Exam 2 Flashcards
(201 cards)
1
Q
what is aitken classification B
A
No osseous connection
2
Q
what are some muscles for testing the transhumeral
A
biceps
triceps
deltoid
3
Q
what must you do for a kid right after post opt
A
you must fit the kid with a prothetic right away
4
Q
what is sleeve suspension
A
neoprene or gel sleeve that fits over the socket and rolled onto the thigh
5
Q
what are some physical therapy goals
A
Facilitate as normal a developmental sequence
Prevent or minimize impairments, activity limitations, and participation restrictions
6
Q
Look at slides
A
38 , 39, and 40 of amputation powerpoint
7
Q
what are the elements of LE prosthetic prescription
A
- socket
- feet
- interface
- suspension
- knees
- additional componenets
8
Q
what is anatomical suspension
A
Use of the shape of the patient’s residual limb as a means of maintaining the prosthesis during use.
9
Q
what is the expected outcomes of a child with bilateral transfemoral amputation
A
they will require manual locks at knees until age 6 or older
10
Q
what is K3
A
The patient has the ability or potential for ambulation with variable cadence. A person at level 3 is typically a community ambulator who also has the ability to traverse most environmental barriers and may have vocational, therapeutic or exercise activity that demands prosthetic use beyond simple locomotion.
11
Q
what are the K level ratings
A
0-4
12
Q
what is osteosarcomas
A
this is about 50% of disease amputations
- peak incidence coincides with puberty
- distal femur, proximal tibia and proximal humerus
13
Q
what are some system complications of sensation
A
Neuromas, residual limb pain, phantom pain
14
Q
what are some muscles for testing at the transradial level
A
FCR FCU ECRL ECRB EC
15
Q
what happens within 5 years after the 1st amputations
A
if it is due ot vascular disease they will die
16
Q
what are some suspension methods for the UE
A
pin/locking liner suspension
liner wtih lanyard suspension
anatomical suspension
17
Q
what is sach foot prosthetic
A
solid ankle cushion heel: Simple and stable, low cost, heavy, no flexibility
18
Q
how many births are are born with limb deficiencies
A
2-7/10,000
19
Q
what need to be done for the prostheiss for RL
A
Clean daily
• Routine maintenance
(knee/foot)
20
Q
what is Powered knee:
A
Powered extension with MPK hydraulic knee stability
21
Q
what does pistoning mean
A
problems with suspension
22
Q
what is blistering
A
- Friction
- Reduce friction by improving the suspension or with nylon sheath.
- See CPO ASAP
23
Q
how do you fix bottoming out
A
socks
24
Q
what is tendoesis
A
Tendon to bone
25
what is myofascial
outer fascial layer of the muscle is attached to deeper muscle
26
what are some problems with radiation
long term effects decreased use in children
27
what are some problems with chemotherapy
know specific agents and side effects
28
what is the bilateral body powered prostheses
The prostheses may be tethered with the same harness for suspension, as shown here. Or, the prostheses may fabricated with harnesses that are independent from the other.
The prosthetist balances the need to suspend and control the prostheses with the need for ease of donning
29
what are the components of the feet
- sach
- single axis
- multi axial
- flexible keel
- dynamic response
30
what is the development of prescription (RX)
Primary: prosthetist and the physiatrist
| Therapy team input
31
what are some other UE amputations
forequarter
wrist disarticulation
shoulder disarticulation
32
what are some goals for adolescents for prosthesis
- Monitor and maintain proper fit
- Skin inspection
- Independent donning and doffing
- Independent dressing
- Engage in full range of ambulatory activities
- Recognize when prosthesis needs repair or alteration
33
how many amputations occur in the usa and the cost
185,000
| $8.3 billion
34
what are some post surgical phase PAIN
- residual limb pain
- phantom sensation
- phantom pain
35
what are somethings that need to be addressed for positioning someone after limb loss surgery
Avoid prolonged sitting
Watch pillow placement
36
what is the team approach for limb loss
They are ALL working together to make it work
- family
- social workers
- psychologist
- peer support
- case manager
- chaplain
- pt
- therapy
- prosthetist
- nurse
- physiatrist
- surgeon
37
what is the critical period of limb development
4-6 wk
38
what happens with you fit a child for a UE prothetic after the age of 2
they will think that their arm is just gets in the way BUT if they fit before the age of 2 it will use the arm as a normal part of their body
39
what contractures are common after limb loss surgery
hip and knee
| Develop as a result of muscle imbalance, tightness, withdrawal reflex
40
what needs to be protected during amputations
protection of the neuroma (severed peripheral nerves) allow for faster return to mobility
41
what are some system complications after post surgical phase
```
cardiovascular
integumentary
musculoskeletal
sensation
cognitive
psychological
```
42
what is bench of prosthetic alignement
the initial position of the socket relative to the foot and knee. Each foot/knee has a specified bench alignment.
