Exam 5: Prosthetics TransTib ReadGuide/Lecture/Foot chart, Feet

Question 1

Chart: What are the three overarching categories of prosthetic feet?

Answer 1

1. Conventional
2. Dynamic response, “energy return” (e.g. Flex, Springlite, Seattle,)
3. Microprocessor

Question 2

Chart: What are four types of conventional prosthetic feet?

Answer 2

1. SACH
2. Conventional Single Axix
3. Conventional Multi-Axis
4. Flexible Keel (e.g. SAFE, STEN)

Question 3

What is a SACH foot?

• Articiulating/non-articiulating?
• plus: what SACH stands for, plus 4 points
• Further summary if needed

Answer 3

A type of conventional foot.

non articulating, relies on flexibility of its structure for joint motion simulation

SACH (Solid Ankle Cushioned Heel)

• Before this, it was just a solid block of wood
• Allows smooth foot-flat (loading response)
  
  • simulates eccentric action of dorsiflexors
• Important to stop keel to allow roll over (not true heel off)
• This might would be okay for someone who just wants to transfer, but not more advanced.

From http://www.oandp.com/resources/patientinfo/manuals/9.htm:

The simplest type of non-articulated foot is the SACH (solid ankle-cushion heel) Foot. The keel is rigid. Ankle action is provided by the soft rubber heel which compresses under load during the early part of the stance phase of walking. The rubber heel wedges are available in three densities: soft, medium, and hard.

Question 4

Chart: SACH foot

• Cost
• Indications (4)
• Advantages (5)
• Disadvantages (4)

Answer 4

Chart: SACH foot

• Cost:
  
  • low
• Indications (4)
  
  1. Only need low level ambulation
  2. Juveniles
  3. NOT used for TF prostheses
  4. K1
• Advantages (5)
  
  1. Low Maintenance
  2. Durable
  3. Variety of heel heights available
  4. Good shock absorption
  5. Soft heel helps increase knee stability by creating an extension moment
• Disadvantages (4)
  
  1. Limited Dorsiflexion
  2. no propulsion in terminal stance
  3. Heel hight fixed
  4. No inversion/eversion

Question 5

Chart: SACH Foot Indications (4)

Answer 5

Chart: SACH foot

Indications (4)

• Only need low level ambulation
• Juveniles
• NOT used for TF prostheses
• K1

Question 6

Chart: SACH Foot, Advantages (5)

Answer 6

Advantages (5)

1. Low Maintenance
2. Durable
3. Variety of heel heights available
4. Good shock absorption
5. Soft heel helps increase knee stability by creating an extension moment

Question 7

Chart: SACH foot, disadvantages (4)

Answer 7

Disadvantages (4)

1. Limited Dorsiflexion
2. no propulsion in terminal stance
3. Heel hight fixed
4. No inversion/eversion

Question 8

Conventional Single Axis: What is it? (3 main points)

Answer 8

Single Axis

articulating- can have ankle moment in the sagittal plane

• Inside this foot is a joint (in ankle part)
• Anterior and posterior Bumpers
  
  • Bumpers are hard rubber, compress a little but not a lot
    
    • Posterior side squishes to allow/control actual plantar flexion
      
      • Gives softer foot flat
    • anterior bumper allows a little bit of dorsiflexion (most important in midstance to terminal stance)
• Only allows motion in sagittal plane
  
  • hard to walk on bumpy grass
    
    • whole tibia will want to tilt sideways because foot won’t accommodate

More from: http://www.oandp.com/resources/patientinfo/manuals/9.htm

Articulated feet may have one or more joints. The single-axis foot (one-joint) provides for ankle action that is controlled by two rubber bumpers either of which can be changed to permit more or less motion as needed. It is often used to assist in keeping the knee stable.

