Prosthetic Questions Flashcards
1
Q
Name the purpose of the axilla loop in a figure 8 harness.
A
Acts as an anchor.
2
Q
What type of harness would you use on a patient with a mid-length transradial amputation using a conventional prosthesis?
- Figure 9
- Figure 8
- Figure 8 with shoulder saddle
- Figure 10
A
Figure 9
3
Q
Name the indications for using a strap, cuff, or belt for suspension of a transtibial prosthesis
A
volume fluctuations expected
4
Q
Name the advantages for using a strap, cuff, or belt for suspension of a transtibial prosthesis
A
Amputee adjustable
5
Q
Name the disadvantages for using a strap, cuff, or belt for suspension of a transtibial prosthesis
A
Increased pistoning, decreased comfort, decreased range of motion
6
Q
Name the disadvantages for using a joint and corset for suspension of a transtibial prosthesis
A
Increased pistoning, heavy and bulky, hard to don
7
Q
Name the advantages for using a joint and corset for suspension of a transtibial prosthesis
A
Maximal ML stability
8
Q
Name the indications for using a joint and corset for suspension of a transtibial prosthesis
A
Severe knee instability and/or short residual limbs
9
Q
Name the advantages for using a total surface bearing style prosthesis
A
- Equal loading of all surfaces of the limb
- Increased durability of liners (less thinning of liners)
- Easier mods/casting technique
- Increased stability of internal tissues
10
Q
Name the disadvantages for using a total surface bearing style prosthesis
A
- Volume changes may result in a change of loading
- Must be used with gel liners
- Cannot use load specific mods
- Some loss of rotational control
11
Q
Modifications for a Total Surface Bearing (TSB) style prosthesis
A
- 5-10% reduction on 6mm liner
- Relief for fibular head and distal anterior tibia if limb is boney
- Global reduction over entirety of limb
- No PTB bar
12
Q
Name the advantages for using a patellar tendon bearing style prosthesis
A
- Perspiration will not corrode socket
- Less bulky at knee than with insert
- Contours in socket don’t compress or pack down
- Reliefs or modifications are exactly located
13
Q
Name the disadvantages for using a Patellar tendon bearing style prosthesis
A
- Requires casting and modification skill
- Difficult to fit bony or sensitive limbs
- Not easily modified
14
Q
Name the modifications and purpose of the anterior wall of a PTB socket
A
- Proximal Trimline is distal 1/2 of the patella
- Patellar tendon bar
- Can load areas such as the pre-tibial area for increased rotational control and offloading of the anterior tibia
15
Q
Name the modifications and purpose of the posterior wall of a PTB socket
A
- Must be no lower than MTP height
- Keeps residuum against the PTB bar.
16
Q
Name the modifications and purpose of the medial and lateral walls of a PTB socket
A
- Proximal trim is 65 mm proximal to the MTP
- Medial: must load medial flare area
- Lateral: Relief for fib head, supports fib shaft, counterpressure to medial wall.
