Exam 5: Prosthetics TransTib ReadGuide/Lecture/Foot chart, Feet Flashcards
Chart: What are the three overarching categories of prosthetic feet?
- Conventional
- Dynamic response, “energy return” (e.g. Flex, Springlite, Seattle,)
- Microprocessor
Chart: What are four types of conventional prosthetic feet?
- SACH
- Conventional Single Axix
- Conventional Multi-Axis
- Flexible Keel (e.g. SAFE, STEN)
What is a SACH foot?
- Articiulating/non-articiulating?
- plus: what SACH stands for, plus 4 points
- Further summary if needed
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.
Chart: SACH foot
- Cost
- Indications (4)
- Advantages (5)
- Disadvantages (4)
Chart: SACH foot
- Cost:
- low
- Indications (4)
- Only need low level ambulation
- Juveniles
- NOT used for TF prostheses
- K1
- Advantages (5)
- Low Maintenance
- Durable
- Variety of heel heights available
- Good shock absorption
- Soft heel helps increase knee stability by creating an extension moment
- Disadvantages (4)
- Limited Dorsiflexion
- no propulsion in terminal stance
- Heel hight fixed
- No inversion/eversion
Chart: SACH Foot Indications (4)
Chart: SACH foot
Indications (4)
- Only need low level ambulation
- Juveniles
- NOT used for TF prostheses
- K1
Chart: SACH Foot, Advantages (5)
Advantages (5)
- Low Maintenance
- Durable
- Variety of heel heights available
- Good shock absorption
- Soft heel helps increase knee stability by creating an extension moment
Chart: SACH foot, disadvantages (4)
Disadvantages (4)
- Limited Dorsiflexion
- no propulsion in terminal stance
- Heel hight fixed
- No inversion/eversion
Conventional Single Axis: What is it? (3 main points)
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)
- Posterior side squishes to allow/control actual plantar flexion
- Bumpers are hard rubber, compress a little but not a lot
- Only allows motion in sagittal plane
- hard to walk on bumpy grass
- whole tibia will want to tilt sideways because foot won’t accommodate
- hard to walk on bumpy grass
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.
Chart: Single Axis foot
- Cost
- Indications (1-2)
- Advantages (2)
- Disadvantages (4)
Chart: Single Axis foot
(conventional)
- Cost
- low
- Indications (1)
- Need for increased knee stability
- (this aspect can apply to multiple types of feet)
- Need for increased knee stability
- Advantages (2)
- Adjustible bumpers increase knee stability
- Can change bumpers for activity changes
- Disadvantages (4)
- Heavy
- Requires maintenance
- Parts may loosen and make noise
- Debris can enter and interfere
Chart: Single Axis Foot, Indications (1)
Indications (1)
- Need for increased knee stability
- (this aspect can apply to multiple types of feet)
Chart: Single Axis Foot, Advantages (2)
Advantages (2)
- Adjustible bumpers increase knee stability
- Can change bumpers for activity changes
Chart: Single Axis Foot, Disadvantages (4)
Disadvantages (4)
- Heavy
- Requires maintenance
- Parts may loosen and make noise
- Debris can enter and interfere
What aspect of the Single axis foot can apply to multiple types of feet?
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)
Conventional Multi-axis foot: What is it?
articulating/non-articulating?
(plus 3-4 points)
summary
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.
Chart: Multi Axis foot
- Cost
- Indications (1-2)
- Advantages (1)
- Disadvantages (5)
Chart: Multi Axis foot
- Cost
- low-mod
- Indications (1-2)
- Need to ambulate uneven terrain
- (this aspect can apply to multiple types of feet)
- Need to ambulate uneven terrain
- Advantages (1)
- good shock absorption
- Disadvantages (5)
- Heavy
- Less Stability on smooth surface
- Requires maintenance
- Parts may loosen and make noise
- Debris can enter and interfere
Chart: multi-axis foot, indications (1-2)
Indications (1-2)
- Need to ambulate uneven terrain
- (this aspect can apply to multiple types of feet)
Chart: multi-axis foot, Advantages (1)
Advantages (1)
- good shock absorption
Chart: multi-axis foot, Disadvantages (5)
Disadvantages (5)
- Heavy
- Less Stability on smooth surface
- Requires maintenance
- Parts may loosen and make noise
- Debris can enter and interfere
What aspect of the multi axis foot can apply to multiple types of feet?
Need to ambulate uneven terrain
Flexible Keel: What is it?
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)
Two examples of Flexible Keel Feet
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)
Picture of a STEN foot and more about it
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.
Picture of a SAFE foot and more about it
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.
Chart: Flexible Keel foot
- Cost
- Indications (2-3)
- Advantages (4)
- Disadvantages (3)
Chart: Flexible Keel foot
- Cost
- Moderate
- Indications (2-3)
- Need for ease of ambulation, including uneven terrain, stairs, and inclines
- Obese K1
- Advantages (4)
- Low maintenance
- Variable heel heights
- Pediactric sizes available
- Smoother rollover
- Disadvantages (3)
- Heavier than SACH
- Costlier than SACH
- Poor push-off
Chart: Flexible Keel, indications (2-3)
Indications (2-3)
- Need for ease of ambulation, including uneven terrain, stairs, and inclines
- Obese K1
Chart: flexible keel, advantages (4)
Advantages (4)
- Low maintenance
- Variable heel heights
- Pediactric sizes available
- Smoother rollover
Chart: flexible keel, disadvantages (3)
Disadvantages (3)
- Heavier than SACH
- Costlier than SACH
- Poor push-off
Dynamic Response, “energy return” foot: What is it?
