825-prosthetic mobility 2.4

What are the primary goals of prosthetic training?

Limb volume management, mobility, transfers, balance, obstacle negotiation, return to activities

What are the prosthetic recovery timeframes?

Acute 1–14 days; post-acute to 8 weeks; intermediate 2–6 months; stable transition 6–18 months

Where should the TT static alignment weight line fall?

Bisects socket at mid-patellar tendon; between posterior and middle thirds of foot

Where should the TF static alignment weight line fall?

Through greater trochanter, near knee center, and posterior third of foot

What is dynamic prosthetic alignment?

Prosthetist adjusts alignment during standing/walking for contractures, balance, and shoe height

What knee moment occurs when GRF passes posterior to the knee?

External knee flexion moment

What knee moment occurs when GRF passes anterior to the knee?

External knee extension moment

Excessive prosthetic foot dorsiflexion produces what knee tendency?

Excessive knee flexion

Excessive prosthetic foot plantarflexion produces what knee tendency?

Excessive knee extension or hyperextension

How does excessive hip flexion in stance affect the kinetic chain?

Couples with increased knee flexion and ankle dorsiflexion

Why must prosthetic alignment account for shoe heel height?

The prosthetic limb cannot actively compensate like an intact ankle

What foot spacing is recommended during static postural assessment?

5–10 cm (2–4 inches)

What are the main static postural assessment checkpoints?

Center COM, minimize rotation, extend knees, compare iliac crests and PSIS

What can quarter-inch foam under the prosthetic foot help assess?

Whether a leg-length adjustment improves standing posture

What is the first setup step before finding center?

Position feet 5–10 cm apart and assess standing alignment

What does finding center mean in prosthetic balance training?

COM centered between feet with symmetrical weight bearing

How is hand support progressed during finding center?

Two hands to one hand to no hands

Why might equal weight bearing feel excessive on the prosthetic side?

The patient is accustomed to unloading the prosthesis

How does the PT facilitate prosthetic assimilation?

Apply approximation through pelvis into prosthetic limb

What does pelvic approximation facilitate?

Joint mechanoreceptors and postural responses

What cue encourages loading through the prosthetic foot?

Squash a bug under the middle of the foot

What exercises develop static balance maintenance?

Rhythmic stabilization, head turns, eyes closed, chopping, ball toss

How can static balance be progressed for advanced patients?

Reduce hand support and add compliant surfaces or visual challenges

What percentage of weight may TT patients place on the sound limb during sit-to-stand?

More than 60%

Why is sit-to-stand often asymmetrical after amputation?

Greater reliance on sound limb increases its hip and knee moments

What determines how much TF patients can load the prosthesis during transfers?

Prosthetic knee mechanism and available stance resistance

How does the PT facilitate symmetrical sit-to-stand?

Apply medial pressure at lateral pelvis and distal femur/knee toward prosthesis

What should be assessed before correcting a sit-to-stand transfer?

Observe COM location and weight-bearing symmetry

Which prosthetic knees can provide controlled resistance during stand-to-sit?

Appropriate hydraulic stance-control knees and MPKs

Why can stand-to-sit be difficult with a manual locking knee?

Knee may not provide controlled flexion resistance for symmetrical descent

What assistive-device progression does the lecturer prefer?

Rolling walker until ready for one standard cane

Why is a standard walker less desirable for prosthetic gait?

Lifting it requires prolonged single-limb support

What is the target minimum step length emphasized in the lecture?

At least 12 inches on each side

What is the typical step width during prosthetic gait?

5–10 cm (2–4 inches)

What should the PT observe during gait evaluation?

One limb and joint at a time, from all planes

What is the three-step gait problem-solving sequence?

Identify deviation and phase; determine cause; treat and reassess

What patient factors should be evaluated for gait deviations?

Motor control, ROM, sensation, pain, strength, and balance

What temporal-spatial gait parameters should be observed?

Speed, step/stride length, width, stance/swing time, support time

What knee flexion is expected at initial contact?

0–5 degrees

What hip and pelvic positions are expected at initial contact?

Hip 20–30 degrees flexion; pelvis 5 degrees forward rotation

What knee and ankle positions occur in loading response?

Knee 0–20 degrees flexion; ankle 5–10 degrees plantarflexion

What are prosthetic causes of an abducted limb during weight acceptance?

Long prosthesis, medial brim discomfort, poor lateral wall, suspension or knee friction

What are patient causes of abducted prosthetic gait?

Wide BOS strategy, abduction contracture, weak hip muscles, pain, poor training

A TF patient abducts the prosthesis because of medial brim pain. What is indicated?

Refer to prosthetist to assess socket fit

What prosthetic alignment errors cause excessive knee flexion in weight acceptance?

Excessive DF, firm heel, flexed TT socket, long prosthesis, anterior TF knee axis

What patient factors cause excessive TT knee flexion during loading?

Knee/hip contracture, weak quadriceps, pain, poor balance

A TF knee buckles during loading despite strong muscles. What motor deficit may explain it?

Delayed hip extensor activation against posterior socket wall

Why must TF hip extensors fire rapidly during loading?

Create closed-chain stability in socket to prevent knee collapse

What prosthetic factors cause external foot rotation?

