Ch 6 - Prosthetic and Orthotics: Lower Limb Flashcards
1
Q
What is the most common cause of lower extremity amputation?
A
Peripheral arterial disease (PAD), also referred to as peripheral vascular disease (PVD)
2
Q
What is Ankle-Brachial Index (ABI)?
A
Ratio of brachial systolic pressure to ankle systolic pressure
3
Q
What are the scales of Ankle-Brachial Index (ABI)?
A
– ABI 0.91 to 1.30: Normal
– ABI 0.71 to 0.90: Mild PAD
– ABI 0.41 to 0.70: Moderate PAD
– ABI 0.00 to 0.40: Severe PAD
4
Q
What does a Ankle-Brachial Index (ABI) >1.30 suggest??
A
Calcified, noncompressible vessels, which can produce false negative results. This is common in diabetics
5
Q
When is Doppler velocity waveform analysis used?
A
If screening ABI is abnormal, Doppler waveform analysis is performed to localize the lesion
6
Q
Describe Doppler velocity waveform analysis.
A
Doppler waveforms are obtained at multiple sites and a change in waveform from one level to the next is indicative of PAD
7
Q
What is the gold standard imaging for PAD?
A
Intraarterial contrast angiography
8
Q
What is Myodesis?
A
Muscles and fasciae are sutured directly to bone through drill holes
9
Q
When is Myodesis contraindicated?
A
Severe dysvascularity in which the blood supply to the bone may be compromised
10
Q
What is Myoplasty?
A
Opposing muscles are sutured to each other and to the periosteum at the end of the cut bone with minimal tension
11
Q
What is the procedure of choice in severe dysvascular residual limbs?
A
Myoplasty
12
Q
Describe a partial toe amputation.
A
Excision of any part of one or more toes
13
Q
Describe a toe disarticulation.
A
Disarticulation at the metatarsophalangeal (MTP) joint
14
Q
Describe a Partial foot/ray resection.
A
Resection of a portion of up to three metatarsals and digits
15
Q
Describe a Transmetatarsal amputation (TMA).
A
Amputation through the midsection of all metatarsals
16
Q
Describe a Lisfranc amputation.
A
Amputation at the tarsometatarsal junction
17
Q
Describe a Chopart amputation.
A
Midtarsal amputation—only talus and calcaneus remain
18
Q
Describe a Syme’s amputation.
A
Ankle disarticulation with attachment of heel pad to distal end of tibia; may include removal of malleoli and distal tibial/fibular flares
19
Q
Describe a Long BKA (transtibial) amputation.
A
> 50% of tibial length
20
Q
Describe a standard BKA (transtibial) amputation.
A
20% to 50% of tibial length
21
Q
Describe a Long BKA (transtibial) amputation.
A
<20% of tibial length
22
Q
Describe a knee disarticulation.
A
Amputation through the knee joint, femur intact
23
Q
Describe a Long AKA (transfemoral) amputation.
A
> 60% of femoral length
24
Q
Describe a Standard AKA (transfemoral) amputation.
A
35% to 60% of femoral length
25
Describe a Short AKA (transfemoral) amputation.
<35% of femoral length
26
Describe a hip disarticulation.
Amputation through hip joint, pelvis intact
27
Describe a hemipelvectomy.
Resection of lower half of the pelvis
28
Describe a hemicorporectomy.
Amputation of both lower limbs and pelvis below L4, L5 level
29
What are unsatisfactory levels for elective sites of lower limb amputation?
Distal 2/5's of tibia
Very short BKA proximal to tibial tubercle
Very high AKA
30
What are causes of toe, metatarsal ray or TMA amputations?
```
Trauma to the toes
Loss of tissue due to an infection, or gangrene
Frostbite
Diabetes
Arterial sclerosis
Scleroderma
Buerger’s disease
```
31
What function does a TMA amputation maintain?
Preserves the attachment of the dorsiflexors and plantar flexors and their function
32
What is a Pirogoff amputation?
Vertical calcaneal amputation
33
What is a Boyd amputation?
Horizontal calcaneal amputation
34
What do patients with Lisfranc and Chopart amputations develop?
Foot often develops a significant equinovarus deformity resulting in excessive anterior weight bearing with breakdown
35
What can prevent equinovarus deformity in amputees?
