9.1 Physiotherapy Modalities

9.1 Physiotherapy Modalities

Quick Answer: Part III tests whether you can match a physiotherapy modality — heat, cold, ultrasound, electrical stimulation, laser, or traction — to the correct clinical indication and recognize its contraindications. The exam favors vignette items: a patient presentation plus "which modality is most appropriate" or "which of the following is a contraindication to this modality."

Why Modalities Matter on Part III

Physiotherapy modalities fall under the Supportive Interventions domain, which makes up 9% of the TMCQ/EMCQ portion of the exam. Questions rarely ask you to recite a textbook definition; instead they describe a patient — an acute ankle sprain, chronic low back pain in a patient with a pacemaker, a third-trimester pregnancy — and ask which modality is indicated or contraindicated. Success depends on knowing three things for every modality: (1) its primary physiologic effect, (2) its best clinical indication, and (3) its absolute and relative contraindications.

Superficial Heat

Superficial heat (moist heat packs, paraffin baths, fluidotherapy) raises tissue temperature only 1-2 cm deep. Its effects are vasodilation, increased tissue extensibility and blood flow, decreased muscle spasm and pain, and increased collagen elasticity — which is why heat is typically applied before stretching or manual therapy, not immediately after acute injury.

Indications: subacute or chronic muscle spasm, joint stiffness, chronic low back pain, preparation before stretching or mobilization, and decreased soft-tissue extensibility.

Contraindications: acute inflammation or injury (roughly the first 24-72 hours), impaired thermal sensation, impaired circulation, active bleeding or bleeding disorders, malignancy in the treatment area, recent application of a liniment or analgesic balm (burn risk), and infants or very young children with immature thermoregulation.

Cryotherapy (Cold)

Cold packs, ice massage, cold immersion, and vapocoolant sprays produce vasoconstriction, decreased nerve conduction velocity, decreased muscle spindle activity, and local analgesia. Cold is the modality of choice during the acute inflammatory phase and after exercise or manipulation to limit secondary edema.

Indications: acute injury or inflammation (first 24-72 hours), post-exercise or post-manipulation edema control, acute muscle spasm, and analgesia for acute pain.

Contraindications: Raynaud's phenomenon, cold urticaria or cold hypersensitivity, cryoglobulinemia, paroxysmal cold hemoglobinuria, impaired circulation (peripheral vascular disease), impaired sensation, application over a regenerating peripheral nerve, and very young or cognitively impaired patients who cannot reliably report a cold injury.

Therapeutic Ultrasound

Ultrasound uses high-frequency acoustic energy (commonly 0.8-3 MHz) to produce deep heating in continuous mode or nonthermal mechanical effects in pulsed mode — cavitation and microstreaming that can accelerate tissue repair without significant temperature rise. Frequency and depth of penetration are inversely related, and this pairing is a favorite exam distractor: 3 MHz treats more superficial tissue (about 1-2 cm), while 1 MHz penetrates deeper (up to about 5 cm).

Indications: subacute or chronic soft-tissue injury, scar tissue and adhesions, joint contracture, tendinopathy, and (pulsed, nonthermal mode) promoting tissue healing without significant heating.

Contraindications: over malignant tissue, over the pregnant uterus, over a pacemaker or other implanted electronic device, over the eyes, over the heart, over the gonads or reproductive organs, over epiphyseal (growth) plates in skeletally immature patients, over thrombophlebitis or DVT, over acute inflammation (for thermal/continuous mode), and over anesthetic or insensate skin.

Electrical Stimulation: TENS, IFC, and NMES

Electrotherapeutic modalities are grouped by clinical purpose, not just current waveform.

Shared contraindications across electrical modalities include a demand-type cardiac pacemaker or implanted defibrillator, application over the carotid sinus, transcerebral application (across the head), application over the anterior neck/laryngeal region, over the pregnant uterus, over active malignancy, over thrombophlebitis, and over broken or infected skin. Epilepsy is a relative contraindication for stimulation applied to the head or neck region.

Low-Level Laser Therapy (LLLT)

Cold laser, or photobiomodulation, delivers light energy that is absorbed by mitochondria to stimulate cellular metabolism, reduce inflammatory mediators, and promote tissue repair — without a significant thermal effect.

Indications: myofascial pain, tendinopathy, wound healing, and adjunctive pain management for musculoskeletal conditions.

Contraindications: direct application over the eyes, over the thyroid gland, over a pregnant abdomen, and over known or suspected malignancy; use caution with patients taking photosensitizing medications.

Mechanical Traction

Cervical and lumbar traction apply a distraction force that separates vertebral segments. This can reduce disc pressure or bulge, open the intervertebral foramen to relieve nerve root compression, stretch shortened paraspinal musculature, and mobilize hypomobile facet joints.

Indications: cervical or lumbar radiculopathy from disc protrusion, foraminal stenosis, facet joint hypomobility, and muscle spasm associated with nerve root irritation.

Contraindications: spinal instability or fracture, vertebral malignancy, acute inflammatory conditions of the spine, uncontrolled hypertension, vertebrobasilar insufficiency (cervical traction), abdominal or aortic aneurysm (lumbar traction), pregnancy (lumbar traction), rheumatoid arthritis of the cervical spine with atlantoaxial instability, severe osteoporosis, and any presentation where traction reproduces or worsens neurologic symptoms — the same centralization-versus-peripheralization logic used in exercise testing applies here: stop if symptoms travel further down the limb.

High-Yield Pattern: The Universal Contraindications

Four findings disqualify nearly every physical modality regardless of type, and Part III tests this pattern repeatedly: active malignancy in the treatment field, pregnancy over the treatment area for deep-penetrating modalities, a demand-type cardiac pacemaker for electrical or deep modalities, and impaired sensation or circulation — the patient cannot feel or perceive a burn or cold injury, or cannot physiologically dissipate the modality's effect. When a vignette buries one of these four findings in the history, it is almost always the deciding factor for the correct answer.