week 11- gait deviations

inability to functionally shorten the prosthesis

what is pseudo-LLD?

pseudo-LLD, incorrect alignment, poor suspension, incorrect resistance to knee flexion, incorrect extension bias

potential causes of limb length discrepancy during gait

knee instability

patient’s knee “shakes” during heel strike, causing hip extensors to fire inconsistently due to instability

heel strike

during which part of gait does knee instability occur?

knee too anterior, excessive PF resistance, insufficient socket flexion

prosthetic causes of knee instability

increased shoe heel height, weak hip extensors

patient causes of knee instability

abducted gait

laterally-deviated prosthesis throughout swing and stance phase

pressure on ramus, pain at distal lateral femur, inadequate support on femur from lateral wall, prosthesis too long, excessive socket abduction

prosthetic causes of abducted gait

weak/contractured abductors, lack of balance

patient causes of abducted gait

lateral trunk bending

patient’s shoulders move outside base of support while the pelvis maintains its position over the base of support

excessive foot outset, wide ML dimension of socket

prosthetic causes of lateral trunk bending toward sound side

weak hip abductors, poor balance

patient causes of lateral trunk bending toward sound side

prosthesis too short, excessive foot inset, insufficient socket adduction, wide ML dimension of socket, pain at pubic ramus

prosthetic causes of lateral trunk bending toward prosthetic side

short residual limb, contracted hip abductors, poor balance

patient causes of lateral trunk bending toward prosthetic side

lateral thrust (tredenlenberg)

patient maintains shoulder over the base of support while the pelvis moves outside of it

poor alignment

prosthetic causes of lateral thrust

weak hip abductors, balance issues, patient habit

patient causes of lateral thrust

midstance

during which phase of gait does drop off occur?

prosthetic

does drop off occur on the sound or the prosthetic side?

drop off

early prosthetic knee flexion near midstance, making the knee appear to bend

toe lever too short, knee center too far anterior

causes of drop off

heel off

other name for drop off

stance

does excessive lumbar lordosis occur more during stance or swing phase?

insufficient socket flexion, painful IT WB

prosthetic causes of excessive lumbar lordosis

weak core muscles or hip extensors, hip flexion contracture, short residual limb

patient causes of excessive lumbar lordosis

preswing

during which phase does medial whip occur?

knee axis in excessive external rotation

prosthetic causes of medial whip

socket donned with too much external rotation, silesian belt worn too tightly, weak limb musculature

patient causes of medial whip

knee axis in excessive internal rotation

prosthetic causes of lateral whip

socket donned with too much internal rotation, weak limb musculature

patient causes of lateral whip

circumduction

prosthesis is swung in a wide arc during swing phase

excessive resistance to knee flexion, prosthesis too stable, too much extension bias, prosthesis too long, medial brim pressure, inadequate suspension

prosthetic causes of circumduction

patient lacks confidence, inadequate hip flexion

patient causes of circumduction

vaulting

active heel rise during stance of the sound side while the prosthetic side completes swing phase

prosthesis too long, excessive resistance to knee flexion, too much stability, too much extension bias, inadequate suspension

prosthetic causes of vaulting

patient habit

patient causes of vaulting

terminal swing

during which phase does terminal impact occur?

terminal impact

rapid forward movement of the shank, allowing the knee to reach full extension with too much force prior to heel strike

insufficient knee friction, extension bias too strong

prosthetic reasons for terminal impact

patient habit to ensure that knee is in full extension at initial contact

patient causes of terminal impact

uneven step length

gait deviation caused when patient cannot extend on the prosthetic side

insufficient initial socket flexion, unaccommodated hip flexion contracture

prosthetic causes of uneven step length (prosthetic side long)

mid-late stance

when does inadequate socket flexion occur

inadequate socket flexion

patient has a fixed hip flexion contracture and cannot achieve hip extension in their current alignment

insufficient pre-flexion of socket during bench alignment

prosthetic causes of inadequate socket flexion

hip flexion contracture, weakness

patient causes of inadequate socket flexion

poor suspension, painful socket, insufficient knee friction, unstable knee

prosthetic causes of uneven step length (prosthetic side short)

poor balance, weak hip flexors

patient causes of uneven step length (prosthetic side short)

longer

for uneven step length, is it more common for the prosthetic side to have a longer or shorter step?

initial-midswing

when does toe drag occur?

toe drag

prosthetic foot contacts ground near midswing, stopping the progression of swing

weak hip abductors on sound side, poor balance

patient causes of toe drag

poor suspension, poor socket fit

prosthetic causes of toe drag

poor suspension

prosthesis slides down residual limb during swing phase, creating a functionally long prosthesis and pistoning during stance phase

ill-fitting prosthesis, faulty suspension

prosthetic causes of poor suspension

weight fluctuation

patient causes of poor suspension

foot rotation at heel strike

gait deviation where the foot rotates laterally upon initiation of stance

excessively firm heel, PF bumper, poor alignment

prosthetic causes of foot rotation at heel strike

weak quads, patient fear of instability

patient causes of foot rotation at heel strike

complex deviations

deviations that combine patient and prosthetic complications