FAQs

Alpha® Liners - General

How should Alpha® Liners be cleaned?

What should Alpha® Liner wearers do to deal with daily changes to the volume of their limbs?

What might cause an Alpha® Liner user to develop a skin irritation?

Are there any tips for traveling with Alpha® Liners?

 

Alpha® SmartTemp™ Liners Featuring Outlast®

How is this liner different from other liners, regardless of silicone, urethane or thermoplastic elastomer?

How does this liner work in cold temperatures?

How does this liner stop a patient from sweating?

This is a silicone liner but the details say it acts like a thermoplastic elastomer. What’s the liner durometer, or firmness, like?

Who is this liner appropriate for…or for what activity level?

Does the Alpha SmartTemp Liner retrofit with other liners?

Do these liners need to be stored differently?

What are the care instructions for the silicone of this liner?

Will the performance of the Outlast® material reduce over time?

Is this liner suitable for use with amputees who are also diabetic?

How does the Alpha SmartTemp Liner compare to the Alpha Silicone or WillowWood Express Liners?
 

WillowWood Express Liners

What does ‘soft’ silicone mean and how can it replicate the feel of TPE?

What sizes other than Medium Plus and Large may be ordered in the Express Liner?

How does sizing compare between the Express Liners and the Alpha Classic and Hybrid Liners?

When will additional liner profiles be available?

Is a new socket needed in order to use an Express Liner?

Does the Express Liner have mineral oil in it?

Can amputees use mineral oil or other skin conditioners with the Express Liner?

Are lubricants or powders needed in order to don this silicone liner?

Can the Express Liner be heat-stretched?

How much testing has been done on the Express Liner?

What are the care instructions for the silicone of the Express Liner?

How should a clinician modify a shape for a vacuum socket if a patient has been cast over the Express Liner?

WillowWood has previously stated that the Original fabric now being used on the Express Liner is inappropriate for use in a vacuum environment. What makes it OK to use it now?

How much does the WillowWood Express Liner, made of silicone, weigh in comparison to an Alpha Classic or Hybrid Liner that was made of TPE?


Feet

What makes the Pathfinder® II different from other feet?

Which prosthetic foot is best for a particular patient?


LimbLogic®

Do you offer training courses on the LimbLogic VS?

Can LimbLogic VS be used with Thermoplastic Sockets?

What comes in a LimbLogic VS box?

What comes in the Thermoplastic Drop-in Adapter kit?

To fabricate a thermoplastic LimbLogic VS socket, do I need a tooling kit?

How many applications are available from the Resin Kit that comes with the Thermoplastic tooling kit?

Is the LimbLogic VS waterproof?

What changed from the old unit to the new waterproof version of LimbLogic VS?

May I return an older LimbLogic VS unit (1500 series) and get the new waterproof version (1600 series)?

Can the LimbLogic VS 1500 series be used in water?

What is the warranty for the LimbLogic VS?

Is there a trial period for the LimbLogic VS?

How much does the LimbLogic VS vacuum pump weigh?

What is the battery life for the LimbLogic VS?

Are any special procedures required for fabricating a socket for use with LimbLogic VS?

When using the LimbLogic VS, does the socket need to be sealed?

What type of maintenance is required for the LimbLogic VS?

What are the LimbLogic VS system settings?

What type of liners should be used with the LimbLogic VS?

How do I convert from inches of mercury (in-Hg) to millimeters of mercury (mm-Hg)?

How does vacuum suspension work?

What is the difference between suction suspension and vacuum suspension?

What L-codes are suggested for the LimbLogic VS system?

What is the torque required to attach the LimbLogic VS pump to the prosthesis?

What is the difference between the System Maximum, the User Maximum, and the Upper Set Point?


Pediatric

Does WillowWood make prosthetic components for children?

What is the difference between the Pediatric SACH Foot and the Pediatric  Impulse® Foot?


Suspension

When should a suspension sleeve (or seal) be worn?

Which type of suspension is best – suction, vacuum, or locking pin?


General

I am an amputee. Can I buy directly from WillowWood?

Does weight gain or weight loss impact the comfort of a lower extremity prosthesis?

Can you recommend an amputee support group?

In addition to support groups, are there any additional resources for parents of amputees?

How do I find the best prosthetist for me?

