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American Orthotic & Prosthetic Association Assembly 2005
As noted previously, the 2005 Assembly in Las Vegas was the best-attended AOPA national meeting in history. As always, there were continual concurrent programs, so only those sessions I attended are summarized in this report. Undoubtedly, there were many other equally valuable presentations; I just haven't figured out how to be in two or more places at once!
Scientific Sessions - Part Two
This article continues with selected reviews of presentations at the most recent AOPA meeting. The first papers are from the Lower Limb Prosthetics sessions.
Ian Fothergill, MBAPO presented some clinical experiences with the OSSUR Seal-In roll-on liners with hypobaric seals. He emphasized observing the following contraindications to avoid adverse results:
- Conical, bulbous, or boney residual limbs
- Short residual limbs
- Limbs with unstable volume
- Use in high impact activities
- Hand dexterity issues
Ian recommended a tapered volume reduction from 3% proximally to 1% just proximal to the seal for the first test socket. Reduction over or distal to the seal is NOT advised but it may be necessary to narrow the AP diameter just at the seal level if it loses contact with the socket wall when seated. He suggested avoiding petroleum based lubricants as they will soften the sealing membrane over time.
Bill Spence, MSc presented the results of a very nice experiment he conducted to investigate the contribution of the patellar tendon region to weight bearing support. He carefully instrumented the PT region and 20 other sites in the sockets of several transtibial amputees and measured the socket interface pressures. The experimental sockets were then varied randomly to increase and decrease the PT bar indentation from the "standard" position as follows: 2 millimeters tighter, standard depth, 2 millimeters looser, 4 millimeters looser. In other words, he varied how aggressive the bar was modified over a range of 6 millimeters.
His results showed clearly that a more or less aggressive patellar tendon bar simply increased or decreased local skin pressure but did not alter the weight bearing in the rest of the socket. These objective results support the widespread clinical impression that the role of the PT bar has been overestimated in the past and that there is no weight bearing advantage to providing more than a mild contour in this region. Presumable his results will be submitted to a peer-reviewed journal and published in detail next year.
Dale Berry CP reported on the status of an outcomes measurement tool under development by the Hanger Orthopedic Group. It is a checklist format that has been patented and trademarked under the name Patient Assessment Validation Evaluation Tool or PAVET that records subjective needs, functional capabilities, prosthetic reliance, and some special considerations. The potential utility of such a questionnaire was illustrated by noting the correlation HOG practitioners had observed between a patient's PAVET scores and indications for various microprocessor-controlled prosthetic knees. Although this instrument has not been validated, Dale commented that Hanger is already licensing it to insurance companies and governmental agencies to use as criteria for screening prosthetic claims. The University of Minnesota is beginning validation studies at this time.
Charlie Bisbee PhD, one of the engineers from Freedom Innovations, presented a novel argument regarding stance flexion with prosthetic knee components. His fundamental thesis is that the loss of active ankle power is the greatest barrier to energy efficient ambulation that high level amputees face, citing a number of controlled studies showing that even the most advanced feet currently available restore at most one third of lost propulsion in late stance.
Several researchers have noted that highly active amputees often prefer a more stable prosthetic knee alignment than would be expected. Charlie speculates that such individuals, who rarely exhibit much stance flexion in gait studies, may prefer the delayed knee flexion in late stance that results from such stable alignment because this should allow them to load the carbon fiber forefoot slightly longer and to take a more normal stride. In theory, unloading the deflected keel later in the gait cycle might translate into more forward propulsion. To test this hypothesis, Freedom Innovations is developing proprietary software for their upcoming microprocessor-controlled knee that will delay knee flexion in late stance.
The most intriguing thing about this "Bisbee Hypothesis" to me is the potential interaction between knee alignment and ankle-foot function, which has not been scientifically investigated to the best of my knowledge. Clinically, we tend to view the ankle alignment as affecting the knee function more than the reverse but Charlie is probably correct in believing this is a two-way interaction. Hopefully future instrumented gait studies will be able to shed some light on this possibility and offer us some more solid guidance as to dynamic alignment protocols for specific knee-ankle-foot systems.