43
what is the body powered motion of the scapular abduciton
Spreading the shoulder blades apart in combination with humeral flexion, or alone will open the terminal device.
44
what is residual limb pain
– Confined to residual limb
– Usually recovers after 4-6 weeks
– Primary cause is the prosthesis. Or may be due to ischemia, inflammation, infection, bone spurs, neuroma, referred pain
45
what is static of prosthetic alignement
the initial alignment as the person stands on the prosthesis.
46
what is the body powered motion of the shoulder depression , extension , abduction
This will simulate the motion required to lock and unlock the elbow in the individual with transhumeral amputation.
47
what are some types of disease related amputations
osteosarcoma
| ewings sarcoma
48
what is Fluid-controlled:
allows for variable cadence, increased weight and cost
49
what is Microprocessor knee (MPK):
maximum knee stability with computer driven swing and stance and variable cadence, expensive
50
what kind of cognition support after surgery of a limb
- Entire Rehab Team is responsible for reassurance and education
- Clear expectations
- Steps to rehab mapped out
- Education & PMH guidance
- Open environment
51
what is aitken classification D
Absent femoral head and acetabulum
52
what are the 5 classic stages of grief
1 denial and isolation (this isnt happening to me )
2 anger (why is this happening to me)
3 bargaining (i promise ill be a better person if)
4 depression ( i dont care anymore )
5 acceptance and hope ( im ready for whatever comes)
53
what is phantom pain
– Chronic pain syndrome felt in the phantom limb
| – Interferes with mood and participation in activities
54
what is body symmetry awareness for UE amputations
```
Scapular stabilization exercises and core strengthening
Decreased edema
Accelerate wound heeling
Decrease hospital stay
Improve proprioceptive input
```
55
what are the components fo the TF prosthesis
- foot-ankel assembly
- shank
- knee unit
- socket
- suspension device
56
what are some physial therapy goals for infancy and toddler
monitor developmental progress, rom, and strength needed for prosthetic use
57
what is the expected outcomes of a child with unilateral transtibial amputations and walking
they woudl achieve an almost normal gait
| - no difficulty with stairs
58
what is K2
The patient has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs or uneven surfaces. This is typical of the limited community ambulator.
59
what are some system complications of musculoskeletal
Weakness, contractures, boney overgrowth,heterotrophic ossification, bone density
60
what is the exoskeleton of the shank
Wood or rigid plastic
- shaped to simulate the contour of an anatomical leg
- Lack the ability to change angulation
Cosmetic purpose
61
how to treat aitkens B and C
amputation/ revision
| prosthetic fitting
62
what should the wearing schedule be like for someone with a UE amputation
start with 15-30 min and increase to 8 hours within 1-2 weeks.
63
what are some skin problems
- bottoming out
- distal edema
- pistoning
- bell capping
64
what is a key part of intervention after limb loss
mobility
-Specific and Individually developed
-Hip Extension, Hip abductors, knee extensors, knee flexors
======Indicator for prostatic ambulation potential
-Include Trunk Strength
-Don’t forget about coordination & motor control
65
Prosthetics PP slide
30
66
what si the clinical presentation of PFFD
- Shortened thigh held in flexion and abduction and external rotation
- Hip and knee flexion contractures
- Severe leg length discrepancy with the foot often at the level of potilital crease
- Knee instability due to absence or deficient crucitate ligaments
67
what are some kinds of control systms of the UE
passive
body powereed
externally powered
hybrid
68
what is dynamic response foot prosthetic
Patients feel dynamic response at push-off, shock absorption, costly
69
what is flexible keel foot prosthetic
: Allows smooth rollover, but limited push-off
70
what is a post surgical phase complications
infection
- - this should be monitor throughout phases
- - look for warmth, redness, pain, swelling
71
what are some cognition issues after surgery
Initial Reactions
Future Unknown, body image sexual function, support system responses, employment, Long-Term Adjustments
72
what are the different types of TF sockets
- quadrilateral socket
- ischial weight bbearing
- sub ischial socke t
73
what are some interventions for phantom pain
* Distraction
* Exercise and Diet
* Biofeedback
* Relaxation training and hypnosis
* Massage: Acupressure, Acupuncture, Topical Agents
* Visual feedback: Mirrors, Virtual Reality
* Neuro-stimulation (TENS)
* Surgery
* Injection
* Medication
74
what is the elevatd vacuum suspension
The use of a pump to reduce the atmospheric pressure within the socket there by maintaining the prosthesis on the residual limb during use.
