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Prosthetics&Orthotics > L3: KAFOs > Flashcards

L3: KAFOs Flashcards

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1
Q

KAFOs

Things to consider…

A
  • Pts goal/Lvl of function
  • Consistent use/acceptance depend on how well orthosis meets needs/goals
  • Consider Dx!
    • improve? get worse? stay same?
      • MS, GBS**
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2
Q

KAFOs

Indications:

A
  • Excessive motion @ knee in stance NOT effectively controlled by just AFO
    • ballistic hyperEXT
    • uncontrolled knee flex (buckling) during wt acceptance
    • excess vaRus/valGus
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3
Q

KAFOs

Guidelines:

A
  • Cannot assess knee as isolated entity!
  • Proper align/function of knee→ result of poor hip and/or ankle align/strength
  • 3 Functions KAFO:
    1. protect jt it crosses
    2. structural integrity
    3. inc function
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4
Q

KAFOs

Stability vs Mobility

A
  • Inverse relationship bw functionality (mobility) vs stability***
  • improved function not always equal to “normal”
  • Goals of stability/protection==> improved function compared to gait w/out orthotic
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5
Q

KAFOs

2 types:

A
  1. Conventional (metal+leather)→ old school
  2. Molded thermoplastic
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6
Q

“Conventional” think….

A

Metal + leather

Old skoooool

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7
Q

Conventional AFOs

Three-point force system

A
  • 3-point system:
    • Two anteriorly directed forces:
      • PROX=> posterior thigh band
      • DIST=> shoe and posterior calf band
    • One posteriorly directed force:
      • Anterior knee pad OR anterior thigh and calf strap
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8
Q

Molded Thermo. KAFO

Force system

A

see pics

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9
Q

Conventional KAFOs

Advantages vs. Disadvantages

A
  • Advantages
    • Strong, durable, easy adjust
  • Disadvantages
    • heavy, must attach to shoe, less cosmetic, fewer contact pts reduce control (hard to control varus/valgus stress)
      • ALL REASONS THEY WON’T WEAR IT*
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10
Q

Conventional KAFOs

Indications:

A
  • Need max strength/durability
  • Obese
  • Flucuating/uncntrld edema
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11
Q

Conventional KAFOs

CONTRAindications:

A
  • Energy expenditure issues (it’s heavy)
  • When control in transv or frontal plane important
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12
Q

Thermoplastic KAFOs

The deets

A
  • Custom made→ intimate fit
  • Distal shell→ foot, ankle, lower leg (solid or artic. ankle)
  • Prox shell→ thigh- greater troch to prox. fem condyles
  • Metal knee jts + sidebars→ connect dist + prox shell
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13
Q

Thermoplastic KAFOs

Fit, counterforces, design

A
  • Intimate fit= larger interface w/ limb= control/force dispersion
  • A/P Counterforces→ control sag. plane
  • Total contact design→ transv/frontal plane control
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14
Q

Thermoplastic KAFOs

Advantages vs Disadvantages

A
  • Advantages
    • lt. weight, interchangeability w/ shoes, more cosmetic*
  • Disadvantages
    • hot to wear
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15
Q

Thermoplastic KAFOs

Indications

A
  • MAX control needed
  • When energy expenditure makes wt of orthotic an issue
  • When control in transverse plane needed***
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16
Q

Thermoplastic KAFOs

CONTRAindications

A
  • Intimate fit diff w/ obesity
  • Intimate fit compromised w/ uncontrolled/fluctuating edema
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17
Q

KAFOs

Ankle Control Options

A
  • SAME AS IN AFOs→ bc still an “ankle” component…. Knee Ankle Foot Orthosis
  • Ankle config + GRFs influence knee function and forward progress. during gait*** KNOW THIS!!!!
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18
Q

KAFOs

Ankle Control

If Immobilization is desired @ knee…

A
  • You want MORE MOTION @ ankle joint→ improves function by allowing tibia to easily advance over fixed foot
  • NOT in pts best interest to have BOTH ankle/knee locked
    • IF both locked→ CPO adds EXT shoe mods to facil. all three rockers
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19
Q

Primary reason for rx KAFO vs AFO

A

Poor knee motor control/strength

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20
Q

KAFOs

Knee Control→ Single axis (AKA: straight knee joint w/out drop lock or “free knee”)

Permits what to prevent/provides what?