- Controls rotation, contains soft tissue, provides ML stability
17
Q
Build ups for PTB sockets Tibial crest: Lateral Tibial Flare: Fibular Head: Distal Fibula: Distal End of Tibia:
A
Build ups for PTB sockets Tibial crest: 2mm Lateral Tibial Flare: 2mm Fibular Head: 3mm Distal Fibula: 2mm Distal End of Tibia: 4+mm
18
Q
Recommended users for liners
A
- Peripheral vascular disease
- Thin, sensitive, scarred, boney skin
- Peripheral neuropathy
- Bilateral
- Active patients
19
Q
Advantages of p-lite or silicone liners
A
- Soft, protective interface
- Appropriate for most limbs
- Distraction of liner may assist circulation
- Easily modified
20
Q
Disadvantages of p-lite or silicone liners
A
- Deterioration of materials
- Unsanitary if not cleaned regularly
- Increased Knee bulk
- May compress/change fit
- Increased weight
21
Q
Advantages to distal end pads
A
- May aid in venous and lymphatic return
- Provide increased comfort
- Protect distal end volume
- Facilitate future mods
- Usually standard in all prostheses
22
Q
PTB-SCSP Indications
A
- Very short limbs
- Ligament laxity
- Patients needing ML stability
- Patients who hyperextend
- Previous wearers
23
Q
PTB-SCSP Advantages
A
- Increased weight bearing surface
- Provides rigid hyperextension stop
- Increased ML stability
- Improved cosmesis
24
Q
PTB-SCSP Disadvantages
A
- Mods over patella and condyles must be precise
- Uncomfortable while kneeling
- Difficult to achieve suspension on obese or muscular thighs
25
Suspension Sleeve Advantages
- Good suspension
- Hides trimlines
- Minimizes pistoning
- Good auxiliary suspension
26
Suspension Sleeve disadvantages
- Provides no knee stability
- Difficult to don w/o strong finger function
- Perspiration
- Wears out easily/holes
- May restrict ROM
- Contraindicated for vascular patients
27
Elevated vacuum indications
- Sensitive, scarred or bony limbs
- Patients experiencing internal migration and movement
- High activity patient
- Improve circulation
28
Elevated vacuum advantages
- Stabilization of limb volume
- Liner material that flows over high pressure areas
- Greater coupling and proprioception of prosthesis
29
Elevated vacuum disadvantages
- Increased componentry and length for vacuum
| - Requires patient compliance and monitoring
30
An inset foot will cause what moment at the knee and where will the forces be felt within the prosthesis?
- An increased varus moment at the knee
| - Forces will be coupled at the medial proximal and distal lateral.
31
An outset foot will cause what moment at the knee and where will the forces be felt within the prosthesis?
- An increased valgus moment at the knee
| - Forces will be coupled at the lateral proximal and distal medial.
32
A posteriorly positioned foot/anteriorly shifted socket will cause what moment at the knee and where will the forces be felt within the prosthesis?
- An increased flexion moment at the knee
| - Forces will be coupled at the posterior proximal and distal anterior.
33
A anteriorly positioned foot/posteriorly shifted socket will cause what moment at the knee and where will the forces be felt within the prosthesis?
- An increased extension moment at the knee
| - Forces will be coupled at the anterior proximal and distal posterior.
34
```
Standard bench alignment includes:
___ degrees of flexion
___ degrees of adduction
Foot inset to ___
and Foot posterior ___
```
5-7 degrees of flexion
5 degrees of adduction
Foot inset to 1/2 inch
and Foot posterior 1-1.5 inches
35
What are the benefits of a varus moment
- Energy efficient gait
- Minimize center of gravity
- Narrow base of support
36
Why is it advantageous to pre-flex a transtibial socket?
- Prevent knee hyperextension
- Load anterior panel
- Match natural gait knee flexion during loading response
- Creates smooth rollover
37
List four malalignments that may cause distal anterior pain in a TT patient
- Foot is too posterior
- Foot too dorsiflexed (socket too flexed)
- Heel too firm
- Socket relief inadequate
38
List four malalignments that may cause knee hyperextension during midstance in a TT patient
- Foot is too anterior
- Foot too plantar-flexed
- Socket too extended
- Heel too soft
39
List three malalignments that may cause lateral trunk bending in a TT patient
- Foot too outset
- Prosthesis too long or short
- Pain in residual limb
40
List two malalignments that may cause a lateral thrust or lateral gaping in a TT patient
- Foot is too inset
| - Socket ML it too large
41
List two malalignments that may cause a medial leaning pylon in a TT patient
- Foot is too outset
| - Socket is adducted
42
List two malalignments that may cause a lateral leaning pylon in a TT patient
- Foot is too inset
| - Socket is abducted
43
List three malalignments that may cause a drop-off sensation in a TT patient
- Foot too posterior
- Foot too dorsiflexed
- Keel too short
44
List four malalignments that may cause a rapid knee flexion in a TT patient
- Foot too posterior
- Foot too dorsiflexed
- Heel too firm
- Weak quads
45
List four malalignments that may cause an early heel rise in a TT patient
- Foot too anterior
- Insufficient socket flexion
- Heel too soft
- Foot too plantar-flexed
46
Where does the weight bearing take place in a quad socket?
