4. Upper Limb Prosthetics Flashcards
Mention disability rating for UL amputation 🔑🔑 EXAM 2019
- Thumb 23% (50% of one hand)
- One Hand 45%
- Upper limb 50%
Braddom 6th Edition Chapter 9 Table 9.5
When do you name (x) upper amputee as short or long? 🔑🔑
💡 Lower Limb 90-50-20 & 60-35-0
Wrist Disarticulation Pros & Cons. Whats ur advice? 🔑🔑 Dr. Jamal
Pros
- Spares distal radial ulnar articulation to preserve full forearm supination and pronation.
Cons
- Extremely long residual limb
- Needs special thin wrist unit is used along with terminal device (TD)
- Poor cosmesis
Advice
- Any wrist disarticulation = less options and poor cosmesis
- Drawbacks often outweigh the advantages in the long run
- Below-elbow amputation may be a more appropriate amputation level.
Cuccurollo 4th Edition Chapter 6 P&O pg466
Transradial Amputation Pros & Cons. Mention 3 Levels. 🔑🔑 What is the minimal length? Dr. Jamal
Pros:
- High level of functional recovery (Longer = More Strength & Supination)
Levels
Long: Residual limb length of 55% to 90%
Retains 60 degrees to 120 degrees of supination and pronation.
Optimal body-powered prosthetic restoration to perform physically demanding work.
Good cosmesis with enough space for electronic components
Short: Residual limb length of 35% to 55%
Limited wrist suspension and elbow ROM and flexion strength
Very short: Residual limb length <35%
Retains <60 degrees
Ulna 1.5 to 2 inches long is able to preserve the elbow joint
Cuccurollo 4th Edition Chapter 6 P&O pg466
Elbow Disarticulation Pros & Cons.
Pros
- Reduction in surgery time and blood loss
- Improved prosthetic self-suspension
- Allows greater lifting, pulling, and pushing power compared to above-elbow amputation.
- No risk of bone spur or heterotopic bone formation at the elbow disarticulation level
Cons:
- Limitations in externally powered elbow mechanisms at this level of amputation
- Poor cosmetic appearance
Cuccurollo 4th Edition Chapter 6 P&O pg467
Transhumeral Amputation. Mention 3 Levels 🔑🔑
1. Standard transhumeral
Residual limb length of 50% to 90% (best control and function)
2. Short transhumeral
Residual limb length of 30% to 50%
3. Humeral neck
Residual limb length of <30% (shoulder disarticulation)
Cuccurollo 4th Edition Chapter 6 P&O pg467
Shoulder Disarticulation Pros & Cons. Whats ur advice?
No Pros
Cons
- Most difficult to fit with a functional prosthesis
- Suspension is difficult to maintain.
Advice
- Better option is to provide a passive, cosmetic prosthesis (shoulder cap)
- Ultralight passive prosthesis.
Cuccurollo 4th Edition Chapter 6 P&O pg467
What requirements must an amputee meet before fitting a permanent prosthesis? 🔑
- Stump must be edema and pain free
- Adequate strength and ROM
- Adequate cognitive ability
PMR Secrets 3rd Edition Chapter 35 pg285 q12
Mention 4 functional grips 🔑🔑
Passive Prosthesis. Advantages & Disadvantages.
Advantages
- Lighter
- Best cosmesis
- Less harnessing
Disadvantages
- High cost if custom made
- Least function
- Low-cost glove stains easily
Cuccurollo 4th Edition Chapter 6 P&O pg468-469
DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2036 Table 74.6
Body powered Prosthesis. Types, Advantages & Disadvantages. 🔑🔑 Dr. Jamal & Abdulrazaq
-
Voluntary opening (Advantage)
- Device maintained in closed position by rubber bands or tension springs
- The amputee uses cable-control harness powered by proximal muscles to open the terminal devices against the force of the rubber bands or spring.
- To grasp, patient releases the opened terminal device on an object; the rubber bands or spring provide the prehensile force.