75
what is Manual Locking knee:
flexion is locked for maximum knee stability
76
what are some training goals for infants
- Comfort with the prosthesis
- Wearing tolerance
- Ability to stand by leaning against a table
- Ability to cruise around furniture
- Ability to walk with and without support from toy grocery cart or other supporting toy
77
what is some surgical management for children
- amputations
- --skin healing
- --termial overgrowth
- --phantom limb sensation
- limb lengthening
- limb sparing
78
what race has the most amputationts
African Americans
79
what is the main cause of limb loss (from the 1st slide)
vascular diseases (54%)
trauma (45%)
cancer (less than 2%)
80
what are some comorbities that need to be addressed pre op of a amputations
Cardiovascular
Pulmonary
Metabolic
Nutrition
81
what is ewings sarcoma
this is about 40% of disease amputation
| -weight bearing bones of LE and pelvis
82
what is K4
The patient has the ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress or energy levels. This is typical of the prosthetic demands of the child, active adult or athlete.
83
what are some other complications that can happen post surgical phase
- blood loss requiring transfusion
- deep vein thrombosis
- pulmonary embolism
- systemic complication (pneumonia, renal failure, stroke, sepsis)
- complications at the surgical site include hemorrhage or hematoma, wound infection, and failure to heal requiring additional operative interventions
84
Prosthetics PP
slide 22
85
what are some training goals for toddlers
= Full–time wear of prosthesis, except
= Use of the prosthesis in age-appropriate ambulation activities
Parents
86
how do you have a high success rate for UE rehab
if fitted asap after surgery
87
what are the knee components
- single axis
- polycentric
- fluid controlled
- microprocessor knee
- powered knee
- powered knee
- stance control
- manual locking knee
88
what is surgical phases and the skin flaps
most common: equal length of both and anterior and posterior flaps
- long posterior flap for increased blood supply
- skew flap (angular)
89
what is important for a kid to get an UE prothetic
to resotre symmetry
90
what are some signs and symptoms of the PVD and limb loss
- rest leg pain
- gatigue with mobility
- col ot touch
- ulcer that isnt healing
- lack of toenail growth
- little to no leg hair
- pale/blue tint to toes and feet
91
what is a post surgical phase PT examination
History
Systems Review: Vitals
Cognition: Emotional Status, Alert and Orientation
Integumentary: Skin, Vascularity
Sensory: Pain
Motor: Strength, Range of Motion, Limb Length
Balance: Sitting & Standing, Static and Dynamic
Function: Transfers, Mobility
92
UE amputation look at slide
20
93
what is the body powered motion of the humeral flexion
allows the terminal device to open. Scapular abduction and humeral flexion are the basic motions for the individual with transradial amputation.
