Amputations and Prosthetics Flashcards
What is a prosthesis?
An artificial limb
What is the most common cause of cause of amputations?
Peripheral vascular disease
What is trans metatarsal amputation (Lisfranc)?
Partial foot amputation that preserves the DFs and PFs.
What is a hemicorporectomy?
Surgical removal of both LEs and the pelvis below L4-L5 level.
What is a hemipelvectomy?
Surgical removal of one half of the pelvis and LE.
What is a hip disarticulation?
Amputation of entire lower limb with the pelvis preserved
What is a transfemoral amputation?
Above knee amputation with 35-60% of femoral length spared
What is a knee disarticulation?
Amputation through the knee joint, keeping the femur intact
What is a trans tibial amputation?
Below the knee amputation with 20-50% of tibial length spared
What is a Syme’s amputation?
Amputation through the ankle joint where the heel pad is preserved and attached to the distal end of the tibia for weight bearing.
What is a Chopart’s amputation?
Amputation through the talonavicular and calcaneocuboid joints.
Preserves the plantar flexors, but sacrifices the dorsiflexors often resulting in an equinus contracture.
What is a forequarter amputation?
Scapulothoracic amputation involving amputation of the UE including the shoulder girdle
What is a shoulder disarticulation?
Amputation through the shoulder joint
What is a transhumeral amputation?
Above elbow amputation
What is a transradial amputation?
Below elbow amputation
What is an elbow vs wrist disarticulation?
Amputation through the elbow or wrist joint
All prosthetic devices contain a ____ and a ____ with varying components in between.
Socket
Terminal device
List 3 functions of a prosthetic socket.
- Contain the residual tissues
- Provide a means to suspend the prosthetic limb
- Transfer forces from the prosthesis to the residual limb
Liners are used in every suspension system except _____.
Anatomical suction
What is the function of a prosthetic sock? When is the number of socks decreased versus increased?
Purpose: Used to accommodate changes in volume on the residual limb
Increase the # of sock plies when limb volume is decreased
Decrease the # of sock plies when limb volume is increased
What is the purpose of a terminal device?
Provide an interface between the amputee’s prosthesis with the external environment
LE prosthesis TD = foot
UE prosthesis TD = hook or hand
List 5 functions of the foot ankle assembly component of a trans tibial prosthesis.
Absorb shock at heel strike
Plantarflex in early stance to achieve foot flat
Dorsiflexion during mid and terminal stance to store energy
Plantarflexion in pre-swing to push off
Provide cosmetic replacement of the foot
What is the most commonly prescribed foot for a trans tibial prosthesis? What population is this commonly prescribed for?
Solid ankle cushion heel (SACH) foot
Used primarily in youth and more sedentary individuals
List 2 functions of a SACH foot.
Limits plantarflexion
Assists in hyperextension of knee (knee stability) during stance
Describe a single axis foot.
Articulated foot with the lower shank
Motion is controlled by anterior and posterior rubber bumpers that limit dorsiflexion and plantarflexion
Promotes knee stability in stance phase
Describe a multi-axis foot.
Articulated foot with the lower shank
Allows PF, DF, inversion and eversion to conform to uneven surfaces
What are the advantages of using a spring leaf shank?
Decreased energy consumption due to smoother gait pattern and energy return during terminal stance
Describe a microprocessor foot.
Microcomputer control of PF and DF based on the position of the foot
Improves ability to ambulate on inclines, stairs and uneven surfaces
List 2 functions of a prosthetic shank.
Provides leg length and shape
Connect and transmit weight from socket to foot
What is a patellar tendon bearing socket?
A total contact socket that allows for moderate loading over the area of the patellar tendon
List the 6 pressure sensitive areas of a typical trans tibial residual limb.
Anterior tibial condyle Anterior tibial crest Fibular head and neck Fibular nerve Distal cut end of tibia and fibula Patella
List the 4 pressure tolerant areas of a typical trans tibial residual limb.
Medial tibial plateau
Tibial and fibular shafts
Patellar ligament
Gastrocnemius muscles
Describe a total surface bearing socket. What liner MUST be used with this type of socket.