A
  • Permits unrestrict. flexion and FULL Ext in sag. plane
    • Prevents→ hyperEXT
    • Provides→ medio-lateral stability
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21
Q

KAFOs

Knee Control→ Single axis

Indications

A
  • M/L jts placed bw medial ADD tubercle and medial tib plateau
  • Indicated for→ pts w/ enough mm function to ensure knee stability early in Stance BUT may move into recurvatum later in stance OR sig. structural (M/L, ACL) instability***
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22
Q

KAFOs

Knee Control→ Single axis locking knee

What is it? Indications?

A
  • Single axis knee locked t/o gait
  • Indicated→ pts unable to control knee in Stance
  • **NOTE: NEGATIVE effects on clearance and swing phase
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23
Q

KAFOs-Knee Control

Offset Knee Jt

Key feature+ Axis of rotation where (aka where is it offset?)

A
  • Key Feature: POSTERIOR alignment of the knee axis
  • Bench alignment places AOR posterior to anatomical knee
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24
Q

KAFOs-Knee Control

Offset Knee Joint

The bench alignment for an offset knee joint places the axis of rotation posterior to anatomical knee

What happens as a result of this in early stance (LR)?

Study These Flashcards
A
  • GRF passes closer to the center of the axis of the orthotic joint→ REDUCES magnitude of the external FLEX moment that is acting to flex the limb
25
KAFOs-Knee Control ## Footnote **Offset Knee Joint** **IC→MSt** **\*pay attention to KAFO axis of rotation (blue dot)**
**Bc of POSTERIOR alignment→ LESS _flexion moment_ on knee jt.** **As body progresses forward (into MSt, when knee EXT is happening)→ the GRF moves MORE QUICKLY ahead of the orthotic joint= mech. extensor force** see pics KNOW THESE PICTURES AND _EXPLAIN THEM_!!!!!
26
KAFOs-Knee Control ## Footnote **Offset Knee Joint** **Explain what happens as body progresses forward**
* As body progresses forward the **GRF _more quickly_ moves ahead of the orthotic joint==\> mechanical EXTENSOR force that augments _stance phase stability_** * drop locks can be added for long term standing (you know what these are!)
27
KAFOs-Knee Control ## Footnote **Offset knee joint** **Appropriate for?**
* Pts w/ **limted knee control:** * LMNL (Lower Motor Neuron Lesions) * Polio * Spina Bifida * Lower T/S SCIs
28
This KAFO for knee control is designed for **those w/ knee flexion contractures (stuck in knee flex) _who can NOT attain full knee EXT_**
Think…**Dial Lock knee jt** Variable position knee joint (**Dial Lock)**
29
Dial Lock think…..
Knee flexion contractures!!!
30
KAFOs- Knee Control ## Footnote **Variable Position Knee Joint (DIAL LOCK)** **What is going on w/ a knee that is stuck in _flexion?_**
* Knee that is stuck in _flexion_ (i.e. **crouched gait)** * GRF remains **posterior** to anatomical knee * → Diff for pt w/ **weakness or decd motor control** to maint. necessary counteractive force for **stance stab.**
31
KAFOs-Knee Control ## Footnote **Variable position knee joint (DIAL LOCK\*)** **How is it set and why?**
* Locked in **most EXTd pos. possible →** External mechanical stability * serrated disc→ **1 serration=6degs** * **\*may also provide _low load prolonged stretch_→ decs severity of contracture**
32
Various types of KAFOs **knee joints**
see pics
33
This KAFO **mimics a regular knee VERY closely** ## Footnote **\*similar to wt. activated prosth. knee**
Stance and Swing Phase Influencing joints ***Think “quad weakness”*** **\*\*\*\*\*\***
34
KAFOs-Knee Control ## Footnote **Stance and Swing Phase Influencing Joints**
* **Specifically for→** QUAD WEAKNESS * **Stance control W/OUT being locked in swing** * **Allows→** knee to _lock_ @ a point approximating IC (**first rocker)** and _unlock_ @ heel off (**beginning third rocker)** * **\*\*More natural gait pattern**
35
**Stance and Swing Phase Influencing Joints** **in a nutshell….**
**Locks** when you're about to hit IC (**first rocker)** and **Unlocks** when you're about to do Heel Off (**start of third rocker)**
36
