Walk into your local pharmacy or even many grocery stores and you’ll be able to have your foot scanned and pick up a “customized” orthotic instantly. Turn on the television to watch your favorite show and you’ll most likely see a commercial claiming an arch support will cure your back pain. Finally, as you are walking the down the street to get a cup of coffee, you’ll most likely pass a specialized shoe store that sells “custom” foot orthotics. We’ve all had patients walk come into our podiatric practices with a bag full of various arch supports that they’ve collected over the past several years, hoping that you will be the one to really help realign their feet.
According to IndustryArc, the global “Foot Orthotic Insoles Market” registered revenues of nearly $2.5 Billion in 2014 and is that dollar amount is estimated to grow 5.8% to reach $3.5 Billion by 2020. 45% of those sales occurred in the North America. This is an indication that there are a lot of people with misaligned, over-pronating feet that are willing to fork over money to get some relief. The only problem is that there is little to no evidence that something placed in your shoe can actually have a positive effect to normal or reduce excessive pronation.
One of the many items discussed is the role of foot/arch supports both over-the-counter (OTC) and hand-made custom-made devices. The overwhelming consensus is that these devices have a limited ability if-any to control excessive foot pronation. Yet, the estimated annual revenue for arch supports will continue to grow year after year.
It is absolutely amazing that, when asked, how does a foot orthotic limit or control foot pronation, the majority of foot specialists have no answer. It should be very important to understand the exact mechanism of action the form of treatment a physician is prescribing to their patient to make sure that form of treatment is providing them correction of their pathologic deformity.
How exactly does an arch support function to reduce or limit excessive pronation? The general, most common answer is that it functions by altering the weightbearing surface in a manner to prevent excessive pronation. Also, it “fills” the arch area in an attempt to prevent the arch from “falling.” Podiatric physicians will have a more thorough understanding of the actual complexity of a real custom-made orthosis. The first aspect that must be taken into consideration is the posting of the heel. This is an attempt to prevent the calcaneus from everting at heel strike. Then there’s the arch filler to prevent the arch from “falling.” Finally, there could be an extension for the ball of the foot to support a “dropped” metatarsal head or an extension to accommodate an unstable or misaligned 1st metatarsal bone.
Where is the “science” to back up the claims that foot orthosis can prevent calcaneal eversion, navicular drop, or rebalance the 1st ray instability. This is a major problem with the use of arch supports and that it is an unregulated industry. All kinds of false claims can be made without penalty. Anything placed into someone’s shoe will give the sensation of a different feeling, but that does not mean the foot is now aligned and the excessive motion no longer is occurring during the gait cycle.
Another issue is the limited validation of this treatment measure. What is the best diagnostic tool to evaluate foot alignment, a “test” that is standardized, validated, and reproducible from clinician to clinician? It is not range of motion testing or gait analysis, rather it is weightbearing radiographs. Each image provides valuable, measureable data that can be used to diagnose the alignment or misaligned of the osseous foot structure. Furthermore, the use of weightbearing radiographs can evaluate the effectiveness of a prescribed treatment. A pre-treatment and post-treatment radiograph should show normalization of pathologic measurements.
Numeric values are essential in the treatment of metabolic and musculoskeletal diseases. Symptom relief is not the gold standard, it is the silver standard. The gold standard is to truly “fix” the problem not just to cover-up the symptoms or offer pain relief. Pain is an indication that something is wrong. It is below the standard of care to only give pain-relief measures without fixing the underlying etiology. If you don’t address the underlying cause of the pain it will only be a matter of time until that symptom or pain returns. The leading issue in the treatment of musculoskeletal diseases is recurrence of primary symptom. Again, this tells us that the underlying etiology was never truly “fixed.”
Imagine someone was a diabetic and the only form of treatment is simply to make sure the patient doesn’t end up in a diabetic coma. Or another example is someone with hypertension, should the goal be focused purely on the symptom relief? Of course not, the goal is to normalize their blood pressure. The standard of care for the treatment of a misaligned foot should be that the foot is realigned and that there are pre- and post-treatment measurements made to validate the realignment that are reproducible from clinician to clinician.
When “fixing” a problem, it is crucial to understand the underlying etiology. So we must ask the question, what is the exact cause of over-pronation? This simple question is critical in the treatment of most musculoskeletal pathologies to the foot, ankle, knee, hip, and back. Yet, the vast medical professionals who treat these pathologies have failed to make the connection between the symptom and the underlying foot alignment pathology. They do know the term over-pronation, but don’t know the exact mechanism defect that leads to a prolonged unlocking of the foot bones during the gait cycle.
