L2: AFOs Flashcards

1
Q

When we refer to “Traditional” orthotic

Whats that mean

A

Metal bars and leather

Old School!!!!!

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2
Q

Orthotics always go one joint above what you want to control

A

******

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3
Q

Rockers:

3

A
  1. Heel
  2. Ankle
  3. Toe (Forefoot)
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4
Q

Rockers:

Heel

A
  • IC→Foot flat
    • DEceleration of foot→floor
    • Wt Acceptance
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5
Q

Rockers:

Ankle

A
  • MSt as tibia advances over fixed foot
    • Triceps surae eccentrically controls speed of tibia (decelerates)
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6
Q

Rockers:

Toe (Forefoot)

A
  • Tst→ Push-off
    • BW rolls over MTP jts
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7
Q

AFO Terminology

A

NOTE: trimlines, straps, footplates

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8
Q

AFOs

Goals and Gait Prereqs:

A
  • Goal:
    • Safe, energy efficient gait
  • Gait Prereqs:
    • Stability in stance
    • Swing phase prepositioning
    • Clearance in swing
    • Adequate (symmetrical) step length
    • Energy conservation
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9
Q

Note about step length involved vs uninvolved

A

Involved LE will CAUSE shorter step length on contralateral side (good side)

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10
Q

AFOs

Stability in Stance

A
  • AFO controls instability by optimally aligning ankle
    • application and loc of forces in M/L or A/P directions
  • Ideal for pes equinus or ankle vaRus deforms
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11
Q

AFOs

Stability in Stance

Fulcrum vs Counter Forces

A
  • Fulcrum→ Anterior ankle
  • Counter forces→ Plantar surf foot and posterior proximal calf
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12
Q

AFO

Clearance in Swing

A
  • Keeps foot neutral==incd qual of swing due to:
    • Dec DF strength
    • poor timing
    • abnorm EXT synergy
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13
Q

AFO

Swing Phase Repositioning

A
  • Maintains ankle in neutral DF and ev/inv to prep for wt acceptance
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14
Q

AFO

Adequate Step Length

A
  • Maints stability of talocrurcal joint in TSt and PSw→ allows CONTRALAT. LIMB to maint. proper step length
  • effective propulsion of limb in Sw when needed
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15
Q

AFO

Energy Conservation

*CRITICAL in neuro pop.

A
  • Critical neuro pop→ return to IND community amb.
  • Controls ankle and knee jts during St and Sw===Less energy cost
  • *Less compensatory mechs==Less energy !!!
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16
Q

PF + DF associations

A

Excess PF== Knee EXT (PE class**)

Excess DF== Knee FLEX (buckling)

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17
Q

AFO

*rigid solid ankle AFO that fixes ankle in DF prevents

A

Knee HyperEXT

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18
Q

AFO-Force Systems

What all AFO’s do inherently

A
  • Notice where Fc is and what is being controlled!!!
  • Fp= proximal force
  • Fd= distal force
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19
Q

AFO force system

PF control

A

NOTE: Fprimary

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20
Q

AFO controlling excessive PROnation

notice Medial flange

A
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21
Q

MOST AFOs are ________

A

Custom Molded (MAFOs)

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22
Q

MAFOs

Custom Molded

A
  • Intimate fit, light, distributes forces effectively, fits most shoes, modified for relief,
  • Does NOT accommodate for fluctuating edema ***
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23
Q

AFO Types: 2

Classified by function

A
  1. Static Ankle Foot Orthosis
    1. MAX control
  2. Dynamic Ankle Foot Orthosis
    1. Incs DOF→ someone w/ better control
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24
Q

Static AFO’s

4:

A
  1. Solid Ankle
  2. Anterior Floor Reaction
    1. set in PF→ knee hyperEXT bias
  3. Patella Tendon Bearing
  4. Supramalleolar (SMO)
    1. high top→ PEDS
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25
Dynamic AFOs (DAFO) 4:
1. Posterior Leaf Spring (PLS) (Thermoplastic) 2. Conventional DF assist 3. Articulating thermoplastic 4. Hybrid (metal-plastic)
26
AFOs ex's
see pics
27
Static AFO's (max control) ## Footnote **Primary function**
* maint. ankle/foot in a **fixed pos.** @ TCJ, STJ, forefoot * **Effectively:** * assist w/ Sw clearance * preposition foot for IC * EXT stability for knee & ankle t/o **stance**
28
Static AFO ## Footnote **Solid (non-articulated) ankle AFO** **Drawbacks and what to do about it**
* **Drawback→** all rockers compromised * **AFO fabrication→ Shoe mods:** * Inc cushion heel→ compensates for **heel rocker** * **Rocker bottom (**entire sole)→ comps for **2nd/3rd rockers===** smooth forward translation t/o Stance
29
Solid Ankle AFO: ## Footnote **Indications**
* Those who need **total immob. of ankle/foot complex** * **Controls:** * Inv/Ev * foot drop (but not all need MAFO) * Ext tone/synergies→ Mod Ashworth know it!! * Knee hyperFLEX (biases to PF)/knee hyperEXT (biases to DF) → **you know WHY!!**
30
Solid Ankle AFO Thermoplastic piece
* Thermoplastic piece encompasses **most of lower leg** * Trimlines→ anterior to malleoli
31
Solid Ankle AFO ## Footnote **To control for abnorm toe grasp (CP, spastic CVAs):**
LONGER toe/footplate Tone inhibiting bar
32
Static AFOs **w/ articulation** have ability to max. control: ## Footnote **4 things:**
1. Ankle DF/PF 2. Inv/Ev 3. Knee hyperEXT 4. Knee buckling (hyperFLEX)
33
Static AFOs **w/ articulation have ability to max. control:** ## Footnote **Ankle DF/PF** **HOW?**
* **A/P force coupling→** 3pt system * Length of foot plate * Thickness of foot plate
34
Static AFO's **w/ articulation** have ability to max. control: ## Footnote **Inv/Ev** **HOW?**
* Med→Lat force coupling * Ankle/foot trimlines\*\*
35
Static AFOs **w/ articulation** have ability to max. control: ## Footnote **Knee hyperEXT** **HOW?**
Ankle/foot set in **slight DF** ***bc DF associated w/ FLEXION*****\*\***
36
Static AFOs **w/ articulation** have ability to max. control ## Footnote **Knee Buckling (hyperFLEX)** **HOW?**
Ankle/foot set in **slight PF** ***bc PF assoc'd w/ EXTENSION*****\*\*\***
37
Static AFO: ## Footnote **Anterior Floor Reaction** **\*protects against buckling**
* Harnesses **GR moment/force (GRF)** and converts into **sagittal plane stability** for the knee jt during **stance** * **\*Set in _slight PF_ to create _EXT moment_ @ knee** * **→** Bias towards keeping knee in EXT→ controls knee buckling/flex
38
Anterior Floor Reaction ## Footnote **More on PF role and setting:**
* Amt of PF, rigidity, length of toe plate== **degree of knee control** * PF-knee EXT **force couple** * padded anterior shell @ prox anterior tibia→ absorbs EXT moment
39
Anterior Floor Reaction ## Footnote **What is actually happening when set in _neutral_ or _slight PF_**
* Tibia restrained from advancing over fixed foot→ **2nd rocker** * GRF anterior to knee _earlier_ in St==more knee EXT force * Length+stiffness of toe plate INCs==3rd rocker limtd → biases knee into EXT
40
Anterior Floor Reaction + **Ground Reaction Moments**
41
Anterior Floor Reaction AFO ## Footnote **Biomechanically, what does it do?** **Indicated for based off of that?**
Enables pt w/ **little quad function** to be stable t/o **stance phase** * **Indications:** * **Weak quads**→ remember quads have to counter knee flexion moment\*\*\*\* * **Crouched gait**→ bc will lessen demand on quads by moving GRF anterior to knee sooner
42
Anterior Floor Reaction AFO ## Footnote **Based off what you know biomechanically….** **NOT indicated for:**