What can an individual do to ensure that a prosthesis is covered by medical insurance companies?

Some amputees wear cosmetic coverings over their prostheses and others don’t. Is there any reason for wearing a covering or not?

Plaster casting is so messy and time-consuming. Are there any alternatives?

 

Answers


How should Alpha® Liners be cleaned? 

At the end of the day, wash the liner with water and a body soap that does not irritate the skin. Allow the liner to dry on the drying stand overnight. Once a week, disinfect the liner by wiping the gel with ethyl or isopropyl alcohol and allowing the liner to dry overnight. 

Back to top


What should Alpha Liner wearers do to deal with daily changes to the volume of their limbs?

Back to top


What might cause an Alpha® Liner user to develop a skin irritation? 

Back to top


Are there any tips for traveling with Alpha® Liners? 

Back to top

How is this liner different from other liners, regardless of silicone, urethane or thermoplastic elastomer?

The Alpha® SmartTemp™ Liner uses Outlast® technology to pull heat away from an amputee’s limb throughout the day as well as during times of high-activity or elevated temperature. To help illustrate this, think of a sponge. When dry, a sponge is firm to the touch. When placed in water, a sponge soaks up the water until is it completely saturated. Once all the water is absorbed by the sponge, over a period of time the water evaporates out of the sponge and it returns to its dry state. The Alpha SmartTemp Liner with Outlast® goes through the same basic cycle, but with heat rather than the water in our sponge example. The length of time it takes for all the absorbed heat to be released can vary depending on a person’s environment and if the liner is left on a residual limb or removed.

The Alpha SmartTemp Liner also differs from other liners in regards to its firmness. Using the same sponge example as above, the dry sponge is firm to the touch. As the sponge absorbs water, it becomes softer to the touch and more flexible. After the water is removed from the sponge and it dries, the sponge returns to its firm state. The Alpha SmartTemp Liner with Outlast® responds similarly to heat as it is absorbed and stored in the liner. The silicone of the liner is firm before it is donned onto a residual limb. As the liner absorbs heat, the silicone properties begin to act more like thermoplastic elastomer. When the liner is removed from a limb or an amputee moves to a cooler environment, the stored heat is released and the silicone reverts back to its normal state.

At any activity level, the Alpha SmartTemp Liner absorbs heat while on an amputee’s limb creating a comfortable skin temperature level by balancing the amputee’s skin temperature and the liner temperature. The liner though can become saturated with heat and can reach a point at which it can no longer absorb more heat. Once the liner is saturated with heat it needs to be cooled back to room temperature and return to its normal state. After the liner is cooled, which could be achieved by doffing the liner and letting it rest or by going into a cooler environment such as an air-conditioned building, it will once again be ready to absorb and store heat.

Back to top
 

How does this liner work in cold temperatures?

The Alpha SmartTemp Liner with Outlast® works the same in warm or cold temperatures. The liner will absorb heat from the residual limb to create a comfortable skin temperature. However, the colder the environmental temperature, the quicker the liner dissipates the absorbed heat.

Back to top

How does this liner stop a patient from sweating?

The technology in the Alpha SmartTemp Liner does not stop sweating. The Outlast® material that is included in the liner will delay the onset of sweating and should delay patients from excessively sweating. During clinical testing, several amputees reported they could wear the liner 14 to 20 hours without having to remove the Alpha SmartTemp Liner, pour out the accumulated sweat, dry their limbs and liners, then re-don the liners. By incorporating Outlast® with the silicone, the liner absorbs heat from a person’s limb and environment, stores it in the liner, and delays sweat from starting.

Every amputee is different. A person’s activity level, environment, and personal metabolism are all variables that contribute to how long the onset of sweat is delayed. This can vary for each individual yet all amputees who wear the liners will realize the benefits of the liner technology.

Back to top
 

This is a silicone liner but the details say it acts like a thermoplastic elastomer. What’s the liner durometer, or firmness, like?

The Alpha SmartTemp Liner is a silicone and has a durometer similar to our Alpha Silicone Liners. By incorporating Outlast® with the silicone, the liner absorbs heat from a person’s limb and environment and stores it in the liner. Once the Alpha SmartTemp Liner is donned, has absorbed heat, and is warm, the liner durometer then is similar to that of thermoplastic elastomer, or gel liner. The liner actually becomes more comfortable throughout the day as it is worn.

