Week 3-TransFemoral Flashcards
What are the different amputation levels for transfemorals?
Long
Medium
Short
Very Short = Subtrochanteric
What are the different muscle compartments?
posterior
middle
anterior
What is part of the posterior muscle compartment?
Extensors of the Hip & Flexors of the Knee
What is part of the middle muscle compartment?
Adductors
Femoral Triangle
What is part of the anterior muscle compartment?
Flexors of Hip, Flexors of Knee & Extensor of Knee
What is part of the gluteal region?
Gluteus Maximus Gluteus Medius Gluteus Minimus Tensor Fasciae Latae 6 Deep Lateral Rotators
What are the 6 deep lateral rotators?
piriformis,
obtorator internus/externus,
gemellus superior/inferior,
quadratus femoris
What are the socket design goals?
Contouring for functioning muscles
Stabilize skeletal structures
Broad pressure over neuro-vascular bundles
Forces distributed over wide area
What are three important aspects in the design of the quadrilateral socket?
Four well defined walls
Rectangular in shape
Ischial-gluteal weight bearing
What reliefs are required for the quadrilateral socket?
Hamstring tendon
Gluteus maximus
Adductor longus
Rectus femoris
What are three aspects important for the ischial containment socket?
Femur held in adduction
Very intimate fit
Triangular shape
What are the advantages of the quadrilateral socket?
Well documented
Consistent procedure for fabrication
What are the disadvantages of the quadrilateral socket?
Not custom shape
Femur not held in adduction
Lack of support in medial wall
What are the advantages of the ischial containment socket?
Enhanced biomechanical stability
Increased medial wall support
Strong gluteal and hydrostatic loading
Restoration of pelvic-femoral angle
What are the disadvantages of the ischial containment socket?
Too many inconsistent designs
Requires skill to fabricate
What are the advantages of the ischial containment socket over the quadrilateral socket/
Bony lock
Counter force-In Quad socket there is distal pressure while in ischial containment it is distributed
What are the different types of suspension systems for transfemorals?
Suction Silicone Sleeve Silesian Belt Hip joint & pelvic band Suspenders
How does suction suspension work?
Socket and interface are smaller than limb
Patient is pulled into the socket
Valve is screwed in, doesn’t let air in, only out
Positive-negative pressure pump
What are the indications for suction sockets?
Long limbs Stable volume Good skin integrity Good upper limb strength Majority of patients
What are the contraindications for suction sockets?
Patients with volume fluctuation
Short residual limbs
Severe scarring
Upper extremity involvement
What are the indications for silicone suction?
Longer residual limbs
Stable limb volume )can add socks)
No upper limb involvement
What are the contraindications for silicone suction?
Unstable limb volume
Upper limb involvement
Skin sensitivity to material
What are the advantages of silicone suction?
Provides positive suction suspension-can add socks
Does not limit range of motion
Reduces shear forces
What are the disadvantages of silicone suction?
Difficult to don-seal can pinch and create air channel
Skin reaction to material
Rotation Control-due to cylindrical shape
What can a Silesian belt be made of?
Webbing, cotton or TES
What components make up a Silesian belt?
Belt, elastic strap, neoprene belt with leg section
Where does the Silesian belt attach?
Attached lateral and fastened anteriorly
What’s the difference between the true silesian and the modified silesian belt?
True has a double anterior attachment while the modified only has one
What are the indications for the silesian belt?
Auxiliary suspension is required Rotational control needed When suction cant be used May aid in coronal control Patient security
What are the contraindications for the silesian belt?
When there is no need for frontal plane control (long limbs with good strength primarily)
What are the advantages of the silesian belt?
Easy to don
May add coronal stability
Adjustable
What are the disadvantages of the silesian belt?
Increased straps and buckles
Increased bulk around waist
What are the five aspects of the HIP JOINT & PELVIC BAND?
Single axis joint at hip Laminated into the socket Pelvic band is located between the iliac crest and trochanter Leather belt with buckle Usually worn with socks
What are the indications for the HIP JOINT & PELVIC BAND?
Maximum ML control Weak hip Abductors or short residuum Ease of donning is important, Previous wearers Easy Hip Dislocation
What are the contraindications for the HIP JOINT & PELVIC BAND?
