2.6 Gait, Assistive Devices, Weight-Bearing Status
Key Takeaways
- Weight-bearing statuses: non-weight-bearing (NWB) 0%; toe-touch weight-bearing (TTWB) ~10-15% body weight for balance only; partial weight-bearing (PWB) 30-50%; weight-bearing as tolerated (WBAT) patient-limited; full weight-bearing (FWB) 100%.
- Axillary crutch fit: tip 2 inches lateral and 6 inches anterior to the shoe, axillary pad 2-3 fingerbreadths (~5 cm) below the axilla, elbow flexed 20-30 degrees; weight is borne on the hands, never the axilla.
- A single-point cane is held in the hand OPPOSITE the affected lower extremity; the cane and the affected leg advance together to reduce hip abductor demand.
- Walker height is set so the top reaches the wrist crease with arms hanging at the sides, producing 20-30 degrees of elbow flexion when grasped.
- The Rancho Los Amigos gait cycle divides stance into initial contact, loading response, midstance, terminal stance, and pre-swing, and swing into initial, mid, and terminal swing.
Weight-Bearing Statuses
The surgeon or physical therapist (PT) sets the weight-bearing status; the PTA implements it and collects adherence data. Standard categories across U.S. PT practice:
| Status | Abbreviation | Percent Body Weight | Practical Description |
|---|---|---|---|
| Non-weight-bearing | NWB | 0% | Surgical limb cannot touch the floor |
| Toe-touch weight-bearing | TTWB / TDWB | ~10-15% | Toe rests on floor for balance only |
| Partial weight-bearing | PWB | 30-50% (often specified, e.g., 50%) | A defined percentage applied through the limb |
| Weight-bearing as tolerated | WBAT | Variable | Patient bears as much weight as is comfortable |
| Full weight-bearing | FWB | 100% | No restriction |
A bathroom scale at the parallel bars is a PTA-friendly way to teach a patient what an assigned percentage feels like before ambulating. Confusing TTWB with PWB is a classic trap: a toe-touch patient should never load 50% through the limb.
Assistive Device Fitting
Axillary Crutches
- Tip placed about 2 inches lateral and 6 inches anterior to the shoe.
- Axillary pad 2-3 fingerbreadths (~5 cm / 2 inches) below the axilla.
- Hand grip set for 20-30 degrees of elbow flexion.
- Weight borne through the hands, never the axilla — sustained axillary pressure can compress the radial nerve and brachial plexus ("crutch palsy").
Forearm (Lofstrand) Crutches
- Cuff sits 1-1.5 inches below the olecranon.
- Hand grip set for 20-30 degrees of elbow flexion.
- Suited to patients with adequate upper-extremity strength who need a long-term aid.
Cane (Single-Point or Quad)
- Held in the hand opposite the affected lower extremity.
- Height equals the floor-to-wrist-crease distance (ulnar styloid level) with the arm relaxed; elbow flexed 20-30 degrees when grasped.
- The cane and affected leg advance together to share load and reduce hip abductor demand, lowering the joint reaction force at the affected hip.
Walker
- Top reaches the wrist crease with arms relaxed; 20-30 degrees elbow flexion when grasping.
- Sequence: advance the walker first, then the affected leg, then the stronger leg.
- A rolling walker fits a patient who cannot safely lift and advance a standard walker.
Common Gait Patterns
| Pattern | When Used |
|---|---|
| Two-point | One crutch/cane and opposite leg advance together; mild bilateral involvement |
| Three-point | Both crutches and the affected leg advance, uninvolved leg follows; NWB or restricted weight-bearing |
| Modified three-point | Like three-point but the affected leg bears partial weight; PWB or WBAT |
| Four-point | Reciprocal — right crutch, left leg, left crutch, right leg; most stable, bilateral involvement |
| Swing-to / Swing-through | Both crutches advance, then both legs swing to or past them; spinal cord injury, bilateral LE weakness |
Rancho Los Amigos Gait Cycle
The modern terminology used on the NPTE-PTA divides one cycle into eight phases:
Stance (~60%):
- Initial contact (heel strike)
- Loading response (foot flat)
- Midstance
- Terminal stance (heel off)
- Pre-swing (toe off)
Swing (~40%):
- Initial swing (acceleration)
- Midswing
- Terminal swing (deceleration)
Double-limb support occurs twice per cycle (loading response and pre-swing) and disappears at faster speeds, which is the kinematic boundary between walking and running.
Common Gait Deviations a PTA Documents
| Deviation | Common Cause |
|---|---|
| Trendelenburg gait (pelvic drop on swing-leg side) | Weak hip abductors (gluteus medius) on the stance side |
| Antalgic gait (shortened stance time on painful side) | Pain in the loaded limb |
| Foot drop / steppage gait | Weak dorsiflexors, often peroneal nerve or L4-L5 involvement |
| Circumduction | Functional leg-length discrepancy, weak hip flexors, or a knee that cannot flex |
| Knee hyperextension in midstance | Quadriceps weakness, plantarflexion contracture |
| Forward trunk lean in stance | Quadriceps weakness, hip flexor contracture, anterior knee pain |
When a PTA observes a Trendelenburg sign during gait training, the appropriate action is to collect and document the finding and report it to the supervising PT, who decides whether to revise the plan of care — the PTA does not independently change the diagnosis or program.
Matching Device, Pattern, and Stairs to the Scenario
Device-selection items reward matching the level of support to the patient's weight-bearing order, balance, and upper-extremity strength, then applying the correct gait pattern and stair sequence.
Device by Stability Need (Most to Least Support)
| Device | Relative Support | Typical Candidate |
|---|---|---|
| Standard / rolling walker | Greatest | Marked balance deficit, NWB/PWB lower extremity, deconditioning |
| Axillary crutches | High | Temporary NWB/PWB with good upper-extremity strength |
| Forearm crutches | Moderate | Long-term users, better UE function |
| Quad cane | Low-moderate | Hemiparesis, needs a wider base than a single cane |
| Single-point cane | Least | Mild balance or single-joint off-loading |
Stair Sequence (Memorize)
- Going UP: the uninvolved (stronger) leg leads, then the involved leg and device follow — "up with the good."
- Going DOWN: the involved (weaker) leg and device lead, then the uninvolved leg follows — "down with the bad."
This sequence keeps the stronger leg doing the work of lifting and lowering the body, protecting the surgical limb and reducing fall risk. A PTA who reverses it forces the weak limb to control the descent or power the ascent.
Guarding and Safety
The PTA guards on the involved side and slightly behind the patient, using a gait belt, and clears the path before training. If a patient begins to fall, the PTA controls the descent toward the floor while protecting the head rather than trying to hold the patient fully upright. These safety behaviors and the device-fitting standards are PTA-implemented; reassigning the weight-bearing status or prescribing a different device class is a PT decision the PTA requests, not makes.
A PTA is fitting axillary crutches for a patient with a right ankle fracture (toe-touch weight-bearing). Which fitting finding requires correction BEFORE gait training begins?
A patient with left hip osteoarthritis arrives walking with a single-point cane in the LEFT hand, and the PTA notes a pelvic drop on the right during left-stance phase. What is the MOST appropriate PTA action within the plan of care?