Adequate dorsiflexor tendon reattachment with Achilles tendon lengthening
36
What are pros to a Symes amputation?
1. Maintains length
2. Heel pad for WB
3. Early fitting of prosthesis
4. Partial WB after the procedure with a proper rigid casting (~ 24 hours)
37
What are cons to a Symes amputation?
Poor cosmesis
| Prosthesis fitting difficult
38
Describe functional ability of elderly patients after BKA.
50% worse function
| 5% improve function
39
What are advantages of BKA over AKA?
Dec energy expenditure
| Dec mortality rates d/t better healing and tissue viability
40
Describe the proper cuts through bone in BKA.
Fibula cut 2 to 3 cm shorter than the tibia
| Tibia beveled anteriorly
41
When is a knee disarticulation preferred over BKA?
Severe flexion contracture (> 50°)
| Limb is ischemic
42
What is a Modified knee disarticulation?
Moderate trimming of the femoral condylar prominences and patellofemoral arthrodesis in the intercondylar notch
43
What degree of hip flexion contracture can be accommodated in a socket?
20 degrees
44
What is the ideal shape for transtibial residual limb?
Cylindrical
45
What is the ideal shape for transfemoral residual limb?
Conical
46
What is a removable rigid dressing (RRD) for the transtibial amputee?
Plaster or fiberglass cast suspended by a stocking and supracondylar cuff
47
How should elastic bandages be applied to residual limb post op?
Figure-8 wrap
48
What size elastic bandages should be used on residual limbs?
Double length 4-inch for transtibial limb
| Double length 6-inch for transfemoral limb
49
When should elastic shrinker socks be used?
Once staples or sutures removed for 24 hrs/day
| Fit to groin in AKA's
50
When can shrinker socks be stopped?
Once fit for definitive prosthesis
| Can use for edema at night
51
How are hip flexion contractures prevented?
```
Avoid soft mattress
No pillow under back or thigh
No HOB elevation
No standing with AKA on crutch
Prone lying 15 min/day or supine with active extension of amputation
```
52
How are hip abudction contractures prevented?
No pillows between legs
53
How are knee flexion contractures prevented?
Do not lie with leg hanging off bed
No pillow under knee
Avoid sitting for prolonged periods
Sit with knee on board under WC cushion with towel wrapped over board
54
Describe a K0 functional level.
Nonambulatory (bedbound)
55
What prosthesis components are allowed for a KO functional level?
No prosthesis allowed
56
Describe a K1 functional level.
Limited to transfers or limited household ambulator
57
What prosthesis components are allowed for a K1 functional level?
Manual lock or stance-control knee
| SACH or single-axis foot
58
Describe a K2 functional level.
Unlimited household but limited community ambulator
59
What prosthesis components are allowed for a K2 functional level?
Pneumatic or polycentric knee
| Multiaxis foot
60
Describe a K3 functional level.
Unlimited community ambulator
61
What prosthesis components are allowed for a K3 functional level?
Hydraulic knee
| Energy-storing foot
62
Describe a K4 functional level.
High energy activities (sports, work)
63
What prosthesis components are allowed for a K4functional level?
Hydraulic knee
| Energy-storing foot
64
When is a preparatory (temporary) prosthesis used?
3 to 6 months postsurgery—until maximal residual limb shrinkage has been achieved
65
What does a preparatory (temporary) prosthesis allow?
* Provides prosthetic fitting before the residual limb volume stabilizes
* Helps in shrinking and shaping
* Early prosthetic training (gait and functional training)
* Trial when uncertainty about potential prosthesis
66
Describe the socket for a Symes amputation.
Medial or posterior opening to allow bulbous residual limb in.
67
Describe feet for a Symes amputation.
– Syme solid ankle cushion heel (SACH)
– Syme stationary ankle flexible endoskeleton (SAFE)
– Energy-storing carbon fiber foot (low profile)
68
What are the components for a BKA prosthesis?
Socket
Suspension
Shank
Prosthetic foot
69
What is the standard socket for an average BKA prosthesis?
Total-contact patellar tendon bearing (PTB) socket
70
Describe the total-contact patellar tendon bearing (PTB) socket.
Custom-molded thermoplastic or laminated socket that distributes weight through convex buildups (bulges) over pressure-tolerant areas and concavities (relief areas) on pressure-sensitive areas
71
What are pressure tolerant areas in the total-contact patellar tendon bearing (PTB) socket?