Total contact socket with lower profile and rounder shape than a PTB socket for more intimate fit
Weight is borne equally throughout the socket on bones and soft tissue
Must use a gel type liner for suspension and to distribute pressures
Describe a supracondylar socket suspension. What is the advantage of using this type of suspension?
Medial and lateral walls of the socket extend up and over the femoral condyles
Provides increased mediolateral stability for very short residual limbs
What is an external suspension sleeve?
Neoprene type sleeve that covers the proximal socket and distal thigh to suspend the limb
What is the most stable knee unit for transfemoral amputations?
Manual locking knee
Describe a manual locking knee.
Lock is engaged for standing and walking, manually unlocked for sitting
Provides maximal stability for individuals with significant weakness in the LE
Describe a microprocessor knee.
Knee stability in stance and ability to flex in swing are controlled electronically
Prevents knee from buckling when weighted
Can be used to ascend and descend stairs step over step
Describe a single axis knee.
Allows for weight activated stance control
Permits knee motions to occur around a fixed axis
Requires an extension assist
Describe a polycentric knee system.
Changing axis of motion allows for adjustments to the center of knee rotation
Describe a hydraulic/pneumatic knee unit.
Adjust resistance dynamically to the individual’s walking speed
Appropriate for younger and more active individuals
Describe single axis knees. What is needed to use a single axis knee?
Continous resistance is provided by a clamp that acts on the knee mechanism
Must have good hip extensor control to promote knee extension in midstance.
What is the least stable type of knee for a transfemoral prosthesis?
Single axis/constant friction knee
Describe an ischial containment socket.
Triangular shaped socket that holds the femur in an adducted position
Lateral wall of socket extends for proximally to provide lateral stability and to ensure the ischial tuberosity is seated within the socket for a more intimate fit
Describe a quadrilateral socket.
Rectangular shaped socket with a broad horizonal posterior shelf for seating of the ischial tuberosity and gluteals
Medial and posterior walls are the same height, while the anterior and lateral walls are 2.5-3 inches higher
Describe anatomical suction suspension. Advantages?
Suction is employed to maximize contact and suspension; air pumped out of one way release valve at bottom of socket
Good proprioception due to direct skin to socket total contact
Describe silicon suction suspension. Advantages?
Silicone liner with either a locking pin/cuff used to maintain the prosthesis on the limb
Reduces shear within the socket and provides pressure relief for the residual limb to increase comfort
Describe total elastic suspension. Advantages?
Neoprene belt is applied to prosthesis and wraps around the pelvis to anchor the prosthesis on the residual limb
Adjustable and readily accommodates to volume changes
What is a Silesian belt? Advantages?
Strap that anchors the prosthesis by reaching around the pelvis (below the iliac crest)
Able to control rotation in the transverse plane
Describe a hinge suspension. Advantages?
Hinged hip joint attached to metal/leather pelvic band, anchored around the pelvis
Adds control for medial/lateral stability of hip
Reduces Trendelenburg gait deviation
What positions should be avoided following a transtibial amputation to prevent contractures? What methods can be used to counteract these contractures? (2)
Prolonged flexion and external rotation of the hip and knee flexion
Counteract with use of posterior board to keep knee straight while in wheelchair
Regularly scheduled time in prone lying
What positions should be avoided following a transfemoral amputation to prevent contractures? What methods can be used to counteract these contractures? (1)
Flexion, abduction, external rotation of the hip
Counteract with regularly scheduled time in prone lying
What tool does Medicare use to classify amputees based on functional ability?
Medicare Functional Classification Level (MFCL), also known as K levels
What outcome measure can be used to determine a patient’s K-level?
Amputee Mobility Predictor (AMPPRO)
Describe K-level 0 and the knee unit and foot/ankle assembly a patient at this level would be eligible for.
Prosthesis will not enhance quality of life or mobility
Knee Unit: Not eligible for prosthesis
Foot/ankle assembly: Not eligible for prosthesis
Describe K-level 1 and the knee unit and foot/ankle assembly a patient at this level would be eligible for.
Transfers
Ambulate on level surfaces
Fixed cadence
Limited or unlimited household ambulator
Knee Unit: Single axis, constant friction mechanism
Foot/ankle assembly: SACH or single axis
Describe K-level 2 and the knee unit and foot/ankle assembly a patient at this level would be eligible for.
