PHYSICAL MODALITIES,THERAPEUTIC EXERCISE,EXTENDED BEDREST,AND AGING EFFECTS PHYSICAL MODALITIES
Modalities that use physical energy for their therapeutic effect.
Includes:
– Pressure
– Thermotherapy—Heat and cold
– Hydrotherapy
– Light therapy—ultraviolet radiation, laser
– Electrotherapy
– Manipulation, mobilization, traction, massage, acupuncture
These are used as adjuncts to a therapy program including exercise and patient education
THERMOTHERAPY
• The amount of energy a tissue gains or loses depends on several factors:
– Nature of the tissue
– Agent used
– Duration of exposure
• Temperature has an effect on:
– Viscosity
– Nerve conduction—heat increases nerve conduction velocity; cold decreases it
– Blood flow—heat increases arterial and capillary blood flow; cold decreases blood flow
– Collagen extensibility—heat increases tendon extensibility, collagenase activity is
increased; cold decreases enzyme activity
• Temperatures > 45–50°C (113–122 °F) or <>20,000 Hz) can produce
thermal (heating) and nonthermal (cavitation, acoustic streaming, and standing waves)
effects
Thermal effects
• Ultrasound interacts with skin, fat, and muscle during treatment. Heating occurs at all of
these tissue as a result of beam attenuation and absorption. Its effect is more pronounced
at tissue interfaces where sound transmission discontinuities occur.
• Ultrasound is absorbed and attenuated more in bone, followed by tendon, followed by
skin, muscle, and fat.
• Lehman (1967) found that US produces the highest temperature in cancellous bone
(spongy bone).
• Absorption (heating) is greatest at the bone–muscle soft-tissue interface.
• Thermal effects include increased distensibility of collagen fibers.
Nonthermal effects
• Cavitation—produces gas bubbles in a sound field due to turbulence, which, by their
forced oscillation and bursting, are capable of disrupting tissue
• Acoustic streaming—unidirectional movement of compressible material or medium due
to pressure asymmetries caused by US waves
• Acoustic streaming and cavitation are associated with wound contraction and protein synthesis
• Standing waves—In a stationary US field standing waves produce fixed areas of elevated
pressure and rarefaction. They have not been found to have physiological benefits
Ultrasound indications
• Bursitis
• Tendinitis (calcific tendinitis)
• Musculoskeletal pain
• Degenerative arthritis and contracture (adhesive capsulitis, shoulder periarthritis and
hip contracture). Helps to maintain a prolonged stretch and increases ROM
• Subacute trauma
Less established:
– Scar tissue (keloids)
– Postherpetic neuralgic pain
– Plantar warts
Ultrasound Contraindications
• General heat contraindications
• Near brain, cervical ganglia, spine, laminectomy sites (can cause spinal-cord heating)
• Near the heart, reproductive organs
• Near pacemakers—may cause thermal or mechanical injury to the pacemaker
• Near tumors
• Gravid or menstruating uterus
• At infection sites
• On contact lenses, eyes (fluid filled cavity with risk of cavitation and heat damage).
• Skeletal immaturity—open epiphysis can be affected with decreased growth due to
thermal injury
• Total hip arthroplasties with methylmethacrylate or high density polyethylene. These
have a high coefficient of absorption, more than soft tissue, and the prosthesis may loosen
due to unstable cavitation in the cement. (Lehmann, 1990)
• Arthroplasties—the effect on bony ingrowth arthroplasties is not well defined, for this
reason the most prudent course is avoiding US over these areas
Ultrasound precautions
• Avoid intensities over 3 W/cm2
• Use multiple ports over large joints
• Ultrasound can be used under water but only if water is degassed. This can be achieved
by putting it into a container and allowing it to sit overnight.
• Use stroking technique
Ultrasound prescription
• Frequency— Most common 0.8–1.1 MHz
• Intensity—0.5–2.0 W/cm2. Spatial average intensity is described as the total power output
divided by the effective radiating area. World Health Organization (WHO) suggested
maximal intensity is 3.0W/cm2.
For tendonitis/bursitis the intensity used is 1.2–1.8W/cm2, or in the 0.5 to 2.0 W/cm2 range
– Generates temperatures up to 46° C/114.8° F in deep tissues. Ultrasound deep
heating is superior to microwave and short wave diathermy. In general, 45° C temperature
increases will be seen at 8 cm depth. Increased temperature will remain for 2
minutes following US application.