94
what is a prosthesis
this is a tool
95
what is the standard approach to getting a new limb
3-6 months after complete wound feeling
96
what is the optimum time for fitting for UE in a kid
6 months (but you have to start 3 months)
97
what are some PT interventions after limb loss
```
Pain control
Edema control
Prevent contracture: Positioning, Range of motion
Strengthening
Cardiovascular
Balance/Mobility
Home exercise program
Functional Activities and ADLs
```
98
what is the semirigid dressing
Unna Boot: gauze impregnated with zinc oxide
99
what are the 2 limb lengths that can happen after limb loss
TT: Medial Tibial Plateau
TF: Ischial Tuberosity/Greater Trochanter
100
what are the driving factor for a prosthetic
Rating system used by Medicare to indicate a persons rehab potential & indicates a person’s potential to use a prosthetic device
-this allows set up for payment for that prosthetic device
101
what ismyotraining of the UE
proportional contorl
--myosite testing and training may begin 2-3 wk post injury
sequential vs simultaneous
102
what are the risks factors of the PVD and limb loss
- age
- diabetes
- smoking
- high blood pressure
- high cholesterol
- race
- dialysis
- family hisotry
103
what is the surgical phase acute goals
- removal of part of the limb
- allow for primary and secondary wound healing
- construct a residual limb for optimal prosthetic fitting
- ---skin flaps
- ----scarring
104
what is the success rate if someone is fitted within a month of surgery
93% of success rate
105
how do they do leg reconstruction
allograft or endo prosthetic implant
106
what are some shanks of TT
- endoskeleton
| - exoskeleton
107
what is K1
The patient has the ability or potential to use a prosthesis for transfers or ambulation on level surfaces at fixed cadence. This is typical of a household ambulator or a person who only walks about in their own home.
108
what are the medical management of cancer
- radiation
| - chemotherapy
109
what is Stance-control:
for knee stability, delayed swing phase, fixed cadence
110
what are some limitations to the wound healing post surgical phase
```
Smoking,
severity of preexisting vascular problems,
diabetes,
renal disease,
physiological problems,
cardiac disease
```
111
what is Single axis (constant friction):
simple, inexpensive, fixed cadence and low stability
112
what are the socks
Fabric socks come in various thickness or Ply’s
(1,2,3-5 ply)
Allows for adjustments to be made with changes in edema
>=15ply sock need to see the prosthetist for adjustments
113
what is the surgical phase muscle stabilization
- myoplasty
- myofascial
- myodensis
- tendoesis
114
what are the primary goal for socket of TT
Provide fit for residual limb
interface between the residual limb and the rest of the prosthesis
fits securely on the residual limb, providing a comfortable surface for weight bearing and stability for the transmission of forces between the body and the environment.
115
are limb loss in PVD patients preventable
yes about 60% of them are preventable
116
what is myodensis
muscle to bone
117
what are the types of limb shapes
Cylindrical, conical, bulbous end
“Dog Ears”
“Adductor Roll”
118
what is single axis foot prosthetic
Simple and low cost, knee stability for low level AK, keel is not flexible
119
what is the proximal femoralfocal deficiency
- Absence of part of the proximal femur
- Underdevelopment of some or all of the acetabulum, femoral head, patella, tibia and fibula
- Aitken Classification A-D
- 1:50,000 births
- 15 % are bilateral
- instability of the knee joint
- totla longitudinal deficiency of the fibula
120
what are the different socket types fo TT
- patellar tendon bearing
| - total surface bearing
121
what is pre prosthetic and prosthetic training of the UE amputations
within a month after amputations which is the golden window
122
what is microprocessor foot prosthetic
very high tech
123
what is the hard socket
rarely provided anymore.
124
what are some congenitial limb issues
Critical period of limb development
20% genetic
10% environmental
60-70% unknown
125
what is the success rate if someone is fitted after a month of surgery
42% of success rate
126
what are the types of dressings for the post surgical phase
- rigid
- semirigid
- soft
127
what are some post surgical phase RED flags
* Increased pain
* Excessive swelling
* Decreased muscle strength or sensation along a motor and/or sensory nerve distribution
* Sudden shortness of breath
* Decreased oxygen saturation increased resting heart rate
* Change in mental status
128
what needs to be done for liners the RL
Clean daily
129
what happens with the shorter level arm
the harder it is to control flexion concentrates
130
what are the most common amputations
```
Amputations of the Toes
Metatarsal Head Resection
Ray Resection
Transmetatarsal Amputation
Midfoot Amputation – Lisfranc and Chopart
-ankle disarticulation
transtibial amputation
transfemoral amputation
```
131
what are some positioning goal after limb loss surgery
Extension
TT: full ROM of hips and knee
TF: full ROM of hip extension and adduction
132
how to asses pre and post amputations fx status
-amputee mobility predictor amp
- -tools specific to amputation and prosthetics
- 21 item outcome measure to assess activity level
- designed to measure fxal capabilities w/o a prostheiss and to predict ability to ambulate with prosthesis
133
what is phantom sensation
– Sense or feeling of the presence of the limb
134
what are the process of TT prosthesis
- tib and fib transected
- retention of anatomical knee
- indicated in vascular diseases
1foot/ankle assembly
2 shank
3 socket
4 suspensino system
135
what are the longitudinal deficiency
Reduction or absence
May have normal distal elements
Named in a proximal-distal sequence
(this is basically missing a bone)
136
Prosthetics PP slide
32-36
137
what is strap suspension
may be a cuff strap or a waist belt
138
what is aitken classification C
Severe dysplasia, absent femoral head
139
Preventing contractures picutres
slide 36
140
what is the skeletal deficiency
Anatomic and radiologic basis
141
what is the acute care goals for UE amputations
promote healing of the wound, mobility and education
142
what is the pin or lanyard suspension
use of a gel liner that includes a physical connection to the prosthesis. May include tab suspension systems.
