5.2 Therapeutic Modalities

Physical therapy modalities are used as adjuncts to therapeutic exercise and manual therapy. The NPTE heavily tests the indications, contraindications, parameters, and physiological effects of each modality.

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Thermal Agents

Cryotherapy (Cold)

Physiological Effects:

• Vasoconstriction → decreased blood flow → decreased inflammation and edema
• Decreased nerve conduction velocity → pain relief
• Decreased muscle spindle firing → reduced spasm
• Decreased metabolic rate → reduced secondary injury

Contraindications:

• Raynaud disease or phenomenon
• Cold hypersensitivity or cold urticaria
• Cryoglobulinemia
• Impaired sensation (risk of frostbite)
• Over open wounds (ice pack only — cold whirlpool may be appropriate)
• Peripheral vascular disease (compromised circulation)

Superficial Heat

Physiological Effects:

• Vasodilation → increased blood flow → promotes healing
• Increased tissue extensibility → improved stretching effectiveness
• Decreased pain via gate control mechanism
• Increased metabolic rate → promotes tissue repair
• Decreased muscle spasm

Contraindications (ALL heat modalities):

• Acute inflammation or trauma (first 48-72 hours)
• Over malignancy
• Impaired sensation
• Impaired circulation (PVD)
• Active hemorrhage or bleeding disorders
• Over the eyes, reproductive organs, growth plates

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Deep Heating Modalities

Therapeutic Ultrasound Parameters Summary

Ultrasound Contraindications:

• Over the eyes, heart, brain, reproductive organs
• Over growth plates (epiphyseal plates) in children
• Over malignancy
• Over spinal cord after laminectomy
• Over joint cement or plastic components (thermal mode)
• Over thrombophlebitis/DVT
• Pregnancy (over abdomen/pelvis)

Shortwave Diathermy

• Deep heating using electromagnetic energy (shortwave radio frequencies)
• Heats tissues to 3-5 cm depth (similar to 1 MHz ultrasound)
• Particularly effective for heating large tissue volumes
• Absolute contraindication: metal implants (internal or external) — electromagnetic energy heats metal rapidly
• Also contraindicated over pacemakers, pregnancy, malignancy, and areas with impaired sensation

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Mechanical Modalities

Traction

Traction Contraindications:

• Ligamentous instability
• Vertebrobasilar insufficiency (VBI) — for cervical
• Rheumatoid arthritis with atlantoaxial instability
• Malignancy in the spine
• Acute disc herniation with progressive neurological deficit
• Osteoporosis (severe)
• Pregnancy (lumbar)
• Untreated hypertension

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Iontophoresis

Iontophoresis uses direct current (DC) to drive charged medication ions through the skin:

Rule: The medication is placed under the electrode with the same charge (like charges repel, driving the ions into the tissue).

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Intermittent Pneumatic Compression

Intermittent pneumatic compression (IPC) uses an inflatable sleeve to mechanically reduce edema and assist venous and lymphatic return. Typical inflation pressures are roughly 30-60 mmHg for the upper extremity and 40-80 mmHg for the lower extremity, kept below the patient's diastolic blood pressure to avoid impeding arterial flow. IPC is indicated for venous insufficiency, lymphedema (as an adjunct to manual lymphatic drainage), and DVT prophylaxis.

Key contraindications mirror the danger of moving fluid or a clot centrally: acute DVT, acute pulmonary edema, uncompensated congestive heart failure, and acute infection in the limb. As with compression bandaging, coexisting significant arterial disease (a low ABI) is a contraindication.

Biophysical Agent Decision-Making

The NPTE rewards matching the agent to the tissue phase. During the acute inflammatory phase (first 24-72 hours), choose cold to limit secondary injury and edema; heat is contraindicated. During the chronic phase, heat and continuous ultrasound increase extensibility before stretching contractures, while pulsed (non-thermal) ultrasound and electrical stimulation support tissue repair. The classic sequence to maximize a stretch is heat (or thermal ultrasound), then stretch while the tissue is warm, then ice in the lengthened position to "set" the gain.

Universal Contraindications and Safety Checks

Several contraindications recur across nearly every modality and are heavily tested: impaired sensation, impaired cognition/inability to report, impaired circulation, malignancy, over the abdomen/pelvis during pregnancy, and over an active DVT or area of acute hemorrhage. Electromagnetic agents (shortwave diathermy) add pacemakers and any metal as absolute contraindications.

Before any thermal or electrical modality, the PT confirms intact sensation, inspects the skin, screens for contraindications, and re-checks the area during and after treatment. A frequent test trap is selecting an effective modality for a patient who has a contraindication to it — the contraindication always overrides the indication, because patient safety is the governing principle of modality application.