Durability Advice of HealthyStep Devices
Patients (and practitioners) often ask “How long will my insoles last”; or raise concerns about signs of wear on the devices. It is important that we as clinicians can offer an honest answer. Good information as in all aspects of treatments help to manage patient expectations.
It is important that the orthosis you provide is of appropriate durability to the presenting problem. For a diagnosis with short term symptoms with resolution expected over the short term, good insole durability is not that important. For someone with a long term dysfunction that may require a lifetime of intervention, good durability is essential.
Remember it is often desirable, and even necessary to change a prescription over time. I can’t emphasise enough the importance of this aspect in MSK treatment. The most common reason for adjustment is that the original problems are improving, the tissues healing and strengthening so that the original prescription on the foot orthosis has become excessive. High durability insoles can be far more difficult to adjust to accommodate changes.
There are a number of factors that affect durability, and these will each influence how you answer the patients question of how long the insole will last:
- Material – the orthosis is made of
- If the patient does wet/dirty jobs with the insoles on.
- Mass – size of the patient in relation to the size of the insole
- How often insoles are likely to be moved from shoe to shoe.
- Activity – levels of the patient.
For those readers that like acronyms, how about ME(N)TAL ?
Factors That Affect Insole Durability
(N) Weight/Mass (in Newtons)
T Transference of the devices from show to shoe
AL Activity Levels
A piece of information given by Martyn Shorten (well-known research Biomechanist, who is well published on footwear science) to a question from myself at the 2018 Staffordshire conference on clinical biomechanics gives us a clue as what stresses our orthoses. This is as yet unpublished data but confirmed my suspicions. Foot orthoses interact far more closely with the shoe not the foot! This means the top of orthoses will be subjected to the same stresses that the insock of the shoe sustains from the foot movement inside the shoe.
There are certain points on insoles that will be particularly prone to surface wear. Heel cups are not only stressed during use, but also as the foot is taken in and out of the shoe.
In foam material orthoses this often wrinkles the heel cup material. Top covers become worn most in the heel cup and forefoot areas as they are loaded with higher forces than the mid-sections of the orthoses. Often these areas will wear through long before the integrity of the insole support is lost. With higher arch-supporting prescriptions, where the arch is also significantly loaded instance there will tend to be worn over the arch covering material.
Warn the patient that these sorts of wear patterns are to be expected and they won’t worry about them. Point out that such wear is often useful is ascertaining whether the orthoses is doing what you want it to do, for indeed if stresses need to be moved or directed to certain points such wear patterns are very useful.