When not needed/indicated
What are the advantages for the HIP JOINT & PELVIC BAND?
Easy to don, Good swing phase control, Increased ML stability
What are the disadvantages for the HIP JOINT & PELVIC BAND?
Extremely bulky, Inherent pistoning, Increased weight
What two aspects make up the suspender suspension?
Suspension over the shoulders
May operate knee unit
What are the indications for suspender suspension?
Last resort
Previous wearer
Need to reduce forces around pelvis
Patient with abdominal scarring
What are the contraindications for suspender suspension?
Whenever anything else will do
Really bulky
What are the different categories for knee systems?
Outside Hinge Constant Friction Weight Activated Polycentric Manual Locking Microprocessor Controlled
What are the two most important factors of knee systems?
Voluntary control
Inherent stability
What is the order for inherent stability from least to most with the knee systems?
Outside hinges Single Axis – Constant Friction Weight Activated Stance Control Polycentric Manual Locking
What is the order for voluntary control from least to most?
Manual Locking Polycentric Weight Activated Stance Control Single Axis – Constant Friction Outside hinges
What is voluntary control?
Stability a patient can willfully control
Limb length
Limb musculature
What is inherent stability?
Prosthetic Knee Type
Alignment»_space; TKA Line (trochanter-knee-ankle line)
What are the knee friction goals?
Primarily for swing phase
To control knee friction
Limit heel rise
Prevent terminal impact
What are the knee friction types?
Mechanical Friction
Fluid Friction
Outside Friction
What is mechanical friction
Simple in design Adjustable Constant friction Static resistance to force Offers no stance phase stability
What is fluid friction?
Complex in design Heavier, more maintenance Dynamic resistance to force Offers some stance phase stability Smooth gait Patients with varying cadence
What are outside hinges for knee joints?
Free swinging
Required back-check and extension assist
What are the advantages of outside hinges?
Avoid knee length discrepancy
Durable
What are the disadvantages of outside hinges?
No inherent stability-no ML stability
No inherent friction control
Poor cosmesis
What is the K-level for single axis-constant friction knee system?
K 2-4
What are the indications for single axis-constant friction knee system?
Single speed walkers
Pt. with good hip extensors
Heavy duty use
What are the contraindications for single axis-constant friction knee system?
Highly active patients
Weak patients
When px weight is important
Variable speed walkers
What are the advantages for single axis-constant friction knee system?
Durable, Inexpensive, Reliable
What are the disadvantages for single axis-constant friction knee system?
Low stability, difficult to adjust
What K-levels are required for the single axis-Hydraulic/Pneumatic Controlled knee?
K 3-4
What are the indications for the single axis-Hydraulic/Pneumatic Controlled knee?
Active walkers (120 steps/min)
Variable cadence walkers
Pts with good strength
Pt have voluntary control
What are the contraindications for the single axis-Hydraulic/Pneumatic Controlled knee?
Single speed walkers
Weak patients
What are the advantages for the single axis-Hydraulic/Pneumatic Controlled knee?
Possible manual stance locking feature
Highly adjustable
Smooth extension assist and gait
What are the disadvantages for the single axis-Hydraulic/Pneumatic Controlled knee?
High cost, weight and maintenance
What are the K-levels for the Weight Activated - Stance Control?
K 2-3
What are the indications for the Weight Activated - Stance Control?
Geriatrics
Low px weight is required
Increased knee stability
What are the contraindications for the Weight Activated - Stance Control?
Pts needing heavy duty option
Variable cadence walkers
What are the advantages for the Weight Activated - Stance Control?
Easily adjusted, durable, stance locking features
Low weight, cost, and maintenance
Stable because it has extension assist-adjustable tension
What are the disadvantages for the Weight Activated - Stance Control?
Only allows single speed cadence
Pt. must unload to break knee
What are the K-levels for the polycentric knee?
K 2-4
What are the indications for the polycentric knee?
Long TF amputations
Children
What are the contraindications for the polycentric knee?
Pt. needs variable cadence knee
What are the advantages for the polycentric knee?