1. Patellar tendon
2. Pretibial muscles
3. Popliteal fossa—Gastroc-soleus muscles (via gastrocnemius depression)
4. Lateral shaft of fibula
5. Medial tibial flare
72
What are pressure sensitive areas in the total-contact patellar tendon bearing (PTB) socket?
1. Tibial crest, tubercle, and condyles
2. Fibular head
3. Distal tibia and fibula
4. Hamstring tendons
5. Patella
73
How is the socket aligned on the shank in total-contact patellar tendon bearing (PTB) socket?
Slight flexion (about 5°)
74
What is the maximum degree of flexion to accommodate at knee flexion contracture in total-contact patellar tendon bearing (PTB) socket?
Max of 25° of flexion
75
What are commons suspension systems for BKA?
* Supracondylar cuff suspension socket
* Brim suspension
* Rubber or neoprene sleeve
* Pin suspension
* Suction suspension
* Thigh corset
76
Describe a Suction suspension.
Silicone or gel insert or liner with the use of a one-way expulsion valve in the distal aspect of the socket that allows air to escape from the socket but not enter
77
What does the design of a Solid ankle cushion heel (SACH) foot allow for?
Compressible heel and wooden keel simulate the motions of the ankle in normal walking (plantar flexion at heel strike) without actual ankle movement occurring
78
What are the main uses for Solid ankle cushion heel (SACH) foot?
* General use
* Kids-durable
* Limited ambulation needs
* K1 users
79
What are advantages of Solid ankle cushion heel (SACH) foot?
* Inexpensive
* Light (lightest foot)
* Durable
* Reliable
80
What are disadvantages of Solid ankle cushion heel (SACH) foot?
* Energy consuming
* Rigid
* Best on flat surface
81
Describe a Single-Axis Foot.
Movement in 1 plane (DF and PF)
| Heel height-adjustable single-axis feet available
82
What is the main use of a Single-Axis Foot?
* To enhance knee stability
* AKA who needs greater knee stability (goes to flat foot quick before knee buckles); knee goes back into extension (gives stability in early stance)
* K1 users
83
What are the advantages of a Single-Axis Foot?
* Adds stability to prosthetic knees
| * Increased weight (70% heavier than SACH)
84
What are the disadvantages of a Single-Axis Foot?
* Increased cost
| * Increased maintenance
85
Describe a Multi-Axis Foot.
Allow PF, DF, inversion, eversion, and rotation
86
What is the main use of a Multi-Axis Foot?
* Used for ambulation on uneven surfaces
* Absorbs some of the torsional forces created in ambulation
* K2 users
87
What are the advantages of a Multi-Axis Foot?
* Multidirectional motion
* Permits some rotation
* Accommodates uneven surfaces
* Relieves stress on skin and prosthesis
88
What are the disadvantages of a Single-Axis Foot?
* Relatively bulky
* Heavy
* Expensive
* Increased maintenance
* Greater latitude of movement may create instability in patients with ↓ coordination
89
Describe a SAFE Flexible Keel.
SAFE (stationary ankle flexible endoskeleton)
90
What is the main use of a SAFE Flexible Keel?
* Used for ambulation on uneven surfaces
| * K2 users
91
What are the advantages of a SAFE Flexible Keel?
* Flexible keel
* Multidirectional motion
* Moisture and grit resistant
* Accommodates uneven surfaces
* Absorbs rotary torques
* Smooth rollover
92
What are the disadvantages of a SAFE Flexible Keel?
* Heavy
* Increased cost
* Not cosmetic
* Does not offer inversion/eversion
93
What are uses for a STEN (stored energy) flexible keel?
* Used when smooth roll-over needed
| * K2 users
94
What are advantages of a STEN (stored energy) flexible keel?
* Elastic keel
* Moderate cost
* Accommodates numerous shoe styles
* ML stability similar to SACH
95
What are disadvantages of a STEN (stored energy) flexible keel?
* Moderate-heavy weight
| * Cannot be used with Syme’s amputation
96
Describe a Seattle foot.
Consists of a cantilevered plastic C- or U-shaped keel, which acts as a compressed spring
97
What are uses for a Seattle foot?