The talotarsal joint (TTJ) mechanism is the most complex and most important joint of the lower extremity. Its function is to redirect the weightbearing forces from the body above and the counter weightbearing forces from below. Approximately 52% of those forces should act on the posterior talocalcaneal facet and 48% anterior to the sinus tarsi. While this is an important function, there is yet an even more important responsibility given to the TTJ. That is, it is responsible for the locking-stabilization and unlocking-destabilization of foot structure. This is accomplished with supination and pronation of the TTJ. TTJ supination provides for a rigid lever action of the foot. The TTJ should be in a locked-supinated positive at heel strike and it only should be in a pronated position during the 1st 30% of the mid-stance portion of the gait cycle. The rest of the mid-stance to toe-off requires the TTJ to be supinated so that the foot structure can propel the foot forward.
It is important for the reader to understand that, at heel strike, the leg is internally rotated and the contact of the heel should occur to the outer-lateral posterior heel. The vertical bisection of the talus should be located within the 1st intermetatarsal space. As the foot continues its path onto the weightbearing surface, there will be a redirection of forces from internal rotation forces as the TTJ pronates into order to accommodate for an uneven weightbearing surface. Immediate the talus will need to resupinate in order to prepare the foot for heel lift. Failure of this transition will place excessive strain on the spring ligament, plantar fascia, posterior tibial tendon, 1st metatarsocunieform and 1st metatarsophalangeal joints.
The loss of stability between the talus on the tarsal mechanism (calcaneus and navicular) will lead to a prolonged period of foot pronation. In other words, the exact cause of over-pronation is begins and ends with the stability or instability of the TTJ, specifically, the lack of stability of the talus on the calcaneus and/or navicular. (Please read this again).
Now we have to go back and think about the ability of something placed on the bottom of the foot to control excessive talar rotation. Can something acting below the calcaneus realign and stabilize a bone on top of it? The answer is simply no. There is no evidence that an orthotic can realign and stabilize the talus on the calcaneus. Should that mean that an orthotic should be considered below the standard of care in the treatment of over-pronation? Possibly.
The goal is treatment is not to just cover up the symptoms, but rather fix the underlying problem. Arch supports cannot fix over-pronation, they try to reduce it. But it is possible they could actually increase the duration of pronation rather than reduce it. The foot orthotic will have to stop the internal-medial rotation of the talus on the calcaneus to redirect the center-of-force acting on the foot.
Foot orthosis are therefore a sub-therapeutic form of treatment. A good example is a patient who is a poorly controlled insulin-dependent diabetic. The goal is not to keep the patient symptom-free, it is to normalize their blood sugar level. Diet only cannot help. Just like shoes cannot “fix” over-pronation or talotarsal joint instability. Oral medications may help a little to lower the blood glucose, but it cannot normalize blood glucose in a type I, insulin dependent diabetic. Similarly, arch supports cannot realign and stabilize the talus on the calcaneus. The only way to normalize the blood sugar levels is to have insulin injected into their body. Likewise, the use of a sinus tarsi implant is a superior option over arch supports to realign the talotarsal joint.
Many medical professional feel that it is better to offer a “conservative” option rather than performing a corrective surgery. While this may seem to make sense, further analysis reveals that it doesn’t make sense at all. Should a patient wait months or years to normalize their blood sugar level by using insulin, or should they just continue to take oral medications. One could argue that administering a sub-therapeutic form of treatment is below the standard-of-care.
Talotarsal joint instability is named as the underlying etiology or major contributing factor to the develop of many symptomatic areas of the foot, ankle, knee, hip, and back. If you, as the foot-expert, realize your patient’s over-pronation is not being corrected by a form of treatment you’ve prescribe and you do nothing that is called supervised neglect. That’s because thousands of times a day, with every step taken, excessive abnormal forces are leading to the destruction of soft tissues of the lower extremity. The hindfoot misalignment will lead to joint misaligned and can contribute to the formation of osteoarthritis.
There is an evidenced-based, proven solution to the realignment and stabilization of the talotarsal joint. Extra-osseous talotarsal joint stabilization (EOTTS) is an amazing option that is time-tested. This conservative form of treatment should be considered the standard-of-care in the treatment of talotarsal joint instability. That’s because it fixes the deformity while still allowing a normal range of motion. Traditional surgery such as calcaneal osteotomy or arthrodesis procedure should be reserved for patients who are not candidates for the EOTTS procedure.
Millions of patients around the world are told to try a subtherapeutic form of treatment. Every year the number of patients suffering with chronic musculoskeletal complaints continues to raise. Just like the medical expenditures on the treatment of chronic musculoskeletal disease. The time has come to expose foot inserts as below the standard of care in the treatment of talotarsal joint instability and to recommend a better form of treatment that actually does the job of realigning and stabilization the talotarsal joint mechanism.
