Academy Meeting in Orlando
Scientific Presentations
This Academy meeting was one of those events where there was a burst of new information. Because there were many concurrent sessions and workshops, it was impossible for one person to attend every great presentation, but I found excellent sessions every day.
Mark Geil, PhD presented a very frank paper on his preliminary studies of the alignment of transfermoral prostheses. Like most engineers, Dr. Geil viewed TF alignment as a mysterious and subjective process with ample room for improvement, and wondered if a system of computerized alignment would be helpful. The available literature is of limited value in helping scientists understand dynamic alignment since the studies focus on only a few of the many clinical variables that are involved. The published data suggests that "good" alignment is highly variable, and differs between different prosthetists and in successive prostheses.
Dr. Geil recruited five ABC Certified Prosthetists with varying levels of experience and had them each align multiple prostheses for several patients. All patients underwent objective gait analysis and the resulting alignment was documented and compared. Much to the surprise of the engineers, the gait patterns each patient demonstrated - regardless of the CP who did the alignment - were extremely consistent. Although there are undoubtedly many reasons this occurred, these results did not support the concept of developing a computerized system to make alignment more consistent.
When the final alignments were compared, it became clear that there were really only 3 "basic alignments" for all of the cases studied, and they varied primarily in the positioning of the ankle-foot assembly. This suggests that there are a limited number of "alignment philosophies" among good prosthetists and that dynamic walking trials are much more precise than was previously appreciated.
Hopefully Dr. Geil will publish more details from this study in the Journal of Prosthetics and Orthotics so we can study his work in more depth. I suspect that Dr. Andrew Hansen's work with Dr. Childress on the concept of "prosthetic foot roll-over shapes" will be useful in sorting out these results. [Go to www.oandp.com/news/jmcorner/2001-03/4.asp?searchquery=rocker for more details.]
It is important that we validate and document the science that lies under the art of prosthetic and orthotic fitting. This study is another step in that long but important journey.
Brian Giavedoni CP(c) did a very nice job of providing the first objective evidence to support the longstanding custom at the Atlanta Scottish Rite hospital of providing articulated knees to toddlers starting about 10 months of age. The traditional approach has been to fit with a non-articulated prosthesis until the child is much older, and able to "control" a free knee.
But, like many of our hoary maxims, this practice is based more on decades of custom than on any objective justification. The general trend in recent decades has been to provide fully activated prostheses to children at about the time they would normally start learning to use such functions, and the Atlanta folks have had very good clinical results with such a philosophy. But, the arguments rage on between the "passive limb first" and the "facilitate learning to use an active prosthesis" camps.
Brian and his colleagues conducted gait analysis studies on two children who were 22 months old and had been using an articulated transfemoral prosthesis since they were infants. The results showed quite clearly that, when they were forced to walk on a locked knee, their gait velocity decreased and the number and magnitude of compensatory gait deviations increased.
Obviously, further studies with larger numbers of children will be needed to verify these pilot findings. But, these results were so striking clinically that we should all consider being more aggressive when working with toddlers in the future. The availability of several stable polycentric knees suitable for small children makes early fitting with articulated knees technically feasible. Brian's data suggests that such an approach will also reduce gait deviations, increase gait efficiency, and foster the development of a more normal gait pattern.
Gary Bedard, CO did his usual excellent job of explaining some of the engineering intricacies of thermoforming plastics, using examples that the practicing orthotist can understand. He focused on practical methods to increase the crystallinity of the finished device to decrease the tendency of the plastic to creep over time and lose its original contours. One of the most effective practical means to accomplish this was to wrap the freshly vacuum-formed orthosis in Mylar-coated bubble wrap from the local Home Depot. This retarded the rate of cooling and made the material more crystalline and therefore more stable.
The days of "garage manufacturing" of orthoses using retired pizza ovens and shop vacs are waning, and work such as Gary's provides the scientific rationale for moving to better controlled manufacturing methods. Once the International Standards Organization releases their recommendations for structural testing of lower limb orthoses, I anticipate a surge of interest in better thermoforming. The bar has been steadily raised for orthotic clinicians in recent years, and it is logical that the standards for fabrication of orthoses will also increase in the future. The technician of tomorrow, in my view, will be a much more highly trained fabrication specialist who understands the science of materials and the principles of quality control in considerable detail.
Tom Coburn CO gave an excellent presentation on how to interpret radiographs to blueprint a scoliosis TLSO. His wealth of experience in this area was evident, and the graphics and concepts presented were crystal clear. The Academy Spinal Society has been doing a very good job for several years in bringing clarity and consensus to this sometimes-controversial area of clinical practice, and Tom's lecture was a great illustration of the quality of the information being shared by experts in this aspect of orthotic practice.
There were many other outstanding talks, including Dr. Bunch's interactive session on "Ethics" and Troy Farnsworth's review of upper limb Immediate Post-Operative Prostheses. Hopefully, many of these will be repeated at regional and local meetings in coming years so this information is available to a wider group of practitioners. These brief summaries should give the reader a "taste" of what went on at this outstanding meeting, and motivate you to mark your calendar for March 19-22, 2003 when the next Academy meeting will be held in San Diego.