* Jogging, general sports, conserves energy
| * K3 and K4 users
98
What are advantages of a Seattle foot?
* Energy storing
| * Smooth roll-over
99
What are disadvantages of a Seattle foot?
* High cost
| * No SACH heel makes it difficult to change compressibility of heel
100
Describe a Flex foot.
– Pylon and foot incorporated into 1 unit
| – The flex-foot keel extends to the bottom of the transtibial socket (and in AKA, to the level of the knee unit)
101
Describe a Flex-walk.
Shorter version of the Flex-foot, attaching to the shank at the ankle level
102
What are uses for a Flex foot?
* Running, jumping, vigorous sports, conserves energy
| * K3 and K4 users
103
What are advantages of a Flex foot?
* very light
* Most energy storing
* Most stable mediolaterally
* Lowest inertia
104
What are disadvantages of a Flex foot?
* very high cost
| * Alignment can be cumbersome
105
Describe a polycentric knee.
Unlike the single-axis knee, has an instantaneous center of rotation that changes and is proximal and posterior to the knee unit itself
106
What does a polycentric knee allow for?
Greater knee stability
More symmetrical gait
Equal knee length when sitting
107
What are other names for an ischial containment socket?
Narrow mediolateral socket
| Contoured adducted trochanteric-controlled alignment method (CAT-CAM) socket.
108
Where is weight bearing concentrated in an ischial containment socket?
Medial aspect of the ischium and the ischial ramus
109
Describe flexion in an ischial containment socket.
Preflexed 5° to 7° to maximize hip extensor muscle control
| Max of 20° flexion is allowed to accommodate flexion contracture
110
Describe the shape of a Quad socket.
Narrow anteroposteriorly and relatively wide mediolaterally
111
Where are there reliefs in a Quad socket?
Adductor longus
Hamstring
Greater trochanter
Gluteus maximus, Rectus femoris
112
Describe needs of a total suction socket.
Worn without socks on residual limb
Provides the best suspension biomechanically but requires minimal volume fluctuation, good hand strength and dexterity, good balance, and good skin integrity.
113
Describe needs of a partial suction socket.
Uses a socket with a suction valve, but it is worn with socks, which reduces the airtight suction fit
114
Describe a Constant friction knee unit.
Friction mech used in swing control knee to dampen the pendular action of the prosthetic knee during swing phase, to dec the incidence of high heel rise in early swing, and dec terminal impact in late swing
115
When is a Constant friction knee unit is used?
* Single walking speed
* Kids
* No stance control; a screw used to adjust the friction to determine how fast or slow the knee swings
* K1 ambulator
116
Describe a Stance-Control knee/Safety knee/weight Activated Friction brake.
* Single-axis knee with stance control
| * Stance control acts as a brake system
117
When is a Stance-Control knee/Safety knee/weight Activated Friction brake unit is used?
1. Geriatrics
2. Short residual limb
3. General disability
4. Uneven surfaces
5. Amputees with weak hip extensors
6. K1 ambulator
118
When can a Stance-Control knee/Safety knee/weight Activated Friction brake unit is NOT be used?
ilateral AKA (knees won’t bend with loading) → cannot bend both knees at the same time (patient cannot sit down)
119
What activities are NOT compatible with a Stance-Control knee/Safety knee/weight Activated Friction brake unit?
Activities that require knee motion under weightbearing, such as step-overstep stair descent
120
Describe a Polycentric/4-bar knee.
* No stance control, but inherently stable
| * Short knee unit → can be used in knee disarticulation and long residual limb
121
When is a Polycentric/4-bar knee used?
K1 ambulator
122
Describe a Manual locking knee.
Spring-loaded pin that automatically locks the knee when the amputee stands or extends the knee and knee is kept extended throughout the entire gait cycle to ↑ stability
123
When is a Manual locking knee used?
Last resort
Blind
Stroke patient with amputation
K1 ambulator
124
Describe a Fluid-Controlled knee.
1. Hydraulic (oil)
2. Pneumatic (air)
•Cadence-responsive knee units through cadence-dependent resistance
125
When is a Fluid-Controlled knee used?
1. For patients who vary cadence frequency
2. Active walkers
3. Ambulation in uneven terrain
4. K3 and K4 ambulators
126
What is the standard prosthesis for a hip disarticulation?
Canadian hip disarticulation prosthesi
