Chapter 6A- Upper-Limb Prosthetics Flashcards
What are body powered prosthetics?
The force to operate components comes from mechanical transmission of muscluar effort generated elsewhere in the body
What are externally powered prosthetics?
A source outside the body generates power to operate the components
What are the advantages of body powered devices?
Low cost
Light weight
High reliability
What are the disadvantages of body powered devices?
Harness restricts work envelope
Harness encumbers the noninvolved side
Uses their own energy- might tire
Cosmetic
What are the two classes of terminal devices?
Passive
Prehensile
What are the advantages of passive devices?
No moving part- less mechanical problems Lightweight Reliable Social acceptance Functional static grasp
What are the two types of passive devices?
Passive hand
Mitts
Which passive devices is usually recommended for infants?
Mitts
Which passive device is usually recommended for sporting activities?
Mitts
What is a prehensor terminal device?
Offers active grasp
What are the two classifiers for prehensors?
Voluntary-opening Devices
Voluntary-closing devices
What can classifiers for prehensors be subdivided into?
Hand like shapes
Utilitarian shapes
What is the traditional utilitarian shape?
Split hook
When is stainless steel used for utilitarian devices?
Usually for heavy-duty Transradial patients
What does the letter “X” indicate when looking at the hook types?
The addition of neoprene rubber finger linings to improve friction and grasp
What does the letter “A” indicate when looking at the hook types?
Made from aluminum
What is the percent of weight that is reduced by using an aluminum hook?
50%
What are the different series hook types?
Series 5- Male Series 8- Females Series 9- adolescents Series 10- children Series 12- Infants Work hook
What does the letter “P” indicate when looking at the hook types?
Plastisol- soft rubber material made in Negroid and Caucasion tones
What is a work hook/Farmer’s hook?
Heavy duty stainless-steel hook, with a large opening between the two “fingers” that is designed to grasp shovels or similar objects
What does canted mean?
The slanted configuration of the hook fingertips
What does the canted hook provide?
Visual inspection during fine motor tasks
Bilateral amputees are usually given which type of hooks?
One canted
One straight
What is the CAPP terminal device
A voluntary-opening utilitarian shape that is not a hook but looks like a crab claw.
Where was the CAPP terminal device made?
Child Amputee Prosthetic Project at UCLA
Who usually uses the CAPP terminal device?
Children
Though, there are adult sizes as well
Who was the APRL hook developed by?
Army Prosthetics Research Laboratory after WWII
Which classification does the APRL hook fall under?
Voluntary-closing
What are some advantages of the APRL hook?
The fingers automatically lock in any position once grasp is accomplished
Has a selector switch
Operator lever is on the ulnar side of the device
Allows graded prehension
What does the selector switch on the APRL hook allow the amputee to choose?
A large finger opening
A small finger opening
Freewheeling- A small opening with the locking function eliminated
What was the APRL hook originally developed to use?
Biceps cineplasty
What are the disadvantages of the APRL hook?
Mechanical complexity
Expensive
Prone to breakdown
Who might benefit from an APRL hook?
Bilateral amputees- only on one hand
Previous users
Who created a series of voluntary-closing utilitarian devices?
Bob Radocy a recreational therapist and transradial amputee
What materials are Bob Radocy’s hooks?
Aluminum
Stainless steel
Plastic
Who likes Bob Radocy’s braces the best?
Children
Athletes
Unilateral transradial amputees
Long residual limbs
What is different about Bob Radocy’s hooks?
No locking mechanism
Amputee must maintain force to grasp object
What are the disadvantages of the voluntary-closing hand
Frictional loss
Rubber cosmetic glove impedes motion
Contours block visual inspection of the fingertips
What are the disadvantages of the voluntary-opening hands?
Friction loss
Glove restricting movement
Visual impedance of fingers
Limited pinch force
Who would not do well with Voluntary-closing/opening hands?
Bilateral amputees, due to limited functional capabilities
What is the Becker Plylite Hand?
