19. Assistive Devices

Course Context & Lecture Objectives

  • PT 7312 – Patient Care Skills I (Lecture date: July 18, 2025)

  • Instructor: Steve Spivey, PT, DPT

  • Session focus: Ambulatory Assistive Devices

  • Learning goals

    • Describe multiple devices used for ADLs, transfers, and gait

    • Compare strengths / weaknesses of every gait device

    • List & demonstrate gait patterns applicable to each device

    • Safely guard patients while teaching correct device use

    • Recognize patient & environmental safety issues

    • Correctly perform patient-specific device fitting

Indications for Selecting an Assistive Device (AD)

  • \text{1) Weight-bearing limitations}
    • E.g., surgical precautions, fractures, post-injury protocols

  • \text{2) Weakness} (global or focal; UE/LE/trunk)

  • \text{3) Decreased balance} (sensory, vestibular, neuro)

  • \text{4) Pain} (acute or chronic; limits loading & quality of gait)

Patient- & Context-Specific Factors Affecting Device Choice

  • Physical endurance / fatigue tolerance

  • Attention span & ability to dual-task

  • Cognitive status & safety awareness

  • Pain level & medication side-effects

  • Prescribed weight-bearing status (see below)

  • Muscular strength (UE, LE, core)

  • Environment: home set-up, community terrain, stairs, tight spaces

  • Social & lifestyle demands (work, hobbies, caregiver support)

  • Co-morbidities (cardiac, pulmonary, neuro, vision, etc.)

Review of Weight-Bearing (WB) Categories

  • FWB – Full Weight Bearing (no restrictions)

  • WBAT – Weight Bearing As Tolerated
    • Patient self-limits based on comfort; clinician imposes no %, no pound limit

  • PWB – Partial Weight Bearing
    • Typically prescribed as % body weight (commonly 50\%) or specific pounds

  • TTWB – Toe-Touch / Touch-Down Weight Bearing
    • Toes may rest for balance only; no axial load through extremity

  • NWB – Non-Weight Bearing
    • Foot does not contact ground at any time

Hierarchies to Memorize

Relative STABILITY (greatest → least)

  1. Parallel bars

  2. Walker

  3. Axillary crutches

  4. Forearm (Lofstrand) crutches

  5. Two canes

  6. One cane

Coordination DEMAND (least → most)

  1. Parallel bars

  2. Walker

  3. One cane

  4. Two canes

  5. Axillary crutches

  6. Forearm crutches

Parallel Bars

  • Highest external stability; best initial teaching station

  • Permits therapist to assist LE placement & manually correct gait pattern

  • Not functional for community mobility → transition promptly to portable device

  • Strengths

    • \uparrow stability & patient security

    • Adjustable height/width (electric units ≈ fastest)

    • Therapist can physically guide hips/knees/feet

  • Weaknesses

    • Foster "hanging" or "pull-through" compensations

    • Risk of dependency; non-portable; limited availability in HH / sub-acute

Walkers

Main Categories

  1. Conventional / Standard Walker (SW) – pick-up style

  2. Front-Wheeled Walker (FWW) or Rolling Walker (RW)

  3. Four-Wheeled Walker (often w/ seat & brakes) – "Rollator" / tripod variant

  4. Platform Walker (UE weight-bearing through forearm platform)

  5. Pediatric posterior or reverse walkers

General Strengths

  • High BOS & \uparrow stability versus canes/crutches

  • Simple motor learning: \"move walker – bad leg – good leg\"

  • Can incorporate accessories (trays, baskets, oxygen tank holders, seats)

  • Better ability to unload involved LE for PWB prescriptions

General Weaknesses

  • Bulky & heavy; transport/storage issues (cars, small closets)

  • Wider than bathroom doors / narrow hallways; limited on stairs

  • Rolling versions hazardous on inclines if brakes failed or absent

Sizing & Adjustment

  • Stock sizes: Tall, Adult, Youth, Child

  • Key landmarks

    • Handgrip inline with greater trochanter (GT) or level of ulnar styloid ("wristwatch trick")

    • UE elbow flexion 20^{\circ} - 30^{\circ} when patient stands inside walker

  • Ensure all four tips/wheels contact floor simultaneously

Accessories (clinical judgment!)

