Foot Orthoses – shoe inserts or orthotics
Foot Orthoses – shoe inserts or orthotics
Knee, ankle, foot and heel pain are common problems among society. Achilles tendonitis and plantar fasciitis are just some of the conditions that cause these problems. In our clinic we have great success using orthoses to treat these problems but what are orthoses and how do they work?
Historically, it has been documented that there is a “normal” alignment which we should all conform to, and if we don’t we are considered abnormal and therefore at risk of significant injury or pain. This “textbook normal” was usually depicted as vertical. So if we took a marker pen and drew a line down the middle of the back of your leg and also one down the middle of the back of your heel, these lines should perfectly marry with each other (and in turn be perpendicular with the ground). On the basis that any individual who was not set up this way was considered abnormal, they were told they needed orthoses (shoe inserts) to re-align their skeleton back to its correct position.
There are only 2 problems with this paradigm. Firstly, the concept that we should all be the same is hugely flawed and incorrect (research has shown it to be so). Person to person variation is vast (not to mention activity to activity variation), and in the current day this variation is considered normal in itself. Feet are a bit like noses – we all have them and they can look wildly different from one another’s – but as long as they function appropriately we do not require them to all look the same. However although there is not one position considered normal, it is a fair assumption that there is a range which it is ideal to be functioning within.
The second problem is that even if we did require all individuals to be in one particular position – orthoses do not work by holding individuals in one particular position. Of all of the scientific studies investigating foot orthoses not one has shown them to ‘hold’ the foot in a given position. This is a good thing; the human foot is designed to be a dynamic structure when being used; i.e. it needs to move.
So how do orthoses work? Well, introducing them into a shoe will directly change the way the foot interacts with the surface beneath it. Orthoses can change the amount of pressure beneath the foot, and the location of this pressure (i.e. offload a painful region if required). They can change the movement in joints of the foot and ankle (i.e. encourage a foot to rotate in a certain direction if required). The type of orthoses issued (the materials used and prescription decided upon) will therefore greatly depend on what is actually trying to be achieved, and this in turn will depend on the presenting complaint/injury.
What is trying to be achieved with foot orthoses therapy is therefore seldom a re-alignment of the skeleton to “normal” (vertical). It is instead to try and reduce the damaging loads/forces on injured tissues. To give a common example, imagine a runner who gets significant pain in their Achilles tendon when running distance of over 3 miles. If the way the foot moves during running is significantly increasing the tension within the Achilles tendon and therefore significantly contributing to the problem, then no amount of rest will lower the risk of that Achilles tendon pain returning when running is resumed. The underlying mechanical cause of the issue (the way the foot is moving) has to be addressed or changed for the best long term outcome to be achieved. So orthoses may be indicated, and the prescription variables which are known to lower the tensional forces within the tendon are applied.
In the case of the uninjured sportsman who wants an opinion on their alignment things are obviously a little trickier. If the main aim of orthoses therapy in the injured is to reduce damaging forces on tissues (identified by pain) then what is the aim in the uninjured where no pain is present? Put simply, it is to deduct whether there are any current patterns of movement which are thought to be risk factors for future pain or injury. As previously mentioned it is thought there is probably a range within which it is optimal to function, and thereby allow the tissues to tolerate the loads and impact associated with sporting activity. It is often clear when someone is functioning at an extreme of this range (or perhaps outside of it), and in these cases orthoses can be beneficial in a preventative capacity – their aim is again not to restore a fictional “normal” position, but rather minimise the risk of future injury by keeping the tissues within their zones of optimal stress.