This is part 15 of a series that should be read in order.
Key Points:
- How does C1 change from BC?
- What is the difference between C1 and C2?
The Shock Absorption Orthosis (continued)
I am excited about discussing the shock absorbing orthoses. I had a long talk with Jacob Karp at KevinRootMedical who pointed out that I really needed ordering Rx data for all the types I have been discussing. Whereas you may have your own preferences on some of the components of your unique devices, giving you my ordering info for each one will help give the novice some perspective. Last week I introduced these Shock Absorption orthoses and talked about the simplest as BC, which simply adds more padding or cushion into your Gold Standard B device. This can be either done initially, or after the patient gives feedback to you after trying to break in the device. So, today I will discuss C1 and C2 which still use plastic as the frame.
C1: This is really the first change towards compromise from our B devices. We are willfully going to trade some stability for shock absorption. And remember, my mantra is “Always make a patient more stable”. I make a concession in my brain by calling poor shock absorption “vertical instability”. The body needs help as it impacts the ground, and you can be the help it needs. This trade-off however is sometimes dramatic, as you can not fully predict the loss of stability, but there will be a loss in stability with C1 and C2 from BC, also in C4 and C5 over C3, and C7 over the more stable C6. Therefore, if you are just trying to go down the list to more and more shock absorption or cushion, go from BC to C1 to C2 to C4 to C5 to C7. BC, C3 and C6 can be the right mixture for patients when stability and cushion are needed, and are exceptions to the progression rule I used in P, S, and ML devices. More on this later.
How is C1 achieved? This is very similar to BC. You have to work through BC to C1, as you are only changing material to soften the device. For Shock Absorption, I design my B device first, add shock attenuating material where I want it (heel only, forefoot only, or full foot) for my BC device, and then I lower the polypropylene thickness or change to sub-ortholen (™) for C1 device. 5/32 inch or 4 mm polypropylene is my gold standard, so I am typically either going softer with a â…› inch polypropylene (3.3 mm) or a 4 mm subortholen (™). Doctors will prefer in general a full frame EVA fill to their devices, or a rear foot extrinsic post. This will be modified, not in C1, but in C2. With C2 you will soften the frame fill or rearfoot post, add motion to the rearfoot post, and definitely add poron (or similar) material under the heel and forefoot. These are all subtle but powerful changes to the patient. At no time, with any of the shock absorbing inserts are you lowering the arch from your B device.
Prescription for C1 Device:
- Balanced cast to Heel Vertical (only in B1)
- Lab discretion balancing B2
- Can also use same principles in any P, S, or ML device
- Polypropylene thickness lowered or changed to 3 mm Sub-Ortholen (™) Here I would use 1/8 inch polypropylene, or 5/32 inch if my initial orthosis was 3/16 polypropylene
- Frame Fill on Sub-Ortholen (™) 45 durometer and full (when using) There is no frame fill on polypropylene
- 18 mm Heel Cup Heights
- Standard Width and Arch Height
- Zero degree Extrinsic Rearfoot Post
- 1/8 inch Spenco full length
- Add soft material (poron or Spenco (™) as forefoot extension
- Common to use soft poron as heel cushion (not required)
C2: This uses the softer material, whether polypropylene or sub-ortholen (™) of C1, with a softer base also. Whether your B product would have included a full frame fill (with sub-ortholen (™) or extrinsic rearfoot post, this is much softer (less durometer). Changing my birko-cork hard post to a softer 40 durometer EVA post is one example. Changing the bottom frame fill from 45 durometer to 30 durometer is another example. When stability is still needed, this makes a huge durability problem, as softer posts or frame fills compress easier. Yearly orthotic checkups should help in this regard in identification of any problems needing fixing. When the orthotic devices are being worn all the time, I encourage patients with these ever changing devices to have a second pair made at the year follow up for sure (and even at 6 months).Therefore, when you have to take the device for refurbishing, they will still have their other pair. This basic philosophy holds true for all shock absorbing orthotic devices, especially C2, C4, C5, C6, and C7. One important rule with soft based orthoses: “Soft Based Orthoses tend to feel great to the patient even when the stability is severely breaking down”. This is when you tell the patients that refurbishing is needed and they will be without their orthoses for up to a month. It is best that they wait for a new pair, and wear them for several weeks, before handing in the other pair for refurbishment. This should be discussed when you give the devices originally so that they are prepared for this ahead of time.
Prescription for C2 Device:
- Balanced cast to Heel Vertical (only in B1)
- Lab discretion balancing B2
- Can also use same principles in any P, S, or ML device
- Polypropylene thickness lowered or changed to 3 mm Sub-Ortholen (™) Here I always use 1/8 inch polypropylene
- Frame fill on Sub-Ortholen changed to 30 durometer but still full thickness (there is no frame fill on polypropylene)
- 18 mm Heel Cup Heights
- Standard Width and Arch Height
- 4 degrees varus with 4 degrees motion Extrinsic Soft Rearfoot Post 40 durometers
- 1/8 inch Spenco full length
- Add soft material (poron or Spenco (™) as forefoot extension
- Use soft poron as heel cushion
Review of all the Orthotic Types Being Presented
Corrective Orthotic Devices
↓
- Balancing (B): (B1 and B2)
- Pronators (P): BP, P1, P2, P3, P4, P5, and P6
- Supinators (S): BS, S1, S2, S3
- M/L Instability (M): BML, ML1, ML2, ML3, ML4, ML5, and ML6
- Shock Absorption (C): BC, C1/C2, C3/C4/C5, C6, and C7
- Sagittal Plane (H): BH, H1, H2, and H3