143
what are some expectations for a child and amputations
- variation in rate of neromuscular deve.
- lower energy output
- accommodate growth
144
Is a child with an amputation different than an adult?
Yes due to the fact that they are still growing
145
what is the advantages of the rotationplasty
```
Increased limb length
Improved prosthetic function
Improved weight bearing capacity
Elimination of terminal overgrowth and pain
Run, jump and play
```
146
how to treat aitkens A
lengthening only
147
what shoudl an evaluation of the UE amputation
```
limb volume measurements,
wound description,
scar evaluation,
sensitivity,
pain (surgical/limb pain vs phantom pain), FIM
psychological support
gross motor: posture
desensitization
compression garments
```
148
what are some limb sparing procedures
- an option for children with bony malignancies
- resection of tumor
- leg reconstruction
- contraindication
149
what is the expected outcomes of a cld and bike riding
25 children with unilateral and 5 with bilateral TTA rode tricycles and bicycles
13/14 children with TFA rode while wearing limb
150
what are some common skin problems
abrasion
| blistering
151
what are the causes of limb loss
1 peripheral vascular disease (PVD)
| 2 trauma
152
what is bell clapping mean
distal end shrinkage
153
what are some accommodate growth for a child with amputations
New prosthesis
Socket liners
Compliment developmental alignment
154
what are some system complications of integumentary
Wound care, edema, early post-op complications
| Skin: Skin adherence to bone, skin grafts, burns,
155
how do you select the amputation level
based on many factors
- vascularization
- neuropaty
- infection
- malignancy
- function and rehabilitation potential
156
what is surgical phases pre-op
- selection of appropriate amputation level
- optimize medical comorbidities
- develop treatment plans
- patient and caregiver education
157
what are 8 steps of applying RRD
1) apply the wound dressing as needed,
2) wear proper layers of socks of various lengths,
3) apply the plaster cast; use a plastic sheath to reduce friction,
4) pull the suspension stockinette upward covering the plaster cast,
5) place the supracondylar cuff and fasten the Velcro closure,
6) pull the suspension stockinette tight,
7) fold suspension stockinette downward and anchor on the suspension cuff
8) knee flexion is possible and encouraged.
158
what are some interventions for edema control
Postoperative Dressings
• Soft dressing
– Ace wrap
– Shrinker (After removal of sutures)
– Compression pump
• Rigid dressing
– a. Non-weight bearing rigid dressing (NWB)
– b. Immediate postoperative prosthesis (IPOP)
– c. Custom rigid removable dressing (RRD)
– d. Prefabricated rigid removable dressing (RRD)
– e. Prefabricated pneumatic immediate postoperative prosthesis (AirPOP)
159
what are the socks for the RL
Clean daily
| • No wrinkles
160
what is donning
putting ON the prosthetic
```
- this will depend on the type of socket
• Cuff
• Sleeve suspension
• Liner
– pelite foam
– gel: cushion, pin, lanyard, seal-in
• Socks (Altered by limb volume)
• Pull-in
```
161
what are some muscles for testing the shoudler disarticulation
```
pec major or minor
trap
teres minor
lats
supraspinatus
infraspinatus
```
162
what are some everyday care fo the prothetic
limb and skin care
prosthesis
socks
liners
163
what are the most common UE amputations
Transhumeral
| Transradial
164
what needs to be done mandatory everyday
- skin checks
- build up wear time and document
- blanchable redness OK
- education patients on how to check skin
165
how do you fix distal edema
needs to see cpo asap
166
what are some goals of preschool and shcool age kids for prosthesis
- Independence in self-care skills, mobility including running
- -----Use of feet or mouth is acceptable
- Acquire school skills such as coloring, cutting and writing
- Surgeries in PFFD
- ------Limb length on prosthetic side is 5 cm shorter than other femur
167
what is the rigid dressing
Immediate postop prosthesis (IPOP) “total contact cast”
| Removable Rigid Dressing (RRD): adjustable, AirLimb
168
what are some contraindications fo children and limb sparing
Extensive invasion of surrounding soft tissue, neurovascular supply or intramedullary cavity
169
what is a the limb loss time line
- surgical phase
- post surgical phase
- prosthetic phase
170
How many people live with limb loss
2 million
171
what should be some patient education for UE amputation
- RL tolerance/ care
- frequent inspection of limb
- wearing schedule
- daily washing of limb
172
what is the prosthetic liner (gel)
A skin prosthesis interface typically made of silicon or mineral oil gel to provide cushion to the residual limb. This is often a component of the suspension system.