- Each rubber band provides about 1 lb. of pinch force
- To control the amount of prehensile force, the patient must generate a continued opening force
-
Voluntary closing (Disdvantage)
- Prolonged prehension (grip) requires constant pull on the harness
- Terminal device remains awkwardly open when not in use
Advantages
- Moderate cost
- Moderately lightweight
- Most durable
- Highest sensory feedback
- Variety of prehensors available for various activities
Disadvantages
- Most body movement to operate
- Increased energy expenditure
- Most harnessing
- Least satisfactory appearance
Cuccurollo 4th Edition Chapter 6 P&O pg468-469
DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2036 Table 74.6
List 4 Advantages of hooks. 🔑
💡 Fits labor worker with low income.
- Ability to grasp small objects
- Durability
- Efficiency
- Lower maintenance and repair cost
- Lighter weight
- Resist heat more than artificial hand
- Basic grasp function
Braddom 6th Edition
Chapter 6 UL Prosthetics pg167 Box 9.12
Battery powered Prosthesis. Types, Advantages & Disadvantages.
-
Myoelectric-controlled
- Use surface electrodes placed on the muscles of the residual limb
-
Microswitch-controlled
- Push-button switch or a pullswitch to activate the TD
Advantages
- Moderate or no harnessing
- Least body movement to operate
- Moderate cosmesis
- More function-proximal areas
- Stronger grasp in some cases
Disadvantages
- Most expensive
- Most maintenance
- Limited sensory feedback
- Extended therapy time
Reasons
- Generate a pinch force greater than that of body-powered controlled hooks (up to 25 lb)
- Allow for more precise control
Cuccurollo 4th Edition Chapter 6 P&O pg468-469
DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2036 Table 74.6
Wrist Units. Function & Types of Locking Mechanism 🔑🔑
💡 Do not add components unnecessarily: They increase weight and cost, and can break and need frequent repair.
WRIST UNITS
- Attach terminal device
- Allow supination pronation
- Allow flexion
LOCKING MECHANISM
- Friction lock
- Made from compressed rubber
- Hold it in a selected position by friction from a compressed rubber washer
- Mechanical lock
- Adjusted by manual rotation and lock
- Prevents unwanted rotation of the terminal device in the wrist unit when a heavy object is grasped.
- Able to add flexion for activities of daily living [ADLs]
- Electric wrist rotator units
WIRST FLEXION UNIT
- Allows manual positioning of the terminal device in either the straight or the flexed position for improved ADL functions.
Cuccurollo 4th Edition Chapter 6 P&O pg469
Components of Transradial (Below-Elbow) Amputation Prostheses. 6 marks 🔑🔑
- Terminal devices + control cable #1
- Wrist units
- Socket
- Elbow hinge
- Upper arm cuff/pad
- Harness
How to operate terminal device in UL prosthesis
- Shoulder flexion
- Shoulder abduction
- Scapular Retraction “Elbowing”
Types of sockets for transradial amputation
1. Split socket
- Socket encloses the forearm as a shell which is separated during flexion
- Used for very short residual limbs.
2. Muenster “Anterior-Posterior”
- Position of pre-flexion
- Encloses the olecranon and the epicondyle of the humerus.
- Figure-9 harness (light weight) for control purposes only
3. Northwestern “Medio-Lateral”
- Medial-lateral compression of the arm above the epicondyles
- Less restrictive anterior-posterior compression
4. TRAC socket
- Both anterior-posterior and medial-lateral compression
- More aggressive contouring of the limb to maximize load-tolerant areas
Cuccurollo 4th Edition Chapter 6 P&O pg470
Name the three basic types of below elbow hinges. What are the indications? 🔑🔑
1. FLEXIABLE
- Long below elbow amputee is required
- Allow flexion, supination and pronation
2. RIGID
- Short transradial amputations, more stability is needed.
- Allows flexion only
- Single Axis (one joint-pivot): Provide M-L stability and hyperextension stop
- Double Axis (two joints-pivot, polycentric)
- Set up Hinge: Very short transradial amputation, takes twice the force (energy cost doubles)
3. FIXED/LOCKED
- Significant elbow flexor weakness
Cuccurollo 4th Edition Chapter 6 P&O pg470
PMR Secrets 3rd Edition Chapter 35 pg288
Under which condition is a Münster suspension is most often prescribed 🔑 Explain the advantages the epicondyle suspension prosthesis (Münster-type)
Very short transradial amputation, the socket is set at 30 degree elbow flexion
PMR Secrets 3rd Edition Chapter 35 pg287 q23
List 3 types of suspension in transhumeral prostheses and advantages and disadvantages
SELF SUSPENDING
- Muenster & Northwestern
- Ease of use
- Cons
- Limited lifting capacity
- Reduced elbow flexion
- Poor cosmesis
HARNESS
- Figure-9
- Light duty activies
- Allow terminal device control cable only
- Figure-8
- Normal duty activities
- Simple, durable, adjustable
- Allow dual control cable (elbow & terminal device)
- Shoulder saddle and chest strap
- Greater lifting ability
- More comfortable than figure-8
- Difficult to adjust in women because straps cross breasts.