Gerry Stark CP did a very cogent review of Professor Radcliffe's theories of Alpha and Beta stability of polycentric prosthetic knees, noting that the former fosters involuntary control while the latter enhances voluntary control. Gerry suggests combining both factors into an Alpha/Beta ratio that he feels is a better clinical predictor of functional stability than just the linear offset in the sagittal plane of the knee axis. To support his impression, Gerry showed how several knees that are considered to be clinically similar but have markedly different centrode pathways have very similar A/B ratios.
Karl Barnes CPO showed some highlights from his work with highly competitive athletes who were amputees and offered some general guidelines for other clinicians who want to work with such individuals. He stressed his experience that special activities often demand marked changes in alignment and component selection than does simple ambulation, encouraging the audience to "go beyond the 'walking rules'" for these cases. Karl suggested that, since there is no large body of clinical consensus to guide us when designing activity-specific prostheses, one of the best guidelines is to heed the patient's feedback and to try whatever changes they think might enhance their performance. He also noted that the benefits of engaging in active sports and recreational activities can be extended to most amputees, encouraging colleagues to facilitate all levels of participation rather than focusing on elite athletes exclusively.
The next batch of presentations were on Upper Limb Prosthetics. Harold Sears PhD gave a nice overview of some of the features of the latest Utah Elbow, the U3 version. Because the U3 has dual microprocessors, elbow control and terminal device control can now be adjusted independently, without removing the forearm shell, using a PC interface. The latest software seems well thought out, featuring a branching structure that provides step-by-step wizards for newbies as well as shortcuts that lead directly to the adjustment in question for those who have mastered the principles thoroughly. The new auto detect feature makes hybridizing electronic TDs much simpler as does the auto calibrate option that establishes a reasonable baseline adjustment for the EMG signal preamplifiers.
Many, but not all, users prefer to use the U3 so that they have simultaneous, independent control of the elbow and TD. In Harold's experience, it is most successful to offer this type of control to new amputees at the outset rather than to try later to upgrade from the simpler sequential control methodology. The elbow can be controlled by EMG signals or by various switches, with the linear potentiometer being the preferable non-EMG option.
Harold showed a clever adaptation of the Michigan roller harness concept done by Ron Hopkins CP that used shoulder elevation to actuate a linear pot which, in turn, raised and lowered the elbow. He also noted that many high level amputees find the complexity of simultaneous control difficult or impossible master and are therefore often better served with sequential control. Seq Control allows the patient to first position the elbow and then to focus on TD operation, analogous to the way the historic body powered elbows operate with a dual control harness.
Shawn Swanson OTR introduced a new size 7 hand from Otto Bock that offers an adult level of pinch force in a chassis that is actually shorter than the largest System 2000 pediatric hand. This will fill the niche for those patients who cannot use the 7 ¼ adult hand but are not satisfied with the largest Sys 2000 offering.
Ken Woodward CPO gave a talk with the provocative title "Train Your Therapists" noting the chronic difficulty practitioners have finding therapists who have any experience training upper limb prosthesis wearers. He argued that when the prosthetist arranges specialized training for interested local OTs, having such resources in the community permits a larger number of upper limb patients to receive comprehensive care close to home. Based on his experience in Michigan, when good training is not available locally, some patients travel great distances to get both their prosthetic care and rehabilitation, which is more costly and more inconvenient than if they could be treated where they live and work. Others, who choose not to attend remote clinics, are simply denied access to many types of upper limb prostheses because only very basic care can be delivered in their communities. Julie Schick OTR/L, CP continued the presentation by reiterating the value of good local therapy, commenting that the experienced OT works with the amputee long before fitting commences and completes most of the training and strengthening prior to the first test socket. This enhances prosthetic fitting and increases the odds for a good long term outcome because most patients can operate the prosthesis from the first day post-delivery. The savvy therapist also emphasized practical use training in activities of daily living that are pertinent to the individual's needs, which helps new patients realize the functional advantages of modern artificial limbs.
Harold Sears PhD returned to the podium to present the status of a survey being conducted by Julie Shaperman MSPH, OTR on the effectiveness of passive, locking wrist units on prosthetic function. Preliminary results are said to be encouraging and suggest that being able to lock the TD in extension or flexion as well as in neutral facilitates many common tasks of daily living. The final results will be published once the research has concluded.
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Amputacion Translumbar.
