Upper Limb Prosthesis Guide

UPPER LIMB PROSTHESISUPPER LIMB PROSTHESIS
Astha PatniAstha Patni

IntroductionIntroduction
• Upper limb prosthesis designed to
replace, as much as possible, the
function or appearance of a missing
limb or body part
• Prosthesis can replace some grasping
and manipulating functions of hand
• No sensory feedback
• Role of dominant function replaced to
contra-lateral hand and prosthesis
assists bimanual function

• A successful prosthesis
– comfortable to wear
– easy to don and doff
– light weight and durable
– cosmetically pleasing
– must function well mechanically
– have reasonable maintenance
– motivation of the individual

• Factors
– Amputation level
– Expected function of the prosthesis
– Cognitive function of the patient
– Vocation of the patient
– Avocational interests of the patient
– Cosmetic importance of the prosthesis
– Financial resources of the patient

• Reasons for upper limb amputation
– 0-15 years: Correction of a congenital
deformity or tumor
– 15-45 years: Trauma, tumor
– 60 years: Rare ; tumor or medical
disease

AMPUTATION LEVELSAMPUTATION LEVELS
• Transphalangeal amputation: Resection of the
thumb or fingers at distal interphalangeal (DIP),
proximal interphalangeal (PIP), or
metacarpophalangeal (MCP) levels, or at any
level in between
• Transmetacarpal amputation: Resection
through the metacarpals
• Transcarpal amputation: Resection through
the carpal bones
• Wrist disarticulation: Transection between the
carpals and radius/ulna

AMPUTATION LEVELSAMPUTATION LEVELS
• Transradial amputation: Below-elbow amputation
(may be classified as long, medium, or short)
• Elbow disarticulation: Transection through the elbow
joint
• Transhumeral amputation - Above-elbow (Standard
length is 50-90% of humeral length.)
• Shoulder disarticulation: Transection through the
shoulder joint
• Interscapulothoracic disarticulation (forequarter):
Amputation removing the entire shoulder girdle (scapula
and all or part of the clavicle

TYPES
• Body powered or conventional
• External powered or electric
• Cosmetic or passive
• Hybrid

Body powered orBody powered or
conventionalconventional
• Pros
– low cost
– Moderately lightweight
– Most durable
• Cons
– Most body movement to operate
– Most harnessing
– Least satisfactory appearance

External powered or electricExternal powered or electric
• Pros
– Moderate or no harnessing
– Least body movement to operate
– Moderate cosmesis
– More function – proximal levels
• Cons
– Heaviest
– Most expensive
– High maintenance
– Limited sensory feedback

Cosmetic or passiveCosmetic or passive
• Pros
– Most lightweight
– Best cosmesis
– Least harnessing
• Cons
– High cost if custom made
– Least function

Upper limb prosthesisUpper limb prosthesis
• Prosthetic components
– Terminal devices
– Wrists
– Elbows
– Shoulders
• Socket
• Suspension

Terminal devicesTerminal devices
• Functional activities of hand
– Non prehensile
– Prehensile

• Non prehensile
– Touching, feeling, pressing down with
fingers, tapping, vibrating the cord of
musical instrument, lifting or pushing
with hand
• Prehensile
– Precision grip (i.e. pincher grip), Tripod
grip, Lateral grip, Hook power grip,
Spherical grip

• Active
– Hooks
– Functional hands
– Activity specific devices
• Passive
– Cosmetic hands

Hook / Hand
Mechanical Electrical
VO VC Electrical Myoelectric
Digital Proportional
PassiveActive

• Lack sensory feedback
• Limited mobility and dexterity
• Hand – three-jaw chuck
• Hook – lateral pinch

• VO
– Practical
– In closed position, by springs
– Patient pulls the cable to open
– Prehensile force – spring
• VC
– Physiological
– In open position
– Patient pulls the cable to close
– Prehensile force – patient
– Greater proprioceptive input

Voluntary-Closing HooksVoluntary-Closing Hooks
• APRL hook
developed by the
Army Prosthetics
Research
Laboratory

Voluntary-Opening HookVoluntary-Opening Hook
Terminal DevicesTerminal Devices
• Hosmer-Dorrance work hooks
• Sierra two-load hook
• United States Manufacturing
Company (USMC) hook
• CAPP terminal device (originally
developed at the Child Amputee
Prosthetics Project at UCLA)
• Otto Bock and Hugh Steeper

. Voluntary-opening hook-. Voluntary-opening hook-
type terminal devicetype terminal device

Voluntary-Closing HandsVoluntary-Closing Hands
Otto Bock system
hands

Voluntary-Opening HandsVoluntary-Opening Hands
• Becker Plylite Hand
• Becker Lock-Grip and Imperial
Hands.
• Robin-Aids Mechanical Hand
• Robin-Aids Soft Mechanical Hand
• Sierra Voluntary-Opening Hand
• Hosmer-Dorrance Functional
Hands

ELECTRIC TERMINAL DEVICESELECTRIC TERMINAL DEVICES
Hand like shape
• Otto Bock System
Electric Hands
• Steeper Electric
Hands
Not having hand like
shape
• Otto Bock System
Electric Greifer
• Hosmer NU-VA
Synergetic
Prehensor
• Steeper Powered
Gripper
• NY-Hosmer
Prehension Actuator

Otto Bock System
Electric Hand (left)
and Steeper
Electric Hand
(right). A with
mechanism covered
by handlike shells;
B with internal
mechanism
exposed.

