Chapter 2: Cold Therapy Modalities

INTRODUCTION

The use of cold as a therapeutic agent has a long history, beginning in Egypt around 2500 bc.¹ However, the use of cold for injury management and rehabilitation did not become prevalent until the 1950s and 1960s.^2,3,4 Although many technological advances have been made in the realm of therapeutic modalities in the past century, the use of cold (water, ice, or gel) remains one of the most effective and least expensive modes of acute injury and pain management.

Cryotherapy, defined as the use of cold modalities for therapeutic purposes, is used as a first-aid measure after trauma and as an adjunctive tool in the rehabilitation of musculoskeletal and neuromuscular dysfunctions. The basis for cryotherapy is grounded in the physiological responses that occur when tissue temperature is lowered. Cold decreases blood flow and tissue metabolism, thus decreasing bleeding and acute inflammation immediately or soon after injury or surgery. Muscle spasms and tightness from myofascial trigger points can be diminished, allowing for greater ease of motion. Cold can elevate a patient's pain threshold, facilitating ease of exercises with less discomfort. Muscle force production can also be temporarily altered with tissue cooling.

Cold can be easily applied through a variety of means, including cold packs, ice massage, cool baths, cold compression devices, hypercooled air, or vapocoolant sprays. Caution should be taken, however, to avoid undue exposure to cold in persons with cold hypersensitivity, impaired circulation, diminished sensation, or hypertension. This chapter includes discussions on the physical principles, biophysical responses, and clinical applications of cold therapy modalities.

PHYSICAL PRINCIPLES

Cooling is accomplished by removing or abstracting heat from an object rather than by adding cold. Therefore, when a therapeutic cooling agent is applied, the temperature of the skin and underlying tissues is lowered by abstracting heat from the body (Fig. 2-1). The principal modes of energy transfer used for therapeutic cooling include conduction, convection, and evaporation (Table 2-1).

Conduction

Conduction is the transfer of heat by direct interaction of the molecules in the warmer area with those in the cooler area.⁵ Warmer, rapidly moving particles give up, ...