Ischial-gluteal weight bearing
47
What shape is a quad socket?
Rectangular
48
Does a quad socket have a narrow AP or narrow ML?
Narrow AP,
49
What reliefs are built into a quad socket?
Rectus Femoris and adductor relief.
50
What is a disadvantage of a quad socket?
Lack of medial proximal stabilization.
51
List three Indications for a quad socket
- Previous user
- Prosthetist preference
- Funding considerations
52
What are three functions of the medial wall of a AK socket?
- Provide even pressure, with relief of hamstring and adductor longus tendons, along adductors muscles to increase control in adduction
- Contain all medial tissues to prevent adductor roll
- Medial wall represents the line of progression
53
Three causes of crotch pressure or burning include:
- AP is too large, ischium is slipping off and ramus is absorbing the pressure.
- The socket is too small causing adductor roll
- To small of an ML pushes led medially and crowds ischium.
54
What are two indications for using a locking liner?
- To accommodate small volume fluctuations
| - Patient preference for "secure" suspension
55
Secure suspension is a characteristic advantage of what suspension type?
Locking liner suspension
56
What is a disadvantage to using a locking liner for suspension?
Rotation may occur.
57
A lanyard style suspension adds what benefit to above knee suspension?
Rotational control along with ease of donning.
58
True or false: A lanyard style suspension would not be appropriate for highly active users?
True
59
True or false: Above knee anatomical suspension is appropriate for patients with knee disarticulation and/or malformations?
True
60
Advantages of anatomical suspension include:
- Rotational control
| - Distal end bearing is possible
61
A patient with a transfemoral amputation presents with a high amount of volume fluctuations throughout the day as well as rotation in his above knee prosthesis. What type of suspension would be best to address these issues?
Silesian belt for rotational control.
62
What disadvantages could an AK patient expect to experience with strap/belt suspension in an AK prosthesis?
- Increased pistoning
- Decreased comfort
- Decreased range of motion.
63
A patient with a transfemoral amputation presents with severe hip instability as well as a short residuum. What type of suspension would be best to address these issues?
Hip joint and belt
64
What AK suspension method offers the best ML stability?
Hip joint and pelvic band
65
What are three disadvantages to hip joint and belt suspension in an above knee prosthesis?
- Heavy and bulky
- Hard to don
- Increased pistoning
66
List two advantages to an ischial containment socket.
- Enhanced biomechanical stability
| - Increased comfort
67
List the disadvantages to an ischial containment socket.
More difficult to design
| Expensive
68
Four indications for a ischial containment socket.
- Prosthetist preference
- Patient preference
- More active or young individuals
- Good funding.
69
True or False: The quad socket provides superior femoral adduction control than that of an ischial containment socket?
False. An IC socket restores normal femoral adduction angle.
70
Mods for an IC socket require that the posterior lateral corner (or wallet hollow) be at what angle to the line of progression?
30-45 degrees
71
What is the purpose of the posterior lateral corner (wallet hollow)?
Stabilize the femur at heel strike: prevent external rotation from heel strike to midstance.
72
The deepest point of the scarpus triangle should be how many millimeters from the medial wall?
25mm
73
AP measurement for an IC socket are measured from where to where?
Medial adductor longus to ischium.
74
The posterior medial corner of an IC socket is set at what line angle compared to the line of progression?
15-25 degrees. Should capture the angle of the pubic ramus. Females tend do have a higher angle.
75
What anatomical landmarks represent the TKA and what is the TKA used to determin?
- Trochanter, knee, ankle
- Determines knee stability
- Used for guidance during bench alignment
76
A TKA that is posterior to the knee may cause what in the knee?
- Knee flexion moment
| - Instability at knee
77
A TKA that is anterior to the knee may cause what in the knee?