* **Not indicated:** * Uncontrolled genu recurvatum * **bc already hyperEXTd** * _Structural_ knee instab. (ligs) * Knee flex contracture \>10\* * AFR AFO will still control DF and knee flex, but will not create true EXT moment
43
Anterior Floor Reaction AFO stops/limits…
DF \*bc remember DF assoc'd w/ knee flex which could = buckling!!!
44
AFR AFO depicted in picture form…
see pics **read description!!!!**
45
The AFO w/ the “Knee pad” looking thing
Patella Tendon Bearing “PTB” AFO
46
PTB AFO ## Footnote **Primary goal:**
* Reduce **axial loading** to the **knee, foot, ankle**
47
PTB AFO ## Footnote **HOW does the PTB AFO reduce axial loading to knee, foot, ankle?**
* Set in **slight knee flex (10\*)** * BW _loaded_ onto anterior shell + patella tendon * ==\> DECd loads on tib, fib and bones of foot\*\*\*
48
PTB AFO EXCELLENT OPTION for…
* anyone who reqs **reduced WB thru foot:** * CMT ankles * Neuropathic ulcers on **plantar surface** * slowly healing fx's of foot
49
PTB AFO pics
see pics
50
Supramalleolar Orthotic (SMO) ## Footnote **Biomechanical function:**
* Incs control of **STJ valGus and vaRus** by lengthening proximal lever arm upward * Think “**high-top sneaker”**
51
SMO ## Footnote **Based off biomechanic function….** **Indications:**
* CP after corrective sx→ tendon lengthening * Chronic INV instab.→ STJ trauma * Periph neuropathy * MM disease * Pts w/ adequate **knee strength/control** * **\*\*\*SMO won't correct knee!!!!**
52
Static AFOs **prevent** DF/PF ankle mvmts necessary to perform functional activities efficiently see pics and **notice compensations**
see pics
53
Posterior Leaf Spring (PLS)→ Dynamic AFO \***2 things to remember:**
1. **Narrow trimline** 2. **MORE _intrinsic_ mobility of foot**
54
Posterior Leaf Spring PLS→ Dynamic AFO ## Footnote **ALL _Dynamic AFOs_ allow this:**
Sagittal plane motions @ ankle\*\*\*
55
**PLS Distinction** from all dynamic AFOs
* Trim lines **well behind med/lat malleoli==\> more flexibility** * **\*_Thickness_ of thermoplastic==\> determines flexibility**
56
PLS and the Rocker Systems ## Footnote **1st→3rd**
* **1st Rocker** * PLS provides **controlled lowering of foot** toward ground * **2nd Rocker** * **Flexibility** of PLS allows enough DF for **tibial advance.** over foot in **MSt** * **3rd Rocker (PSw) and Sw** * PLS hold ankle @ 90\* (neutral)→ assists w/ **clearance + pos'ing for next heel strike**
57
PLS trades _____ for \_\_\_\_\_\_\_
PLS trades **stability** for **mobility**
58
**Drawbacks of PLS**
* DECd **mediolateral control** * DECd **knee control** * not structured to control knee * NOT effective w/ **mod-severe spasticity** * they'll burst right thru it PLS trades stability for **_mobility_**
59
Spiral AFOs
\*Semirigid plastic * **During stance→** Uncurls (widens) as limb accepts wt * **MSt→** ankle comes to neutral→ returns to orig. shape * **MSt-TSt→** sprial compresses (like coiled spring)→ aids in push-off as ankle DFs * **Swing→** spiral returns to orig shape to **hold foot in neutral**
60
Only difference bw **Spiral AFO vs. HemiSpiral AFO**
Hemi employs same mechanics w/ **slightly greater control of Pes Varus (supination)\*\*\***
61
Hemi-Spiral AFOs
* Same mechanics as spiral _BUT_→ **slightly greater control of _pes varus_ (supination)** * No fasteners, light wt. * **Intimate fit→** NOT for edetamous limbs * **Mod control of foot and ankle** * trimline ht and thickness thermoplastic
62
Spiral and hemi-spiral AFOs Ex's
63
Conventional AFO→ Dynamic AFO aka
Metal uprights w/ leather
64
Conventional AFO→ Dynamic AFO ## Footnote **Ankle control**
* Ankle control w/ ***stops*** and ***assists*** * Biochannel adjustable ankle lock (BiCAAL) vs single channel joint * **Ankle stops named** for **motion they _RESTRICT_\*\*** * DF stop or PF stop * **Most common→** 0\* PF stop (stops unwanted PF) * useful to clear foot during Sw