KAFOs-Knee Control ## Footnote **Stance and Swing Phase Influencing Joints** **BENEFITS**
* **_Unlocking_ knee @ onset of 3rd rocker→** LESS compensatory mechs reqd to **clear foot** that would occur w/ a **locked knee** * circumduction, hip hike * LESS **enrgy expend. and low back stress**
37
GOLD STANDARD FOR **KNEE ORTHOTICS**
**Stance and Swing Phase Influencing Joints**
38
**Stance and Swing Phase Influencing Joints** **GOLD STANDARD FOR…**
KNEE JOINT ORTHOTICS
39
**Stance and Swing Phase Influencing Joints** **In essence, what is happening?**
* Dynamic loads trigger **locking and unlocking** of knee joint **depending on _where in gait cycle_ limb is** * LOCKING→ IC, MSt, * UNLOCKING→ LR, TST/PSW, SWING
40
KAFOs-Knee Control ## Footnote **Stance control orthotics**
* **Internal cams→** lock knee from upward press. on push rod * IC→Mst * **Cam unloads in late stance (TSt-PSw)→** lock disengages== knee flexion for limb clear.
41
KAFOs and knee control ## Footnote **Depends on 3 things:**
1. **Pts ability to understand _timing of gait_** 2. **Environment** 3. **Nature of task**
42
Orthotic knee can be set in 1 of 3 modes:
1. Auto stance control→ locks in **certain pos's** 2. Unlocked 3. Always locked
43
KAFOs-Knee Control LOOK THESE UP!!!
* UTX Swing and free walk * Swing phase lock * Load response joint * G knee * E knee
44
KAFOs-**Locking Mechanisms** ## Footnote **Ring or Drop Lock** **\*you've seen this** **What is it and who NOT to use w/**
* Standard lock captures m and f portions of upright **preventing unwanted flex or hyperEXT** * **Need FULL ext before lock/unlock** * **NOT INDICATED FOR:** * limtd hand function * sig LE spasticity * diff balancing w/ one AD
45
KAFO-**Locking Mechanisms** **Bail Lock** “the one where you have to back up into the table/chair to unlock the knee”
* Lever system connects Med/Lat locks * back up to seating surface * **Quad/glute strength to control descent OR use UEs** * **\*USE:** * Paraplegic pts who must maint. B/L UE support on crutches while standing
46
Designed for pts **w/ paraplegia _w/out_ hip control**
Craig-Scott KAFO
47
**Special** KAFO designs: ## Footnote **Craig-Scott**
* **For→ Paraplegia w/out hip control** * MIN bracing, MAX stability * **Single thigh (below isch tube) and calf band (below knee)**
48
**Special KAFO desigs** **Craig-Scott** **How it works**
* Has **DF assist** and **offset locking knee jt** * Teach to **hang in “Y” ligs of ant. hip** w/ **hyperlordosis @ L/S** * → induces GRF falls just **ant to knee (ext mom.) and post to hip (ext mom.)** * **Result→** No mm control reqd
49
**Special KAFO designs** **Craig-Scott** **Indicated for?**
* Good body awareness and proprio * Swing thru pattern for loco. * **Also effective→** DMD, spina bifida peds
50
KAFO w/ NO STABILITY
Single axis UNlocked
51
KAFO w/ MAX stability
Single axis LOCKED
52
OFFSET knee design and GRF
keeps GRF **anterior** to knee =\> inc stability in knee EXT
53
This KAFO accommodates Crouch Gait
Variable position locked \*DIAL LOCK
54
Indications vs Contraindications for Orthotic Knee Joint Designs ## Footnote **Chart**
See chart
55
Single Axis UNlocked ## Footnote **Indicated**
* Control genu valgum/varum
56
Single Axis LOCKED ## Footnote **Indicated**
* Stab. of flail knee w/out use of knee EXT moment and free knee jt motion * control genu recurvatum→ **IF orthosis only locked during amb.** * **control genu valgum/varum**
57
Offset UNlocked ## Footnote **Indicated**
* Stab. of flail knee w/ knee EXT moment and free knee joint motion * control genu recurvatum * control genu varum/valgum
58
Offset LOCKED ## Footnote **indicated**
* stab of flail knee w/OUT use of knee EXT moment and free knee jt motion * control genu recurvatum→ **when indiv will lock knee intermitt.** * control genu varum/valgum
59
Variable Position Locked (DIAL LOCK) ## Footnote **indicated**
* Reduction of knee flex contracture

Prosthetics&Orthotics (19 decks)

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