Simple, Lightweight, voluntary-opening hand with the only moving component being the thumb.
It has an optional locking mechanism
What is the Becker Lock-Grip and Imperial Hands?
Voluntary opening hands with control cable tension that causes all five fingers to open.
Lock-Grip has a mechanism to lock all fingers in a closed position
Imperial model has easy adjustment of finger prehension force with the use of a screw driver
What is the Robin-Aids Mechanical Hand?
Voluntary-opening hand with control tension that causes digits 2,3,4 and 5 to move away from a stationary thumb
The thumb can be prepositioned for normal or large opening prehension.
What is the Robin-Aids Soft Mechanical Hand?
Voluntary-opening with the thumb and first two fingers to open. Made of plastisol and covered with urethane foam that provides softness
What is the Sierra Voluntary-Opening Hand
Two position stationary thumb. The first two fingers move away from the thumb
Has a Bac Loc feature in all fingers and allows patients to hold heavy objects securely
What is the Hosmer-Dorrance Functional Hand?
Voluntary opening permits prosthetist to adjust finger prehension by the installation of different tension springs
What is a prosthetic glove?
Rubberized covering that determines the external appearance of the prosthesis.
What are the three cosmetic glove types?
Stock glove
Custom Production glove
Custom-Sculpted Glove
What is a stock glove?
Most generic type comes in a few shades of Caucasion and Negroid plastics.
Need basic hand size and general skin tone
What is a custom production glove?
Made from doner mold of hand similar in shape to the amputees and then cover is selected for the best fit
Wider variety of skin tones
What is a custom-sculpted glove?
Hand-made from a sculptured reverse copy of remaining hand.
Made from silicone rubber-more durable
Can cover myoelectric hand
What are the two basic functions of wrist units?
Attach a terminal device to the forearm of the prosthesis
Permit the amputee to preposition the terminal device for operation
Why are wrist units important to transhumeral amputees?
They have lost all the ability to supinate and pronate the prosthetic arm. Wrist unit allows the needed ROM in the wrist to complete tasks
What are the various types of Friction Wrist Units?
Oval-shaped
Round
Wrist disarticulation wrist unit
What do the wrist units allow the amputee to substitute for?
Supination/Pronation
What’s the advantage of the oval-shaped friction wrist unit?
Cosmesis- Better transition between prosthetic hand and prosthesis.
More natural appearance
What is the disadvantage of the oval-shaped friction wrist unit?
Not constant friction
What is the difference between the wrist disarticulation wrist unit and the other wrist units?
They are made as thin as possible to conserve the length of the prosthetic forearm
What don’t the foregoing wrist units provide?
Constant friction
What are constant-friction wrist units designed to provide?
Constant friction throughout the range of rotation of the terminal device.
What do constant friction units use in the device to allow for the constant friction?
A nylon-threaded insert with steel lead threads
How can the constant friction unit be fixed?
Replacing the entire nylon insert
What are the four sizes for the round configuration of the constant friction wrist?
Infant
Child
Medium
Adult
What are the sizes for the oval configuration of the constant friction wrist?
Medium
Adult
What is the quick-change wrist unit?
A wrist unit designed to facilitate rapid interchange of different terminal devices, usually a hook and a hand
What does the quick-change wrist unit allow the amputee to do?
Remove the terminal device from the wrist unit
Repalce the terminal device with a different device
Manually position the terminal device in supination or pronation
Lock the terminal device in the desired attitude of sup/pro
What do most quick change wrist units use?
An adapter to be placed on the changing terminal devices
What does light downward pressure cause allow, on a quick change wrist unit?
Unlocking of the terminal device to reposition
What does a proximally directed axial force allow the amputee to do on a quick change wrist unit?
Lock the device in the new position
What does a heavy downward pressure on the quick change wrist unit allow the amputee to do?
Eject the terminal device and switch it
What does a wrist flexion unit allow the amputee to do?
Toileting
eating
shaving
dressing
Which group of people do not necessarily need a wrist flexion unit?