Excellent stability, adjustable stability
Cosmesis for long limbs
Possible stance control feature
Possible inherent stance locking feature
Durable
What are the disadvantages for the polycentric knee?
Increased weight, cost, maintenance
May take pt. long time to master usage
What happens at each instant of flexion?
There is a different center of rotation
What K-levels are indicated for manual locking knees?
K 1-2
What are the indications for the manual locking knees?
Max knee stability
Knee of last resort
What are the contraindications for the manual locking knees?
Active patients
Community ambulators
What are the advantages for the manual locking knees?
Pt. knows the knee is locked
What are the disadvantages for the manual locking knees?
Difficulties sitting
Un-cosmetic gait
Increased energy expenditure
What are different types of microprocessors?
Rio, C-Leg, Power Knee, X3 knee
What are the indications for microprocessor knees?
Active patients, good cognitive ability
Has mastery with hydraulic or SNS knee
What are the contraindications for microprocessor knees?
Weak musculature
Limited cognitive ability
Unable to vary cadence over 300 yards
What are the advantages for microprocessor knees?
MPC controlled
Knee sense chance in cadence and adjusts
Hydraulic control or comparable
What are the disadvantages for microprocessor knees?
Battery powered, expensive, maintenance
Not for heavy duty use
What does SNS stand for?
Stance and Swing
Where should ML stability of the pelvis during mid-stance be placed?
On the prosthetic side
How can you conserve energy?
By minimizing excessive lateral
displacement
When should AP stability of the pelvis of the prosthetic knee joint occur?
During Initial contact and Terminal stance
For ML stability, what are the forces controlled by?
The hip Abductors
What 8 things influence ML stability?
- Ischial weight bearing
- Foot position
- ADduction of the lateral wall of the socket
- Proper contouring of the lateral wall
- High medial wall
- ML dimension
- AP dimension
- Belt/band/hip joint
What occurs because of Ischial weight bearing?
Displaces the fulcrum medial, reducing the magnitude of the moment. Less force is needed to move the leg.
What is the proper position of the foot for the quad socket?
0-65mm outset
What is the proper position of the foot for the ischial containment socket?
25-37mm outset
What does the proper alignment of the foot cause?
A Varus moment at the knee
What does adduction of the lateral wall of the socket do?
Re-establishes the normal
angulation of the femur (6-7o) and Puts the hip ABductors on stretch – better mechanical advantage for the limb
What does Proper contouring of the lateral wall do?
Allows for even distribution of forces over the lateral aspect
of the residual limb
What does a High medial wall do?
applies the counter pressure to maintain good contact between the femur and the lateral wall of the socket Counter pressure to lateral wall Distributive pressure system Restrict ML movement Take pressure on ischium Sub-ischial triangle
What does an improper ML dimension do?
Too large an ML will reduce the effectiveness of the lateral and medial walls to stabilize the femur
How do you measure the skeletal ML?
At the angle of the Ramus-ramus to trochanter
What does proper AP dimension do?
Keeps ischium on the seat
What does an too large AP dimension do?
IT is displaced anteriorly
Painful ramal contact
Gait deviations
• antalgic gait, lateral trunk bending, abducted gait
What is anther name for skeletal AP?
Antero-Lateral Measurement
When should a silesian belt or hip joint be use?
When hip ABductors are weak
When working with someone that has a short residual limb
High walls are not enough, they gap away and loose
stability
Maximum stability is achieved through a hip joint and pelvic
band
How can you conserve energy?
By minimizing excessive lateral
displacement
Narrow base of support
When should you compromise energy consumption?
For comfort
What are the Compensatory Motions for finding comfort?
Lateral Trunk Bending
ABducted Gait
How can you make sure that the GRF remain anterior to the knee through IC to TS?
Knee alignment Foot alignment and selection Component selection Voluntary control (hip extensor power output)
What happens with a too soft heel durometer?
Will reach foot flat too quickly
Moving the GRF force ahead too quickly
What happens with a too hard heel durometer?
May cause instability at the knee joint
May cause lateral rotation
When is a softer heel durometer desired?
High amputation patients because it allows them to reach foot flat.
Why is the keel needed?
Anterior support
What happens when the keel is too stiff?
a sideward gait
