effective as it does not require specialised equipment like a spray or probe. However, multiple applications may be necessary to achieve an adequate freeze-thaw cycle for optimal results.
• Whole Body Cryotherapy:More recently, whole-body cryotherapy has become popular among athletes to help aid recovery, as well as in persistent pain patients, such as those with rheumatological conditions. More research is needed to understand the effect on the body and its relation to pain.

Duration of cryotherapy

Duration of Cryotherapy:

The recommended duration and frequency of ice application in cryotherapy vary. Common suggestions include applying ice for 10–20 minutes, 20–30 minutes twice daily, or 30–45 minutes within the first two hours following an injury. In a study by Bleakley et al., the effectiveness of continuous ice application for 20 minutes was compared to intermittent application (10 minutes on, 10 minutes off, followed by another 10 minutes). The findings indicated that intermittent cold therapy significantly reduced pain compared to continuous application, although both methods were equally effective in reducing swelling.

Myrer et al. recommended a cryotherapy treatment duration of 20 minutes, but this cannot be considered a universal standard. The appropriate duration may depend on the individual case and the severity of the injury. Several factors influence temperature changes at both the skin's surface and deeper tissues during cryotherapy, such as the type of cooling agent used, the location of application, the inclusion of compression, and individual variations in sensitivity. Therefore, treatment times may need to be adjusted based on these factors to optimise effectiveness.

Indications

Cryotherapy can be utilized as an adjunct to treatment for the following conditions:

• Acute soft tissue injuries (e.g., ankle sprain, muscular strain, ligament sprain)
• Myofascial trigger points
• Muscle spasm
• Muscle guarding
• Tendinitis
• Tenosynovitis
• Acute swelling
• Bursitis
• Post orthopedic surgery (e.g., TKR(Total knee replacement), ACL(Anterior cruciate ligament ) reconstruction, arthroscopic shoulder surgery.)
• Reducing temperature
• DOMS(Delayed onset muscle soreness )

Contraindications

Be aware of conditions in which cryotherapy is contraindicated:

• CRPS(Complex Regional Pain Syndrome)
• Hemoglobinuria
• Cryoglobulinemia
• Peripheral vascular disease
• Impaired circulation
• Raynaud’s disease
• Urticaria
• Hypersensitivity to cold
• Skin anesthesia
• Over a regenerating peripheral nerve
• Open wounds

Precautions

When applying cryotherapy, be cognisant of the following:

• Over a superficial nerve
• Hypertension
• Impaired cognition
• Patients who are very young or very old

Expected Sensations to Cryotherapy

Prior to the application of cryotherapy, it is important to understand the expected sensations that one might experience. While the sensations listed may be uncomfortable, they are both normal and necessary to achieve the desired effects from cryotherapy. Throughout the duration of treatment, the expected sensations begin with a cold feeling and should reach numbness by the end.

Expected sensations to cryotherapy

Physiological Effects of Cryotherapy

The following physiologic effects are the expected responses to cryotherapy:

• Decreased local temperature
• Decreased metabolism
• Vasoconstriction of arterioles and capillaries, initially
• Decreased blood flow, initially
• Decreased nerve conduction velocity
• Decreased delivery of leucocytes and phagocytes
• Decreased lymphatic and venous drainage
• Decreased muscle excitability
• Decreased muscle spindle depolarisation
• Decreased formation and accumulation of oedema
• Extreme anaesthetic effects

Lewis Hunting Reaction

The Lewis hunting reaction refers to the process of alternating vasoconstriction and vasodilation in extremities exposed to cold. This phenomenon, also called the Lewis reaction, was first described by Thomas Lewis in 1930. Initially, vasoconstriction occurs to minimise heat loss, which in turn leads to significant cooling of the extremities. Approximately five to ten minutes after cold exposure begins, the blood vessels in the extremities suddenly vasodilate. This is likely due to a reduction in the release of neurotransmitters from the sympathetic nerves to the muscular coat of the arteriovenous anastomoses in response to localised cold. This cold-induced vasodilation increases blood flow and raises the temperature of the fingers. The vasodilation is followed by another phase of vasoconstriction, after which the cycle repeats.

Vasodilation can be induced by cold after an initial period of vasoconstriction if the cold exposure lasts for more than approximately 15 minutes or if the temperature drops below 10°C

Lewis Hunting Reaction Graph

Joint Mobilization with Cryotherapy

Evidence regarding cryotherapy suggests that analgesic effects are achieved when tissues are cooled to between 10°F and 15°F. With the reduction of pain due to the cryotherapeutic agent, mobilisations can be performed with less discomfort and greater effectiveness.

In addition to the increased pain threshold resulting from cryotherapy, a decrease in muscle spindle activity is also observed. This reduction in muscle guarding facilitates greater improvements in range of motion and joint mobilisations.

Cryotherapy pre exercise

While cryotherapy is often used after exercise sessions, new evidence suggests benefits of using it pre exercise. Recent evidence has shown cryotherapy to the knee joint in the form of an ice pack wrapped around the knee may help to cause disinhibition of the quads, causing an increase in quad strength, most notably of the vastus medalis. Evidence suggests this quad disinhibition is due not only to a reduction in pain, but also due to a direct reduction in arthrogenic muscle inhibition - a common phenomenon after knee surgery. It is suggested that applying ice to the knee joint before quad exercises may be helpful for increasing strength, as shown in the knee surgery patient population.

Pros

• Pain relief
• Swelling reduction
• Decreased surface temperature
• Effective on a wide range of soft tissue injuries

Cons

• Little evidence regarding duration and frequency of treatment is effective.
• Compression has been shown to be more effective post operatively.
• In rare cases, bradycardia and frostbite symptoms have been observed.
• Some more advanced cryotherapy devices can reduce the range of movement following TKR due to immobilization of the joint.

Possible Risks/Undesirable Effects

Inhibit Muscle Function

• Ice burn

• Cryotherapy-induced nerve injuries
• Generalised cooling and decrease in core temperature
• Reduced range of motion

Inhibit Muscle Function

• Cooling can temporarily Inhibit muscle function with potential for increased risk of injury/re‐injury
• Be cautious when having patients weight bear/undertake complex exercise after icing a lower extremity

Ice Burn

Elderly patients with impaired sensation and/or circulation will be more vulnerable to an ice burn. Therefore, consider using less intense icing techniques (e.g., moderately cold ice pack wrapped in insulating layer(s) of towel/cloth).

• Younger patients with intact sensation and circulation may benefit most from direct immersion of the limb in cold water, then progressively adding ice cubes.
• Cold gel packs stored in a freezer have a surface temperature below 0°C (32°F), and thus an insulating layer should be used between the cold pack and the patient’s skin.

Cryotherapy‐Induced Nerve Injuries

• Most common when cold is applied in combination with compression
• Check capillary refill during application of ice combined with compression therapy to ensure adequate blood flow

Generalized Cooling and Decrease in Core Temperature

• Shivering and piloerection are signs of decrease in core temperature which may compromise patient safety (especially in the elderly and those with fever)
• The application of therapeutic cryotherapy should produce only local effects

Reduced ROM

Ice may contribute to the shortening of collagen fibres in connective tissue.

• After gaining range of motion (ROM) by warming, stretching, and then strengthening in the newest part of the ROM, it is likely counterproductive to cool the tissue in a shortened position.
• If one wishes to cool the tissue post-stretch and exercise, it is best to do so with the tissue in a lengthened position.
• In patients with significantly restricted ROM due to scar tissue, it may be preferable not to use ice.