Transfemoral Prosthetics Flashcards
True or False:
We want to hold the femur in adduction (varus)
True
True or False:
It is easier to hold the femur in adduction (varus) with a longer femur (residual limb)
True
What is successful prosthetic management of transfemoral and knee disarticulation (4)
- Comfortable in containing the residual limb
- Stable during the stance phase of gait
- Smooth in transition to the swing phase of gait
- Acceptable in appearance
True or False:
We mostly make endoskeleton prosthesis due to ease of adjustment
True
What must the prosthetic team consider when selecting components of the transfermoral or knee disarticulation prosthesis (5)
- Weight
- Function
- Cosmesis
- Comfort
- Cost
True or False:
The most functional or technologically sophisticated components are also the heaviest, most expensive, most likely to need maintenance, and least cosmetic
True
True or False:
Longer residual limb makes recovery and potential better than a short residual limb
True
What happens to energy cost of gait as length of the residual limb decreases
Increases
True or False:
Individuals with a transtibial amputation walk 36% more slowly expending 2% more kilocal’s per min and 41% more kilocal’s per meter vs normal
True
True or False:
Individuals with a transfemoral amputation amputation walk 43% slower, energy cost is reflected as 5% more kilocals per min and 89% more kilocal’s per meter vs normal
True
True or False:
Increase in energy cost is manifested as an increased rate of oxygen consumption, elevated HR, and notable decrease in comfortable walking speed
True
What is a quadrilateral transfemoral socket design
4 distinct walls fashioned to contain thigh musculature with a flat posterior shelf for ischial weight bearing
What does the anterior wall of the quadrilateral socket design do
Creates a posterior counterforce at Scarpa’s triangle stabilizing the ischium on posterior shelf
What is an ischial containment transfemoral socket design
Stabilizes socket on the residual limb and controls socket rotation by containing the ischial tuberosity and ramus it also maintains femoral adduction and distributes pressure through socket along the shaft of the femur
Where is the quadrilateral socket narrow
A-P
Where is the ischial containment socket narrow
M-L
What is the goal of transfemoral socket design (3)
- Achieve comfort in weight bearing
- A narrow base of support in standing and walking,
- As close to normal swing phase as possible
What are the 2 socket options
- Hard socket
2. Flexible socket
How is the hard socket made
Thermoplastic or thermosetting resin
How does the hard socket fit
Intimate total contact fit worn with prosthetic sock as interface
What is the advantage to a hard socket (3)
- Very durable
- Easy to clean
- Less expensive
What is the disadvantage to a hard socket
More difficult to adjust fit on bony or sensitive residual limbs
How is the flexible socket made
Vacuum formed with flexible thermoplastic materials encased in a rigid frame
What is the advantage of the flexible socket (3)
- Accommodates to change in muscle shape
- Provides relief for bony prominences
- Comfort in sitting
What is the disadvantage to a flexible socket (3)
- Less durable
- Bulkier
- More expensive to make
How do you weight bear in an exoskeletal system
Through laminated shell
How do you weight bear in an endoskeletal system
Through an internal pylon with a soft foam cover
What is the advantage to an exoskeletal system (2)
- Very durable
2. Requires little maintenance
What is the disadvantage to an exoskeletal system
Cannot be easily aligned or adjusted
What is the advantage to an endoskeletal system (2)
- Quickly adjust alignment
2. Can replace modular components
What is the disadvantage to an endoskeletal system
Durability of foam cover
What does an extenion aid internal spring or elastic strap do
Initiate knee extension in early swing and control heel rise
What do torque absorbers do
Decrease shear on limb
What do transverse rotational units do
Allow you to cross legs
What is a traditional pull in suction suspension system
You lubricate the skin and milk your limb down into the prosthesis using negative pressure by pulling an ace bandage through a small hole and push a button to suck remainder of air out
What is the advantage of the traditional pull in suction suspension system (2)
- Enhance prosthetic control
2. Intimate fit
What is the disadvantage to the traditional pull in suction suspension system (2)
- Recent amputation (within last year)
2. Need to control volume and weight
What is a roll on suction liner suspension system
Liner is turned inside out and rolled over skin can have a locking pin but not all have them
What is the advantage to roll on suction liners (2)
- Decrease shear on skin
2. Don while seated
What is the disadvantage to roll on suction liners (3)
- Expense
- Durability
- Hygiene
What is a Silesian belt suspension system
Leather belt system that attaches to lateral socket encircles the pelvis runs to buckle on anterior surface
What patient is the Silesian belt system indicated for
Long residual limbs who are not vigorous ambulators
What is the disadvantage to the Silesian belt system
If sole means of suspension it has an inability to control rotation
True or False:
You need to load the prosthesis before tightening the waist belt or else it could cause rotation of prosthesis
True
What is the total elastic suspension belt system
Distal sleeve fits snugly around proximal half of transfemoral socket with a belt that encircles the waist
What is the advantage of the total elastic suspension belt (3)
- Easy to don
- Comfortable
- Excellent auxillary suspension
What is the disadvantage of the total elastic suspension belt (3)
- Controlling rotation
- Durability
- Heat
What is the pelvic belt and hip joint suspension system
Leather belt that is attached to transfemoral socket with metal hip joint now we have light weight plastic with the joint center positioned anterior/superior to apex of trochanter
What is the advantage of the pelvic belt and hip joint system (3)
- Controls rotation
- Provides M-L stability
- Very short residual limb
What is the disadvantage of the pelvic belt and hip joint system (3)
- Bulky
- Weight
- Uncomfortable when sitting
What is the goal of all prosthetic feet
Achieve foot flat quickly
True or False:
Normal ambulation has a dynamic symmetric relationship between head, spine, and upper and lower extremities
True
True or False:
With a transfemoral prosthesis ambulation becomes asymmetric which leads to uneven cadence increased energy cost of walking and postural adaptions and balance reactions
True
True or False:
Patients with impairment of musculoskeletal neuromusculr systems are common with diabetics and advanced age leading to increased instability/falls
True
What are the 3 ways the normal gait muscles of hip knee and ankle work
- Muscle contraction provides stability during stance by resisting the effects of gravity
- Provide propulsion and accelerate limb during push off and early swing phase
- Decelerate forward progression especially in late swing in preparation for initial contact
What are the 3 variables influencing knee stability during stance
- How well individual is able to voluntarily control knee using muscular power
- Alignment of the knee unit with respect to the weight line (TKA)
- Inherent mechanical stability of the knee unit
What does TKA stand for
Trochanter, knee, ankle
What does the weight line (TKA) being posterior to the knee do
Causes flexion at the knee
What does the weight line (TKA) being anterior to the knee do
Causes hyperextension at the knee
Do we see the weight line (TKA) falling anterior to the knee
Not really because it makes gait difficult
When would you want the weight line (TKA) to fall pposterior to the knee
When the patient is lacking knee flexion