65
Conventional AFO ## Footnote **More on Ankle Stops** **What stop would be useful for controlling _knee buckling (excess. flexion)_ from LR→MSt?**
DF Stop \***Bc excess DF assoc'd w/ excess Knee Flexion (buckling)**
66
Conventional AFO (double upright AFO) w/ Jt Controls
Bichannel (2 channels) adjustable ankle lock (BiCAAL)
67
Conventional AFO ## Footnote **DF Assist**
* **MOST Common→** Spring mech. incorp'd into mech. ankle jt to assist **DF\*\*\*** * Mech. that produces force to aid in desired jt motion * **Compressed** during **late stance** and **recoils during Swing** * To ADD/DEC DF assist: * tighten/loosen screw adding tension to spring\*\*\*
68
Conventional AFO-**DF Assist**
* **Approp for→** gross DF strength defs * peroneal N. palsy, CMT * **DF assist/PLS not ideal→** those w/ hypERtonicity and neuromotor equinovaRus * \>\>\> option for fluctuating edema * **Drawbacks→** * incd wt. * dec surf area * min→none M/L stability
69
Conventional AFO w/ **Calcaneal VaRus/ValGus Control Strap**
* Named for where the **wider, non-buckle side of strap is (see pics)** * **LATERAL strap→** CORRECTS calcaneal vaRus (subtalar INversion) * **MEDIAL strap→** CORRECTS calcaneal vaLGus (subtalar EVersion)
70
Conventional AFO w/ **calcaneal varus/valgus control strap** ## Footnote **\*named for side where BIG lg surface area part of strap is!!! see pic for example slide 50** **LATERAL STRAP**
* L→M force * Corrects **calcaneal vaRus or subtalar INversion**
71
Conventional AFO w/ **calcaneal varus/valgus control strap** ## Footnote **\*named for side where BIG lg surface area part of strap is!!! see pic for example** **MEDIAL STRAP**
* M→L force * Corrects **calcaneal valGus** or **subtalar EVersion**
72
Articulating (**hinged)** Thermoplastic AFO \*NOTE: person must have how much **active** DF to be able to use?
5\* **active DF**
73
Articulating (**hinged)** thermoplastic AFO
* bw foot/calf * **5\* active DF needed\*\*\*** * **Effective how?→** adding **PF stop** mechanism (usually @ 90\*)
74
One of the Goals w/ Orthotics
Wear least amt of extrinsic stuff while controlling as much as we can\*\*\*\*
75
Articulating Thermoplastic AFO Benefits of the hinge mech.
* Easy progress thru 1st/2nd rockers * Controls **knee hyperEXT in MSt** * INC mobility * Energy efficient
76
Articulated thermoplastic AFOs Ex's
**A&B→** True single-axis joints **C→** Allows mvmt into DF/PF _w/out_ an _actual articulation_
77
Articulated (hinged) thermoplastic AFO Can have a DF/PF stop T/F?
TRUE!!!!
78
Hybrid (**Plastic→Metal) AFO** ## Footnote **Defined:**
* _Adjustable_ ankle-locking jt. * NOT METAL uprights→ thermoplastic instead
79
Hybrid Plastic-Metal If you **WANT MOTION→**
* Coil spring placed in channel + screw tightened d
80
Hybrid Plastic-Metal If **motion needs to be _BLOCKED_→**
* Solid steel pins inserted **instead of spring** to **stop motion** _beyond particular point_ * **NOTE:** Can stop PF and **allow PF** as neuromotor control dictates\*\*\*
81
Hybrid Plastic-Metal
* Versatile/adjustable→ easy to work with * **Indications→** * those who have _rapid changes_ in **functional status**
82
Static\>\>\>\>Dynamic AFOs
see pics
83
AFO and shoes ## Footnote **AFO use and benefit _interrelated_ w/ _cond/type_ of shoe\*\*\***
* INC **½ to 1 shoe size** * **Heel hts→** dramatically alter biomechanics or orthotic * **More stable, solid AFO==\>** SOFTER heel reqd * Ex. rocker bottom (bc rockers lost w/ these) * \*PLS loses effectiveness in loafer/slippers
84
Ex's AFO Conventional, MAFO, Articulating
see pics
85
Take Home Messages ## Footnote **AFO's**
1. Must be **comfortable** 2. Must **look good** 3. **Thermoplastic==MOST COMMON** 4. AFO should provide **support for stability in stance** AND **clearance in Swing** _WITHOUT COMPROMISING_ **rocker systems**