Traverse low level barriers: curbs, stairs, uneven surfaces
Limited community ambulator
Knee Unit: Polycentric, constant friction mechanism
Foot/ankle assembly: Flexible keel foot or multi-axial ankle/foot
Describe K-level 3 and the knee unit and foot/ankle assembly a patient at this level would be eligible for.
Variable cadence ambulator
Unlimited community ambulator
Traverse most environmental barriers
Prosthetic use beyond simple locomotion
Knee Unit: Hydraulic/pneumatic, microprocessor, variable friction mechanism
Foot/ankle assembly: Energy storing, dynamic response foot, multiaxial foot/ankle
Describe K-level 4 and the knee unit and foot/ankle assembly a patient at this level would be eligible for.
Exceeds basic ambulation skills
Exhibits high impact, stress or energy levels
Typical child, athlete, or active adult
Knee Unit: Any system
Foot/ankle assembly: Any system
List 2 pressure tolerance areas of a transfemoral residual limb.
Ischium
Soft tissue of residual limb
List 6 pressure sensitive areas of a transfemoral residual limb.
Greater trochanter Pubic tubercle Pubic ramus Pubic symphysis Distal end of femur Perineum
What is the typical wear schedule for a new amputee?
Wear the prosthesis at least 1 hour everyday, with 30 minutes spent ambulating
If the patient is able to tolerate wearing the prosthesis with no evidence of breakdown, an hour of wear time is added each day.
List the appropriate widths of the ace wraps when wrapping UE versus trans tibial versus transfemoral amputations.
2-4 inch wrap for UE amputations
3-4 inch warp for transtibial amputations
6 inch wrap for transfemoral amputations
What are the most common contractures for trans metatarsal/Syme’s vs, transtibial vs transfemoral amputations?
Transmetatarsal/Syme's = equinus deformity Transtibial = knee flexion contracture Transfemoral = hip flexion and abduction contracture
What anticoagulant is commonly prescribed to reduce risk of DVT following surgery?
Heparin
List 3 interventions that can be used to help desensitize a residual limb.
Weight bearing
Massage
Tapping
What is a neuroma?
Bundle of nerve endings that group together and can produce pain due to scar tissue, pressure from the prosthesis or tension on the residual limb
What is a phantom limb versus pain?
Phantom limb = painless sensation where the patient feels that the limb is still present
Phantom pain = the patient’s perception of some form of painful stimuli as it relates to the residual limb
List 4 prosthetic causes of a lateral bending gait deviation.
Prosthesis is too short
Improperly shaped lateral wall
High medial wall
Prosthesis aligned in abduction
List 6 prosthetic causes of an abducted gait deviation.
Prosthesis is too long High medial wall Poorly shaped lateral wall Prosthesis positioned in abduction Inadequate suspension Excessive knee friction
List 4 prosthetic causes of a circumducted gait deviation.
Prosthesis is too long
Excessive knee friction
Socket too small
Excessive plantarflexion
List 4 prosthetic causes of excessive knee flexion during stance gait deviation.
Socket set forward in relation to foot
Excessive dorsiflexion
Stiff heel
Prosthesis is too long
List 4 prosthetic causes of a vaulting gait deviation.
Prosthesis is too long
Inadequate socket suspension
Excessive alignment stability
Excessive plantarflexion
List 4 prosthetic causes of rotation of forefoot at heel strike gait deviation.
Excessive toe out built in
Loose fitting socket
Inadequate suspension
Rigid SACH heel cushion
List 3 prosthetic causes of a forward trunk flexion gait deviation.
Socket too big
Poor suspension
Knee instability
List 4 prosthetic causes of a medial/lateral whip gait deviation.
Excessive rotation of the knee
Tight socket fit
Valgus in the prosthetic knee
Improper alignment of toe break
What outcome measure is similar to the TUG, but is used specifically with the amputee patient population?
The L-Test
What is the difference between and endoskeletal and exoskeletal shank?
Endoskeletal = consists of rigid pylon covered with a material designed to simulate the contour and color of the contralateral limb
Exoskeletal = consists of a rigid external frame covered with a thin layer of tinted plastic to match the skin color distally
What is a myoelectric prosthesis?
A device using electromyography signals to control movements of the prosthesis with surface electrodes or implantable wires