Ciudad de Mexico 3 de Enero, 2006.
Estimado John Michael CPO, FAAOP, FISPO: un reconocido medico de Argentina nos pregunta sobre resultados obtenidos en una cirugia de amputacion translumbar en los Estados Unidos (hemicorporectomy) y desea... read more
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Re: Amputacion Translumbar.
Translumbar amputation is a decidely rare proceedure, as you well know Sr. Castillo. I've been unable to identify anyone with a large experience fitting this population although functionally the prosthesis for most patients with this level... read more
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Feliz Navidad y Prospero Año Nuevo 2006.
Ciudad de Mexico 24 de Diciembre, 2005.
Estimado John Michael y familia:
Le deseamos una Feliz Navidad y un Prospero Año Nuevo para usted y toda su familia. Que el proximo año le colme de Salud, Trabajo y Amor y que continue
dandonos ... read more
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John Michael Reporting on the Benefits of The Ertl Procedure /Money and Med
Those of you digesting Mr.Micheal's newest report re: the use and benefits of the "non classic " Ertl procedure for amputation surgery,and modified versions in the article , might first be best served reading "all" the information provide... read more
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Re: John Michael Reporting on the Benefits of The Ertl Procedure /Money and Med
Thanks for sharing your perspective, Tony. I plan to continue highlighting whatever peer reviewed evidence comes to light regarding the Ertl method so that information is available to everyone who is pondering this topic. Hopefully that w... read more
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Re: John Michael Reporting on the Benefits of The Ertl Procedure /Money and
Thank you John . John Ertl MD and his son , Jan Ertl MD lectured for a large group of surgeons in Sao Paulo,Brazil in 1992 including Dr. Marco A. Guedes de Souza Pinto MD whom performs the "Ertl " on a routine basis. It appears from your p... read more
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Re: Re: John Michael Reporting on the Benefits of The Ertl Procedure /Money an
Thanks Tony- I met Dr. Guedes for a number of years ago and know well of his strong interest in amputation techniques. Just to clarify, I'm not conducting any sort of study personally: I have all I can handle with the multi-year grant to ... read more
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Re: Re: Re: John Michael Reporting on the Benefits of The Ertl Procedure /Mone
This appears to be a one way communication between us , but netherless perhaps the readers will join in and learn something .Ill say you have your plate full in "advancing education requirements of the P&O field in the USA". Dr.Fishman and... read more
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Re: Re: Re: Re: John Michael Reporting on the Benefits of The Ertl Procedure /
I suspect a number of people read these missives, Tony, so I wouldn't worry too much about having a one-to-one coversation. And, since these Corner's are archived on the Web, more and more people will read what's written in the future. Yo... read more
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Re: Re: Re: Re: Re: John Michael Reporting on the Benefits of The Ertl Procedu
While new to this thread, I'm not new to the Ertl procedure. I am an RBK amputee, using the Ertl procedure performed by Dr. William Ertl in Oklahoma City on 04 December 2003. The operation was performed after two and a half years of tryin... read more
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Re: Re: Re: Re: Re: Re: John Michael Reporting on the Benefits of The Ertl Pro
Thanks for your comments, Ron; it's good to know that your Ertl revision was so successful. To clarify, a guillotine procedure is where the flesh and bone are all severed at the same level and this is very rarely done in the developed worl... read more
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Re: Re: Re: Re: Re: Re: Re: John Michael Reporting on the Benefits of The Ertl
Dear John,
I wanted to add my thoughts on the subjective basis of whether the Ertl Procedure does in fact create a better quality of life for those that have under gone the procedure compared to the more accepted traditional amputation. Wh... read more
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Re: Re: Re: Re: Re: Re: Re: Re: John Michael Reporting on the Benefits of The
I agree, Dan, that some controlled studies would be a big help in developing a better understanding of the objective benefits of the Ertl procedure. This is quite a complex undertaking, however, and one that is far beyond my capabilities. ... read more
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Re: Re: Re: Re: Re: Re: Re: Re: John Michael Reporting on the Benefits of The
I agree, Dan, that some controlled studies would be a big help in developing a better understanding of the objective benefits of the Ertl procedure. This is quite a complex undertaking, however, and one that is far beyond my capabilities. ... read more
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