Keys To Prescribing Orthoses For Limb Asymmetry And Heel Pain
Given the common presentation of limb asymmetry, these panelists describe how leg length discrepancy affects orthotic prescription. They also offer insights on effective orthotic management of patients with heel pain.
In what percentage of patients do you find differences in lower extremity structure or function, and how does this asymmetry affect your orthotic prescription?
All four panelists have found that most patients have asymmetry in terms of lower extremity structure or function.
“Virtually all patients I examine have some degree of structural or functional asymmetry,” says Joseph D’Amico, DPM. “In any given year, one would be hard-pressed to find an orthotic prescription that is the same from one foot to another.” However, Dr. D’Amico cautions that not every one of those patients has a limb discrepancy.
As Justin Wernick, DPM, notes, most patients have a limb length discrepancy. He notes the design of the shell of the device along with the modifications will vary from one foot to the other depending on what one is looking to accomplish. Furthermore, there are circumstances in which only one device is necessary for one foot and the other foot needs a simple shoe modification, according to Dr. Wernick.
Ronald Valmassy, DPM, always advises his patients that their limbs are typically asymmetrical from one side to the other, generally leading him to prescribe orthotic devices in an asymmetrical fashion.
“There clearly are instances (in which) a patient may have a forefoot varus deformity on one foot and a forefoot valgus deformity on the other,” he notes.
In evaluating a limb asymmetry, Stanley Beekman, DPM, first starts with a biomechanical examination, which he has reduced to a few important measurements in adults. He measures dorsiflexion and the anterior superior iliac spine and the posterior superior iliac spine to the ground in neutral and relaxed calcaneal stance positions. From this evaluation, Dr. Beekman can determine if he should treat the asymmetry via heel lifts, orthoses or refer the patient to an osteopathic physician or a chiropractor.
Some patients will have issues such as a dysfunctional posterior tibial tendon or a tarsal coalition, which may lead to a very obvious asymmetry in foot type and function, according to Dr. Valmassy. However, he feels that even in the more routine cases that present on a day-to-day basis, asymmetry exists quite commonly. For that reason, Dr. Valmassy advises podiatrists to consider orthotic devices as completely independent prescriptions from the right to the left side.
If an elevation of one extremity is required, how would this affect your orthotic prescription?
For patients with limb length discrepancy, Dr. Wernick uses a heel lift in the shoe first to see if he has the right correction. He generally does not like to put a lift of more than 1/4 inch on an orthotic device itself as higher elevations create shoe fit problems. When adding elevations to the orthoses, Dr. Wernick says it is important to modify the addition by lowering the distal edge so the orthosis does not rock in the shoe.
In his early years, Dr. D’Amico would ascertain and equalize limb length discrepancies based on clinical and radiographic measurements, and sacral leveling. Today, he relies on dynamic assessment of the phases of gait as well as weight distribution and pressure patterns that he obtains through computer assisted gait analysis. Dr. D’Amico performs this testing two weeks after orthotic dispensing.