- A knee extension moment
| - Inherent knee stability
78
AK bench alignment: TKA should be positioned where?
Through or anterior to the prosthetic knee center
79
AK bench alignment: Socket should be in what alignment in the sagittal plane?
5 degrees of flexion. If a hip contracture is present, must accommodate for the contracture + 5 degrees.
80
AK bench alignment: In the transverse plane, where should the knee be located?
Externally rotated by 5 degrees.
81
AK bench alignment: In the transverse plane, where should the foot be located?
Externally rotated by 7 degrees.
82
What effect does pre-flexing the socket have on the lumbar spine?
Preflexion prevents increased lumbar lordosis and facilitates normal step length.
83
What effect does pre-flexing on the hip extensors?
Preflexion puts the hip extensors on stretch which increases control of the prosthesis during ambulation.
84
TRUE OR FALSE: In bench alignment the foot is aligned with the ischium, this creates a valgus moment about the ischium.
False. It creates a varus moment about the ischium increasing inherent stability within the socket due to the ischium making contact with the ischial seat.
85
A foot that is aligned under the ischium has what effect on the abductors of the hip?
Puts tension on the abductors increasing stabilization to the pelvis.
The lateral wall of the socket provides a counterforce and restores a natural femoral adduction angle.
86
What are four causes of knee instability at initial contact for an AKA.
- TKA is posterior to the knee
- Heel is too firm
- Insufficient socket flexion
- Weak hip extensors
87
What are four causes of a shortened step length on the prosthetic side at initial contact for an AKA.
- Knee instability due to TKA
- Knee friction is too low
- Femur pain
- Mistrust of prosthesis
88
What causes foot slap for an AKA?
- Plantar flexion bumper is absent or too soft
89
What are five causes for external rotation at initial contact in an AKA?
- Heel too firm
- Excessive toe out
- Subischial triangle angle is too tight.
- Poor muscle control
- Socket tension too loose
90
What are some causes of an abducted gait in an AKA? (7 listed)
- Medial brim pain
- Socket is abducted
- Femur pain
- Prosthesis is too large
- Poor suspension
- Habit
- Prosthesis too long
91
What are some causes that may lead to a lateral trunk bend during ambulation in an AKA? (8 listed)
- Prosthesis is too short
- ML is too big
- Abductor weakness (trendelenburg)
- Insufficient socket adduction
- Short residual limb
- Foot is too outset
- Abductor contracture
- Lack of counterforce
92
You notice your transfemoral patient is ambulating with hyperlordosis. What are some causes the may lead to excessive lordosis?
- Insufficient socket flexion
- Short residual limb
- Ischial pain
- Hip/core weakness
93
A medial whip is caused by what malalignment?
Knee is too externally rotated.
94
A lateral whip is caused by what malalignment?
Knee is too internally rotated.
95
Causes of a "whip" in an above knee amputee.
- Poor muscular control
- Knee either too internally or externally rotated.
- Improperly donned
96
Pistoning in a prosthesis is caused by...
- Poor suspension
- A socket that is too large
- Improper sock ply
97
Delayed heel rise in an above knee amputee may be caused by what two knee characteristics?
- Knee is too stable (too posterior to the TKA)
| - Knee friction is too high
98
Excessive heel rise in an above knee amputee may be caused by what two knee characteristics?
- Knee friction is too low
| - Extension aid is too low.
99
What are some causes that my lead to a circumduction during swing phase in an AKA? (9 listed)
- Medial brim pain
- Socket is abducted
- Friction is too high
- Insufficient knee bend (extension aid may be too high)
- Prosthesis is too large
- Poor suspension
- Habit
- Prosthesis too long
- Hip flexor weakness
100
5 reasons you may observe vaulting.
- Prosthesis is too long
- Friction is too high
- Extension aid is too high
- Habit
- Poor suspension
101
Terminal impact can occur due to... (3 listed)
- Insufficient knee friction
- Too strong of an extension aid
- Habit
102
A long prosthetic step may be caused by what malalignment?
