Gait Deviations Flashcards
How wide is BOS?
2 to 4 inches
What is standard bench alignment in the socket?
5 degrees of flexion and 5 degrees of adduction
Reason for bench alignment:
elongate quads muscles so they are better prepared to accept full weight of the body
Reason for bench alignment in adduction:
ensures that the foot is sufficiently inset to create the appropriate varus moment during stance; this properly loads the proximomedial and distolateral aspects
Four goals in prosthetic alignment:
- Facilitating heel strike at initial contact
- Providing adequate single limb stability during stance phase
- Creating smooth forward progression during the transition from early to late stance phase
- Insuring adequate swing phase toe clearance
Causes of hyperextension:
Heel cushion that is too soft
Keel or toe level arm that is too long or too firm
Laxity of posterior capsule or hamstring tendon
When is pistoning seen?
Socket it too large or inadequate suspension
Where is pistoning best observed?
bottom of shin
near knee cap
What can cause excessive varus?
Too much inset of prosthetic foot
What causes drop off?
Keel or toe level is too soft or too short
Shoe heel height too high
What is foot slap?
rapid PF after heel contact
Causes of foot slap:
Soft plantarflexion bumper
Insufficient plantarflexion resistance in prosthetic foot
Causes of hyperextension of knee:
Heel cushion too soft; keel or toe lever arm that is too long or too firm
Antomical cause of hyperextension of the knee:
laxity of posterior capsule of knee or hamstring tendon
Where is pistoning seen?
bottom of shin
near knee cap: shape between limb and socket wall
Causes of pistoning:
Socket it too large or inadequate suspension
Heel cushion too soft
What is excessive external rotation?
Lateral movement of forefoot at beginning stance
Causes of excessive external rotation:
keel is too hard/firm
Causes of excessive varus:
Too much inset of prosthetic foot
M-L dimension is excessive
Toe out
Causes of vaulting:
Too long prosthesis/suspension
Lack of toe clearance
Knee too stiff
Causes of asymmetrical shoulder movement:
Leg length discrepancies
Causes of drop off:
Keel or toe lever is too soft or too short
Shoe heel height too high
Causes of excessive abduction:
Walking on lateral side of foot; socket in excessive abduction relative to limb
Causes of excessive adduction:
Walking on medial side of foot, socket maybe in excessive adduction
Causes of excessive heel compression:
heel to soft
Causes of excessive valgus:
Insufficient medial displacement of foot
Causes of hip hiking:
Prosthetic too long
Knee with insufficient friction
Causes of medial whip:
excessive ER of knee
Causes of lateral whip:
excessive IR of hip
Causes of lateral trunk bending:
Insufficient length of prosthesis
Weak hip abductors
Causes of excessive heel rise:
Inadequate resistance to knee flexion
Causes of ER of foot:
Too firm heel durometer;
insufficient space in socket to accommodate for muscle contraction
Socket too tight
Causes of abducted gait:
Excessive pressure on ramus
Medial brim is too high
Causes of circumduction of leg:
Knee flexion resistance to provide forefoot clearance
Antalgic gait mechanism when medial brim impinges tissue
Excessive rim/lengthen
Causes of terminal impact:
Too little control of flexion=excessive and forceful knee extension
Not sufficient resistance to extension
Causes of unequal step length:
Excessive lumbar lordosis
Less time on prosthesis
Potential causes of knee extended:
- Too long of a toe lever
- Socket to far posterior to foot
- Insufficient knee flexion (socket or patient)
- Soft heel
- Inadequate training
- Weak quads
Causes of knee instability; shorten stance phase on prosthetic side:
- Socket to far forward over foot
- Heel is too hard
- Too much knee flexion (socket or patient)
- Higher heeled shoes
- Too short of toe lever
Knee Instability: Initial Contact to Midstance
- The knee axis may be aligned too far anterior to the TKA line, promoting a flexion moment.
- The socket may not have been set in the optimal preflexed position, which places the hip extensor muscles at a biomechanical advantage for stabilizing the knee.
- The prosthetic foot may have been aligned in excessive dorsiflexion.
- The plantar flexion bumper or SACH heel may be too stiff.
Excessive knee flexion/knee instability
Excessive transtibial socket flexion (anterior tilt)
Transtibial socket positioned anterior to prosthetic foot
Excessive heel cushion stiffness (SACH foot)
Prosthesis too long
What do shoes with lower heels create?
an extension moment at the knee
What do shoes with higher heels create?
flexion moment at the knee
Transradial sockets:
standard socket covers 2/3 forearm
standard socket may be shortened to allow for increased pronation/supination
supracondylar sockets are self-suspending and require no additional harness apparatus
Transhumeral socket:
standard socket extends to acromion level
modified design allows for more stability with rotational movements
lightweight friction units may be used with passive prosthetic arm
Suspension for transradial
triceps cuff
harness
cable system
Suspension for transhumeral
harness
cable system
suction
Elbow unit for transradial
attaches to either triceps cuff or upper arm pad
flexible or rigid hinge connects socket proximal component
Elbow unit for transhumeral
internal or external locking elbow unit
Transradial / transhumeral wrist unit:
quick change unit
wrist flexion unit
ball and socket
constant friction
Transradial/ transhumeral terminal device
voluntary opening or closing
body-powered, externally powered, myoelectric or hybrid
hook, mechanical hand, cosmetic glove
