Tidbits from CAPO
As many readers know, the Canadian Association of Prosthetists and Orthotists traditionally holds their national congress in even-numbered years. The meeting for 2002 was in Edmonton, Alberta adjacent to the world's largest shopping and entertainment mall. I have been a CAPO member since the day I earned my ABC Certification, and always look forward to an opportunity to learn from our northern colleagues. Unfortunately, I wasn't able to stay for the entire meeting this time, because my son's wedding in Minnesota was the same week.
But, I did find time to cruise the exhibition hall, give my talks, and to attend as many concurrent lectures as possible. And, of course, the informal meetings with old friends after hours were invaluable for swapping information and brainstorming about clinical and reimbursement challenges the field faces. I spotted a couple of interesting items that are highlighted below.
Bock mini-shock unit
Otto Bock has finally come up with a simple vertical shock/torque absorbing element and its North American debut was at the CAPO meeting. It looks compact, feels light, and presumably has the legendary Bock reliability. It's basically just a telescoping tube with interchangeable elastomeric springs.
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But, what caught my eye was that it is possible to install different durometer torsion elements. Hans Mauch argued decades ago that this should facilitate a more normal gait pattern since having a stiffer resistance in one direction can enhance the amputee's ability to push off, and this feature was first incorporated into his hydraulic ankle. [Unfortunately, chronic durability problems killed the Mauch ankle despite enthusiastic amputee acceptance of the functions it offered.]
Pricing and availability were not finalized at press time.
Motion Control Battery Slice
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Harold Sears, PhD from Motion Control had an interesting sample in his review course at CAPO: a fairly thin Lithium Ion battery intended to be mounted permanently inside the forearm of the prosthesis. It appeared to be about half the thickness of even the sleekest of the interchangeable battery systems, so it may be particularly useful in reducing the inevitable "bumposis" for patients with wrist disarticulation and other long transradial amputations.
A small recharging port can be mounted wherever space permits; in this sample, it is located just proximal to the wrist unit. Plugging the charging cable in automatically disconnects the battery from the components.
It's always a challenge to finish the prosthesis so it looks sleek and esthetic despite the need for a power source. This battery configuration will give us one more option when finishing an electronic arm.
Ankle Joint Actuation of Horton's SCOKJ
The folks at Karl Hager Limb & Brace Ltd. in Edmonton invited one of their patients to attend the CAPO Qualifying course to share his experiences with the stance control KAFO. The control method and finishing techniques they used when fabricating his device were very nicely done.
The laminated carbon fiber construction resulted in a very sleek, thin contour and a stiff but lightweight structure. Because the patient was accustomed to using a Klenzak type ankle joint, they decided to modify the mechanism to engage and release the knee control as well as to provide the necessary dorsiflexion assist.
One technical challenge was to retain the ability to adjust the spring tension even though the knee-actuating rod runs inside the screw and spring. This was accomplished by grinding flats on the screw threads so it could be turned with a wrench.
Establishing the optimal length for the actuating rod was also tricky, but once all the details were figure out, it worked flawlessly. This is one of the sleekest implantations of Horton's SCOKJ that I have seen to date, and the patient reported that he was very pleased with the clinical performance of his KAFO. You can contact Frank Hayday CPO[c] and his staff for more information, or for details on their central fabrication capabilities, by emailing them at khagerlb@telusplanet.net.
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Pylon clamping device
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I spotted a lab tool that I had not noticed previously: kind of a giant "Vice Grip" with plastic jaws for safely clamping 30mm and 34mm prosthetic pylons and components during fabrication. It's always a pain in the neck to hold the pylon in your hands while cutting it to length with a tubing cutter, but that's the recommended technique to avoid scarring the finish and creating a stress riser that can lead to catastrophic failure over time. Of course, soft jaws in a bench vise are another option, but it takes a light touch to avoid squeezing the tube out of round - which makes assembly and disassembly a real struggle.
In addition to making cutting and burnishing the pylon end much easier, this tool can also be used in the Milmo vertical fabrication fixture during transfers. For more information, send an email to: sales@orthoactive.com.