CAD / CAM or Heinz 57 Casting ?
BY SHANE HAYES , C . PED .
On the evolutionary chart , when chimpanzees became bi-pedal , they decided that a foot impression in dried mud might be a reproducible technique for making foot orthoses . Thus , began the age old argument between the apes and the chimps on whether it needed to be volcanic mud or if any mud puddle would do . It wasn ’ t until Charlton Heston fell out of the sky to the “ Planet of the Apes ” and a computer was introduced into the equation that the argument of casting modalities progressed . The new argument became Simian or Simulation ?
That ’ s a whimsical look at the evolution of orthotic casting but reasonably accurate . As time progressed , the “ Root ” of a theory emerged as the gold standard in the late ‘ 60s to early ‘ 70s . By 1989 , an article in The Journal of Current Podiatric Medicine 1 stated :
The problem for podiatry is that the current research has shown that STJ Neutral is not a reliable location and Root ’ s theories are not reinforced by physics and engineering studies performed by The International Biomechanics Community . At present , there are no true standards to the science of biomechanics . Today , the same patient , examined by ten different practitioners , would get ten different diagnoses and ten different orthotics .
The first CAD / CAM systems were introduced in the late 80 ’ s to early 90 ’ s to a lukewarm reception . When comparing the cost of plaster to the new technology , most opted for the least expensive option . That calculation omitted the manual hours spent working the plaster . A CAD / CAM system would pay for itself in the first year of use on the manual hours saved alone . If the tax write offs are included , then a computerized system wins the price war . Since , the new technologies were not being presented in the medical classroom , the earlier casting modalities prevailed .
The revolution of evolution continued thru 2002 as evidenced in these two studies : Evolution of the foot orthotics – part 1 : coherent theory or coherent practice ? The use of foot orthoses is well documented for the treatment of many maladies , yet clinical successes have been achieved both inside and outside of the classic Root paradigm . Clearly , a more complete theoretical understanding of the mechanisms of foot orthotics awaits discovery .
Evolution of foot orthotics--part 2 : research reshapes long-standing theory . Considerable evidence supports the exploration of new theories and paradigms of orthotics use . Investigations of flexible orthotic designs , proprioceptive influences and the three-dimensional effects of subtalar joint motion on the entire kinetic chain are areas of research that show great promise .
Today , the argument / discussion of the best casting technique continues as
evidenced by the numerous articles in this magazine . Practitioners naturally start with the techniques taught in the medical classroom . As they progress with their career , many will vary those techniques or switch to a different one based upon clinical experience and continuing education . The classic example of this was an article a few years ago when podiatrists were randomly selected from various parts of the country and queried about their casting technique – no two of them agreed 100 %. Pedorthists are riding high in that same boat ! ■
1
Dennis Shavelson , D . P . M . June 1989 Biomechanics issue of The Journal of Current Podiatric Medicine edited by Justin Wernick , D . P . M . The Future of BIOMECHANICS
2
J Manipulative Physiol Ther . 2002 Feb ; 25 ( 2 ): 116-24 , J Manipulative Physiol Ther . 2002 Feb ; 25 ( 2 ): 125- 34Ball KA , Afheldt MJ . Biomechanics / Gait Research Laboratory , Foot Levelers Gait Research Program , New York Chiropractic College , Seneca Falls , NY 14450 , USA . kball @ nycc . edu
Shane Hayes , C . Ped ., a Seymour Lefton award winner , is a Certified Pedorthist and orthotic fitter based in Seattle , Wash . His work has been published in the Journal of American Medical Association and , he is a former president of PFA .
Photo by Ezioman
20 Pedorthic Footcare Association www . pedorthics . org