Week 2- TransTibial Flashcards
What is considered a very short Transtibial?
Less than three inches
What is considered a short Transtibial?
3-5 inches
What is considered a normal transtibial?
3-7 inches
What is considered a long transtibial?
Greater than 7 inches
What is a symes amputation?
Removal of the tibia and fibula above the malleoli and covering it with the heel pad.
What is an ankle disarticulation?
Does not cut through the periosteum but may adjust the pointiness of the tibia and fibula and wrap the heel pad around it.
What does PTB stand for
Patellar Tendon Bearing
What does TSB stand for?
Total Surface bearing
What are the pressure intolerant areas of a PTB socket?
Patella
Fib head
Distal end of fib and tib
Medial side of Tibial plateau
What are the pressure tolerant areas of a PTB?
The Patellar tendon bar
The length of the fibula and tibia
What shape does the PTB create?
A triangular shape
What are the indication for a PTB?
Previous wearer Extreme Atrophy Selective Hot Spots • Neuromas • Callusing
Where are the pressures during initial contact?
Has greater Distal anterior pressure
Greater Proximal posterior pressure
What are the pressures during Loading Response?
less pressure distally
What are the pressures during Terminal Stance?
More pressure proximal anterior and distal posterior
What should be the main goal of the socket?
Distribute pressures from intolerant areas to tolerant areas
What are the different types of support or interface options for PTB sockets?
Lines
Hard
Soft
Air Cushioned
What is an example of a lined interface for a PTB socket?
Pelite liner or similar
What is an example of a hard interface for a PTB socket?
Hard Plastic
What is an example of a soft interface for a PTB socket?
Distal pad
What is an example of a air cushioned interface for a PTB socket?
Flexible liner
What are the different types of suspension options for a PTB?
Cuff
Side Joint and Thigh Lacer
Supracondylar
Supracondylar/suprapatellar
What are examples of a cuff suspension for a PTB socket?
Leather or Dacron
What is an example of a supracondylar suspension for a PTB socket?
Supracondylar lateral brim-Fixed or removable medial wedge
What is an example of a supracondylar/suprapatellar suspension for a PTB socket?
Supracondylar lateral brim-Suprapatellar anterior brim
What is assumed for a TSB socket?
Even distribution of pressures
Total contact fit
What are the indication for a TSB socket?
Majority of Patients
Mild to Moderate Atrophy
Patients with Skin Conditions or considerations
Unstable volume or Edema
What does a TSB often involve?
A gel liner
Which socket should be used when the patient has a very short fibular compared to Tibia?
PTB
Which socket should be used when the patient has a bulbous end?
TSB
What is the definition of a flexed socket?
The Proximal socket moves anterior in relation to the distal end
What is the definition of an abducted socket?
The distal end of the limb is in an abducted position. The lower leg of the prosthesis will compensate.
Where should the foot be in relation to the blumbob line?
12mm or 1/2 inch inset or directly under line.
What is the bench alignment for the foot bolt?
1 inch anterior to the midline of the lateral brim of the socket
What is the bench alignment of flexion?
5-10 degrees of flexion
What is the bench alignment for adduction?
2-5 degrees of adduction
What produces a flexion moment of the knee?
Force proximal posterior and distal anterior
What produces a varus moment of the knee?
Force proximal lateral and distal medial
What produces an extension moment at the knee?
Force distal posterior and proximal anterior
What produces a valgus moment at the knee?
Force distal lateral and proximal medial
What moment at the knee is desired at midstance?
Varus moment at the knee
What is never desired at midstance?
A Valgus moment
What influences the amount of force?
The distance.
The bigger the distance the greater the force
What is the equation for pressure?
Pressure=force/area
What are the forces in the coronal plane of the socket/
Fulcrum at MTP
Distal Lateral Forces
Proximal Medial Forces
Loading Pressure Tolerant Areas
What are the forces in the sagittal plane of the socket?
Proximal Posterior
Anterior Pre-tibials
Proximal Anterior Patellar Tendon
What are the biomechanical goals for a socket?
Maximize the weight-bearing capacity of the
residual limb
Provide ML stability at Mid-Stance on the prosthetic side
Encourage knee flexion throughout stance phase
How do you maximize weight-bearing capacity?