Insufficient socket flexion
103
A trendelenburg gait in an AKA can have several causes. List 6 of them.
- Abductor weakness on the stance side
- A ML that is too large
- Poor ischial containment
- Insufficient socket adduction
- Hip pathology
- Short residual limb
104
List four advantages of a Symes amputation as compared to a more proximal amputation.
- Potential for full weight bearing.
- Prosthesis is self-suspending
- Minimal disturbance to growth in children
- Natural gait pattern
105
List four disadvantages
- Can be difficult healing
- Limited in build height
- Bulbous end can limit cosmesis
106
List three socket designs for a Symes.
- Push in with soft insert
- Bivalved with posterior door
- Medial door
107
Advantage and disadvantage of medial door style Symes prosthesis.
Advantage: Ease of donning, lighter, reduced forces around window during end bearing.
Disadvantages: Hole in outer shell, may limit structural integrity.
108
Advantage and disadvantage of Bivalve, posterior door style Symes prosthesis.
Advantage: Ease of donning
Disadvantages: Structurally weak, forces around opening are increased when end bearing is allowed.
109
Advantage and disadvantage of push in style Symes prosthesis.
Advantage: Easy to don, no hole in outer shell of socket.
Disadvantages: Heavier, hard to adjust.
110
True or False: Tibial bowing is common with a Symes amputation. Oftentimes the foot must be positioned at the lateral part of the distal end to accommodate the deformity.
True. A lateral set foot will allow the patient to achieve foot flat during midstance and allow a slight varus moment at the knee.
111
What modification can be made to a transhumeral prosthesis to reduce pressure on the thoracic wall?
Medial side flattening
112
A transhumeral prosthesis for a short residual limb should have what proximal trimlines?
- Posterior trimline should extend 25 mm medial to the lateral border of the scapula.
- Anterior trimline should encompass the delto-pectoral groove
- Lateral trimline extends up to the acromion and AC joint.
113
True or False: An elbow disarticulation prosthesis should not "purchase" on the epicondyles as it will cause nerve impingement.
False: Allowing purchase of the epicondyles can aid in humeral rotation.
114
In a hip disarticulation prosthesis, the hip joint lies (BLANK) to the trochanter
- Anterior and superior
- Posterior and superior
- Anterior only
- Posterior only
Anterior and superior
115
Name the purpose of the anterior support strap on a figure 8 harness.
Axillary suspensor, elbow lock control.
116
Name the purpose of the control attachment strap on a figure 8 harness.
Terminal device (TD) operation.
117
Name the proper location of the cross point ring on a figure 8 harness.
Inferior to C7 and towards sound side.
118
Name the purpose of the lateral support strap on a figure 8 harness.
Main suspensor, prevents socket rotation.
119
Name the purpose of the cross back strap on a figure 8 harness.
Keeps control attachment strap low to increase excursion.
120
A muenster type socket is for what type of residuum?
A short transradial
121
The best socket type of a medium transradial patient would be a
Northwestern style
122
A floating brim style of transradial prosthesis is for what limb length and allows what unique motions
Long transradial or wrist disarticulation and it allows for pronation/supination.
123
What muscles are the primary movers for elbow flexion in a body powered forequarter prosthesis?
Latissimus dorsi contraction and scapular abduction on the contralateral side.
124
What muscles are the primary movers for terminal device control in a body powered forequarter prosthesis?
Latissimus dorsi contraction and scapular abduction on the contralateral side.
125
What mechanism is used to control elbow lock in a body powered forequarter prosthesis?
Nudge control
126
What muscles are the primary movers for terminal device and elbow flexion control in a body powered shoulder disarticulation prosthesis?
Biscapular abduction and lats
127
What muscles are the primary movers for terminal device control in a body powered transhumeral prosthesis?
Biscapular abduction and glenohumeral flexion
128
What mechanism is used to control elbow lock in a body powered shoulder disarticulation prosthesis?