- Reduced control compared to figure-8 harness
SUCTION
- Suction socket with air valve
- Good soft-tissue cover
- Secure suspension
- Elimination of suspension straps
- Requires stable residual volume
- Harder to don
- Gel sleeve with locking pin
- Compromised limbs with scarring or impaired skin integrity
- Accommodate limb volume change with socks
- Reduced skin shear
- Greater cleaning and hygiene requirements.
- Can be uncomfortable in hot climates
DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2037 Table 74.7
Transradial amputation - give 3 common self-suspending systems for a prosthesis 🔑
- Muenster
- Northwestern
- OttoBock
Supra-condylar trans-radial socket / Self-suspending socket Advantages, Disadvantages.
Humeral epicondyles and the posterior olecranon
Advantage
- Simple donning on and off
- Durable
- Less expensive
- Light weight
- Shorter stumps can be fitted
Disadvantage
- Limited lifting capacity (Suspension is relatively poor)
- Poor cosmesis
- Decreased elbow flexion (Munster type)
- Socket pressures may cause discomfort
DeLisa 5th Edition Chapter 74 UL & LL Prosthetics pg2037 Table 74.7
Benefits of Harness Suspension 2 marks. List 3 types and their advantages and disadvantages 3 marks.
BENIFITS
- Suspend the prosthesis from the shoulder so the socket is held firmly on the residual limb
- Utilize body motions as sources of power or force
- Transmit this force via a cable system to operate the TD.
1. FIGURE-9 HARNESS
- Only for controlling the TD
- Self-suspended transradial socket
- Lighter and provides a greater freedom and comfort
2. FIGURE-8 HARNESS
- Transradial, Transhumeral
- Normal duty activities
- Simple, durable, adjustable
- Axillary pressure reduces discomfort
3. CHEST STRAP WITH SHOULDER SADDLE
- Greater lifting ability
- More comfortable than figure-8
- Difficult to adjust
- Reduced control compared to figure-8 harness
Cuccurollo 4th Edition Chapter 6 P&O pg471
The suspension system for a conventional upper extremity prosthesis can be either a figure of 8 or figure of 9 harness. What is the single most important factor when choosing the figure of 8 system instead of the figure of 9 system?🔑🔑MOCK
Most Important Factor
The figure of 8 system allows the user to carry more weight thus resists displacement of the socket on the residual limb when the prosthesis is subjected to heavy lifting.
Reference: Atlas of Amputations and Limb Deficiencies third edition page 133
Other Factor
Figure of 8 allow for dual control cable system for terminal device and elbow control, while figure of 9 allow for terminal device control only.
Dr. Maitham
How much weight can typically be lifted with the upper limb fitted with a prosthesis?
Transradial amputation can typically lift 20-30 lb
Transhumeral amputation can be expected to lift 10-15 Ib.
PMR Secrets 3rd Edition Chapter 35 pg289 q28
Types of control cable and how to use them
Single-control cable system (Bowden cable system)
Prosthesis: Transradial
- Single purpose, to operate the terminal device only.
Dual-control cable system
Prosthesis: Transhumeral, one cable with two function
- Flex the elbow unit when the elbow is unlocked
- Operate the terminal device when the elbow is locked
Elbow disarticulation is more desirable in two cases
- Growing child as epiphysis is preserved and bony overgrowth is prevented.