Back to top

Who is this liner appropriate for…or for what activity level?

The liner is suitable for any activity level. Amputees who regularly experience mild/moderate perspiration or discomfort from heat or sweat are candidates for the Alpha SmartTemp Liner. Additionally, amputees who currently wear silicone and like its durability yet desire a more comfortable interface are also be appropriate candidates for this liner.

However, amputees with fragile or highly-sensitive skin may not be best suited for Alpha SmartTemp Liner.

Back to top
 

Does the Alpha SmartTemp Liner retrofit with other liners?

Yes! Any liner with WillowWood’s progressive or symmetrical AK profiles will retrofit with the Alpha SmartTemp Liner. Alpha Classic Liners, Alpha Hybrid Liners, and Alpha Silicone Liners with progressive profiles will retrofit with an Alpha SmartTemp Liner with a progressive profile. Likewise, an Alpha Classic AK Liner, Alpha Hybrid AK Liner, or Alpha Silicone AK Liner with a symmetrical AK profile will retrofit with the Alpha SmartTemp AK Liner.

Back to top

Do these liners need to be stored differently?

No, Alpha SmartTemp Liners may be stored the same as other Alpha Liners.

Back to top
 

What are the care instructions for the silicone of the this liner?

The care instructions for this liner have not changed. At the end of each day, wash the liner with water and a body soap that does not irritate the skin. Allow the liner to dry on the drying stand overnight. Once a week, disinfect the liner by wiping the interior with ethyl or isopropyl alcohol and allowing the liner to dry overnight.

Back to top

Will the performance of the Outlast® material reduce over time?

No, Outlast® does not degrade over time.

Back to top
 

Is this liner suitable for use with amputees who are also diabetic?

The Alpha SmartTemp Liner is suitable for a variety of patients. Several of our test patients who participated in clinically testing this liner were diabetics. These patients had healthy residual limbs and experienced no problems with the Alpha SmartTemp Liner. The decision to use this liner on diabetic amputees is up to an individual’s clinician. An amputee’s lifestyle/activity level, environment, and metabolism as well as skin sensitivity should be considered in clinical decision-making.

Back to top
 

How does the Alpha SmartTemp Liner compare to the Alpha Silicone or WillowWood Express Liners?

All of these liners use a proprietary, platinum-cured, medical grade silicone. The liners do share some common traits such as profiles and fabrics yet they also each have unique characteristics.

WillowWood Express Liner is a softer-durometer silicone that replicates the feel and comfort of thermoplastic elastomer (gel) liners. The profiles of this liner are uniform for transtibial use and AK for transfemoral use. Original or Select fabrics are used for transtibial liners and Spirit or MAX fabrics are used for transfemoral liners.

Alpha Silicone Liner is unique blend of silicone, Vitamin E, and skin conditioners with a surface that is non-greasy and comfortable against the skin. The profiles for this liner are progressive for transtibial use and Symmetrical AK for transfemoral use. The Alpha Silicone Liner uses the one-way stretch Select fabric to control pistoning.

Alpha SmartTemp Liner featuring Outlast® is the only liner in the WillowWood product line, as well as within the industry, that blends silicone with Outlast®, the original heat management technology. The liner absorbs heat from the residual limb, stores it, then releases the heat as the liner cools, thereby delaying the onset of sweat and helping an amputee stay comfortable throughout the day. The profiles for the Alpha SmartTemp Liner are progressive for transtibial use and Symmetrical AK for transfemoral use and can retrofit with any Alpha Liner having these same profiles. The liner uses Select fabric.
 

Back to top

 

What does ‘soft’ silicone mean and how can it replicate the feel of TPE?

We’ve adjusted the silicone formula used in our Alpha Silicone Liners in order to create what can best be described as a ‘soft’ silicone. This means that the durometer of the soft silicone is much less than the silicone in our Alpha® Silicone Liners.

The silicone of the Express Liner is soft to the touch and exhibits some performance characteristics common to our Alpha Classic Gel. For example, the soft silicone in the Express Liner flows away from high-pressure areas yet rebounds back to its original shape like that of silicone.

Back to top

What sizes other than Medium Plus and Large may be ordered in the Express Liner?

