Not all patients respond to the standard measurements for orthotics. Modification and fine tuning of orthotics is normal and should be expected for some of your patients.

n occasion, a patient just does not respond as well as expected to custom-made foot orthotics. Once you have eliminated potential problems—such as poorly designed or wrong-size shoes, generic insoles left in, not wearing orthotics 75%–80% of the time spent on the feet—consider that your patient may need to have the orthotics modified. Some chiropractors (and many patients) think that this means something is wrong. Perhaps the doctor performed the casting procedure incorrectly, or the orthotics laboratory manufactured it inaccurately.

While both the doctor and the lab technician are human, and errors are possible, it is much more likely that your patient needs modification. In fact, you can expect that a small percentage of patients fitted for orthotics will need further customization.

Why Are Modifications Needed?

One of the amazing qualities of human beings is their variability. Unfortunately, this makes it difficult to standardize treatments and tests. One thing that you learn after being in practice for a while is that every patient is an individual. Each person requires slight modifications to standard chiropractic methods.

The same holds true for any attempt to provide a standard, consistent treatment approach, such as orthotics. In fact, it is precisely because of these individual characteristics that custom-made orthotics are often the best approach.

In spite of customization, some patients simply will not respond to the standard corrections based on the usual measurements and calculations.

I attribute this to the concept of normal distribution. Any time we measure or test humans, we always come up with a significant normal variation. No matter what is being investigated, scientists consistently find that the results can usually be graphed into a figure that is shaped like a bell. The curve of the bell describes the expected findings. The average of all of the individual points is the mean, which is about in the middle of the curve. About 95% of the data points fit under the curve.

This leaves two tails—one on either side of the curve—that are still normal, but do not fit under the curve. It is these individuals who often need to have their orthotics modified, because they either cannot tolerate the usual amount of arch correction, or they need more than the standard amount of correction. This does not imply that either the measurements or system for determining the amount of corrections is flawed. Rather, it recognizes that some individuals will do better with more, and some with less, than the standard amount of correction.

While there is no way of predicting who will fall under the tails, the good news is that the usual amount of arch correction works for somewhere around 95% of the population. Others will need additional fine-tuning to obtain full benefits from the orthotics address their individual needs.

Types of Modifications

The major biomechanical components in the most advanced orthotics consist of support for all three arches, corrections for the metatarsal region, and support for heel alignment. When a patient has either too much or not enough support from one of these areas, the doctor must be prepared to provide customization. This can be done temporarily in the office, or permanently by reconstruction at the orthotic laboratory. The first (and easiest) approach is usually to add to the height of one of the arch supports. Alternately, changing the angle of the heel (increasing or decreasing the pronation wedge) can be tried.

Medial arch. A common modification in this region is needed for patients who have previously worn rigid orthotics. They often do not feel the medial arch support and worry that they are not getting sufficient correction. Rather than try to convince them that, ideally, they should not notice any pressure under the medial arch, I find that increasing this support is helpful. By turning the orthotic over and placing several strips of athletic tape along its medial aspect, I can try out an increase. I let the patient wear this for about a week, and then re-evaluate. When I find the correct amount (what the patient says is not too much or too little) and spinal balance is restored, I return the orthotic to the lab with the tape left in place. This allows the technicians to measure the added correction and rebuild the orthotic to match. When a patient finds that the medial arch is too high, a 25% decrease is usually enough change to ensure a good response.

Transverse and lateral arches. Similarly, decreasing the anterior transverse arch support (under the metatarsal arch) or raising the lateral arch (under the cuboid) is easily accomplished. Occasionally, the metatarsal pad needs to be moved forward or back a slight amount. This is usually secondary to a suboptimal cast, and is best determined by obtaining a more accurate weight-bearing image to send to the laboratory.

Heel alignment and lifts. The alignment of the calcaneus at heel strike and into foot flat (midstance) is critical to smooth biomechanical function of the foot and leg. A pronation or varus wedge is often needed to help control excessive pronation. Adding to this wedge (using tape) will sometimes be necessary when a patient feels the medial arch is too high. Increase the height of the medial aspect of the heel to effectively decrease the stress on the medial arch and first toe.

When leg length continues to be asymmetrical, a heel lift may need to be added to provide better support for the spine and pelvis. Once the final height has been determined (after a gradual buildup to allow for adaptation), a permanent lift built into the orthotic is the ideal correction for an anatomical short leg.

Specific accommodations. Additional modifications that can be added include a divot in the heel to accommodate a persistently painful heel spur (heel spur correction) and a special cutout for a bunion. Most orthotic labs can be quite inventive in accommodating for arthritic overgrowth, anomalous bone formations, and even permanent foot injury. In these cases, it is important to work closely with a service representative in order to determine the best approach for the patient.

Clinical procedures. When I work with a patient to provide custom modification of an orthotic, I want each change to be tested for at least a week. If the patient is unsure whether the approach is helping, I increase the temporary correction to the point where it becomes obviously too much and then begin to back down to find the optimal point. Patients are surprisingly sensitive to small changes, and report back quite accurately.

Patients appreciate doctors who are willing to work with them to obtain optimal orthotic function. While only a very small percentage of patients require this level of attention, I have found the effort to be rewarding. Modifications to custom-made orthotics are not commonly needed. When they are, a simple trial-and-error approach that uses patient feedback can be employed to quickly determine the fine-tuning required.

Guidance and advice from service representatives from the orthotic laboratory can be invaluable, since they deal with these concerns regularly. CP

Tim Maggs, DC, specializes in sports and industrial medicine and is a graduate of the National College of Chiropractic. He writes and produces a talk radio show on sports medicine and speaks at numerous engagements. Maggs can be reached via email: runningdr@aol.com.