6: Transfemoral Flashcards
(92 cards)
1
Q
After a TFA, how much weight can be placed directly on the end of the residual limb?
A
Very little to none
2
Q
How are thigh muscles balanced following a TFA?
A
Flexors and abductors overpower the extensors and adductors
3
Q
What is the goal of TFA?
A
regain muscle balance and position the femur for weight bearing and ambulation
4
Q
Are the primary hip flexors and hip abductors affected by TFA?
A
No because their attachment sites are more proximal than the amputation level
5
Q
What causes adductor and extensor weakness following TFA?
A
Loss of distal muscle attachment sites
6
Q
Where are adductor muscles secured?
A
To the residual femur to prevent abduction
7
Q
Why is it important to prevent the femur from abducting?
A
Weight cannot be loaded as easily and the bone my press painfully against the socket
8
Q
With surgically balanced muscles, where does the majority of weight bearing in the socket occur?
A
On the sides of the legs, not on the distal end
9
Q
What is adduction roll?
A
Collection of tissue that sometimes forms high on the inner thigh above the socket line
10
Q
What are common causes of adductor roll?
A
Weight gain, mismatched socket geometry, improper donning of residual limb
11
Q
What is the minimal length for a TFA?
A
7.5 cm
12
Q
What is the optimal length for a TFA?
A
23-30 cm
13
Q
What are the 6 pressure sensitive areas following a TFA?
A
- ASIS
- Greater trochanter
- Pubic tubercle
- Adductor tendon
- Public ramus
- Distal femur
14
Q
What are the five components of a prosthetic for a TFA?
A
Socket, rotator, knee joint, pylon, foot
15
Q
What are the four types of prosthetic knees?
A
- Single axis hinge
- Polycentric
- Pneumatic and hydraulic
- Microprocessor
16
Q
What K level is indicated for a single axis hinge?
A
K1 or K2
17
Q
What K level is indicated for a polycentric knee?
A
K1 or K2
18
Q
What K level is indicated for a pneumatic and hydraulic knee?
A
K3
19
Q
What K level is indicated for a microprocessor knee?
A
K4
20
Q
What are the two types of knee friction?
A
Constant or variable friction
21
Q
What K level is indicated for constant friction?
A
K1 or K2
22
Q
What K level is indicated for variable friction?
A
K3
23
Q
Describe a knee-single axis joint
A
Difficult to reciprocate during gait. Can have a knee extension assist or weight-activated stance phase control. Light weight
24
Q
What types of mechanisms are present in a knee-single axis joint?
A
Constant friction and simple hinge
25
Describe a polycentric joint
Heavier, reciprocal gait is more fluid, may or may not have a knee extension assist or a weight-activated stance phase control. Have four or more pivoting bars
26
Which provides greater stability, polycentric or single axis joints?
Polycentric
27
Describe a constance friction mechanism
Amount of friction does not change with a set cadence and walking speed
28
What type of knee joints have constant friction mechanisms?
Single-axis and polycentric
29
What K levels are indicated for a constant friction mechanism?
K 1 and 2
30
What K levels are indicated for a variable friction mechanism?
K 3
31
Describe the variable friction mechanism during initial swing
High friction to prevent excessive knee flexion
32
Describe the variable friction mechanism during midswing
Friction decreases to allow knee to swing easily
33
Describe the variable friction mechanism during terminal swing
Increase in friction for initial contact
34
Describe a manual locking knee mechanism
Single axis device. Provides stability through a physical lock on the knee until. Knee remains extended and stable when lock is engaged
35
Describe a weight activated knee mechanism
Single axis device with a friction brake that is activated by body weight. Unlocks as weight is relieved and swings freely during swing
36
What population will typically use a weight activated knee mechanism?
Elderly, low level ambulators who may need AT. Needs an extra degree of security while wearing the prosthesis
37
Describe a hydraulic/fluid knee
Single or polycentric axis that uses hydraulics with a liquid mechanism
38
What are the advantages of a hydraulic joint?
Variable friction for improved swing and stance phase. Provides more friction and a smoother gait
39
What are disadvantages of a hydraulic joint?
Heavier, more expensive, more maintenance
40
Describe a pneumatic/air joint
Single or polycentric axis that compresses air as the knee if flexed. The energy is stored, then used to put the knee into extension
41
Describe a microprocessor knee
Contains sensors that detect movement and timing. Multiple programs to accommodate activity level, allow for fluid management for descending stairs, requires charging, variable friction to improve swing and stance phase control
42
What are advantages of a microprocessor?
Decreases fall, more active, enhance confidence
43
What are disadvantages of a microprocessor?
Heavier, expensive, battery
44
What is the most important part of any prosthesis?
The socket fit
45
Describe the design of the socket?
Designed to enclose the skin, tissue, muscle, and bone of the residual limb and serve as an efficient interface between the residual limb and the prosthetic components
46
What are the three criteria for a socket?
1. fit should be comfortable
2. suspension should be effective
3. allow amputee to move and/or ambulate
47
What are the most common transfemoral socket designs?
Quadrilateral and ischial containment socket
48
Where does weight bearing take place with a quadrilateral socket?
Ischial tuberosity by the posterior shelf of the socket
49
How is suspension provided with a quadrilateral socket?
