Talking points in Podiatric Biomechanics
1. Controlling pronation prevents lower extremity pain
-There is no research that shows subtalar joint pronation is abnormal and causes foot pain. With specific types of pronation that are pathological (Posterior tibial tendon failure or rupture, and excessive pronation causing sinus tarsi impingement, for example) orthotics and bracing will benefit. Overpronation is not shown to be a pathological issue. Even with plantar fasciitis/fasciocis-related heel pain, custom and non-custom orthotics have been shown to have equal efficacy
2. Supporting the arch
-The arguement here is that an arch is inherently stable and only needs to be supported from the ends, and not in the center like typical orthotics provide. (https://nwfootankle.com/foot-health/drill/2-Articles)
3. Rigid, supportive shoes will help
-Except for severe traumatic arthritis and severe end-stage degenerative arthritis, rigid shoes may potentiate foot problems by allowing progressive atrophy of musculature and accelerate rigidity of deformities. With arthritis, it is important to keep moving! http://www.arthritis.org/benefits-of-exercise.php. A rigid shoe may help temporarily relieve arthritic pain, but then it's time to get moving again! If movement is good for an arthritic knee joint, why would we think it's not good for an arthritic subtalar or midtarsal joint in the foot? The point here is that movement and strengthening of the muscles around a pathologic joint is the goal, whether that's a foot or knee or shoulder.
-In the podiatric and foot and ankle orthopedic communities, there is an idea that equinus leads to generalized foot and specifically forefoot pain. There is some research backing this, and even more research in diabetics with equinus that develop ulcers (wounds) in the forefoot because of increased pressure. Equinus is our term for a tight achilles tendon (either gastrocnemius muscle only or both the gastroc and soleus muscles may be tight--these both form into the achilles tendon). It is my belief that this tight achilles tendon comes from the heeled shoes we wear though I have no research to support this (even the vast majority of men's shoes usually have a drop ratio of 2:1 from the heel to forefoot). Thus, most people can barely dorsiflex their ankle beyond a 90 degree angle to the leg. This is the reason many people have achilles and calf pain/injury when transitioning to a minimalist shoe or going barefoot.
5. The role of the First Ray
-Summary of how shoes influence the the first ray here:
6. There is a Genetic basis for developing foot pathology.
-There are studies showing a genetic component for developing bunion deformities, though social factors are not controlled for. Grandma, mom and daughter living in Toronto for 3 generations may have bunions, but it is likely they have worn similar shoes and led similar socio-economic lifestyles. One paleontological study showed emergence of forefoot pathology with modern man (Zipfel, B; Berger, LR. 2007, in library section of website). There is another study showing the role of shoes in a similar population cohort across a socio-economic divide, dealing with children and flatfoot (Rao, UB 1992, also in library section) I'd like to see a similar study with adults and bunions.