We have broadened the product offerings for the Express Liner since its initial release. We are working to expand into additional options as quickly as possible. Please check the product page for updates or call our customer care team at 800.848.4930 for the latest.

Back to top
 

How does sizing compare between the Express Liners and the Alpha Classic and Hybrid Liners?

We’ve kept sizing simple. The size worn in an Alpha Classic or Alpha Hybrid is the same size an amputee would wear in the Express Liner. If an amputee wore an M+ Alpha Classic Liner with a 6 mm, uniform profile, they would wear an M+ WillowWood Express Liner with 6 mm, uniform profile.

Back to top
 

When will additional liner profiles be available?

We are working to expand into other profiles as quickly as possible. Please check the Express Liner product page for updates or call our customer care team at 800.848.4930 for the latest.

Back to top

Is a new socket needed in order to use an Express Liner?

For amputees currently wearing a 6 mm, uniform profile Alpha Classic or Alpha Hybrid Liner it should not be necessary to make a new socket if switching to an Express Liner. In our clinical testing, our test patients were able to be retrofitted into the Express Liner and continue to use their existing sockets.

Back to top

Does the Express Liner have mineral oil in it?

No, however our blend of silicone used in the Express Liner includes Vitamin E as well as a skin-friendly emollient that is light, non-greasy, and moisturizing.

Back to top

Can amputees use mineral oil or other skin conditioners with the Express Liner?

Our recommendation would be to use mineral oil or desired skin conditioner overnight rather than when wearing the liner.

Back to top
 

Are lubricants or powders needed in order to don this silicone liner?

No lubricants, oils, or powders of any kind are needed in order to don the WillowWood Express Liner.

Back to top
 

Can the Express Liner be heat-stretched?

If the Express Liner has Original Fabric, it may be heat-stretched. We have tested heat-stretching the Express Liner in Original fabric. It may be done with a slight gain in patient fit. If you wish to heat-stretch, please click here for instructions. Heat-stretching so NOT recommended for Express Liners that have Select Fabric.

Back to top

How much testing has been done on the Express Liner?

We’ve conducted both mechanical and clinical testing on the Express Liners. Performance of the liner has consistently performed at levels comparable to our Alpha Classic Gel throughout our gamut of mechanical tests. Clinically, all Express Liners have successfully retrofitted with existing sockets of our test patients. Additionally, we have previously conducted biocompatibility testing on the elements used in this silicone formula and no concerns were reported.

Back to top
 

What are the care instructions for the silicone of the Express Liner?

The care instructions for this liner have not changed. At the end of the day, wash the liner with water and a body soap that does not irritate the skin. Allow the liner to dry on the drying stand overnight. Once a week, disinfect the liner by wiping the gel with ethyl or isopropyl alcohol and allowing the liner to dry overnight.

Back to top

How should a clinician modify a shape for a vacuum socket if a patient has been cast over the Express Liner?

Volume reductions are consistent with those previously done with Alpha Classic and the Alpha Hybrid Liners.

Back to top


WillowWood has previously stated that the Original fabric now being used on the Express Liner is inappropriate for use in a vacuum environment. What makes it OK to use it now?

It is what is on the inside of a liner that makes the primary difference rather than the fabric. Alpha Classic Liners with Original fabric were composed of thermoplastic elastomer which contained mineral oil. Our testing had found that mineral oil would ‘leech’ through the Original fabric and into the vacuum pump.

The Express Liner uses our soft silicone which contains no mineral oil. This makes the liner, with the Original Fabric, compatible for use with elevated vacuum.

Back to top

How much does the WillowWood Express Liner, made of silicone, weigh in comparison to an Alpha Classic or Hybrid Liner that was made of TPE?

Expect this silicone liner, of equal volume, to be about 25% heavier than an Alpha Classic or Hybrid Liner that was made of TPE.

Back to top
 

What makes the Pathfinder® II different from other feet?

Unlike any other foot, the Pathfinder II features a toe spring, a foot plate, and a pneumatic heel spring all connected in a triangular configuration. This design provides shock absorption during heel strike without diminishing the energy return of the toe spring. The result is a foot that requires less energy for walking or running, yet provides excellent balance and stability.

Back to top


Which prosthetic foot is best for a particular patient?