Suction generated by adequate fit of socket over residual limb
50
What types of limbs is appropriate for a quadrilateral socket?
Mostly used for all types of residual limbs
51
Describe the shape of a ischial containment socket
Narrow medial-lateral walls and the anterior wall is lower
52
What are the four functional goals of an ischial containment socket?
1. Stabilize socket on the residual limb
2. Control socket rotation by containing IT and ramus within contours of socket
3. Maintain normal femoral adduction
4. Distributes pressure through socket along shaft of femur
53
When is an ischial containment socket more appropriate than a quadrilateral socket?
Short and fleshy residual limbs and high-activity sport participation
54
Where does weight bearing take place with an ischial containment socket, and what are the benefits?
All over the surface of the residual limb without localizing one point. Allows for more comfort and better control because ischial tuberosity does not have to do all of the weight bearing
55
Where is the ischial ramus contained in the ischial containment socket?
Medial wall
56
How is suspension provided with an ischial containment socket?
Suction generated by adequate fit of socket over residual limb
57
Which socket is becoming more popular, quadrilateral or ischial containment socket?
Ischial containment socket
58
What are the two types of socket design based on material?
Hard socket or flexible
59
Describe a hard socket
Made of thermoplastic or thermosetting resin. Intimate, total contact fit, prosthetic socks worn as interface
60
What are the advantages of a hard socket?
Very durable, easy to clean, less expensive to produce
61
What are the disadvantages of a hard socket?
More difficult to adjust fit on bony or sensitive residual limbs
62
Describe a flexible socket
Vacuum formed with flexible thermoplastic, encased in a rigid frame
63
What are the advantages of a flexible socket?
Accommodates to change in muscle shape, provide relief for bony prominences, comfort while sitting
64
What are the disadvantages of a flexible socket?
Less durable, bulkier, more expensive to fabricate
65
What are the 5 common types of transfemoral suspension systems?
1. Suction - negative air pressure
2. Roll on cushion liner
3. Silesian BELT suspension
4. Total elastic suspension belt
5. Pelvic belt and hip joint
66
What are the advantages of a traditional pull-in suction suspension negative air pressure?
Enhanced prosthetic control, intimate fit, eliminates pistoning, improved proprioception
67
What are the disadvantages of a traditional pull-in suction suspension negative air pressure?
Recent amputation, need to have control of volume, difficult to don
68
Describe the three main components for use of a traditional pull-in suction suspension with negative air pressure
1. Uses a one way valve
2. Socket must fit very snug
3. Work without a liner
69
What are the indications for a traditional pull-in suction suspension negative air pressure system?
Long residual limb, good skin conditions, good balance, good UE strength
70
What are the contraindications for a traditional pull-in suction suspension negative air pressure system?
Very short residual limb, UE weakness, frequent volume fluctuations
71
Describe a roll on cushion liner
Made of silicone, urethane, and elastomer. Turned inside out and is rolled over the skin. Need a cushion or locking liner
72
What are advantages of a roll on cushion liner?
Decreased shear of skin, don while seated, softer distal support, smoother donning and doffing
73
What are disadvantages of a roll on cushion liner?
Expensive, durability, increased sweating and risk of infection, possible distal end pulling
74
What are indications for a roll on cushion liner?
Short to long residual limbs, minor volume changes
75
What are contraindications for a roll on cushion liner?
Irregular residual limb shape, hygiene concerns, large volume changes
76
Describe a Silesian BELT suspension system
Leather, lightweight webbing with an auxiliary strap for suction suspension. Attached to the lateral socket, encircles pelvis, runs to buckle on anterior surface
77
What are advantages of a Silesian BELT suspension?
Easy to don, adjustable
78
What are disadvantages of a Silesian BELT suspension?
Added bulk around the waist, less anatomic, uncomfortable
79
What are indications for a Silesian BELT suspension?
When other systems are not optimal. Long residual limbs who are not vigorous ambulators
80
Describe a Total Elastic Suspension (TES) Belt
Distal sleeve fits snugly around proximal half of socket, belt encircles the waist
81
What are advantages of a TES?
Easy to don, comfortable, excellent suspension
82
What are disadvantages of a TES?
Controlling rotation, durability, heat
83
Describe a pelvic belt and hip joint
Leather belt attached to socket with metal hip joint that is centered anterior and superior to the apex of the trochanter
84
What does the term osseous integration mean?
Bone ingrowth into a metal implant
85
Describe osseous integration
Implant is anchored and integrated into the bone, which then grows into the implant. Provides direct connection between living bone and prosthesis
86
What are 5 advantages of osseous integration?
1. Increased use of prosthesis
2. More stability in walking and standing
3. Ability to walk longer distances
4. Avoiding the skin problems associated with socket prosthetics
5. Easy to remove and replace a prosthesis
87
What are the 4 disadvantages of osseous integration?
1. Surgery with long recovery
2. Need to regularly maintain and clean the interface between the skin and implant
3. Risk of superficial skin infections or deep tissue infections
4. Potential for the abutment to bend or break
88
What device is shown in the image?
Pelvic belt and hip joint
89
What device is shown in the image?
Total Elastic Suspension (TES)
90
What device is shown in the image?
Silesian BELT Suspension
91
What device is shown in the image?
Roll on cushion liner
92
What device is shown in the image?
Traditional pull-in suction suspension negative air pressure
