Key Takeaways
- Assistive device progression (least to most support): cane → forearm crutch → axillary crutch → standard walker → rolling walker → platform walker
- Cane fitting: elbow flexion 20-30 degrees when holding the cane; top of cane at greater trochanter or wrist crease
- Canes are held on the OPPOSITE side of the affected lower extremity to reduce joint forces and improve gait pattern
- Axillary crutch fitting: 2-3 finger widths below the axilla; weight borne on handgrips, NOT on axillary pads (axillary nerve/brachial plexus compression risk)
- Walker types: standard (pick-up), front-wheeled, four-wheeled (rollator); rollators allow fastest gait but least stability
- Weight-bearing status: NWB (0%), TDWB (toe touch only), PWB (up to 25-50%), WBAT (as tolerated), FWB (100%)
- Wheelchair measurements: seat width = widest point of hips + 2 inches; seat depth = posterior buttock to popliteal fossa - 2 inches; footrest clearance = minimum 2 inches from ground
- TENS (Transcutaneous Electrical Nerve Stimulation) uses the gate control theory of pain; conventional TENS uses high frequency (50-150 Hz), low intensity for pain modulation
Last updated: February 2026
Equipment, Devices & Technologies
The non-systems domain covers equipment selection, fitting, and training that spans across all clinical settings. This section focuses on assistive devices, wheelchairs, and electrotherapy modalities.
Assistive Devices
Canes
Fitting:
- Top of cane at the level of the greater trochanter or wrist crease when standing upright
- Elbow flexion of 20-30 degrees when holding the cane
- Held on the OPPOSITE side of the affected lower extremity
Why opposite side? Holding the cane contralateral to the affected leg reduces the compressive force on the affected hip joint by creating a counterbalancing moment arm. This also promotes a more normal reciprocal gait pattern.
Cane Types:
| Type | Support Level | Indications |
|---|---|---|
| Single-point (straight) cane | Minimal support | Mild balance deficit, slight weight-bearing assist |
| Small-base quad cane (SBQC) | Moderate support | Moderate balance deficit; freestanding |
| Large-base quad cane (LBQC) | Greater support | Significant balance deficit; provides most stability |
| Hemi-walker | Maximum support (cane category) | Hemiplegia, maximal stability needed from one-hand device |
Crutches
Axillary Crutch Fitting:
- 2-3 finger widths (approximately 2 inches) below the axilla
- Handgrips positioned for 20-30 degrees of elbow flexion
- Critical safety point: Weight must be borne on the handgrips, NOT the axillary pads. Leaning on axillary pads compresses the axillary nerve and brachial plexus, potentially causing "crutch palsy" (radial/axillary nerve injury)
Forearm (Lofstrand) Crutches:
- Cuff encircles the forearm below the elbow
- Allows hand release without dropping the crutch
- Preferred for long-term crutch users (better energy efficiency)
- Common in patients with lower extremity paralysis, bilateral involvement
Crutch Gait Patterns
| Pattern | Description | Weight-Bearing Status |
|---|---|---|
| 2-point | Right crutch + left foot, then left crutch + right foot | PWB to FWB bilateral |
| 3-point | Both crutches + affected leg, then unaffected leg | NWB, TDWB, PWB on one leg |
| 4-point | Right crutch, left foot, left crutch, right foot (one at a time) | PWB bilateral, slowest/most stable |
| Swing-to | Both crutches forward, swing feet to crutches | NWB bilateral, paraplegia |
| Swing-through | Both crutches forward, swing feet past crutches | NWB bilateral, fastest, most energy |
Walkers
| Type | Characteristics | Best For |
|---|---|---|
| Standard (pick-up) walker | Must be lifted with each step; most stable | Maximum support, poor balance, limited endurance for crutches |
| Front-wheeled walker | Two front wheels, two rear tips; push forward | Patients who cannot lift standard walker (weakness, coordination) |
| Four-wheeled (rollator) | All four wheels, brakes, often with seat | Community ambulation, endurance training, patients who need periodic rest |
Wheelchair Fitting
| Measurement | Guideline |
|---|---|
| Seat width | Widest part of hips/thighs + 2 inches |
| Seat depth | Posterior buttock to popliteal fossa - 2 inches (prevents pressure on posterior knee) |
| Seat height | Allows 2+ inches clearance between footrests and ground |
| Back height | Below the inferior angle of the scapula (standard); higher for trunk support if needed |
| Armrest height | Shoulders relaxed, elbows flexed 90 degrees |
Common Wheelchair Problems
| Problem | Likely Cause |
|---|---|
| Pressure on posterior knees | Seat depth too long |
| Difficulty reaching wheels for propulsion | Seat width too wide |
| Trunk lean to one side | Seat too wide, scoliosis, weak trunk muscles |
| Skin breakdown at ischial tuberosities | Inadequate pressure relief, poor cushion |
Electrotherapy Modalities
TENS (Transcutaneous Electrical Nerve Stimulation)
| Mode | Frequency | Intensity | Duration | Mechanism |
|---|---|---|---|---|
| Conventional | High (50-150 Hz) | Low (sensory level) | 30-60 min; can use continuously | Gate control theory (large fiber activation blocks pain signals) |
| Acupuncture-like | Low (1-10 Hz) | High (motor level, visible contraction) | 20-30 min | Endorphin release (endogenous opioid system) |
| Brief-intense | High (100-150 Hz) | High (highest tolerable) | 15 min | Gate control + counterirritant |
NMES (Neuromuscular Electrical Stimulation)
- Used to produce muscle contraction for strengthening, motor relearning, or preventing atrophy
- Frequency: 35-80 Hz
- On:Off ratio: 1:3 to 1:5 (to prevent fatigue), progressing to 1:1
- Common applications: Quad strengthening post-TKA, dorsiflexor activation for foot drop, shoulder subluxation post-stroke
Interferential Current (IFC)
- Uses two medium-frequency currents (e.g., 4000 Hz and 4100 Hz) that interfere to produce a low-frequency (100 Hz) current at depth
- Deeper penetration than conventional TENS
- Used for deep pain, edema, and muscle spasm
Ultrasound (Therapeutic)
| Parameter | Thermal Effects | Non-Thermal Effects |
|---|---|---|
| Frequency | 1 MHz (deep, 3-5 cm) or 3 MHz (superficial, 1-2 cm) | Same |
| Duty cycle | Continuous (100%) | Pulsed (20% typical) |
| Intensity | 1.0-2.0 W/cm2 | 0.5-1.0 W/cm2 |
| Effects | Increases tissue temperature, extensibility, blood flow | Cavitation, acoustic streaming, tissue healing |
| Indications | Joint contracture, chronic inflammation | Acute inflammation, wound healing |
Test Your Knowledge
A cane should be held on which side relative to the affected lower extremity?
A
B
C
D
Test Your Knowledge
When fitting axillary crutches, the pad should be positioned:
A
B
C
D
Test Your Knowledge
A patient is non-weight bearing on the right lower extremity. Which crutch gait pattern is MOST appropriate?
A
B
C
D
Test Your KnowledgeMatching
Match each wheelchair measurement to its correct guideline.
Match each item on the left with the correct item on the right
1
Seat width
2
Seat depth
3
Back height
4
Footrest clearance
Test Your Knowledge
Conventional TENS uses which parameters to achieve pain relief via the gate control mechanism?
A
B
C
D
Test Your KnowledgeFill in the Blank
A therapeutic ultrasound frequency of 1 MHz penetrates to a depth of approximately _____ cm, while 3 MHz penetrates to 1-2 cm.
Type your answer below