Question 9

Chart: Single Axis foot

• Cost
• Indications (1-2)
• Advantages (2)
• Disadvantages (4)

Answer 9

Chart: Single Axis foot

(conventional)

• Cost
  
  • low
• Indications (1)
  
  • Need for increased knee stability
    
    • (this aspect can apply to multiple types of feet)
• Advantages (2)
  
  1. Adjustible bumpers increase knee stability
  2. Can change bumpers for activity changes
• Disadvantages (4)
  
  1. Heavy
  2. Requires maintenance
  3. Parts may loosen and make noise
  4. Debris can enter and interfere

Question 10

Chart: Single Axis Foot, Indications (1)

Answer 10

Indications (1)

• Need for increased knee stability
  
  • (this aspect can apply to multiple types of feet)

Question 11

Chart: Single Axis Foot, Advantages (2)

Answer 11

Advantages (2)

1. Adjustible bumpers increase knee stability
2. Can change bumpers for activity changes

Question 12

Chart: Single Axis Foot, Disadvantages (4)

Answer 12

Disadvantages (4)

1. Heavy
2. Requires maintenance
3. Parts may loosen and make noise
4. Debris can enter and interfere

Question 13

What aspect of the Single axis foot can apply to multiple types of feet?

Answer 13

Need for incresaed knee stability is an indication for its use. I think this means that many types of feet can incorporate single axis joint to improve knee stability.

(so you will see this incorporated into multiple foot models)

Question 14

Conventional Multi-axis foot: What is it?

articulating/non-articulating?

(plus 3-4 points)

summary

Answer 14

Mulit-Axis Feet (many types)

articulating- can have ankle moment in sagittal, coronal, and transverse planes

• have features that allow a little bit of inversion/eversion to accommodate bumpy terrain
• split keel is an example of a foot that incorporates multi-axis (picture)
• These also have flexible feet (can’t remember what this means, but it is in my notes)

(conventional category)

More from: http://www.oandp.com/resources/patientinfo/manuals/9.htm

A multi-axis foot is often recommended for people who have to walk on uneven surfaces because it allows some motion about all three axes of the ankle. It is, of course, slightly heavier than the other types of feet and is apt to require more maintenance as well.

Question 15

Chart: Multi Axis foot

• Cost
• Indications (1-2)
• Advantages (1)
• Disadvantages (5)

Answer 15

Chart: Multi Axis foot

• Cost
  
  • low-mod
• Indications (1-2)
  
  • Need to ambulate uneven terrain
    
    • (this aspect can apply to multiple types of feet)
• Advantages (1)
  
  • good shock absorption
• Disadvantages (5)
  
  1. Heavy
  2. Less Stability on smooth surface
  3. Requires maintenance
  4. Parts may loosen and make noise
  5. Debris can enter and interfere

Question 16

Chart: multi-axis foot, indications (1-2)

Answer 16

Indications (1-2)

• Need to ambulate uneven terrain
  
  • (this aspect can apply to multiple types of feet)

Question 17

Chart: multi-axis foot, Advantages (1)

Answer 17

Advantages (1)

• good shock absorption

Question 18

Chart: multi-axis foot, Disadvantages (5)

Answer 18

Disadvantages (5)

1. Heavy
2. Less Stability on smooth surface
3. Requires maintenance
4. Parts may loosen and make noise
5. Debris can enter and interfere

Question 19

What aspect of the multi axis foot can apply to multiple types of feet?

Answer 19

Need to ambulate uneven terrain

Question 20

Flexible Keel: What is it?

Answer 20

Flexible Keel

(conventional category)

Seem to be very similar to SACH foot with a flexible keel to accomodate some ankle/foot motions. non-articulating

• posterior part of heel will bend a little bit at Initial Contact to allow for Loading Response
• As tibia comes forward, the front part of the foot will bend to allow tibial translation
• But it is not an energy return heel.
• Also for lower functional level amputee

Elastic (flexible) keel feet allow motion similar to that of SACH feet. In addition, they allow the forefoot to conform to uneven terrain but still remain stiff and stable during standing and walking. (http://www.amputee-coalition.org/military-instep/feet.html)

Question 21

Two examples of Flexible Keel Feet

Answer 21

SAFE foot (stationary attachment flexible endoskeletal) - pictured

STEN foot (name stands for “STored EN-ergy” foot, but it doesn’t actually store energy - it is a flexible keel)

Question 22

Picture of a STEN foot and more about it

Answer 22

Example of a flexible keel design

http://www.oandplibrary.org/cpo/1987_03_154.asp

Stands for “STored EN-ergy” foot

Slightly heavier than a conventional SACH foot, the STEN Foot differs in its dual articulated keel. In addition to a metatarsal-phalangeal articulation, it also features a tarsal-metatarsal articulation, thus permitting a smoother, more gradual roll-over than a solid SACH keel (Fig. 7).

