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Top 100 Biomechanical Guidelines #35: Use Common Shock Absorption Modifications Routinely

Patients, with or without orthotic devices, should never feel that they do not have hope at a soft comfortable impact against the ground. There are so many products out there for dampening shock, and these products are used in many imaginative ways. Here 3 commonly utilized products for shock absorption are demonstated: gel, spenco, and plastazote. They definitely should be part of every shoe/orthotic program, at least in some form or another. I am showing here how I commonly use these 3 products, but there are many acceptable variations. The goal is that the patient feels supportive, but cushioned. Too much cushion however can make a patient more unstable, so there must be a good balance between cushion and stability.

Plastazote Foam Material - 1/8'' x 6'' x 1 yd. (3.2m x 15cm x 91cm), 1 Roll

One of the most important aspects of designing a good orthotic device is shock absorption. Here adhesive back gel sheets are attached to the heel area of orthotics to help with shock absorption while utilizing a plastic orthotic device for maximal stability. Normally 1/8inch gel is utilized, but up to 1/4inch can be used.

http://www.silipos.com/003_prod/product.aspx?cat_name=Orthopedics&subcat_name=Gel%20Pads%20&%20Sheeting&product_name=Gel%20Squares&product_id=155x5&cat_id=7&subcat_id=7

Spenco is the best shock absorption material as an insert or orthotic cover. Here, a knockoff spenco, is being used. The original Spenco is still the best and is always in green.

http://www.spenco.com/products/footcare/SpencoRX/product-productcomfort-insoles

Pink, or #1, plastazote is the memory foam used as the top layer in a Hannaford custom made orthotic device. Here it used as a forefoot extension on an orthotic device in 1/4". I commonly use 1/8" as a full length top cover on an orthotic device.

http://store.acor.com/products/Plastazote%C2%AE-Polyethylene-Foam-%252d-RETAIL.html

Top 100 Biomechanical Guidelines #34: Understand the Basic Components of a Hannaford Orthotic Device

     This is my last post for awhile on the Hannaford Orthotic Device. It definitely changed my practice of podiatry, and the patients it has helped are forever grateful for them. I have tried to put all of the steps in their manufacturing down, so any laboratory around the world can make them. If you are in need of orthotic devices to help with shock absorption at your feet, shins, knees, hips, or low back, consider this orthotic device. It is the best product for this purpose I have ever seen.

Hannaford Orthotic Device before ground into proper shoe fitting size designed off a cast of the foot.

What are the Basic Components (in summary)?

• 1/2" flesh/pink soft plastazote (also called plastazote #1) full length acts like memory foam--never touch that layer with adjustments as it molds to the individual foot.

http://www.alimed.com/Alimed/product/Plastazote-1-Sheets,15063,169.htm

• 1/2" white medium plastazote (also called plastazote #2) sulcus length gives durability.
• After 30 hours of wear the initial compression has taken place, and the shoe fit is better.
• Barring any problems, the ortho is refurbished in 3 months.
• If the patient loves the orthotic device (and most do), they are encouraged to get a second pair around 6 months, for ease of refurbishing, and for alternating to save the life of the orthotics.

Top 100 Biomechanical Guidelines #32: Stress Fractures and Joint Arthralgia treated with Increase Shock Absorption

     Shock Absorption is needed following the impact (collision) of the foot against the ground. The shock wave that radiates up the leg is approximately equal to your body weight with normal walking, increases as you increase speed or go downhill, and can measure 2 to 5 times body weight with normal running. It is this shock wave that needs to be reduced to help many avoid injury by changes in shoegear, changes in surface, changes in shoe inserts, and custom made shoe devices. The King of all is the Hannaford Device. Hundreds of my patients have benefitted over the last 25 years, and I am hopeful to spread the word on how it is made.

     Hannaford Orthotic Devices, developed by Dr David Hannaford while practicing podiatry in Eugene, Oregon, are 2 layers of 1/2" plastazote material vacuum pressed around a mold, and then ground into shape to fit a typical athletic shoe. The layer of plastazote material against the skin is memory foam, soft in nature. The second layer of material is white plastazote, firmer and more durable in nature.

Impression Casts are used to make a Hannaford Device.

The 2 sheets of plastazote are cut with the memory foam full length and the white, more durable, plastazote cut to sulcus length (just behind the toes).

The length of the soft plastazote is approximately 1 and 1/2" longer than the foot and will be trimmed after the molding to fit better.

This is how the 2 pieces will be pressed with the softer memory foam against the foot.

Before vacuum pressing, both pieces are glued with Barge Cement so they will become like one after the press.

Before pressing, the toe area of the mold is covered with a soft material to flatten this part of the press. Without this, the memory foam molds around the toes too much. You need the orthotic to end up longer than the original foot.

The 2 pieces are placed in the convention oven heated at 475 deg F. Because the white layer heats up slower than the pink layer, the white layer is placed down on the surface.

Within the convention oven, the plastazote material is checked every 20 seconds and removed when the toe area begins to brown. A spatula is used to remove, but it can be handled gently with your hands.

Here it is centered over the mold with overlap around both sides and front and heel. You need to get as far forward in the press as possible for the best press. See the memory foam layer is being placed against the foot.

Once the press is started, you need to push down from the sides to help the vacuum remove all the air. The press is normally done in 20 minutes/foot.

After the press, wrap the mold with plastic wrap tightly for 1 hour to let the material cool completely in the shape of the mold.

Once removed from the wrap, mark the front length approximately 1 and 1/2" from the end of the mold, and mark the sides the exact width of the foot. Since I have a video of the grind, I will let that finish this post off.

Top 100 Biomechanical Guidelines #31: Hannaford Orthotic Devices best for Shock Absorption Issues

Dr David Hannaford from San Rafael California revolutionized the orthotic world for patients with shock absorption problems. These are patients with knee arthritis/pain, hip arthritis/pain, stress fractures, heel bruising, and shin splints. Check out my YouTube video on the grinding process.



You can also see the general discussion of addressing shock absorption issues on this YouTube video.




Any podiatrist, orthotic lab, or pedorthist interested in learning the nuances of manufacturing this device I will be happy to share the steps. Please email me. I will have a full post soon on the entire process.  It is a great device for many patients.

A Hannaford Device is typically full length and made off a cast of the foot. The top layer of soft plastazote material is a memory foam which molds to the patient's foot. A leather top cover is used since it shows all the stress points and can help in discovering the best modifications if necessary.