• Duration—5–10 minutes per site – depends on W/cm2
• Delivery methods—continuous and pulsed
Continuous—thermal effects (heat production)
Pulsed—Mainly nonthermal effects, cavitation, media motion, standing waves
• Techniques—direct and indirect
DIRECT—most common. The applicator is moved slowly over an area of 4 square inches in
a circular or longitudinal pattern. Uses a coupling media (gel) to accommodate for
impedance inconsistencies.
INDIRECT—for uneven surfaces (hands and feet). Applicator and body part are immersed
in a container of degassed water.
SPECIALIZED—
Phonophoresis—A technique that utilizes US to drive medications through the skin, by
increasing cell permeability.
– Frequency—1–2 MHz, delivery method is continuous, or pulsed
– Intensity—1–3 W/cm2 for 5 to 7 minutes
– Medications: Corticosteroids (1% or 10% Hydrocortisone and Dexamethasone)
Anesthetics—1% Lidocaine (Xylocaine®)
– Uses: Tendinitis—Achilles, patellar, bicipital; Tenosynovitis; Epicondylitis (tennis
elbow)
Shortwave diathermy (SWD)
– Produces deep heating through the conversion of electromagnetic energy (radio
waves) to thermal energy
– Federal Communications Commission (FCC) limits use to 13.56 MHz (22m wavelength),
27.12 MHz (11M), and 40.68 MHz (7.5m)
– The most commonly used frequency is 27.12 MHz
– Provides deep heat to 4–5 cm depth, therefore is good for deep muscle.
– The heating pattern produced depends on the type of shortwave unit and water content
and electrical properties of the tissue
Shortwave units can be inductive or capacitive
1. Induction method—produces high temperatures in water-rich tissues (muscles, skin) via a
coiled magnetic field. Applicators in the form of cables or drum. The body acts as a receiver,
and eddy currents are induced in the tissues in its field.
Increases tissue temperature 4–6°C above normal.
• Indicated when heat to more superficial muscles or joints is desired. Muscle tends to
become warmer than fatty tissue
2. Conduction method (capacitive applicators)—produce high temperatures in water-poor
tissues (fat, bone) with low conductivity, via rapid oscillation of an electrical field. The
portion of the body to be treated is placed between two plates to which the shortwave output
is applied.
The body acts as an insulator in a series circuit.
• Indicated for subcutaneous adipose tissue and bone
• Most effective for deeper joints (i.e., hip joint)
• Treatment time is 20–30 minutes
– Precise dosing for shortwave diathermy is difficult, and pain perception is used to
monitor intensity. The best way to monitor frequency depends on the patient’s response
to warmth
– Subcutaneous fat temperature rises to 15° C, 4–6° C increase in muscle at 4–5 cm depth
(Lehman, 1968)
– Terry cloths are used for spacing and to absorb sweat, which is highly conductive and
may cause severe local heating
Shortwave indications
• Chronic prostatitis
• Refractory pelvic inflammatory disease
• Myalgia
• Back spasms
Shortwave contraindications
• General heat precautions
• Metal (jewelry, pacemakers, metallic intrauterine devices, surgical implants) are excellent
electrical conductors and can potentially cause burns. Water is highly conductive and can
have the same effect with resultant severe local heating
• Contact lenses
• Gravid or menstruating uterus
• Skeletal immaturity
Microwave diathermy
– Conversion of electromagnetic energy (microwaves) to thermal energy.
– FCC approved frequencies: 915MHz (33 cm wavelength) and 2456 MHz (12 cm)
– Microwaves do not penetrate tissues as deeply as US or SWD
Microwave indications
• Used to heat superficial muscles and joints, to speed the resolution of hematomas, and for
local hyperthermia in cancer patients
• The lower frequency has a higher depth of penetration, and is better for muscle heating
Microwave contraindications
• General heat precautions
• Skeletal immaturity
• Microwave diathermy selectively heats fluid-filled cavities:
Its use should be avoided in edematous tissue, moist skin, eyes, blisters, and fluid-filled cavities
• Eye protection should be worn by patient and therapist due to risk of cataract formation
Delateur, 1970 noted:
Average temperatures with microwaves at a depth of 1–3 cm. are 41° C/105.8° F.
