Gait Deviations

Question 1

How wide is BOS?

Answer 1

2 to 4 inches

Question 2

What is standard bench alignment in the socket?

Answer 2

5 degrees of flexion and 5 degrees of adduction

Question 3

Reason for bench alignment:

Answer 3

elongate quads muscles so they are better prepared to accept full weight of the body

Question 4

Reason for bench alignment in adduction:

Answer 4

ensures that the foot is sufficiently inset to create the appropriate varus moment during stance; this properly loads the proximomedial and distolateral aspects

Question 5

Four goals in prosthetic alignment:

Answer 5

1. Facilitating heel strike at initial contact
2. Providing adequate single limb stability during stance phase
3. Creating smooth forward progression during the transition from early to late stance phase
4. Insuring adequate swing phase toe clearance

Question 6

Causes of hyperextension:

Answer 6

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

Question 7

When is pistoning seen?

Answer 7

Socket it too large or inadequate suspension

Question 8

Where is pistoning best observed?

Answer 8

bottom of shin

near knee cap

Question 9

What can cause excessive varus?

Answer 9

Too much inset of prosthetic foot

Question 10

What causes drop off?

Answer 10

Keel or toe level is too soft or too short

Shoe heel height too high

Question 11

What is foot slap?

Answer 11

rapid PF after heel contact

Question 12

Causes of foot slap:

Answer 12

Soft plantarflexion bumper

Insufficient plantarflexion resistance in prosthetic foot

Question 13

Causes of hyperextension of knee:

Answer 13

Heel cushion too soft; keel or toe lever arm that is too long or too firm

Question 14

Antomical cause of hyperextension of the knee:

Answer 14

laxity of posterior capsule of knee or hamstring tendon

Question 15

Where is pistoning seen?

Answer 15

bottom of shin

near knee cap: shape between limb and socket wall

Question 16

Causes of pistoning:

Answer 16

Socket it too large or inadequate suspension

Heel cushion too soft

Question 17

What is excessive external rotation?

Answer 17

Lateral movement of forefoot at beginning stance

Question 18

Causes of excessive external rotation:

Answer 18

keel is too hard/firm

Question 19

Causes of excessive varus:

Answer 19

Too much inset of prosthetic foot
M-L dimension is excessive
Toe out

Question 20

Causes of vaulting:

Answer 20

Too long prosthesis/suspension
Lack of toe clearance
Knee too stiff

Question 21

Causes of asymmetrical shoulder movement:

Answer 21

Leg length discrepancies

Question 22

Causes of drop off:

Answer 22

Keel or toe lever is too soft or too short

Shoe heel height too high

Question 23

Causes of excessive abduction:

Answer 23

Walking on lateral side of foot; socket in excessive abduction relative to limb

Question 24

Causes of excessive adduction:

Answer 24

Walking on medial side of foot, socket maybe in excessive adduction

Question 25

Causes of excessive heel compression:

Answer 25

heel to soft

Question 26

Causes of excessive valgus:

Answer 26

Insufficient medial displacement of foot

Question 27

Causes of hip hiking:

Answer 27

Prosthetic too long | Knee with insufficient friction

Question 28

Causes of medial whip:

Answer 28

excessive ER of knee

Question 29

Causes of lateral whip:

Answer 29

excessive IR of hip

Question 30

Causes of lateral trunk bending:

Answer 30

Insufficient length of prosthesis | Weak hip abductors

Question 31

Causes of excessive heel rise:

Answer 31

Inadequate resistance to knee flexion

Question 32

Causes of ER of foot:

Answer 32

Too firm heel durometer; insufficient space in socket to accommodate for muscle contraction Socket too tight

Question 33

Causes of abducted gait:

Answer 33

Excessive pressure on ramus | Medial brim is too high

Question 34

Causes of circumduction of leg:

Answer 34

Knee flexion resistance to provide forefoot clearance Antalgic gait mechanism when medial brim impinges tissue Excessive rim/lengthen

Question 35

Causes of terminal impact:

Answer 35

Too little control of flexion=excessive and forceful knee extension Not sufficient resistance to extension

Question 36

Causes of unequal step length:

Answer 36

Excessive lumbar lordosis | Less time on prosthesis

Question 37

Potential causes of knee extended:

Answer 37

1. Too long of a toe lever 2. Socket to far posterior to foot 3. Insufficient knee flexion (socket or patient) 4. Soft heel 5. Inadequate training 6. Weak quads

Question 38

Causes of knee instability; shorten stance phase on prosthetic side:

Answer 38

1. Socket to far forward over foot 2. Heel is too hard 3. Too much knee flexion (socket or patient) 4. Higher heeled shoes 5. Too short of toe lever

Question 39

Knee Instability: Initial Contact to Midstance

Answer 39

1. The knee axis may be aligned too far anterior to the TKA line, promoting a flexion moment. 2. 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. 3. The prosthetic foot may have been aligned in excessive dorsiflexion. 4. The plantar flexion bumper or SACH heel may be too stiff.

Question 40

Excessive knee flexion/knee instability

Answer 40

Excessive transtibial socket flexion (anterior tilt) Transtibial socket positioned anterior to prosthetic foot Excessive heel cushion stiffness (SACH foot) Prosthesis too long

Question 41

What do shoes with lower heels create?

Answer 41

an extension moment at the knee

Question 42

What do shoes with higher heels create?

Answer 42

flexion moment at the knee

Question 43

Transradial sockets:

Answer 43

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

Question 44

Transhumeral socket:

Answer 44

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

Question 45

Suspension for transradial

Answer 45

triceps cuff harness cable system

Question 46

Suspension for transhumeral

Answer 46

harness cable system suction

Question 47

Elbow unit for transradial

Answer 47

attaches to either triceps cuff or upper arm pad | flexible or rigid hinge connects socket proximal component

Question 48

Elbow unit for transhumeral

Answer 48

internal or external locking elbow unit

Question 49

Transradial / transhumeral wrist unit:

Answer 49

quick change unit wrist flexion unit ball and socket constant friction

Question 50

Transradial/ transhumeral terminal device

Answer 50

voluntary opening or closing body-powered, externally powered, myoelectric or hybrid hook, mechanical hand, cosmetic glove