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.
Three examples of names of Dynamic Response feet:
- Flex
- Springlite
- Seattle
Chart: Dynamic Response foot
- Cost
- Indications (2)
- Advantages (3)
- Disadvantages (3)
Chart: Dynamic Response foot
- Cost
- Moderate - Very High
- Indications (2)
- Increased activity needs
- possibly including sports, running, inclines
- K-level: K2, K3, or K4
- Increased activity needs
- Advantages (3)
- Light so allows jumping, running
- ML stability depends on whether keel is standard or split
- Some have improved cosmesis
- Disadvantages (3)
- High Cost
- Difficult to wear variable heel heights
- No real adaptations to uneven terrain unless split keel used
Chart: Dynamic Response, indications (2)
Indications (2)
- Increased activity needs
- possibly including sports, running, inclines
- K-level: K2, K3, or K4
Chart: Dynamic Response foot, advantages (3)
Advantages (3)
- Light so allows jumping, running
- ML stability depends on whether keel is standard or split
- Some have improved cosmesis
Chart: Dyanmic Response foot, disadvantages (3)
Disadvantages (3)
- High Cost
- Difficult to wear variable heel heights
- No real adaptations to uneven terrain unless split keel used
What is an optional feature on the dynamic response foot that could have a large impact on its functionality?
whether or not it has a split keel
It will be hard to use on uneven terrain unless it has a split keel
Microprocessor foot: what is it?
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?
Chart: Microprocessor foot/ankle
- Cost
- Indications (1)
- Advantages (2)
- Disadvantages (4)
Chart: Microprocessor foot/ankle
- Cost
- High
- Indications (1)
- K3
- Advantages (2)
- automatic DF/PF adjustment for inclines
- Some give propulsion
- Disadvantages (4)
- heavy
- battery/charging
- Maintanence/care
- Single axis
Chart: microprocessor foot/ankle, indications (1)
Indications (1)
- K3
Chart: microprocessor foot/ankle, advantages (2)
Advantages (2)
- automatic DF/PF adjustment for inclines
- Some give propulsion
Chart: microprocessor ankle/foot, disadvantages (4)
Disadvantages (4)
- heavy
- battery/charging
- Maintanence/care
- Single axis
Which prosthetic feet may have low costs? (3)
- SACH
- Single Axis
- Multi Axis (low - moderate cost)
Which prosthetic feet may have moderate costs? (3)
- Multi axis (low - moderate cost)
- Flexible Keel (moderate cost)
- Dynamic Response (Moderate - Very High cost)
Which prosthetic feet may have high costs? (2)
- Dynamic Response (moderate - very high cost)
- Microprocessor (high cost)
Which prosthetic feet may have very high costs? (1)
Dynamic Response (moderate - very high cost)
How does heel height affect knee position?
Greater heel height can potentiate flexion of the knee
TransTib Check out:
What positions/activities should we check and in what order? (6)
After donning prosthesis
- Standing
- Sitting
- Walking in // (parallel bars)
- Take it all off and do skin check
During weight bearing activities, also check for:
- pistioning
- distal contact
TransTib Check out:
Put prosthesis on, stand them up and look: what should we see/check? (4)
(be sure they are in in 50/50 weight bearing for this)
Should see/check:
- Level pelvis
- Pylon should be vertical
- 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
- 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)
Trans Tib Check out:
What should we see with trim lines?
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.
Why can’t posterior trim line be shorter to allow more knee flexion?
- 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.
What is the Paper Test?
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)
Trans Tib Check out:
What should we check in sitting?
make sure pt can get 90 knee flexion to sit
Trans Tib check out:
When pt is walking in // what are 3 suggestions to help us assess the gait?
Walking in // (where they feel safe)
- look at gait from sagittal plane
- look at gait from horizontal plane
- look at one joint at a time
How much pistoning do we want to see during gait?
we want zero
(but up to 1/4 inch is okay)
Trans Tib Check out:
How do we assess for pistoning?
- make a mark at the proximal trimline in weight bearing
- then have them unload prosthesis and check the gap between line and trim line.
**¼ inch is okay
How much distal contact do we want?
- 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
Trans Tib Check out:
How do we check for distal contact?
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!
Trans Tib Check out:
Details about skin check
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
- depends on what type of socket it is
- Redness should go away within ~10 minutes
- if this doesn’t happen it is probably pressure damage is occurring
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!
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
What should you do if the pt says thier prosthesis hurts?
Take it off and look and see if you can figure out what is causing it to hurt.
How can the sock help with fitting, and what would you teach the pt to do with sockes to adjust fit?
To adjust the socket fit
- adjust the ply of sock
- too loose, add ply
- too tight, take ply away
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?
- Too Long/Prosthetic heel too high
- Residual limb not all the way in the socket, (too small)
- Bad fit
- improperly donned,
- for example too many socks
- Painful so lifting up hip to compensate
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?
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).
Trans tibial Check out: Class activity
Name two reasons you might see excess hip pistoning.
(we thought of 5-6)
- Socket too big (might not drop if suspension system well fitted, but she was looking for this answer - and said it was correct)
- Inadequate suspension (suspension is wonky)
- Time of day (volume changes)
- Not enough socks
- Improper donning (not enough socks)
- Atrophy
trans Tib check out:
What should we rule out if the hip is too high?
What should we try first?
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.)