• A "palmar" and B
lateral views of the
Steeper Powered
Gripper (left), Otto
Bock System
Electric Greifer
(center), and Hos-
mer NU-VA
Synergetic
Prehensor (right).

Myoelectric controlMyoelectric control
• tranradial myoelectric
prosthesis (Otto Bock
type) The system
uses two myoelectric
sites on the residual
limb. the signal flow in
a two-site, two-
function myoelectric
hand prosthesis

Activity specific devicesActivity specific devices
• Farming
• Construction
• Cooking
• Photography
• Sports: golf, fishing, skiing

Cosmetic glovesCosmetic gloves
• Digit, hand, extend
till elbow
• Custom made
silicone cosmetic
covers – expensive
and difficult to
maintain

Prosthetic wristsProsthetic wrists
• Provide receptacle for connecting
terminal device
• Pronosupination or flexion based on
functional activities of patient

Types
• Mechanical
– Pronosupination
• Friction (Can rotate)
• Quick-disconnect
• Spring-assisted (B/L amputee)
– Flexion (B/L amputee , longer side)
• Spring-assisted internal or external

• Electric (B/L trans-humeral)
– Pronosupination
• Myoelectric (B/L amputee)
• Switch control

Friction wrist units.Friction wrist units.

Round and oval configurationsRound and oval configurations
of constant friction wrist unitsof constant friction wrist units

Quick-change wrist unitsQuick-change wrist units

Flexion wrist unitsFlexion wrist units

Electric wrist unitsElectric wrist units
• The Otto Bock
Electric Wrist
Rotator. The
rotator, shown
alone at the
bottom,
mechanically and
electrically
interfaces with the
quick-disconnect
adaptor of the
System Electric

Prosthetic elbowsProsthetic elbows
Classification
• Body-powered elbow
– External with or without spring assisted
flexion (elbow disarticulation)
– Internal, with or without spring assisted
flexion
– Internal, with rotating turntable (allows
internal/ external rotation)

Prosthetic elbowsProsthetic elbows
• Externally powered elbow
– Digital switch control
– Proportional switch control
– Digital myoelectric control
– Proportional myoelectric control
• Passive elbow
– Manual lock

Elbow unitsElbow units
Flexible hinges Rigid hinges

ElbowElbow
Polycentric hinges Step up hinges

ELBOW UNITELBOW UNIT
OUTSIDE LOCKING INSIDE LOCKING

Electrical powered elbowsElectrical powered elbows
• Boston Elbow,
• NY-Hosmer Electric Elbow,
• Utah Arm.
These elbows differ from one
another in mechanical configuration,
drive mechanism, and control
options.

Prosthetic socketsProsthetic sockets
Functions
– Comfortable residual limb – prosthesis
interface
– Efficient energy transference to the
prosthesis
– Secure suspension of the prosthesis
– Adequate cosmesis

• Wood
– Chronic edema
– Trophic skin changes
• Plastic
– Total contact
– Decreased weight
– Increased durability

• Two layers
• Inner-contoured to the residual limb
• External- gives length and shape
• Components are attached to external
layer

• Process
– Negative impression of residual limb
(POP)
– Positive mold
– Modify positive mold (remove from
pressure tolerant and add to pressure
sensitive)
– Transparent / check socket
– Trial fit and modify
– New positive mold
– Final socket

Various socketsVarious sockets
• Wrist disarticulation socket
• long Below elbow socket
• Short below elbow socket
• Very short below elbow socket
[ Split sockets]
Muenster sockets

• Elbow disarticulation socket
• Standard above elbow socket
• Short above elbow socket
• Shoulder disarticulation socket
• Forequarter amputation socket

Suspension systemsSuspension systems
• Functions
– Suspension – securing prosthesis to
residual limb
– Control of prosthesis / terminal devices
• Types
– Harness
• Figure of 8 (traditional)
• Chest strap (proximal amputation)
• Shoulder saddle (proximal amputation)

Suspension systemsSuspension systems
• Self suspension
– Condylar
– Muenster (Self suspending; Not
preferred in B/L transradial amputation)
– Northwestern
• Semisuction
– Hypobaric
– Semisuction
• Suction
– Full suction
– Silicone sock
Suction suspension
preferred for
Tranhumeral
amputee with normal
contrlateral limb

• Sock
• Interface between residual limb and
socket
• Layers adjustable to volume changes
• Protect skin and improve hygiene
• Socks with special silicone band and
socket with one way valve are used in
semisuction type of suspension systems

Silicone suction suspensionSilicone suction suspension
• Kristinsson in 1986
• Improved suspension with negative
atmospheric pressure
• Reduction of shear forces on skin
• Allows volume adjustment with
residual limb girth changes
• Simplified donning, better elbow
range of motion, lighter