Scapular elevation on amputated side
129
What mechanism is used to control elbow lock in a body powered shoulder transhumeral prosthesis?
Shoulder depression and abduction and extension.
130
What muscles are the primary movers for terminal device control in a body powered transradial prosthesis?
Biscapular abduction and glenohumeral flexion.
131
True or False: One benefit of a chest strap on a transradial harness is it can reduce axilla pressure.
True. However, while indicated for heavy users, overall a chest strap can reduce comfort and cosmesis as well as decrease excursion.
132
What are some benefits to using a dual ring in harnessing for an upper extremity prosthesis?
- Prevent proximal migration
- Increase excursion (keeps CAS low)
- Kyphosis
- Good for use with short residual limbs.
133
An individual presenting with kyphosis and difficulty gaining enough excursion in their transradial prosthesis would benefit from what harnessing alternative?
Dual ring
134
A crossback strap enables what?
Increased excursion by keeping the CAS low.
135
True or False: A ring crosspoint has better excursion than that of a sewn crosspoint.
False. The sewn crosspoint when done correctly allows the harnessing system to be more responsive to body movements. Thus increasing excursion.
136
What is is the minimum cable efficiency?
70%
137
How do you calculate minimum cable efficiency?
(Force @ hanger) x (efficiency) = force needed to open TD
138
In TD nomenclature, what does the A stand for?
Aluminum
139
In TD nomenclature, what does SS stand for?
Stainless steal
140
In TD nomenclature, what does the P stand for?
Plastisol
141
In TD nomenclature, what does the X stand for?
Neoprene lining
142
In TD nomenclature, what does LO stand for?
Large opening
143
List two benefits of a TD with canted fingers.
- Better sight lines
| - Easier to pick up small objects
144
List a benefit of a TD with lyre fingers.
- Straight approach with larger opening allows for cylindrical objects
145
A CAPP terminal device is usually indicated for which population?
Children
146
Benefits of the CAPP terminal device (4 listed)
- Wide grip
- Safe
- Lightweight
- Spring loaded
147
What motions at the shoulder are used to lock the elbow on a transhumeral prosthesis??
Depression, extension, abduction
148
Which transradial socket is known for its self-suspension via AP compression and no ML suspension?
Muenster style TR socket
149
Two disadvantages of the muenster style socket are...
- User will not be able to achieve greater than 70 degrees of flexion.
- Restricts supination/pronation
- Pull sock needed
150
Which transradial socket design incorporates a muscle belly suspension and a dynamic impression method?
Ottobock (european) design
151
Which transradial socket design is best for very short transradial amputations?
Muenster
152
What is the minimum pinch force required in a TD to perform ADLs?
3 lbs
153
What number indicates a Hosmer TD sized for adults?
#5
154
A size 8 Hosmer TD is most commonly used for what population?
Women.
155
A patient presents with a very short transradial amputation. What would be the best terminal device to accomodate the decreased force the patient will be able to generate?
5xA (adult size, nitrile coating, aluminum)
156
What is the difference between the Hosmer 6 and the Hosmer 7 TD?
Both are work hooks, but the Hosmer 6 has a back lock so that it will not open until actuated.
157
True or False: A bilateral upper extremity amputee should be fit with the same TD on both sides to ensure consistency and ease of learning to utilize the prostheses.
False. Most commonly the patient should be fit with different hooks to increase their work envelope. For instance, one canted, one lyre shape to be able to pick up a wider variety of objects.
158
Which TD is a voluntary closing TD with automatic lock and a manual unlock?
APRL
159
A bilateral UEA patient would benefit most from which style wrists?
At least one flexion wrist component to ensure flexion to midline.
160
True or False: A very short TRA would benefit from a wrist flexion unit in order to ensure TD to midline.
False. A wrist flexion unit is very heavy and will be incredibly difficult for a VSTRA to control due to the short lever arm. This terminal device is best for strong, mid to long transradials.
161
Indication for polycentric hinges on a transradial prosthesis
Increases flexion when there is cubital bunching.
