From a purely mechanical standpoint, they improve symmetry and body alignment. In our office, I find that most people who visit us have body style issues which are inherited and passed down through the generations.
The more asymmetrical someone is built, the more problems you will likely have with your back and neck and it is predictable.
I believe, based on years of practice, that the hit or miss approach to treat a symptom with orthotics, whether using off the shelf orthotics or custom is bound to frustrate many, since it shows a clear lack of understanding from the practitioner, who should know more than the patient.
Do they work and what should you expect? I believe that correct expectations is part of the problem.
1. Orthotics are merely a brace, therefore, they will only correct while you wear them. The question is then : what do they do when you don't wear them? The answer is; they are only effective when they are in ones shoes.
2. What do they really do? They correct (if applied with the proper understanding of their function and the way they were made if custom) gait (the way you walk) and improve body symmetry at the ground level. This means that they will level you out, similar to taking a 2x4 and using it to level the foundation of a house. The difference is, they only correct while you wear them. In other words, if they are not in your shoes, they are not doing anything. You also should be advised to wear sandals in the summer with arches and avoid the flat ones (for more year round correction). Also note, if you are wearing heels over 2 inches, you will not need an orthotic since the feet cannot overpronate (turn out) or supinate (turn in) with high shoes which alters your gait.
3. The device did not help my condition. Orthotics do not fix conditions. They merely, create symmetry at the ground level. The myofascia which controls muscle movement (newest information - check out Thomas Meyers book on Anatomy Trains) will mold according to the forces placed upon it. In other words, if your body is a mess because of your body style, and you have plantar fascia because your body's fascial system is a mess (very common), you will not get relief. Podiatrists will commonly treat the foot and ignore the body above it (lunacy) which is why you have the condition. Using orthotics may level the hips but you are still a mess. A good chiropractor who understands a style of myofascial therapy is a must.
4. They need to be worn all the time. If you can correct the problem 70 percent of the time, in combination with body work (chiropractor, massage therapist, both), you are much more likely to get a successful outcome you will be happy with. If your doctor understands the gait process (few do), your results and the orthotics you get whether custom or non will be much more effective (I see many poorly thought out and casted orthotics from other orthotics).
In closing, orthotics are not a one size fits all solution. Your best bet is to see a practitioner who really understands the gait process. Changes we make with either custom or non custom orthotics are provable and reproducible and I do this all the time showing people how running gait predictably improves with the right shoes and device.
What do you think? As always, I value your opinion. Please write me with your questions at backfixer@aol.com and visit our web sites at http://www.backfixer1.com/ or.http://njrunningdoc.com/. Also, stay tuned for my new book on the subject.