Unilateral amputee because they can do all the activities with their other hand
Who benefits from wrist flexion units?
Bilateral amputees
What are the degrees of flexion available with the wrist flexion wrist unit?
Neutral
30 degrees of volar flexion
50 degrees of volar flexion
What is the disadvantage of the Sierra wrist flexion unit?
Significantly heavier than the flexion wrist units
What are the degrees of the Sierra wrist flexion unit?
0 degrees of volar flexion
30 degrees of volar flexion
50 degrees of volar flexion
What is the advantage of the Sierra wrist flexion unit?
It has a much wider arc because it can rotate on the mount
What is the difference between constant friction wrists and rotational wrists?
Rotational wrist units can be used with high labor/exertion activities and will stay locked in one position, unlike the constant friction wrist which will turn the terminal device with a lot of force
How does the rotational wrist unit work?
Cable controlled, positive locking mechanisms
Allowing pronation and supination in any 360 degree angle
With greater resistance to rotation than friction wrists
What is an advantage of the rotational wrist unit?
The cables cause the terminal devices to rotate back to a neutral position when not locked in place
What is a ball-and-socket wrist unit?
A wrist unit that creates universal prepositioning of the terminal device with constant friction
What are elbow units for the transradial amputees?
Flexible hinges that facilitate the transmission of the residual forearm rotation to the terminal device, minimizing the requirement for manual prepositioning by the amputee
What are the different materials for elbow unit flexible hinges?
Metal
Leather
Dacron
Where are the flexible elbow hinges attached?
Triceps pad
prosthetic forearm
What do the flexible elbow hinges allow?
Transmission of 50% of the residual forearm rotation to the terminal device
What are single-axis elbow hinges designed to provide?
Axial/rotational stability between the prosthetic socket and residual forearm
If correctly aligned, what motions should the single-axis elbow hinges not restrict?
Flexion and extension ROM of the elbow
What sizes are available for single-axis elbow hinges?
Adult
Child sizes
What level of amputation requires the anteroproxiaml trim line of the socket to be close to the elbow joint?
Short transradial amputation
What occurs with a high anterior socket wall, required by patients with short transradial amputations?
Bunching of soft tissue in the antecubital region causing restricted elbow flexion.
What hinge helps increase elbow flexion by reducing the tendency for bunching of soft tissue?
Polycentric hinges
What sizes are polycentric hinges available in?
Adult
Medium
Child
What are the trim lines for amputation that are immediately distal to the elbow joint?
Extremely high trim lines
With extremely high trim lines, what degree is the elbow restricted to during flexion?
90 degrees or less
Which hinge can be used with patients needing extremely high trim lines?
Step-up hinge
What is required of the prosthetic when using step-up hinges?
The prosthetic forearm and socket by separated
What is another name for step-up hinged prosthetics?
Split-socket prostheses
What do step-up hinges do?
Amplify the excursion of anatomic elbow joint by a ratio of approximately 2:1
How much flexion is added when using step-up hinges with an anatomical elbow joint range of 60 degrees?
120 degrees
What is required of the patient to use step-up hinges?
They must exert twice as much force to flex step-up hinges
What sizes are available for step-up hinges?
Adult
Medium
Child
What reasons make it difficult for a high transradial amputee to operate a conventional transradial prosthesis?
Inadequate strength of the elbow flexors
Inadequate flexion ROM
Inability to tolerate the pressure on the volar surface of the forearm when step-up hinges are used
Which hinge is similar to the step-up hinge?
Stump-activated locking hinge because it also has to have a split socket
What flexes the elbow joint when using stump-activated locking hinges?
Shoulder flexion on the amputated side
What does the residual limb do when using the stump-activated locking hinge?
Locking and unlocking the mechanical joint.
What sizes do the stump-activated locking hinges come int?
Adult
Small
With the loss of the elbow joint, what ROM is required for function?
