Insoles: The answer to heel pain and leg over-use injuries?
This is a topic that has always caused debate and can be a bit like Marmite: You either love it or hate it! There are arguments for and there are arguments against insoles, or to give them their correct name; orthotics. Orthotics can correct any foot abnormality and give the wearer a normal foot posture and positioning. Someone who has a foot deformity since birth or who has suffered a significant, dramatic change to their foot would benefit from orthotics. The argument against orthotics is that these can make a sudden change to to how your legs respond and interact, following the sudden change, which can in turn lead to more pain and more injuries. A good rule of thumb has always been: "If you don't need them for walking, then you shouldn't need them for running". I wrote about this in more depth last year. You can read this work here
But what does the latest evidence say?
There have been a couple of articles published in the latest edition of The British Journal of Sports Medicine [BJSM] regarding this. The first article: Foot orthoses for plantar heel pain: a systematic review and meta-analysis. Whittaker et al (2018). There findings support what we as physiotherapists have known about plantar fasciopathy (previously plantar fasciitis) or heel pain in that there is no clinically important change in the long term for the use of orthotics in the management of this condition. In addition, they found no effect with orthotics in the management of pain. You can read the work I wrote previously about regarding this condition here
The authors stated that their research showed there was a high risk of bias towards the use of orthotics in the studies reviewed. There was also no significant difference when comparing bespoke orthotics with sham orthotics and generic heel pads. Also, they suggested the data is of low quality and inconsistent.
The second article: Effectiveness of foot orthoses for the prevention of lower limb overuse injuries in naval recruits: a randomised control trial. Bonanno et al. (2018). Within their abstract conclusion, they state "prefabricated foot orthoses may be beneficial for reducing the incidence of lower limb injury...." Yet, reading the article in full detail, the researchers compared two groups: 1 group wearing customised orthotics and 1 group wearing "flat insoles" over an 11 week training program and compared the incidents of injuries over that time. Their comparison of these two groups only showed that customised orthotics have fewer incidents of injury that flat insoles.
However, there was no control group! In other words: There was no group of individuals that completed the 11 week training program that did not wear orthotics. Therefore, all this study has been able to do is confirm that orthotics lead to some people getting an injury! This study can only say that custom made orthotics are less likely to injure you than flat insoles. 22% of participants in total developed an injury over the 11 weeks . That's more than 1 in 5! There was only a small variance of 13 people fewer sustaining an injury, in favour of custom made over flat insoles. It therefore suggests that this small variance calls into question the authors claim of "prefabricated foot orthoses may be beneficial for reducing the incidence of lower limb injury...."
As an evidence-based clinician, I always ensure that I am using up to date evidence in my practice. When I saw the titles articles in BJSM, I was intrigued to say the least. If the articles had shown that there was evidence to support the use of orthotics in the treatment of heel pain and over use injuries, then I would certainly add them into my treatment plans. On the balance of this evidence, I remain dubious with regards to their efficacy in situations such as these.