Even distribution of forces Inclination of forces • Loads pressure tolerant anterior surface • Encourages knee flexion at heel strike • Prevents knee hyperextension Total contact • Minimize edema • Increase proprioception • Improve weight bearing
How do you provide ML stability at Mid-stance?
Floor reaction line is medial to the knee joint (NHL)
Varus moment at mid-stance (NHL)
• Prosthetic Alignment: Foot initially inset at 12mm (medial)
• Excessive Varus Moment:
• Increased distal-lateral and proximal-medial pressure
Insufficient Varus Moment:
• Valgus moment produced
• Proximal-lateral and distal-medial pressure
What occurs when distal-lateral and proximal-medial are loaded?
Base of support is narrowed
• Decrease in energy expenditure
• Loads pressure tolerant areas and relieved pressure sensitive areas
What happens to the force when mass is increased?
Force increases on the limb
What happens to the force when the foot is excessively inset?
Increase force on the limb
What happens to the force when the limb is lengthened or long?
decrease force on the limb
What happens to the force when the trimlines are increased?
decrease force on the limb
How do you encourage knee flexion throughout stance phase?
Prosthetic Alignment: • Initial foot placement at 37mm posterior to ankle bolt • Foot is dorsiflexed • Socket aligned with 10o flexion • Proper heel stiffness
What could be the problem when there is excessive knee flexion at early stance?
heel too firm, foot too DF, excessive socket
flexion, foot too far posterior, heel too high,
shoe too tight, keel too soft
What could be the problem when the knee is too hyperextended at late stance?
Foot too far anterior, foot too PF, inadequate flexion of socket, heel too soft, keel too stiff
What could be the problem when there is Premature loss of anterior support at late stance (drop off)?
Foot too far posterior, foot size too small, keel too soft.
What are the different modes of suspension?
Joint and Corset Suspension Belt or Cuff Suspension Compression Sleeve Suspension Anatomical • Supra-Condylar (SC) • Supra-Condylar, Supra-Patellar (SCSP) Suction/Expulsion Valve Suspension Elevated Vacuum
What are the indications for using a joint and corset suspension?
Incorporates thigh weight bearing-for patients who cannot weight bear on limb
Improves ML stability
Heavy duty user
Patient preference
Hyperextension problems- has back check to encourage flexion
What are the advantages of joint and corset suspension?
Increases weight bearing surface
Unloads the residual limb
Increases ML stability
Knee extension control
What are the disadvantages of the joint and corset suspension?
Heavy, un-cosmetic, inherent pistoning
What are the contraindications for using a joint and corset suspension?
New users- combersom and can cause atrophy of the thigh
What are the indications for Supracondylar cuff?
Many of TT users prefer
Patients with stable ligaments
Juvenile patients-easily adjustable
Long residual limbs
What are the contraindications for the supracondylar cuff?
Unstable ligaments- suspension can exacerbate the problem by allowing more movement at the knee
What are the advantages of the supracondylar cuff?
Provides good suspension over patella
Adjustable
Can be used in combination with waist belt
What are the disadvantages of the supracondylar cuff?
Can be restrictive
Does not increase ML stability, un-cosmetic
What can be used instead of the suspension cuff?
A figure 8 strap
What are the materials that can be used for a sleeve suspension?
Silicone
Neoprene sleeve
What are the indications for a sleeve suspension?
Many of TT users prefer
Patients with stable ligaments
Juvenile patients
Long residual limbs
What are the advantages of the sleeve suspension?
Provides excellent suspension
Conceals trim lines
Variety of materials available
What are the disadvantages of the sleeve suspension?
Can cause skin problems
Can increase perspiration, hard to don
May not be indicated for vascular patients
Where does the sleeve suspension have to be touching in order to suspend?
The patients skin posteriorly
The socket distally
What are the contraindications for sleeve suspension?
Upper extremity involvement
Poor circulation-can compress and cause further circulation problems
What are the indications for the supracondylar/patellar?
Patients with very short residual limbs
Patients requiring ML stability
Patients who want less straps
What are the advantages of the supracondylar/patellar?
Increase weight bearing surface
Improved ML stability
Improves cosmesis
What are the disadvantages of the supracondylar/patellar?
Can inhibit some motion and activity
Difficult to use on obese or muscular
Difficult to kneel on
What is the trimline for the patella on a supracondylar/patellar?