We view the STEN Foot as an additional flexible keel design, similar to the SAFE foot, permitting a smoother roll-over and somewhat greater forefoot supination and pronation than the more rigid SACH design. Since it is lighter than the SAFE foot, fits the shoe more readily, and is available in a broad range of heel heights and sizes, it may offer some advantages.

Question 23

Picture of a SAFE foot and more about it

Answer 23

Very involved article here, if interested;

http://www.oandplibrary.org/op/1980_03_003.asp?searchquery=SAFE%20foot

The letters S.A.F.E. are the acronym for Stationary Attachment Flexible Endoskeleton or, in simpler language, a prosthetic foot bolted to the shin with a flexible keel as shown in Fig. 1. To be consistent with other endoskeletal systems, the bolt block of this foot and the flexible keel are encased in a soft foam cover, as shown by section in Fig. 2.

Question 24

Chart: Flexible Keel foot

• Cost
• Indications (2-3)
• Advantages (4)
• Disadvantages (3)

Answer 24

Chart: Flexible Keel foot

• Cost
  
  • Moderate
• Indications (2-3)
  
  1. Need for ease of ambulation, including uneven terrain, stairs, and inclines
  2. Obese K1
• Advantages (4)
  
  1. Low maintenance
  2. Variable heel heights
  3. Pediactric sizes available
  4. Smoother rollover
• Disadvantages (3)
  
  1. Heavier than SACH
  2. Costlier than SACH
  3. Poor push-off

Question 25

Chart: Flexible Keel, indications (2-3)

Answer 25

Indications (2-3)

1. Need for ease of ambulation, including uneven terrain, stairs, and inclines
2. Obese K1

Question 26

Chart: flexible keel, advantages (4)

Answer 26

Advantages (4)

1. Low maintenance
2. Variable heel heights
3. Pediactric sizes available
4. Smoother rollover

Question 27

Chart: flexible keel, disadvantages (3)

Answer 27

Disadvantages (3)

1. Heavier than SACH
2. Costlier than SACH
3. Poor push-off

Question 28

Dynamic Response, “energy return” foot: What is it?

Answer 28

Dynamic Response

compression of the keel in late stance is returned as push-off as the swing phase begins

• a whole lot better, because it gives the energy back
• first foot that simulates active toe off like a normal foot
• More the standard for the community ambulator now
• Can combine with split keel for uneven terrain
• Jeremy thought book said this was only for athletic people (I think that’s where they started, but now they are also used in community ambulator - as low as K2 [limited community ambulator])

More from: http://www.oandp.com/resources/patientinfo/manuals/9.htm

In recent years, there has been a proliferation of new designs for artificial feet. Most are capable of absorbing energy in a “flexible” keel during the “roll-over” part of the stance phase of walking and springing back immediately to provide push-off, or assistance in getting the toe off of the ground, to start the swing phase of walking. Although the original idea was to provide the active athlete with more function, amputees who are a lot less active have found these designs useful. These designs are often called “dynamic response” feet.

Question 29

Three examples of names of Dynamic Response feet:

Answer 29

1. Flex
2. Springlite
3. Seattle

Question 30

Chart: Dynamic Response foot

• Cost
• Indications (2)
• Advantages (3)
• Disadvantages (3)

Answer 30

Chart: Dynamic Response foot

• Cost
  
  • Moderate - Very High
• Indications (2)
  
  1. Increased activity needs
     
     • possibly including sports, running, inclines
  2. K-level: K2, K3, or K4
• Advantages (3)
  
  1. Light so allows jumping, running
  2. ML stability depends on whether keel is standard or split
  3. Some have improved cosmesis
• Disadvantages (3)
  
  1. High Cost
  2. Difficult to wear variable heel heights
  3. No real adaptations to uneven terrain unless split keel used

Question 31

Chart: Dynamic Response, indications (2)

Answer 31

Indications (2)

1. Increased activity needs
   
   • possibly including sports, running, inclines
2. K-level: K2, K3, or K4

Question 32

Chart: Dynamic Response foot, advantages (3)

Answer 32

Advantages (3)

1. Light so allows jumping, running
2. ML stability depends on whether keel is standard or split
3. Some have improved cosmesis

Question 33

Chart: Dyanmic Response foot, disadvantages (3)

Answer 33

Disadvantages (3)

1. High Cost
2. Difficult to wear variable heel heights
3. No real adaptations to uneven terrain unless split keel used

Question 34

What is an optional feature on the dynamic response foot that could have a large impact on its functionality?