At frequencies of 915MHz, subcutaneous fat temperatures may increase by 10°–12° C, and
muscles at a depth of 3–4 cm. will be heated only 3°–4° C.
Summary of Diathery
Diathermy—Deeper local elevation of temperature within the tissues, produced without
overheating subcutaneous tissue or skin. Classified as:
1. Ultrasound
2. Shortwave
3. Microwave
All are forms of heating by conversion
B. Cold
Therapeutic effects of cold are based on the following
• Immediate local vasoconstriction
• Local metabolism decrease
• Decreased acute inflammatory response
• Slows nerve conduction velocity—decreased motor and sensory nerve conduction.
• Decreased muscle spindle activity—decreased firing rates of Ia and II afferent fibers
• Decreased pain/muscle spasm—increases nerve pain threshold
• Decreased spasticity
• Increased tissue viscosity with decreased tissue elasticity
• Transient increase in systolic and diastolic blood pressure
• Release of vasoactive agents (histamine)
Indications for cold therapy
Generally used for acute process
• Acute traumatic conditions—reduction of inflammation and edema in the 24–48 hour
period.
• Musculoskeletal conditions—arthritis, bursitis
• Acute and chronic pain
• Spasticity management
• Immediate treatment of minor burns
General precautions and contraindications for cold therapy
• Cold intolerance, hypersensitivity to cold (Raynaud’s disease/phenomenon)
• Arterial insufficiency—areas with circulatory compromise such as ischemic areas in
patients with peripheral vascular disease affecting the arterial system
• Impaired sensation—insensate skin is at risk for burns
• Cognitive and communication deficits that preclude the patient from reporting pain
• Cardiac, respiratory involvement—if severe HTN present, the patient’s BP must be monitored
closely
• Cryotherapy induced neuropraxia/axonotmesis, regenerating peripheral nerves
• Cryopathies: Cryoglobulinemia, Paroxysmal cold hemoglobinuria
• Open wounds after 48 hours
• Note: Reflex vasodilation with hyperemia can occur after removal of ice
Mechanisms of cold transfer
• Conduction: Cold packs, ice massage
• Convection: Cold baths (whirlpool)
• Evaporation: Vapo-coolant spray
The treatment modality depends on the size of the area to be treated and how accessible it is
for cold application.
Conduction
1. Cold packs
• Include ice packs, wraps and sluices, endothermic chemical gel packs and hydrocollator
packs
• The pack is wrapped in moist towels and treatment time is generally 20–30 minutes
• Surface skin temperature can decrease by 15° C after 10 minutes, subcutaneous temperatures
decrease by 3°–5° C
• A study by Knuttson and Mattsson in 1969 showed muscle cooling by 5° C at a depth of 2
cm after 20-minute application of a hydrocollator pack
2. Ice massage
• For cooling of small areas (muscle belly, tendon, trigger point) before applying deep pressure
massage. Combines the therapeutic effect of ice with the mechanical effects of massage
• Direct application of ice to a painful area using gentle stroking motion
• Study by Lowdon and Moore in 1975 showed a reduction of intramuscular temperature by
4.1° C at 2 cm. depth in the posterior thigh region, and up to 15.9° C reduction in biceps
brachii after the 5-minute application time
• Treatment of analgesia can be obtained in 7–10 minutes
Convection
1. Cold baths
• An example of hydrotherapy; uses water-filled containers for distal limb immersion
• Best suited for circumferential cooling of the limbs
• Water temperature: 4°–10° C
• Can be uncomfortable and poorly tolerated
• Effective for treatment of localized burns due to rapid skin temperature reduction
2. Evaporation
Vapo-coolant sprays
• Volatile liquids such as Fluori-methane spray are commonly used
• Used for spray-and-stretch techniques to treat myofascial pain ; also used for local anesthesia
• Produce an abrupt temperature change over a small surface area
• Precautions: risk for skin site irritation and local cutaneous freezing
3. Other techniques
Cryotherapy Compression units
• Combines the benefits of cold with the advantages of pneumatic compression
• Uses sleeves with circulating cold water, attached to an intermittent pump unit.
Edematous extremities are placed inside the sleeves
• Used primarily to treat acute musculoskeletal injury with soft tissue swelling. Also used
after some surgical procedures
• Temperatures used are 45°F (7.2° C) and pressures up to 60 mmHg