  • Folding mechanisms, wheels, glide tips, brakes, seats, handgrip foam, storage pouches

  • Note: Added devices ≈ added weight & cost; only use if it serves a clear functional need

Patient Safety & Guarding

  • Discourage pulling on walker to stand; teach push from armrests then grasp walker

  • In sit→stand, cue patient to reach back for the chair before sitting

  • Gait belt on; clinician typically posterior-lateral to involved side

  • Scan for environmental hazards (water spills, rugs, pets, toys)

  • Stress upright trunk posture & proper step length (don’t shuffle into frame)

Basic Walker Gait Sequence

  1. Advance walker one step-length forward; ensure all feet/wheels stable

  2. Advance involved LE into frame (WB per orders)

  3. Shift BW onto UE & involved LE (if allowed)

  4. Advance uninvolved LE to / beyond walker

  5. Shift weight to uninvolved LE; repeat

Crutches

Two Major Forms

  1. Axillary crutches – underarm support; most common for short-term ortho use

  2. Forearm (Lofstrand) crutches – cuffed; common for neuro, long-term users

Axillary Crutches

  • Strengths

    • Moderate stability ( > cane, < walker)

    • Effective for young athletic pts needing NWB/PWB

    • Indirect trunk support via axilla (benefit for mild trunk weakness)

  • Weaknesses

    • Incorrect axilla weight-bearing → brachial plexus injury risk

    • High coordination requirement; tricky on slick surfaces

    • Occupies both UEs → hampers object carrying, door opening

  • Fitting parameters

    • Distal tips: 6" ant & 6" lat to 5th toe (45°)

    • Handgrip at GT height; elbow flexion 20^{\circ}-30^{\circ}

    • Axillary pad clearance: ≈ 2" (or two fingers) below armpit when shoulders relaxed

  • "Spivey Shortcut"

    • Seated, shoulders flexed 90^{\circ} → measure from flexed elbow to opposing hand 3rd phalanx ≈ crutch length

Forearm (Lofstrand) Crutches

  • Strengths

    • Lighter, less bulky than axillary

    • Hands can release grip without dropping crutch (cuff retention) → functional for ADLs

  • Weaknesses

    • Highest coordination demand among major devices

    • Social stigma & learning curve

    • Same fall risk on wet surfaces

  • Fitting

    • Handgrip & distal tip positions same as axillary

    • Cuff: as high as possible without limiting elbow flexion; snug enough to stay when UE lifted

Global Safety Tips (Crutches)

  • No pulling on crutches to stand; practice push-up from chair then grasp

  • Emphasize small step lengths & looking forward, not at feet

  • Rule of thumb: crunch = crutch; avoid surfaces that could cause crutch slip

Core Crutch / Two-Device Gait Patterns

  • Two-Point
    • Device (R) + LE (L) → Device (L) + LE (R)
    • Mimics reciprocal gait, ↓ energy than four-point

  • Four-Point (Deliberate Two-Point)
    • Sequence: Device 1 → Opp. LE → Device 2 → Opp. LE
    • Always three points on ground; maximal stability among crutch patterns

  • Three-Point (NWB)
    • Both crutches → shift weight to UEs → swing uninvolved LE to/through → repeat
    • Involved LE maintained NWB throughout

  • Swing-Through (fast ambulators, e.g., young trauma pts)
    • Crutches → swing both LE past crutches; higher energy & balance need

  • Swing-To
    • Same as swing-through but LE land even with crutches; often seen with paraplegia + KAFOs or walker users

  • PWB Crutch Pattern
    • Crutches → involved LE (share load per PWB %) → shift weight → uninvolved LE steps through