135 degrees of controlled flexion and extension
What is also required of a prosthetic for elbow disarticulation or transhumeral patients?
Ability to lock in various degrees of flexion/extension
What types of outside-locking hinges are available?
Standard
Heavy-duty
What is provided by a standard outside-locking hinges?
Seven different locking positions throughout flexion
What are the sizes of standard outside-locking hinges?
Adult
Medium
Child
What does the heavy-duty outside locking hinge provide?
Five locking positions
What size does the heavy-duty locking hinge come in?
Adult
What are all the available transradial hinges?
Flexible Rigid Single-axis Polycentric Step-up Stump-activated locking
What are all the available transhumeral/elbow disarticulation hinges available?
Outside-locking Inside-locking Flail arm Friction Spring lift assist
What length of humeral amputation provides adequate space to accommodate inside-locking elbow hinges?
5cm or 2in proximal from the elbow joint
What do inside-locking elbow hinges provide?
11 locking positions
Incorporation of a friction-held turntable
What does the turntable in the inside-locking elbow hinge permit?
Manual prepositioning of the prosthetic forearm as a substitute for external and internal rotation of the humerus
What do flail arm hinges contain?
An oversized clock spring mechanism
What does the clock spring mechanism in a flail arm hinge do?
Counterbalance the weight of the forearm.
What is an option for the use of a clock spring mechanism in a flail arm hinge?
To use is singularly or in pairs depending on the degree of counterbalance desired
What can be combined with a flail arm hinges?
Single free joint
Single locking joint
What do friction elbow units require?
Passive positioning of the forearm
What are the advantages of the friction elbow units?
Lightweight
Simple to operate
What type of patients usually benefit from friction elbow units?
Cosmetic restorations
Pediatrics
Congenital patients
Brachial plexus injury involvement
What elbow joint is similar to the flail arm hinge elbow unit?
Spring lift assist
What is the spring lift assist elbow unit?
A clock spring unit that can be added to any mechanical elbow.
What is the function of the spring lift assist elbow unit?
To counterbalance the prosthetic forearm and reduce the force necessary for elbow flexion.
What are the advantages of using the spring lift assist elbow unit causing the reduction of force requirement?
Allows subtle harnessing adjustments that require less excursion from the amputee
Who is usually prescribed the spring lift assist elbow unit?
Most amputees
Especially users with heavier steel terminal devices or hand prehensors
What is the simplest design of shoulder units?
Bulk head design where the humeral segment is directly connected to the socket and no motion can occur.
Which patients like the bulk head shoulder unit?
Unilateral amputees because they appreciate the weight savings
What are the all shoulder designs available?
Bulk head Friction-loaded Single axis Double axis Triple axis Ball-and-socket
What does the passive friction-loaded shoulder joint provide?
Assistance with dressing and desktop activities
What does the single-axis shoulder unit permit?
Only abduction
What does the double-axis shoulder unit permit?
Abduction and flexion
What does the triple -axis and Ball-and-socket shoulder unit permit?
Universal passive motion
What are the sizes available for all shoulder units?
Small
Medium
Large
What must occur, if locking functions are desired?
Custom-built shoulder joint
What is the nudge control unit?
A paddle-shaped lever that can be pushed by the chin or phocomelic digit, or other environmental objects to provide a small amount of cable excursion.
When are cable units prescribed?
When other body motions are not available
What is the original design of the nudge control unit?
Locking and unlocking the elbow
How can the nudge control unit be adapted?
Adapted to operate other body powered components, including flexion and roation wrist units
Who is the Otto Bock Pylon Arm for?
Transhumeral and shoulder disarticulation amputees
What does the Otto Bock Pylon Arm permit?
Passive or cable-operated elbow flexion with manual locking.
What adapters are used to help the internal or external rotation of the humerus and supination or pronation of the forearm when using the Otto Bock Pylon Arm.
Rotation adapters
What are the terminal device options?
Cable-controlled
Voluntary opening or closing
Passive hand with spring-activated thumb and fingers
cosmetic
