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Prosthetics&Orthotics > L3: Transfemoral Components > Flashcards

L3: Transfemoral Components Flashcards

1
Q

OBJECTIVES:

A
  • ID various components of transfemoral prosthesis including:
    • suspension
    • sockets
    • knee units
  • Adv’s of each
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2
Q

Transfemoral Components:

4:

A
  1. Socket→ where RL goes
  2. Suspension→ holds RL in the socket (usually external)
  3. Knee unit→ the “new” knee
  4. Prosthetic foot→ many diff. types
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3
Q

Transfemoral Components: Socket

2 types

A
  1. Quadrilateral Socket (Quad)
  2. Ischial (IC) or Ischial-Ramal (IRC)
    1. more comfortable
    2. more common
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4
Q

Transfem Components: Socket

Quadrilateral Socket (Quad)

Explain…

A
  • Four (quad) distinct walls w/ flat post. shelf and an ischial seat
  • Ischial Seat→ Primary WB surface for ischium and glutes
  • *Contains ALL thigh musculature
  • Ant. wall contours post. @ Scarpa’s Triangle
    • stabilizes ischium on its prosthetic seat
  • *More narrow ANT-POST dimension vs M/L
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5
Q

Transfem Components: Socket

Quadrilateral

Talk about the more narrow dimensions, where are they w/ this socket?

A

More narrow ANT-POST dimension

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6
Q

TFA→ Quad Socket

ADV’s vs Disadv’s

A
  • ADV’s
    • True UNweighting of distal end→ prevents edema/blood pooling
    • LESS $$$
    • Easier to fit MOST amputees
  • Disadv’s
    • Prox. Posterior and Medial discomfort
      • bc extra tissue here
    • Lateral thrust and trunk bending
      • bc extra space M/L dimension
    • Usually need pelvic belt
    • Pressure on Scarpa’s triangle (aka Femoral Triangle) (remember NAV L→R)
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7
Q

Prox. posterior and medial discomfort w/ Quad Socket

Why?

A

Extra tissue

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8
Q

Lateral thrust and trunk bending w/ Quad Socket

Why?

A

extra space in Quad socket M/L dimensions

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9
Q

Transfem Components: Socket

Ischial (IC) or Ischial-Ramal (IRC)

A
  • Stabilizes socket on RL and controls socket rotation by containing isch tube and pubic ramus
  • Maintains normal femoral ADD. by distributing pressure thru socket along shaft of femur
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10
Q

Transfem Ischial Socket maintains normal ________ by distributing pressure thru socket along __________

A

normal femoral adduction; thru socket along shaft of femur

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11
Q

Transfem Components: Socket

Ischial or Ischial-Ramal

More deets

A
  • OPPOSITE SHAPE TO QUAD SOCKET→ more narrow Med-Lat dimension
    • *matches anatomical shape of indiv’s RL
  • MORE room in the Ant-Post direction→ improves mm function/contractions
  • MORE common today vs Quad socket
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12
Q

Ischial (IC) or Ischial-Ramal (IRC) socket has a more narrow dimension where?

A

More narrow MED-LAT dimension

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13
Q

TFA: IRC Socket

ADVs vs. Disadvs

A
  • ADVs
    • more anatomical
    • more room for muscle contract.
    • Lower medial rim making sitting more comfy
  • Disadv’s
    • poor fit typ for obese pts
      • → due to more narrow MED-LAT dimension
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14
Q

Quad socket: The ischial tube is ______

A

OUTSIDE

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15
Q

IRC Socket: The ischial tube is ________

A

INside, contained

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16
Q

IRC vs. Quad Socket

Ischial Tube positioning

A

see pics

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17
Q

Quad Socket has wider ______ dimensions

A

Wider M-L

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18
Q

IRC Socket has wider _______ dimensions

A

Wider A-P

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19
Q

IRC vs. Quad Socket

A
  • NOTE: IRC socket mushc higher Lateral Wall
    • lower medially— comfier
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20
Q

TFA Socket Material:

RIGID

A
  • Either resin-laminated OR thermoformed plastic
  • Designed for intimate, full interface bw/ socket + limb
  • easy to clean
    • usually worn w/ prosth. socks
  • Uncomf. for those w/ bony or sensitive RL
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21
Q

TFA Socket Material:

FLEXIBLE

A
  • Thermoplastic mat. encased in a rigid frame specific to indiv. pt. (Comfortflex)
  • Accommodates to change in mm shape during contracts→ more comf. w/ prolonged walking
  • Softer mat. does NOT impinge on groin
    • **Groin pain common early on
  • Exc option when used w/ suction susp.
  • Post. brim flexible enough to give under wt. of pt to min. pinching during sitting
  • More $$$, LESS durable
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22
Q

1 reason pts do NOT wear TFA Prosth.