Answer 34

whether or not it has a split keel

It will be hard to use on uneven terrain unless it has a split keel

Question 35

Microprocessor foot: what is it?

Answer 35

microprocessor-controlled hydraulic prosthesis that learns, adjusts, and dynamically adapts to a variety of terrains and gait speeds

Use a sensor in the shoe to tell the foot when to change positions?

Question 36

Chart: Microprocessor foot/ankle

• Cost
• Indications (1)
• Advantages (2)
• Disadvantages (4)

Answer 36

Chart: Microprocessor foot/ankle

• Cost
  
  • High
• Indications (1)
  
  1. K3
• Advantages (2)
  
  1. automatic DF/PF adjustment for inclines
  2. Some give propulsion
• Disadvantages (4)
  
  1. heavy
  2. battery/charging
  3. Maintanence/care
  4. Single axis

Question 37

Chart: microprocessor foot/ankle, indications (1)

Answer 37

Indications (1)

1. K3

Question 38

Chart: microprocessor foot/ankle, advantages (2)

Answer 38

Advantages (2)

1. automatic DF/PF adjustment for inclines
2. Some give propulsion

Question 39

Chart: microprocessor ankle/foot, disadvantages (4)

Answer 39

Disadvantages (4)

1. heavy
2. battery/charging
3. Maintanence/care
4. Single axis

Question 40

Which prosthetic feet may have low costs? (3)

Answer 40

1. SACH
2. Single Axis
3. Multi Axis (low - moderate cost)

Question 41

Which prosthetic feet may have moderate costs? (3)

Answer 41

1. Multi axis (low - moderate cost)
2. Flexible Keel (moderate cost)
3. Dynamic Response (Moderate - Very High cost)

Question 42

Which prosthetic feet may have high costs? (2)

Answer 42

1. Dynamic Response (moderate - very high cost)
2. Microprocessor (high cost)

Question 43

Which prosthetic feet may have very high costs? (1)

Answer 43

Dynamic Response (moderate - very high cost)

Question 44

How does heel height affect knee position?

Answer 44

Greater heel height can potentiate flexion of the knee

Question 45

TransTib Check out:

What positions/activities should we check and in what order? (6)

Answer 45

After donning prosthesis

1. Standing
2. Sitting
3. Walking in // (parallel bars)
4. Take it all off and do skin check

During weight bearing activities, also check for:

1. pistioning
2. distal contact

Question 46

TransTib Check out:

Put prosthesis on, stand them up and look: what should we see/check? (4)

Answer 46

(be sure they are in in 50/50 weight bearing for this)

Should see/check:

1. Level pelvis
2. Pylon should be vertical
3. Check trim Lines (we should have a rough idea on where trimlines should be)
   
   • Proximal trim lines should not be digging in or have gaps (no gaps or bulges - muffin top)
   • posterior trim line should be no more than ½ inch higher than patellar bar, to allow sitting with foot on the ground.
     
     • Don’t make it shorter because it will remove the counter pressure in the back that keeps the weight bearing surface more to the patellar tendon
4. Do Paper Test
   
   • put paper under shoe to see if there are equal forces. Should slide in just a little bit in every direction. If it goes in too far, then there is too much pressure on the opposite side (probably misalignment)

Question 47

Trans Tib Check out:

What should we see with trim lines?

Answer 47

Check trim Lines (we should have a rough idea on where trimlines should be)

1. Proximal trim lines should not be digging in or have gaps (no gaps or bulges - muffin top)
2. posterior trim line should be no more than ½ inch higher than patellar bar, to allow sitting with foot on the ground.

Question 48

Why can’t posterior trim line be shorter to allow more knee flexion?

Answer 48

• Can’t make it shorter because it will remove the counter pressure in the back that keeps the weight bearing surface more to the patellar tendon

**posterior trim line should be no more than ½ inch higher than patellar bar, to allow sitting with foot on the ground.

Question 49

What is the Paper Test?

