Transfemoral Amputation & Prosthetic Components Flashcards
Transfemoral Amputation surgery causes loss of what motions?
Active
- Knee
- Foot
- Ankle
T/F: After TFA it is okay to put weight on the end of the residual limb
False- Very little if any weight can be places on the end
After TFA the thigh muscles are out of balance what two muscle groups overpower the others?
Flexors & Abductors overpower the extensors & adductors
Anatomically, why is there a weakness and limited ability to adduct & extend the hip?
- Primary hip abductor & flexor muscles are attached on greater & lesser trochanter on proximal femur
- Since they are attached above surgical division they are fine
- Adductor & extensor muscles are attached at lower end and will be divided by TFA
Where does the surgeon reattach the adductor and extensor muscles? What does the prevent?
- Femur or Periosteum
- Counterbalances the flexion & abduction forces to prevent the femur from drifting outwards
If the femur abducts, weight cannot be loaded as easily onto the side. What may this cause?
Bone may press painfully against the socket
By surgically balancing the muscles the leg can be positioned in slight (adduction or abduction) in the socket so most of the WB force is where?
- Adduction
- Most WB force is on the sides of the leg & not the distal end
What does the myodesis do during TFA?
- Makes residual limb stronger & more balanced
- Keeps femur centered
- May help reduce adductor roll
What is the adductor roll?
Collection of tissue that sometimes forms high on the inner thigh above the socket line
How does a myodesis help reduce adductor roll?
Secures the adductor muscles & the soft tissue over these muscles which appears to restrict the development of a large adductor roll
What is the minimal length of a TFA?
7.5 cm
What is the optimal length of TFA?
23-30 cm
What are the pressure sensitive areas following TFA?
- Pubic ramus
- Pubic tubercle
- Adductor tendon
- Distal end of femur
- Greater trochanter
- ASAI
A single axis hinge prosthetic knee is used for what K levels?
K1/2
A polycentric prosthetic knee is used for what K levels?
K1/2
A pneumatic & Hydraulic prosthetic knee is used for what K level?
K3
A microprocessor prosthetic knee is used for what K level?
K4
What type of knee friction is used for K levels 1/2?
Constant Friction
What type of knee friction system is used for K3?
Variable friction
Which is heavier: Single axis or polycentric prosthetic knee?
Polycentric
Between single axis and polycentric prosthetic knee, which is more difficult to reciprocate during gait?
- Single knee axis
- Polycentric knee makes reciprocal gait more fluid
How many pivoting bars does the polycentric prosthetic knee have?
4 or more
Between the polycentric and single axis, which prosthetic knee provides greater stability?
Polycentric
T/F: Both the single axis & polycentric may or may not have knee extension assist and/or a weight activated stance phase control
True
In a variable friction mechanism during initial swing there is (high or low) friction to prevent excessive knee (flexion or extension)
- High
- Flexion
In a variable friction mechanism during midswing friction (increases or decreases) to allow the knee to swing easily
- Decreases
In a variable friction mechanism during terminal swing friction (increases or decreases) for initial contact
increases
How does a manual locking knee provide stability?
Through physical lock on the knee joint
In regards to a manual locking knee what position does the knee remain in when lock is engaged?
- Extended & stable
Typically, what patients receive manual locking knees?
Those who need assurance the limb won’t collapse during stance
How is the friction brake activated in a weight activated knee? And how is it unlocked?
- Body weight
- Unlocked as weight is relieved and swings freely during swin
Typically, what patients receive weight activated knees?
- Elderly
- Low level ambulatory who may use AD
- those who need extra degree of security while wearing prosthesis
T/F: In a weight activated knee the knee needs to be completely unloaded before it can flex
True
What are the advantages of hydraulic prosthetic knee?
- Variable friction for improved swing & stance phase control
- Provides more friction for smoother gait
What are the disadvantages of hydraulic prosthetic knee?
- Heavier
- More expensive
- More maintenance
What are the advantages of a microprocessor knee?
- Decrease falls
- More active
- Enhanced confidence
What are the disadvantages of a microprocessor knee?
- Heavier
- Expensive
- Battery
What items should be considered when choosing an appropriate knee?