Foot toed out, loose socket, firm heel, improper donning

What patient factors cause external foot rotation?

Weak hip internal rotators, poor control, short residual limb

A socket rotates and the foot toes out. What should be checked first?

Socket fit and sock ply

Why might double-limb support increase when loading the prosthesis?

Foot stabilization, tissue settling, fear, or delayed femoral stabilization

Why is excessive reliance on the sound limb concerning?

Increases joint loading and risk to vulnerable sound-side skin

Why does the sound foot sometimes cross midline?

To position sound foot beneath COM for perceived stability

What are normal midstance hip, knee, ankle and pelvic positions?

Hip neutral; knee 0–5 degrees flexion; ankle 5 degrees DF; pelvis neutral

Which muscles help maintain prosthetic single-limb stance?

Hip abductors/extensors, TFL, gluteals, and abdominals

What prosthetic problems cause lateral trunk lean in midstance?

Short prosthesis, abducted alignment, poor lateral wall or medial brim impingement

What patient problems cause lateral trunk lean?

Reduced lever arm, muscle/proprioception loss, pain, fear, poor training

Why does lateral trunk lean often shorten the sound-side step?

Patient shifts off prosthesis early due to poor single-limb stability

What causes excessive TT knee flexion during midstance?

Excessive DF, flexed socket, long prosthesis, contracture, weak quads

A TT patient has knee varus thrust. What foot alignment error is likely?

Foot too far inset (medial)

A TT patient has knee valgus thrust. What foot alignment error is likely?

Foot too far outset (lateral)

What patient impairments contribute to TT varus/valgus moments?

Knee deformity, short residuum, ligament laxity, weak hip abductors

How can weak hip abductors contribute to knee valgus?

Contralateral pelvic drop causes thigh adduction and valgus

What prosthetic errors cause TT knee hyperextension?

Excess PF, soft heel, extended socket, footwear changes

A TT patient thrusts knee backward due to weak quadriceps. What deviation results?

Knee hyperextension during stance

What hip extension is expected during terminal stance?

Approximately 20 degrees

What ankle and pelvic mechanics occur in terminal stance?

About 10 degrees DF; pelvis 5 degrees backward rotation

Why is forefoot rocker engagement important?

Allows longer prosthetic stance and slower sound-side step

Why does a SACH foot limit terminal stance?

Short keel and compressible forefoot limit toe rocker

Why is a dynamic-response foot useful for higher-level walkers?

Longer footplate supports forefoot loading and energy return

What prosthetic causes shorten the contralateral step in terminal stance?

Short footplate, excessive DF, overly stiff foot category

What patient causes shorten the contralateral step?

Poor balance, pain, hip flexion contracture, limited backward pelvic rotation

A patient cannot extend the hip past neutral in stance. What gait effect is likely?

Limited terminal stance and shortened sound-side step

What knee flexion is expected during pre-swing?

30–40 degrees

What pelvic movement begins during pre-swing?

Backward transverse rotation transitions toward forward rotation

What prosthetic causes limit knee flexion in pre-swing?

Short prosthesis, short keel/footplate, excessive knee flexion resistance

What patient causes limit knee flexion in pre-swing?

Poor forward pelvic rotation, early lift-off, inadequate toe loading

What knee flexion is expected during initial swing?

Approximately 60 degrees

What hip position is expected during initial swing?

Moves from neutral to 15–20 degrees flexion

Why can a posterior TF knee axis limit swing knee flexion?

Increases stance stability but makes knee flexion initiation harder

A patient reports toe drag but has poor swing knee flexion. Why avoid automatically shortening the limb?

Shortening can impair toe rocker and worsen knee flexion

What controls prosthetic knee motion during midswing?

Hydraulic, pneumatic, or microprocessor swing-control mechanisms

What knee position is expected in terminal swing?

Nearly full extension, about 0–5 degrees flexion

What is terminal impact?

Forceful snapping of prosthetic knee into extension before initial contact

What causes terminal impact?

Low knee friction, excessive extension aid, desire to confirm knee lock

What is medial whip?

Heel abruptly moves medially with external knee rotation

What causes medial whip?

Excess knee ER, poor alignment/donning, weak hip internal rotators

What is lateral whip?

Heel abruptly moves laterally with internal knee rotation

What causes lateral whip?

Excess knee IR, poor alignment/donning, weak hip external rotators

What is vaulting during prosthetic gait?

Premature rise onto sound forefoot to clear prosthesis in swing

What prosthetic causes produce vaulting?

Long prosthesis, excess PF, inadequate suspension, overly stable alignment

What patient factors contribute to vaulting?

Fear of toe drag, pain, poor training, habitual compensation

What is circumduction during prosthetic swing?

Prosthetic limb swings in an outward arc with hip abduction/ER

What prosthetic problems produce circumduction?

Long prosthesis, excessive knee friction, excess PF

What patient problems produce circumduction?

Weak hip flexors, abduction contracture, pain, poor knee flexion

What causes persistent forward trunk flexion in prosthetic gait?

PF/socket malalignment, unstable TF knee, hip contracture, weakness or pain

What six gait actions does FLAG evaluate?

Step width; step length/time; forefoot load; knee flexion; pelvic rotation; arm/trunk motion