Answer 49

Used during Trans Tib Check out while pt is standing

• put paper under shoe to see if there are equal forces. Should slide in just a little bit in every direction. If it goes in too far, then there is too much pressure on the opposite side (probably misalignment)

Question 50

Trans Tib Check out:

What should we check in sitting?

Answer 50

make sure pt can get 90 knee flexion to sit

Question 51

Trans Tib check out:

When pt is walking in // what are 3 suggestions to help us assess the gait?

Answer 51

Walking in // (where they feel safe)

1. look at gait from sagittal plane
2. look at gait from horizontal plane
3. look at one joint at a time

Question 52

How much pistoning do we want to see during gait?

Answer 52

we want zero

(but up to 1/4 inch is okay)

Question 53

Trans Tib Check out:

How do we assess for pistoning?

Answer 53

1. make a mark at the proximal trimline in weight bearing
2. then have them unload prosthesis and check the gap between line and trim line.

**¼ inch is okay

Question 54

How much distal contact do we want?

Answer 54

• we want distal contact to reduce distal edema (and deformities)
  
  • typically a little end pad
• BUT Do not want pressure there! (so not too much)

Contact not Pressure

Question 55

Trans Tib Check out:

How do we check for distal contact?

Answer 55

Put clay or play-dough in the bottom and have pt stand and walk.

• it should be a little deformed but not flattened.

**we want distal contact in order to reduce distal edema (and deformities), BUT Do not want pressure there, so must assess!

Question 56

Trans Tib Check out:

Details about skin check

Answer 56

teach your pt to look very carefully (probably will need a mirror)

• May see some redness
  
  • depends on what type of socket it is
    
    • more likely in PTB (okay around patellar tendon and medial flair)
    • less likely in TSB
• Redness should go away within ~10 minutes
  
  • if this doesn’t happen it is probably pressure damage is occurring

Question 57

True/False: After completing a prosthetic check out, if everything looks okay you should congratulate your patient and tell him to wear it all the time!

Answer 57

False

Pt must have wearing schedule (even if it fits well) to let body accomodate to it.

**Don’t send pt home with prosthesis unless they are trustworthy not to wear all the time

Question 58

What should you do if the pt says thier prosthesis hurts?

Answer 58

Take it off and look and see if you can figure out what is causing it to hurt.

Question 59

How can the sock help with fitting, and what would you teach the pt to do with sockes to adjust fit?

Answer 59

To adjust the socket fit

• adjust the ply of sock
  
  • too loose, add ply
  • too tight, take ply away

Question 60

Trans Tibial Check Out: Class activity

During check out, the amputee’s pelvis is high on ipsilateral amputated side. What are three reasons for this?

Answer 60

1. Too Long/Prosthetic heel too high
2. Residual limb not all the way in the socket, (too small)
   
   1. Bad fit
   2. improperly donned,
      
      • for example too many socks
3. Painful so lifting up hip to compensate

Question 61

Trans Tibial Check Out: Class activity:

Why did dr. M say that the wrong shoe (with heel too high) would not cause the amputee’s pelvis to be high on the ipsilateral amputated side during check out?

Answer 61

Wrong shoe (heel too high), changes the fit. (Dr. M said no. It would cause bilateral change, or most likely knee flexion on the affected side which would drop that hip not raise it. Even if it was a low heel it would cause hyperextension moment, but it won’t cause hip hike. It would cause more hip dip).

Question 62

Trans tibial Check out: Class activity

Name two reasons you might see excess hip pistoning.

(we thought of 5-6)

Answer 62

1. Socket too big (might not drop if suspension system well fitted, but she was looking for this answer - and said it was correct)
2. Inadequate suspension (suspension is wonky)
3. Time of day (volume changes)
4. Not enough socks
5. Improper donning (not enough socks)
6. Atrophy

Question 63

trans Tib check out:

What should we rule out if the hip is too high?

What should we try first?

Answer 63

Hip too high, rule out pt and donning problems.

Try re-donning it to see if it was a donning problem.

• Try without taking off stock first.
• If that doesn’t fix the problem re-don with less socks.
• If that doesn’t fix the problem, it may not be a donning problem (but use your brain and check anything else you think might be going wrong with donning, such as twisting, etc.)