Orthotic Inserts: Why Traditional Advice Is Wrong
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Orthotics are frequently prescribed by podiatrists and orthopedists to help with certain types of foot/ankle pain (which is often caused by injury or overuse of specific muscles and tendons). Also, orthotic inserts are prescribed for knee and hip osteoarthritis, and back pain, which has a multitude of complex causes, not all them discoverable. However, is it true that orthotics are really effective for reducing pain, preventing re-injury, or providing support to those injured/overused muscles, tendons, and ligaments?
Orthotics for treating foot and ankle pain and gait issues
Foot, ankle, knee and hip biomechanics are complex – incredibly complex. Even gait analysis itself is an art as well as a science. And yet, passive insoles or sensomotoric insoles are prescribed for most foot malpositions as an easy solution.
But is it really that easy? Not at all!
The core stabilizing foot musculature is often severely weakened in case of those foot problems. As a result, the foot is no longer appropriately stabilized and can lead to pain and even more severe malpositions over time. Insoles may limit the range of motion (or "mobility") and fix the foot in a malposition.
Orthotics such as passive insoles only have a short-term effect on symptoms. These symptoms include pain and in the long term further weaken the musculature: Orthotics are supposed to stabilize the feet and prevent muscle activity instead of activating the muscles. Ironically, this leads to further weakening of those muscles already weakened by injury or stress, intensifying foot malposition.
These weak muscles are one of the main reasons why many people often feel pain when standing and walking, and those vulnerable feet and leg muscles increase the risk of falling. Without additional intensive training of the foot musculature the pain may return once the orthotics are no longer being used, or return if the orthotics are used past the point of healing of the injury or stress.
According to Dr. Joseph Hamill1, a professor of kinesiology and the director of the biomechanics laboratory at the University of Calgary, orthotics have little effect on kinematics—the movement of the skeleton during a very intense activity such as a run—but they can have large effects on muscles and joints, often making muscles work as much as 50 percent harder for the same movement and increasing stress on joints by a similar amount.
Dr. Heather Vincent, director of the University of Florida Health Performance Center in Gainesville, Florida, agrees2 with this assessment and makes the point that foot orthotics often do not correct the underlying biomechanical problems that cause the pain and dysfunction for which they are prescribed.
In fact, orthotics can actually worsen the conditions they are meant to treat if they are worn too long, she says. "The foot doesn't have the full range of motion," Dr. Vincent explains. "The bones and the muscle in the foot are not being activated the way they should, so the foot gets weaker and weaker over time." Foot orthotics can be compared to a broken arm in a cast: Initially, pain is reduced by keeping the arm immobile, but when the cast is removed is the arm stronger? The cast leads to a weakening of the muscles and also to a reduction of flexibility/mobility due to structural changes of the fascia. The muscles need to regain their strength to support the arm, and not to make it even more injury prone due to weakness.
Reviews of the published literature on the subject by Dr. Hamill’s colleague, Dr. Benno M. Nigg, a professor of biomechanics at the university, finds there is very little scientific rigor in orthotics and injury prevention studies. For example, they did not include groups that, for comparison, did not receive orthotics. Or they discounted people who dropped out of the study, even though dropouts are often those who are not benefiting from treatment.
Dr. Nigg’s overall conclusion? Shoe inserts or orthotics may be helpful as a short-term solution, preventing injuries in some athletes, but it is not clear how to make inserts that work. The idea that they are supposed to correct mechanical-alignment problems does not hold up and in fact, “corrective” orthotics, he states, do not correct so much as lead to a reduction in muscle strength.
Orthotics in treating back pain
In the case of back pain, we find orthotics use even more problematic. The causes of back pain are complex and notoriously resistant to any kind of treatment probably because it is strongly influenced by many factors we do not understand or cannot control (like genetics, or the mind-body connection in low back pain). Today's sedentary lifestyle and prolonged sitting are just one problem. Nevertheless, orthotics or heels lifts are often prescribed for this condition. Since the correlation between back pain and even the most obvious structural/degenerative issues in the spine is poor to nonexistent, it’s unlikely that it would be much affected by subtler biomechanical issues influenced by gait. In fact, the available evidence around orthotics is based on just a few small trials, and that evidence does not support insoles or foot orthotics preventing or treating back pain3.
Even studies with positive results—the few that exist are based on small sample sizes—have obvious flaws4. The trial cited in the footnotes below tested the efficacy of shoe orthotics and chiropractic treatment for chronic low back pain, dividing 225 patients into three groups: 1) A wait-list control group of no care at all; 2) another group received custom orthotics; and 3) a third group got custom orthotics plus chiropractic and massage treatment. Results, according to the authors, were: “Six weeks of prescription shoe orthotics significantly improved back pain and dysfunction compared to no treatment.” However, there were no differences after 12 weeks, leading to the conclusion that the positive outcomes were short-lived at best. This study also had no true “placebo” control group, given that wait-list groups suffer from “frustrebo” – poor outcomes caused by the disappointment of knowing that you are not getting any treatment5. The "frustrebo" effect, as described in the paper in the footnotes below, is "Negative true placebo effects ('frustrebo effects') in the comparison group, and cognitive measurement biases in the comparison group and the experimental group make the non-specific effect look like a benefit for the intervention group."
If not orthotics, then what can you do?
So if orthotics are not the answer for disorders and malpositions, what can an informed consumer do? First of all, talk to your doctor to understand the root of your specific foot, ankle, knee, hip, or back problem. Talk about your options, including everything from orthotics to massage to stretching to physical therapy. Remember orthotics may help you in the short term, but to rehabilitate your musculoskeletal system and prevent further injury, you need to strengthen the entire system. One way is a shoe with a soft elastic sole that can strengthen the foot muscles and stabilize the entire foot. Your foot will learn to actively support itself with its own musculature (insoles stabilize passively).
A physical therapist can show you specific exercises geared toward your injury. They may also suggest you use an active anti-fatigue mat to stand on in your usual daily routine. A springy, soft and supple standing mat will allow the foot to sink in deep and spring right back to its original position, performing as an active dynamic exercise platform for the feet. A good mat encourages the body to constantly make small movements in order to maintain balance and posture. This rebounding effect causes the muscles to tense and relax reciprocally, exercising the muscles in your feet, legs, and core. It improves your balance, coordination, and all-around core fitness without taking extra time: You can stand on it while working at your desk, watching TV, cooking, standing at the sink – any activity that allows you to stand.
The key is to be active: increase movement and exercise. If pain or discomfort limit your freedom of movement, consult with your doctor, and look for technological solutions that can help you become active and mobile by letting your walk and stand pain-free without immobilizing.
3. Chuter V, Spink M, Searle A, Ho A. The effectiveness of shoe insoles for the prevention and treatment of low back pain: a systematic review and meta-analysis of randomised controlled trials. BMC Musculoskelet Disord. 2014 Apr;15:140. PubMed #24775807. PainSci #53612.)↩
4. Cambron JA, Dexheimer JM, Duarte M, Freels S. Shoe Orthotics for the Treatment of Chronic Low Back Pain: A Randomized Controlled Trial. Arch Phys Med Rehabil. 2017 Apr. PubMed #28465224↩
5. Power M, Hopayian K. Exposing the evidence gap for complementary and alternative medicine to be integrated into science-based medicine. J R Soc Med. 2011 Apr;104(4):155–61. PubMed #21502214↩