• Silicone sleeve with distal
attachment pin that fits into shuttle
lock mechanism in socket
• Rolls silicone liner directly over skin
after spraying alcohol
• Socks over silicone to improve fit

• Patients with problems of skin
integrity
– Skin grafting for burns,
– degloving injury,
– insensate skin (diabetes, scleroderma),
– adhesive scar tissue

Control mechanismsControl mechanisms
• Body powered (harness)
– Scapular abduction
– Chest expansion
– Shoulder depression, extension,
abduction, flexion
– Elbow flexion, extension
• Discomfort
• Less cosmetic

MECHANICS OF THE BELOW-ELBOW
(TRANSRADIAL) CONTROL SYSTEM

• Glenohumeral joint
flexion for
operating a
terminal device.

HEAVY-DUTYHEAVY-DUTY
TRANSRADIAL HARNESSTRANSRADIAL HARNESS

BILATERAL TRANSRADIALBILATERAL TRANSRADIAL
HARNESSHARNESS

TRANSHUMERAL CONTROLTRANSHUMERAL CONTROL
SYSTEMSYSTEM
Two types of
control cable
1.Elbow
flexion/terminal
device control
cable
2.Elbow lock
control cable

Trans humeral hareness controlTrans humeral hareness control

The operating sequence of the twoThe operating sequence of the two
cable systemscable systems
• Tension applied to the elbow
flexion/terminal device control cable causes
the elbow to flex;
• When the desired angle of elbow flexion is
achieved, the rapid sequential application
and release of tension on the elbow lock
control cable locks the elbow
• With the elbow locked, the reapplication of
tension on the elbow flexion/terminal device
control cable permits operation of the
terminal device

SHOULDER DISARTICULATIONSHOULDER DISARTICULATION
HARNESSHARNESS

• Externally powered prostheses
• Electric motors inside prosthesis for
wrist rotation / elbow flexion or
extension
• Motors controlled by switches,
myoelectric signals, acoustic signals

Switch
• Inside or outside socket
• Activated on contact by amputee

Myoelectric controls
• Electrical activity generated during
muscle contraction to control flow of
energy from a battery to a motor in
prosthetic device
• Antagonistic muscles in distal portion
with normal voluntary activity

• Electrodes inside socket detect muscle
action potentials, amplify them to turn
on motor which brings about
movements
• Single channel: two electrode sites, one
for each function (open & close terminal
device)
• Multi-channel: single electrode,
amplitude of signal determines function

• High cost
• Low reliability
• Heavy (motors, batteries)
– India: electrodes rust quickly because of
sweat, electronic circuits fail due to dust
/ sweat

Prostheses by level ofProstheses by level of
amputationamputation

Partial hand
• Prosthesis not necessary
• Surgical reconstruction – opposition –
for prehension with proprioception

• Wrist disarticulation
– Distal radial-ulnar articulation preserved
for prono-supination
– Socket: tapered and flattened distally
forming an oval shape
– Wrist unit: thin, to minimize length
– Cosmetically: trans radial

Transradial amputation
Classification (based on length)
• Very short (<35%): rigid elbow hinges
• Short (35-55%): <60º pronosupination,
flexible elbow hinges
• Long (55-90%): 60-120 º
pronosupination, flexible elbow hinges

Transradial amputation with decreased
elbow ROM
• Polycentric elbow joints or split socket
with step-up hinges used to provide
additional flexion
• Decreased elbow flexion power

Elbow disarticulation
• Sockets: flat and broad distally (like
epicondyles)
• External elbow joint with cable operated
lock in medial joint
• Suspension: figure of 8, shoulder
saddle, chest strap
• Control system: 2 cables, one to lock
the elbow, other opens terminal device
or flexes elbow

Transhumeral amputation
Classification (based on length of
humerus)
• Very short (<30%)
• Short (30-50%)
• Standard (50-90%)

• Sockets:
– Residual limb greater than 35% -
proximal trimline within 1cm of
acromion, suspension with figure of 8,
shoulder saddle, or chest strap
– Residual limb smaller than 35% -
proximal trimline 2.5cm medial to
acromion, suspension with chest strap
or suction socket

• Elbow joint
– Internal elbow joint
• Preferred
• Level of amputation 4 cm or more proximal from
epicondyles
• Allows passive internal / external rotation
• Elbow spring-lift assist available
– External elbow joint
• Distal amputation
• Maintains elbow center with contralateral side

• Control system
– Dual cable (like elbow disarticulation)

Shoulder disarticulation andShoulder disarticulation and
forequarter amputationforequarter amputation
• Socket
– Extends to thorax
– Open –frame socket to decrease weight
and heat
• Similar to transhumeral + shoulder
unit

Bulk head
Flex / ext
Universal

• Control:
– Triple cable system
– One for elbow flexion when opposite
humerus is flexed
– Second cable opens terminal device with
chest expansion
– Third cable locks / unlocks elbow with
chin / opposite hand

• Externally powered prosthesis
preferred
• Passive cosmetic prosthetic
restoration in some patients

Upper Limb Prosthesis Guide

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