Front Matter

Chapter 7 Rehabilitation Physical Modalities 137

thereby maximizing the patient’s ability to par­
ticipate in and benefit from other aspects of the
treatment plan.
The decision to use any physical modality
must be based on an in‐depth understanding of
the modality and a thorough assessment of the
patient’s status, both to determine which
modality may be effective and its suitability for
that specific patient. Frequent reassessment
will help the therapist to further the use of a
modality, transition between modalities, or dis­
continue use altogether at the appropriate time.
The scope of this chapter does not permit a
detailed explanation of the physics of each
modality, nor will it provide a comprehensive
list of the research related to each. Textbooks
dedicated to physical modality use in rehabili­
tation medicine are available and should be ref­
erenced for additional information (Cameron,
2013; Bellew et al., 2016). The reader might also
review the current literature as the techniques
and recommendations continue to evolve.

Superficial thermal agents:
cold and heat

Superficial thermal agents are primarily used to
reduce swelling and pain, but can also promote
healing and improve mobility. Some evidence
also indicates that their use can assist with mus­
cle activation. Superficial thermal agents are con­
venient modalities as they are readily available,
involve minimal expense, and are frequently safe
to include as part of a home treatment program.

Superficial cold: cryotherapy

Cryotherapy is the use of cold with a goal of
removing energy from tissues in the form of
heat. Its application can result in tissue cooling
2–4 cm deep (Nadler et al., 2004). In canine reha­
bilitation, this energy transfer generally occurs
through conduction as the cold source is placed
in direct contact with the body. The initial phys­
iological response is cutaneous vasoconstriction
with a resultant reduction in blood flow to the
area (Khoshnevis et al., 2015). Cryotherapy is
therefore most often used in the acute phase of
injury with the goals of reducing inflammation
and pain. However, it may also be used in the

rehabilitation setting to decrease muscle spasm,

lessen muscle spasticity, elicit stronger muscle

contraction during functional movements, and

limit post‐exercise soreness.

Evidence supporting cryotherapy use

Therapeutic effects on pain

There is ample evidence supporting cryother­

apy use when treating acute injuries involving

muscles (Deal et al., 2002; Siqueira et al., 2017),

tendons (Knobloch et al., 2007; Zhang et al.,

2014; Haslerud et al., 2017), and joints (Cobbold

& Lewis, 1956; Pan et al., 2015) to reduce local

blood flow and subsequent development of

inflammation and edema. This anti‐inflamma­

tory effect can in turn alleviate the pain associ­

ated with injury (Zhang & An, 2007). Combining

compression with cryotherapy can provide

additional benefit toward abatement of swell­

ing and pain. In a 2016 meta‐analysis, Song and

colleagues found that patients who received

compressive cryotherapy following knee sur­

gery generally had less swelling and pain than

those who had cryotherapy only, especially in

the early stages of rehabilitation (Song et al.,

2016). This may promote a more rapid progres­

sion into the active rehabilitation phase. While

compressive cryotherapy units have been avail­

able for human patients for some time, units

designed for the canine patient are now available

as well (Figure  7.1). Drygas et al. (2011) found

that dogs treated with compressive cryotherapy

Figure 7.1 Example of a compressive cryotherapy unit

designed for the canine patient. Source: Image courtesy

of Game Ready. Reproduced with permission of Game

Ready.