Every amputee is different, and every amputee has different needs. Amputees must talk to their prosthetists about their pre-amputation activity level, their current activity level, and the activity level they hope to achieve. Foot weight, energy return, and response must also be discussed so that the prosthetist can select a foot that matches the amputee’s needs.

Back to top

 
Do you offer training courses on the LimbLogic VS?

We offer live courses for both prosthetists and technicians at our Education Center. For those who are unable to attend the live courses, we also offer online courses. Click here to register for any of these courses.

Back to top


Can LimbLogic VS be used with Thermoplastic Sockets?

Yes. When ordering the LimbLogic VS, be sure to specify that a thermoplastic socket will be used so that the correct adapter will be shipped.

Back to top


What comes in a LimbLogic VS box?

Each single-unit box includes a LimbLogic VS pump, a hand-held fob, a lamination kit OR a thermoplastic fabrication kit, a patient accessory kit, the patient and prosthetist manuals, a battery charger, and an international power plug.

Back to top


What comes in the Thermoplastic Drop-in Adapter kit?

A drop-in adapter, a Poron Filter, four M6 x 55 screws, a ¼ x 20 Cap Screw, a Plastic Anchor, a Latex Form, and two Forming Sleeves (one large, and one small). The kit also includes a fabrication instructional video.

Back to top


To fabricate a thermoplastic LimbLogic VS socket, do I need a tooling kit?

Yes, a one-time purchase of a Thermoplastic Tooling Kit (LLV-02100) is required.

Back to top


How many applications are available from the Resin Kit that comes with the Thermoplastic tooling kit?

You should get 6-8 applications from the resin in the kit. Additional resin is available by the gallon (LLV-02102).

Back to top


Is the LimbLogic VS waterproof?

The newest version of the LimbLogic VS pump (the 1600 series) is waterproof for FRESH WATER only to a depth of 3 meters (10 feet) for up to 12 hours at a time. The hand-held fob is NOT waterproof and should not get wet.

Back to top


What changed from the old unit to the new waterproof version of LimbLogic VS?

We improved the process for sealing each pump, and we test each unit to guarantee waterproofing.

Back to top


May I return an older LimbLogic VS unit (1500 series) and get the new waterproof version (1600 series)?

Yes, if the LimbLogic VS unit is new and in an unopened box. Call us to get an RMA for the old unit and to place an order for the new unit.

Back to top


Can the LimbLogic VS 1500 series be used in water?

LimbLogic VS has been water resistant since the product was launched. If a patient was in a wet environment, the LimbLogic VS was usually not at risk.

Back to top


What is the warranty for the LimbLogic VS?

Two years. Damage from misuse is not covered.

Back to top


Is there a trial period for the LimbLogic VS?

Yes, there is a 30 day trial period.

Back to top


How much does the LimbLogic VS vacuum pump weigh?

190 gm (0.4 lbs).

Back to top


What is the battery life for the LimbLogic VS?

The pump’s battery life depends on the quality of the seal and the amputee's activity level. Our tests show that the system can normally last between 1 day and 1 week on a patient. We recommend charging the unit daily. The fob has a user-replaceable CR2 camera battery that should last 6 months with normal usage.

Back to top


Are any special procedures required for fabricating a socket for use with LimbLogic VS?

Yes. An airtight socket is critical to proper operation of the overall system. We recommend specific fabrication methods to achieve airtight sockets. These methods are included in the kit instructions, are available on our website, and are taught in our training classes.

Back to top


When using the LimbLogic VS, does the socket need to be sealed?

Yes. An airtight sealing sleeve in normally required, but there may be other methods for achieving a good vacuum seal.

Back to top


What type of maintenance is required for the LimbLogic VS?

Keep debris away from the filter in the socket, and flush the system monthly with water or isopropyl alcohol per the user instructions.

Back to top


What are the LimbLogic VS system settings?

The vacuum is adjustable from 0 to 20 in-Hg (508 mm-Hg) with most BK patients using a 10 to 16 in-Hg upper set point. The default control range is a span of 6 in-Hg.

Back to top


What type of liners should be used with the LimbLogic VS?