- User activity level (K level)
- Ability or potential to reach higher level
- Constant vs Variable friction
- Vocational/recreational
- Maintenance/distance to prosthetist
What criteria should the socket meet?
- Fit should be comfy
- Suspension should be effective
- It should allow the amputee to move and/or ambulate
What is the socket?
Interface between residual limb & prosthetic device
What are the 2 types of transfemoral socket designs?
- Quadrilateral
- Ischial Containment Socket
Which socket type is narrow A-P?
Quadrilateral Socket
What type of residual limbs are quadrilateral sockets most successful on?
- Long, firm residual limbs with firm adductor musculature
- Can be used for mostly all types of residual limbs
Where does WB take place at with a quadrilateral socket?
Ischial tuberosity by the posterior shelf of the socket
How is the suspension provided with a quadrilateral socket?
Suction generated by adequate fit of socket over the residual limb
Which socket has narrow medial - lateral walls?
Ischial containment socket
Which is more successful quadrilateral or ischial containment socket?
Ischial containment socket
With an ischial containment socket where does WB take place?
All over the surface of the residual limb w/o localizing in one point
What are the advantages of hard socket?
- Very durable
- Easy to clean
- Less expensive to produce
What are the disadvantage of hard socket?
More difficult to adjust fit on bony or sensitive residual limbs
What are the advantages of flexible socket?
- Accommodates to change in muscle shape
- Provide relief for bony prominences
- More expensive to fabricate
What are the disadvantage of flexible socket?
- Less durable
- Bulkier
- More expensive to fabricate
What are the 5 common types of suspension systems?
- Suction (traditional pull in suction, negative air pressure)
- Roll on cushion liner
- Silesian BELT suspension
- Total Elastic Suspension Belt
- Pelvic Belt & Hip joint
What are the advantages of traditional pull-in suction suspension negative air pressure?
- Enhanced prosthetic control
- Intimate fit
- Eliminates/minimizes pistoning
- Improved proprioception
What are the disadvantages of traditional pull-in suction suspension negative air pressure?
- Recent amputation
- need to control volume/ weight requires consistent limb volume
- may be difficult to don
Is a traditional pull in suction suspension use a liner?
No, use w/o liner
What are the indication of traditional pull in suction suspension system?
- Long residual limbs
- Good skin conditions
- Good patient balance
- Good upper extremity strength
What are the contraindications of traditional pull-in suction suspension system?
- Very short residual limbs
- UE weakness
- frequent volume fluctuations
What are the advantages of roll on cushion liner?
- Shear on skin
- Don while seated
- Softer distal support
- Smoother donning & doffing
What are the disadvantages of roll on cushion liner?
- Expense
- Durability
- Hygiene (increased sweating or risk of infection)
- Possible distal end pulling
What are the indications of roll on cushion liner?
- Short to long limbs
- minor volume changes
What are the contraindications of roll on cushion liner?
- Irregular residual limb shape
- Hygiene concerns
- large volume changes
What are the Silesian Belt Suspension advantages?
- easy to don
- Adjustable
- long residual limbs who are not vigorous ambulators
What are the silesian belt suspension disadvantages?
- Added bulk around waist
- less anatomic
- uncomfortable
What are the indications of Silesian Belt suspension system?
when other systems are not optimal
What are the advantages of total elastic suspension belt?
- Easy to don
- Comfortable
- excellent suspension
What are the disadvantage of total elastic suspension belt?
- Controlling rotation
- Durability
- Heat
What are the advantages of pelvic belt & hip joint?
- Control rotation/ m-l stability
- very short residual limbs
What are the disadvantages of pelvic belt & hip joint?
- Bulky, weight
- Uncomfortable when sitting
What is osseointegration?
- Scientific term for bone ingrowth into a metal implant
- Surgical implant a rod with an external connector that can interface with prosthesis
What are the advantages of osseous integration?
- Increased use of prosthesis
- more stability in walking & standing
- Ability to walk longer distances
- Avoiding the skin problems associated with socket prosthetics
- Easy to remove & replace prosthesis
What are the disadvantages of osseous integration?
- Surgical procedure with potentially long recovery time
- Need to regularly maintain & clean the interface b/w the skin & implant
- Risk of superficial skin infections or deep tissue infections
- Potential to bend or break
