In addition to discussing the most common problems they see with orthosis irritation and how they remedy these issues, the expert panelists weigh in on two recent studies and their potential impact.
Q: What is the most common orthosis irritation problem that you see in your practice and how do you solve it?
A: The most common problem that Paul Scherer, DPM, encounters is longitudinal arch pain. He says the most common cause is improper casting. If the podiatrist leaves the midtarsal joint supinated, he warns that the contour of the finished orthotic will not match the corrected position of the foot and the point of maximum tenderness will be just proximal to the arch apex.
Dr. Scherer says one can easily avoid this problem by checking if a cast has a forefoot varus component and being sure the foot has a forefoot varus. Dr. Scherer points out this false forefoot varus in the cast results from the forefoot having a more inverted position during casting. This occurs frequently with foam box casting or inadvertent contracture by the patient of the tibialis anterior during plaster casting, according to Dr. Scherer.
Kevin Kirby, DPM, notes that orthotics can commonly cause discomfort or pain on the medial band of the plantar fascia. He says some patients will have significant bowstringing of the plantar fascia into the dorsal orthosis plate during weightbearing activities. Patients with higher medial arch heights or tight Achilles tendons are particularly prone to this, according to Dr. Kirby. Dr. Kirby says this bowstringing will cause increased compression force on the fibers of the medial band of the plantar fascia onto the orthosis plate. This may lead to a type of mild contusion to the mid-portion of the plantar fascia, notes Dr. Kirby.
When patients have plantar fascial irritation, Dr. Kirby grinds a plantar fascial groove into the dorsal orthosis plate in his office. He says this process should take one minute per orthosis for the experienced clinician.
“Plantar fascial grooves often make an orthosis that is barely tolerable become an orthosis that the patient never wants to take out of his or her shoe,” notes Dr. Kirby.
For the majority of patients, Bruce Williams, DPM, uses full-length EVA devices. He says problems with these devices usually arise from too much stiffness at the medial or lateral midfoot arch, and thinning these areas usually takes care of the problem.
In some instances, Dr. Williams notes that what may appear to be a medial arch irritation is actually caused by a lack of proper accommodation from a heel lift on the opposite limb. If the heel lift is not high enough, Dr. Williams says patients will often pronate more on the opposite limb.
Charles Mutschler, DPM, most commonly sees the irritation of heel cup impingement. To avoid this, he measures the fat pad displacement while the patient is weightbearing and then records it on the prescription form. As he explains, the lab can then add the correct amount of expansion based on his impression.
Q: Given the recent Evans study in the Journal of the American Podiatric Medical Association (JAPMA), when should a podiatrist treat or not treat pediatric flatfoot?1
A: Dr. Kirby praises Evans’ study as “a must-read for every clinician who treats children’s flatfoot.” Although he does not necessarily agree that one should not treat asymptomatic pediatric flat feet with foot orthoses, he agrees with Evans that many asymptomatic pediatric flat feet do not need any
treatment. He feels such patients require close monitoring rather than orthotic treatment.
Dr. Scherer cites the significance of Evans’ study, saying it revives the decades-old question of whether there is value to treating children with hypermobile flatfoot. He notes the author develops a very clear algorithm that all doctors can follow, combined with a single case experimental design.
Evans also reviews three of the most important evidence-based articles on pediatric flatfoot with which Dr. Scherer says every podiatrist should be familiar. Lastly, he notes Evans’ recommendation that if one uses orthoses for hypermobile flatfoot in children, prefabricated devices are the most appropriate choice.
When deciding whether to treat flatfoot in a pediatric patient, Dr. Williams takes the patient’s pain level and the biomechanical evaluation into account. He says a child who is experiencing foot pain needs relief via treatment. When a child does not have pain but does have some degree of biomechanical abnormality, he or she may or may not be treated according to the individual evaluation, notes Dr. Williams.
Evans’ article points out the need for evaluation of the child’s family history of flatfoot and other factors, according to Dr. Williams. Ultimately, he says the decision to treat conservatively, via orthoses and/or shoe gear, should be the primary route for patients without pain.
Dr. Kirby says low cost options for asymptomatic flatfoot include prefabricated pediatric orthoses or the addition of varus heel and medial arch wedging to the child’s shoes with adhesive felt. He notes these options can be effective alternatives for parents who want their children to be treated but cannot afford the cost of custom foot orthoses.
Q: Given the article by Davis and co-workers in JAPMA, what are the advantages and disadvantages of “semi-custom” foot orthoses?2
A: Dr. Scherer notes the Davis study provides some insight into the differences between custom orthoses and prefabricated orthoses that the author called semi-custom because several contours of each shoe size were available. As he explains, the study authors found that during running, the custom orthotic device reduced the excursion of rearfoot eversion more than the semi-custom device.
As Dr. Kirby points out, in the study, each patient received two pair of orthoses: a typical casted custom orthosis with no special anti-pronation modifications, and a semi-custom orthosis chosen from a library of pre-made orthoses to fit the plantar cast of the foot. Although the two orthoses showed little difference in their kinematic function, one-third of patients preferred the comfort of the custom foot orthosis to the semi-custom orthosis.
“In my mind, it is unethical and fraudulent for either an orthosis lab or a podiatrist to provide a patient with a pre-made library orthosis without first informing the podiatrist or the patient that they are not receiving a true ‘custom orthosis,’ but are receiving a pre-made orthosis,” asserts Dr. Kirby. “These distinctions in orthosis construction techniques must be understood by all podiatrists so they can make the best informed decisions regarding the quality of foot orthosis therapy for their patients.”
As Dr. Williams says, the primary advantages for semi-custom devices are cost and the immediacy of usage. However, Dr. Williams notes they generally will not hold up as long or as well in the general treatment population in comparison to custom orthoses. In his experience, custom devices usually offer better fit, more comfort and last longer.
Dr. Williams notes that the study authors assessed patients without foot discomfort. He would prefer to see a similar study on a population of patients who actually need treatment.
Dr. Kirby is an Adjunct Associate Professor within the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt College in Oakland, Ca. He is in private practice in Sacramento, Ca.
Dr. Mutschler is in private practice at Advanced Footcare in Miami. He is a member of the American Academy of Podiatric Sports Medicine and is board certified by the American Board of Podiatric Orthopedics and Primary Podiatric Medicine. Dr. Mutschler is the team podiatrist for St. Thomas University in Miami.
Dr. Scherer is the Chairperson of the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt College. He is also the CEO of ProLab Orthotics/USA.
Dr. Williams is a Diplomate of the American Board of Podiatric Surgery. He is a Fellow and the current President of the American Academy of Podiatric Sports Medicine. Dr. Williams practices in Merrillville, Ind.
Dr. DeHeer is a Fellow of the American College of Foot and Ankle Surgeons, and is a Diplomate of the American Board of Podiatric Surgery. He is also a team podiatrist for the Indiana Pacers and the Indiana Fever. Dr. DeHeer is in private practice with various offices in Indianapolis.
For further reading, see the exclusive online sidebar, “When It Is Necessary To Recommend Multiple Types Of Orthoses,” at www.podiatrytoday.com .
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1. Evans AM. The flatfooted child — to treat or not to treat: what is the clinician to do? JAPMA 98(5):386-393, 2008.
2. Davis IS, Zifchock RA, DeLeo AT. A comparison of rearfoot motion control and comfort between custom and semicustom foot orthotic devices. JAPMA 98(5):394-403, 2008.