Most people will be familiar with insoles or orthotics, either having them yourself or family members having them. Orthotics are a shoe insert used to treat a variety of foot and musculoskeletal issues.
When people who received orthotics from a podiatrist were asked how they believe they work, they answered things like ‘correction’, ‘to stop pronation’, ‘realignment’, ‘to hold in position’, ‘to improve posture’ or to ‘protect’. These kind of beliefs about how the orthotics work are focused on the belief that their feet have faulty postures that is causing of their pain or a predictor of injury, and that these need to be corrected by the orthotic.
But is this an accurate mechanism through which your orthotics work?
First of all, do orthotics actually realign our feet to the perfect posture? From our previous post (click here to read) you can see that we don’t actually know what ‘perfect’ or even ‘normal’ foot posture is. Even if we did imagine a visual neutral to be optimal, does having an orthotic under your foot actually achieve this position? From all of the studies that have looked at this, only about 50% showed any effect of an orthotic on the posture of the foot. So, half of the papers didn’t show any change in position at all! Of the papers that did show an effect on foot posture, it did not mean that the foot was perfectly in neutral, and the change was usually only a few degrees. Even if orthotics did change the angles, did they even change it in the right direction? There was a lot of variation in how people responded to the same orthotic. For example, many people in these studies pronated more when put in orthotics specifically designed to be anti-pronating, which is the opposite of what was expected. More importantly, it was not the people who had the biggest changes in alignment that had the biggest improvements in pain. So, this doesn’t support the belief that orthotics correct faulty postures, or that this leads to an improvement in pain.
So then how do orthotics work?
We still don’t fully know everything about how orthotics work. Recently, there has been a shift in the understanding of how orthotics work. We now have good reason to believe that the positive effect of orthotics on people’s pain might better be explained by something we can’t see. Imagine a seesaw in perfect balance, with no external weight on either end. This means that the gravitational forces on each side of the seesaw are equal and opposite.
Now if we were to add a child on each side of the seesaw, who are of the same weight and at the same distance, the seesaw would still be in perfect balance, but the invisible gravitational forces on each side are now different.
This explains how orthotics work as well. When we place an orthotic under your foot, it pushes against the foot in a certain direction, with a certain amount of force. This can help reduce the amount of work particular tissues in the foot have to do, therefore giving them a break. This can also explain why its not the people who had the biggest change in alignment, with an orthotic inserted, that had the best improvement in pain. It seems to be more likely the people, in which the orthotic provided the right amount of force on the foot to help offload the injured tissue, had the biggest improvement in pain.
So, in summary, orthotics doesn’t seem to reliably alter the alignment of the foot. However, they do alter the invisible forces around the foot by applying an external force to the foot. This can lead to a reduction in internal loads on the injured tissue, therefore reducing the experience of pain you experience.
If you want to know if orthotics might be helpful for your pain, have a chat with one of our physiotherapists at Cairnhill Physiotherapy!