???

A

Discomfort in sitting

*BUT remember its not MADE for sitting*!!!

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23
Q

TFA Suspension Systems:

A
  • Keeps socket in an optimum align.
  • More diff. for TFAs compared to TTAs
    • much more mass w/out bony landmarks to assist in susp.
    • Incd distal wt. from knee makes susp more diff
    • More inherent rotation @ hip vs knee
  • Either single system OR combo of systems can be used
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24
Q

TFA Suspension Systems

Bold and *== Primary

A
  • Pull-in suction*
  • Roll on suspension liners*
    • Shuttle lock
    • Lanyard
    • Cushion liner w/ air expulsion valve
      • the “burping” one
  • Silesian belt
  • Total elastic suspension belt/TES
  • Pelvic belt and hip joint
25
Q

TFA Suspension systems

PRIMARY

A
  • Pull in suction
    • neg. pressure built up in socket then capped
  • Roll on susp. liners
    • Shuttle Lock → pin lock
    • Lanyard system→ loop and velcro
    • Cushion liner w/ air expulsion valve→ “burping one”
26
Q

TFA Susp Systems

Secondary Susp Systems

*Cannot act alone!!!

A
  • Silesian belt susp
  • Total elastic susp belt/TES→ velcro
  • Pelvic belt and hip jt
    • always has anatomical “hip joint” built in—– the metal piece
27
Q

TFA Suspension- Pull In Suction

3 components for this system to be effective:

A
  1. Neg. air pressure
  2. Skin to socket contact
  3. Muscle tension
28
Q

TFA Susp- Pull In Suction

A
  • Req’s either:
    • donning sock→ cotton
    • donning sleeve→ nylon
    • elastic bandage
  • why?
    • to pull RL down into socket
29
Q

TFA Susp- Pull In Suction

Once limb in socket…

A
  • Material used to pull limb in is pulled thru the valve housing at the distal/medial aspect of socket
    • you’ve seen this!!!
  • Air expulsion valve then screwed back on
  • Fit is improved via a neg. air pressure build up
30
Q

Pull In Suction Susp.

ADVs vs. Disadvs

A
  • ADV’s
    • Intimate fit;
      • incd control and proprio input for wearing during walking
  • Disadv’s
    • Reqs balance/agility
    • Fluctuating volume or wt changes
    • Incd shear forces precluding those w/ fragile/sensitive skin
31
Q

TFA Susp: Roll-on Liners

A
  • Silicone, urethane, elastomer in varying thick, size, tapers
  • To Don (against skin)→ liner turned inside out then rolled proximally onto RL
  • Neg pressure created and adhesive-like bond to skin
  • Can be used w/ shuttle lock (pin), lanyard, valve
32
Q

TFA Susp:

Roll on liners can be used w/ what?

3:

A
  • Shuttle lock- pin
  • lanyard
  • valve
33
Q

TFA Susp: Roll-on Liners

A
  • Shuttle lock or locking liner has a distal cap and pin screw
  • Pin engages shuttle lock inside bottom of socket when indiv stands and pushes limb into socket
  • To remove, release button on medial aspect of socket disengages pin
34
Q

Roll on Susp Liners

Ex.

A

see pics

35
Q

TFA Suspension: Silesian Belt

Remember this is Secondary suspension****

A
  • Attach. to lateral aspect of socket, encircles pelvis, runs a loop or buckle on ANT of socket
  • Usually secondary suspension aid to another system (see other cards for primary)
    • By itself→ unable to control rotation of RL inside socket
36
Q

TFA Susp: TES Belt

*Remember this is Secondary suspension!!!!

A
  • Same mech. as Silesian belt
    • goes on outside of socket
  • More comfy vs. Silesian
  • Velcro→ easy don/doff
  • Also Secondary or Aux. suspension
37
Q

TFA: Prosthetic Knee Units

ALL

*=Cadence responsive→ walk faster/slower

A
  • Single-axis
  • Polycentric (think about the one hard to move w/ fingers——ecc quad)
  • Manual locking
  • Wt-Activated stance control
  • Hydraulic*
  • Pneumatic*
  • Microprocessors*→ BEST!
38
Q

Prosthetic Knee Units:

1.Single Axis

A

NO LOCK @ KNEE!

  • 1 hinge→ Flex/Ext
  • Stability in stance achieved by combo of pos’ing knee relative to wt. line (alignment, COM) and muscular control (Hip Exts)
  • Low maint, lt. weight
39
Q

Single Axis knee prosthetic

Explain further stability in stance achieved by???