- Functional advantages for the bilateral upper limb amputee
Components of Transhumeral (Above-Elbow) Prostheses. 7 marks
BELOW ELBOW
- Terminal devices + control cable #1
- Wrist units
- Socket
- Elbow hinge
- Upper arm cuff/pad
- Harness & Control System
ABOVE ELBOW
- Terminal devices + control cable
- Wrist units
- Forearm unit
- Elbow unit + control cable
- Upper arm unit
- Socket
- Harness & Control System
Cuccurollo 4th Edition Chapter 6 P&O pg472
Mention 4 main categories of upper limb prosthetic systems. Prior to prescribing prosthesis, what would think about?
- Passive system
- Body-powered system
- Externally powered system
- Hybrid system
Braddom 6th Edition Chapter 9 Box 9.8
Transhumeral socket
Double-wall construction, with the inner wall providing a snug, total-contact fit and the outer shell providing appropriate length and shape.
Lateral socket wall extends to the acromion
Medial socket wall is flattened below the axilla to help prevent inadvertent socket rotation
Cuccurollo 4th Edition Chapter 6 P&O pg472
Elbow unit for transhumeral prosthesis. Types & Indications. 2 marks.
1. External (outside) locking elbow
Elbow disarticulations
- Amputee < 4 cm above the olecranon
- Not enough space for an internal locking mechanism
2. Internal (inside) locking elbow
Transhumeral and shoulder prostheses
- Amputee > 4 cm above the olecranon
- Greater mechanical durability
- Spring assist for elbow flexion may be provided
- Cosmetically more appealing
Cuccurollo 4th Edition Chapter 6 P&O pg473
Suspension in transhumeral prosthesis. Benefits & Types
BENEFITS OF HARNESS
- Transmit power to flex the prosthetic forearm
- Lock and unlock the elbow unit
- Operate the terminal device.
TYPE OF HARNESS
- Figure-8 and chest strap (medium to heavy weight) is most frequently used for transhumeral prostheses
- Remember, figure-9 for terminal device cable control only, no harness
Cuccurollo 4th Edition Chapter 6 P&O pg473-474
Control system for transhumeral prosthesis. Types and Pros & Cons.
💡 Hybrid control systems may combine body-powered and myoelectric control in the above elbow or shoulder prosthesis
- Body-Powered Control Systems
-
Myoelectric Control Systems
- Electrical signal produced by voluntary activation of the residual muscles is detected by surface electrodes incorporated into the prosthetic socket.
- Open terminal device: Wrist extensors (ECR & ECU) or Triceps → Say Hi
- Close terminal device: Wrist flexors (FCR & FCU) or Biceps → Flex the Grip
- Electric Switches
Cuccurollo 4th Edition Chapter 6 P&O pg473-474
Explain how to flex and extend the arm for transhumeral amputee.
- When the elbow is extended and unlocked, flexing the shoulder (humeral flexion; assisted by biscapular abduction) transmits force to the forearm lever loop flexing the elbow to the desired level.
- If the amputee wishes to use the terminal device at this point, first, he or she locks the elbow (by doing shoulder depression, extension, and abduction—“down, back, out”).
- Then, the patient can operate the terminal device by continuation of the control motion ⇒ shoulder flexion and biscapular abduction
- The same combination of shoulder movements are done to lock or unlock the elbow (shoulder depression, extension, and abduction). The elbow extends by gravity when unlocked.
Body-powered prosthesis. 4 Advantages and 4 disadvantages
Advantages
- Lower initial cost
- Lighter
- Easier to repair
- More durable
- Higher sensory feedback
Disadvantages
- Mechanical appearance
- Difficult to use (Needs higher skill)
- Dependent on motor strength
Cuccurollo 4th Eidtion Chapter 6 P&O pg475 Table 6-8
Braddom 6th Edition Chapter 9 UL Prosthetics pg167 Table 9.3
Myoelectric prosthesis. 4 Advantages and 4 Disadvantages 🔑🔑 Leak 21
Advantages
- Better cosmesis
- Less harnessing
- Stronger grasp force (More function-proximal areas)
- Battery powered, doesn’t depend on motor strength
- Least body movement to operate
Disadvantages
- More expensive
- Heavier
- Decreased durability
- Daily recharging of batteries
- Higher repair cost
- Increased energy expenditure
- Dependence on battery life
Cuccurollo 4th Eidtion Chapter 6 P&O pg475 Table 6-8
Braddom 6th Edition Chapter 9 UL Prosthetics pg167 Table 9.3