173
what are the early goals for wearing prosthesis
- comfortably
- begin to use for bimanual play
- pushing up to sitting or quadruped, protective reactions and propping in sitting
- shake or remove toys placed in terminal device by an adult
174
what is Polycentric:
raises the knee center for knee stability, better cosmetic for longer limbs
175
what are some system complications of psychological
Adaptation, PTSD
176
what do new amputees go through
the 5 classic stages of grief
177
what is cushion liner with air expulsion valve
there was nothing
178
what is the primary goals for shank of a prosthesis of TT
Substitute for the human leg
| Above the foot ankle/ Below the socket
179
how common are the diseasee- related amputations
they are rare
180
what is soft dressing
Elastic Wraps – indicated with infections
Elastic Shrinkers – socklike garments, only used after incisions are healed
181
what is multi axial foot prosthetic
Accommodates uneven terrain and reduces stress on skin
182
what is myoplasty
muscle to muscle
183
what is a K level
Rating system used by Medicare to indicate a persons rehab potential & indicates a person’s potential to use a prosthetic device
184
what are some primary goals for TT prosthesis
restore the general contour of the foot
- adsorb shock at heel strike
- restore as much as foot function
185
is rehabilitation for the UE or LE harder for rehabilitation
UE
186
Prosthetics PP slide
28
187
what will happen in 2-3 years for someone with diabetes of the 1st amputations
55% will reuire amputation of the second leg
188
what are some body powered motions for UE amputations
- scapular abduction
- humeral flexion
- shoulder depression , extension , abduction
189
what are the factors that influence prescription
– Residual limb level, shape and condition
– Boby Function (MMT, ROM, Sensaation)
– Presences of Co-morbidities
– Activity/Mobility level and activity potential (pre and post)
– Environment factors
– Personal factors
190
what is post surgical phase
Monitor Complications
Select and Apply dressings
Examination
Initiate Treatment
191
what is aitken classification A
Bony connection between components of femur
192
what is dynamic of prosthetic alignement
changes are made to the alignment based on the individual's gait pattern.
193
what are some of the ISO classification
- skeletal definciencies
- transverse
- longitudinal
194
what is K0
The patient does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance their quality of life or mobility. This level does not warrant a prescription for a prosthesis.
195
what are some age appropraite ambulation activites for toddlers
- encourage use of prosthesis
- provide toys and equipment
- inspect the skin for undue irritation
196
what needs to be done for limb and skin care of a RL
Watch for skin irritation
197
what are some system complications of cardiovascular
arrhythmia, congestive heart failure (CHF),myocardial infarction (MI).
198
what is the prosthetic liner (foam)
A prosthesis interface used for cushion of the residual limb. Commonly used with anatomical suspension.
199
what are the transverse deficiency
Limb develops normally
| Named for where the limb terminates
200
where are abrasion most common
* Fibular head
* Tibial tubercle
* Tibial condyles
* Anterior distal tibia
* Hamstring tendons
201
what is the endoskeleton of the shank
```
Central aluminum or rigid plastic pylon
Adjusts to angulation
Absorbs vertical shock
Reduces stress on joints
Most commonly prescribed
```