Patella is enclosed in trimline
What are the indications for a supracondylar suspension?
Patients with very short residual limbs
Patients requiring ML stability
Patients who want less straps
What are the advantages of the supracondylar supsension?
Less restrictive than PTB-SC
Improved cosmesis
What are the disadvantages of the supracondylar supsension?
Loss of rigid hyperextension stop
Difficult to use on obese or muscular
What are the indications for the silicon suction?
Patients with good subcutaneous tissue
Full function of upper extremities
Want less straps
What are the advantages of the silicon suction?
Excellent suspension
Eliminates pistoning
Increased proprioception
Good torque absorption
What are the disadvantages of the silicon suction?
Can be difficult to don
Good hygiene is required-can have bacterial problems in not cleaned properly
What are the indications for the vacuum and suction suspension?
Patients with good subcutaneous tissue
Patients who want less straps
Patients who can’t tolerate distal pulling from a lock and pin
What are the advantages of the vacuum and suction suspension?
Excellent suspension
Eliminates pistoning
Increased proprioception
What are the disadvantages of the vacuum and suction suspension?
Maintenance is required
Can loose vacuum
Can be complicated to use for some
What are the different components involved with Transtibials?
Socket • PTB, TSB • Endo, Exo Suspension • Joint and corset, cuff, sleeve, silicone suction, vacuum Interface • Dependent on socket design Pylon Ankle Feet
What are three examples of ankle components?
DAS MARS
OWW Earthwalk
Multi-flex Ankle
What are the indication for ankle components?
Torque absorption is needed
Special situations
Accommodation to various surfaces
What are the indications for Shock Absorbers and Rotational Units?
Torque absorption
Active users
Special situations and activities
What are the different prosthetic feet avaliable?
SACH Single Axis Multi-Axis Dynamic Response/Energy Storing Multi-Axis Dynamic Response External Power
What are the indications for SACH feet?
Many lower limb users
Juveniles
What are the contraindications for SACH feet?
Active individuals
When inversion/eversion is required
When knee stability is required
What are the advantages of SACH feet?
Cosmetic, quiet, little maintenance
What are the disadvantages of SACH feet?
Deterioration of soft materials
No torque absorption
What’s the indications for single axis feet?
Patients needing knee stability
What are the contraindications for single axis feet?
Many lower limb users
Active users
When torque, inversion or eversion is needed
What are the advantages of the single axis feet?
More shock absorption
• Promotes knee stability
What are the disadvantages of the single axis feet?
No torque absorption
Requires bumper replacement
What are the indications for multi-axis feet?
Torque absorption needed
Special activities
Need for in/eversion
What are the contraindications for multi-axis feet?
When other components can be used
What are the advantages of the multi-axis feet?
Absorbs torque, shock
Foot conforms to surfaces
What are the disadvantages of the multi-axis feet?
Cosmesis, increased weight
Increased maintenance
What are the indications for dynamic response feet?
Active ambulators
Community ambulators
What are the contraindications for dynamic response feet?
One speed ambulators
What are the advantages of the dynamic response feet?
Smoother gait, less energy expenditure
Light weight, cosmetic, energy storing
What are the disadvantages of the dynamic response feet?
Material durability, limited sizes, expense
What are the indications for the MULTI-AXIS DYNAMIC RESPONSE feet?
Active users, Varying cadence ambulators
Community ambulators, Athletes
What are the contraindications for the MULTI-AXIS DYNAMIC RESPONSE feet?
Single speed ambulators
What are the advantages of the MULTI-AXIS DYNAMIC RESPONSE feet?
Multi-axial capabilities, dynamic response
Energy storing capabilities
What are the disadvantages of the MULTI-AXIS DYNAMIC RESPONSE feet?
Expense
Maintenance
What are the indications for the externally powered feet?
Potentially, all mildly active ambulators
What are the contraindications for the externally powered feet?
K1 level ambulators
Wet or corrosive environments
What are the advantages of the externally powered feet?
Anatomical power and propulsion
Anatomical limits for PF and DF
What are the disadvantages of the externally powered feet?
Batteries, weight, cost
Processing speed
Limited environment use
What are the basic gait deviations for transtibials?
Inadequate flexion or extension Medial or lateral leaning pylon Drop off Erratic movement Heel lever and Toe lever Whip(s)