Our tests show that the best compatibility with vacuum is provided by Alpha Select Liners and pre-fabricated or custom Alpha MAX Liners. When using Alpha Select Liners, we typically use the Progressive gel pattern. You can use the Uniform gel pattern if you like, but the top edge tends to be bulky when it’s folded down onto the Alpha Flex Sleeve.

Back to top


How do I convert from inches of mercury (in-Hg) to millimeters of mercury (mm-Hg)?

The LimbLogic VS System displays vacuum settings in inches of mercury. To convert from inches of mercury to millimeters of mercury, multiply by 25.4.

Back to top


How does vacuum suspension work?

A negative air pressure is created between the outside of a fabric-coated liner and an airtight socket when the vacuum pump pulls the air from the between the liner gel and socket wall. The negative air pressure pulls the liner towards the wall of the socket. The liner gel creates a similar airtight seal to the limb, so when the liner is pulled towards the socket, the limb is held firmly in place.

Back to top


What is the difference between suction suspension and vacuum suspension?

Both methods use a difference in atmospheric pressure to attach the socket to the residual limb. But because suction suspension uses a passive expulsion valve to allow air to leave the socket, a negative pressure differential is only created when the limb begins to move. The active pump used in vacuum suspension doesn't depend upon the limb position.

Back to top


What L-codes are suggested for the LimbLogic VS system?

L-5781 for the vacuum pump, and L-7368 for the lithium ion battery charger.

Back to top


What is the torque required to attach the LimbLogic VS pump to the prosthesis?

The M6 flathead screws provided should be tightened to 9 ft-lbs or 12 N-m of torque.

Back to top


What is the difference between the System Maximum, the User Maximum, and the Upper Set Point? 

Back to top


Does WillowWood make prosthetic components for children?

Our pediatric product line includes feet, durable Alpha® Liners, and tough components...even a growth kit for accommodating growth spurts.

Back to top


What is the difference between the pediatric SACH Foot and the pediatric Impulse® Foot?

The pediatric SACH Foot is a basic foot that is intended for children who are not mature walkers (when they walk, the heel may not come into contact with the ground at all). The pediatric Impulse Foot is intended for children whose gait has matured to the point where they can benefit from more advanced foot function.

Back to top


When should a suspension sleeve (or seal) be worn?

A suspension sleeve should be worn with any kind of suction or vacuum socket to prevent air from entering the socket after it has been expelled. WillowWood offers the LimbLogic Sleeve for use with either vacuum sockets or suction sockets (or with locking sockets if a little additional security is desired).

Back to top


Which type of suspension is best – suction, vacuum, or locking pin?

What works best for one amputee might not be what works best for another, but here are some of the pros and cons of each method:

Back to top


I am an amputee. Can I buy directly from WillowWood?

No. Because the selection and fitting of WillowWood products require the technical and clinical knowledge possessed by certified prosthetists, we do not sell any of our products directly to amputees. If you are interested in one of our products, talk to your prosthetist to see if it might be suitable for you.

Back to top


Does weight gain or weight loss impact the comfort of a lower extremity prosthesis?

Yes. A gain or loss of more than 10 pounds can result in discomfort, change in gait, skin breakdowns, and stress on other parts of the body, and should be reported to the prosthetist so that appropriate adjustments can be made.

Back to top


Can you recommend an amputee support group?

While we do not recommend support groups, we can suggest the following sources for information:

Back to top


In addition to support groups, are there any additional resources for parents of amputees?

The Amputee Coalition holds summer camps for young amputees ages 10 through 17. Find out more at http://www.amputee-coalition.org/youth_camp.html.

Back to top


How do I find the best prosthetist for me?

While we do not recommend specific prosthetists, we can suggest the following sources for information:

Back to top


What can an individual do to ensure that a prosthesis is covered by medical insurance companies?

Back to top


Some amputees wear cosmetic coverings over their prostheses and others don’t. Is there any reason for wearing a covering or not?

This is a very personal decision. Some amputees want to blend in, while others don’t mind if anyone sees their prostheses. There are many options available, ranging from fairly simple to highly customized. Talk to other amputees or to your prosthetist for more insight on this matter.

Back to top


Plaster casting is so messy and time-consuming. Are there any alternatives?

WillowWood offers the OMEGA® System, which allows clinicians to capture the shape of a limb electronically for the creation of a socket, a custom liner, or an orthosis.

Back to top