Canes

Device Spectrum (in descending stability)

  1. Hemiwalker (HW) / Walk-Cane – essentially half walker for unilateral use

  2. Large-Based Quad Cane (LBQC)

  3. Small-Based Quad Cane (SBQC)

  4. Straight / Standard Cane (SC) – wood or adjustable aluminum

Hemiwalker

  • Strengths: highest unilateral stability; stands upright when released

  • Weaknesses: bulky; poor stair negotiation; cannot support PWB orders

Quad Canes

  • Strengths: adjustable BOS size; remains upright; transitional option

  • Weaknesses: awkward gait rhythm in some pts; still less stable than walker; SBQC often tips if placed incorrectly

Straight Cane

  • Strengths: lightest, most normative appearance, customizable styles

  • Weaknesses: provides only balance (not load-reducing); cannot accommodate WB restrictions; easy to drop

Fitting Principles (All Canes & Hemiwalkers)

  • Handgrip at GT / ulnar styloid; elbow flexion 20^{\circ}-30^{\circ}

Safety & Guarding

  • Same sit↔stand precautions: push from armrest, don’t use cane to pull

  • Use cane in opposite hand from affected LE
    • Biomechanics: ↑ BOS, ↓ hip abductor demand on involved side, recreates normal arm swing, ↓ contralateral joint compression

Single-Cane Gait Sequence

  1. Simultaneously advance cane + involved LE (alt: cane then LE if coordination limited)

  2. Shift weight onto cane & involved LE

  3. Step through with uninvolved LE

  4. Re-weight to uninvolved LE; repeat

Clinical Decision Algorithm (Big Picture)

  1. Clarify WB status (FWB → NWB)

  2. Match to minimum device providing necessary stability & safety
    • Example: NWB → crutches or walker; FWB + slight balance deficit → straight cane

  3. Evaluate patient’s cognitive & physical capacity for coordination

  4. Consider environment & long-term goals (stair use, car transfers, community ambulation)

  5. Continually reassess & downgrade device as balance, strength, & confidence improve

Universal Patient & Environmental Safety Themes

  • ALWAYS apply gait belt, stand slightly behind & to involved side

  • Discourage footwear without heel counter / grip (slippers, flip-flops)

  • Surfaces to anticipate: wet tile, gravel, throw rugs, ice, uneven sidewalks

  • Clear clutter, supervise pets & toddlers during early training

  • Check device integrity each session (tips, screws, brake cables)

  • Document fitting values & patient demonstration for legal safety record

Ethical & Practical Considerations

  • "Least-restrictive device" aligns with patient autonomy & fosters independence

  • Avoid unnecessary accessories that increase cost/weight unless justified (insurance scrutiny)

  • Teach patient & family proper maintenance to prevent accidents (e.g., replacing worn rubber tips)

Quick Reference Numbers & Angles

  • Elbow flexion for all hand-held devices: 20^{\circ} - 30^{\circ}

  • Axillary clearance: ~2\text{ in}

  • Distal tip on crutches/canes: 6\text{ in}\; \text{anterior} & 6\text{ in}\; \text{lateral} to 5th toe (≈45° angle)

  • Typical PWB prescription: 50\% \text{ body weight} (always verify physician order)

Practice Lab Expectations

  • Students will guard peers during:

    • Standard walker → basic pattern & turning

    • RW with brakes & glides on multiple surfaces

    • Axillary crutch three-point (NWB) & two-point (FWB) patterns

    • Forearm crutch swing-through for speed analysis

    • Hemiwalker & cane gait focusing on step symmetry & hip kinetics

  • Assessment rubrics: proper fitting, verbal cueing, safety spotting, posture correction, documentation accuracy

End-of-Lecture Prompt

"Questions?" – Reflect on device pros/cons, pattern selection, and how you will integrate weight-bearing orders into every therapeutic decision.