A
  • Combo of:
    • Pos. knee relative to wt. line (alignment)→ COM
      • Wt line behind knee==> Flexion
      • Wt line anterior to knee==> EXT
    • Muscular control
      • Hip Exts
        • Remember must be controlled w/ joint ABOVE!!!
40
Q

Prosthetic Knee Units: Single-Axis

*free moving knee

A
  • NO mech. stability
    • inappr. choice for short RLs OR poor hip and trunk strength
  • Once resistance set→ rate of advance. of shin during swing remains same regardless of walking speed
  • GOOD choice for those w/ long RLs who are able to voluntarily stabilize knee
    • longer moment arm→ closer to “knee” to inc control
    • Active hip EXT against post. wall of socket
41
Q

This prosthetic knee is a GOOD choice for those w/ long RLs and WHY?

A

Single-Axis knee

*Longer moment arm→ closer to “knee” incs control

*Active hip EXT against posterior wall of socket

42
Q

Prosthetic Knee Units:

2.Manual Locking

A
  • Single axis knee w/ pin-locking mech.
  • Knees locked in EXT providing max. stability BUT compromises mobility and clearance in swing
  • Manually UNlocked to sit
  • Good option in initial stages of WB
43
Q

Good option in initial stages of WB

A

Manual Locking knee

44
Q

Prosthetic Knee Units:

3. Polycentric

*Ecc. quad feel one

A
  • 4 bar design simulates anatomical design more closely
    • Moving center of rot. vs single axis
  • Enhances stance phase stability for short RLs and weaker amps.
  • Excellent option for knee disartics. and longer RLs
    • → allows lower leg to tuck under thigh when sitting
  • More mechanical joint=more maintenance!!
45
Q

More mechanical joint=====

A

More maintenance!!!

46
Q

EXCELLENT option for knee disarticulations AND long RLs bc allows lower leg to tuck under thigh when sitting

A

Polycentric Knee

47
Q

Prosthetic Knee Units:

4. Weight Activated Stance Control

aka “Safety Knee”

A
  • Braking system activated thru knee during stance phase
  • “Braking” retards unwanted knee flex during stance
  • Sn can be adjusted to match indiv’s lvl of activity and control
48
Q

Prosthetic Knee Units:

5. Hydraulic

Cadence Responsive***

A
  • Cadence responsive: forward progression of prosthetic shin changes as gait speed changes
    • variable resist. simulates norm. gait
  • LESS swing phase delay
  • Adv’d function brings incd weight, incd maint. and higher $$
  • LESS responsive in cold weather
49
Q

Prosthetic Knee Units:

6. Pneumatic (think “air”

Cadence Responsive***

A
  • Cadence responsive BUT uses air instead of fluid
  • Compressible air easier to change w/in channels of knee to adj. to indiv needs
  • LIGHTER and less $ vs hydraulic
50
Q

Prosthetic Knee Units:

7. Microprocessor Techno.

*Can mimick ecc quads→ STAIRS!

A
  • 1980s
  • Most pop→ C-Leg (Otto Bock)
    • 1st computer controlled limb
  • Recharge battery→ 25-30hrs capacity
  • Knee processor sensor and force sensor gather data @ freq of 50x/sec
51
Q

Prosthetic Knee Units:

C-Leg or Rheo

A
  • Real time data sent to hydraulic damper which controls stance and swing mvmts
  • Greater control on stairs, bike, decline walking (ecc. quad control*****)
  • Customized adjs using PC and specialized software
  • *NOTE: NO flexion mechanism→ cannot flex knee actively
52
Q

Add on components:

Torque absorbers

A
  • Simulate rotation during stance
  • Dec shear forces that translate to socket-RL interface
  • Indicated for:
    • fragile skin
    • sports
    • uneven terrain
53
Q

Add on Components:

Transverse Rotational Units

A
  • Allows passive rotation of shin/pylon
  • Allows crossing legs
54
Q

Suspension

Sockets

Knees

Shanks

Feet

A

see pic

55
Q

Shank:

Endoskeletal (modular)

Wt absorbed where

A

wt absorbed by pylon (metal)

56
Q

Shank:

Exoskeletal (Crustacean)

Wt absorbed where?

A

Wt absorbed by shell

57
Q

TFAs- Latest Gen Knees

A

WATCH VIDEOS

SLIDE 42

58
Q

Knee w/ MOST STABILITY

A

Single-Axis, Locked

*Remember—- more mobility=less stability

Prosthetics&Orthotics (19 decks)

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