Researcher David Wiley, PT
*Shoe insert development via FDA study, *Like-minded podiatry sponsorship
Greetings! My name is David Wiley. I am a physical therapist and inventor of rehabilitative shoe inserts and foot alignment devices designed for return of supinated function for those with a flatfoot condition. I undertook studying available research on flatfoot due to my own moderate to severe painful bilateral flatfoot condition. I am excited to report I have recovered my pain free foot function using the patented rehabilitative shoe inserts, and am now running up hills with return of natural push-off through my large toe region. Read "A Novel Treatment Approach to Overpronation Dysfunction" (1; JAPMA; 2017, PubMed DOI: 10.7547/17-053) This condition is termed Posterior Tibialis Tendon Dysfunction (PTTD), which may also encompass Adult Aquired Flatfoot (AAF) as a common foot dysfunction. A formal definition of PTTD being a symptomatic, progressive deformity of the foot caused by loss of supportive structures of the medial arch.(2) The picture below left shows my flatfoot condition “too many toes" showing sign (3) while the right shows the change in my shoe wear pattern use before and after my rehabilitation.(1)
I received my patent through the LegalCORPS program, a pro bono patent assistance program for under-resourced inventors.(4) My background and experience in this field of research can be found in my Biosketch, emailed if requested.
Muscle balance is a fundamental theory for physical therapy practice. As applied to the foot, Halbach reports over-pronation may occur due to muscle imbalance between the dynamic pronators and supinators of the foot. Therefore rehabilitation needs to address this muscle imbalance for return of function.(5) Kendall & McCreary report exercises which strengthen weakened muscles, and exercises that stretch shortened muscles, are the means by which there is a return of muscle balance. Therefore, rehabilitation should not contain exercises that strengthen the shortened, stronger muscles, or put stretch on already stretched weak muscles.(6) The diagram to the left shows muscle balance intervention.(7)
MacConnel (1944) introduced the term “twisted plate” to describe supination, observing the curved lamina pedis and noted that pronation of the foot untwisted the foot.(8) The twisted plate description of a supinated foot aligns with the wedged rehabilitative shoe insert concept for return of muscle balance from PTTD, also shown in the diagram to the left. Hicks (1954) describes the supinated "twisted" function of the forefoot is to plantar flex the first ray on the push-off phase of gait, providing weight bearing resistance through mechanisms described as the midfoot pulley, incorporating the peroneus longus, and the windlass effect of the plantar aponeurosis.(1,7,9,10) The supinated heel wedging combined with forefoot wedging enhance the above described mechanisms. (1,7) Sarraffian (1987) further expanded on MacConnels' twisted plate to describe that reversing the twist placed greater tension on the plantar fascia.(11)
Above left is the wedging used to support the forefoot with conventional orthotics while the right is wedging I used for my treatment.(4, 7) In the treatment of PTTD, conventional posting of a foot orthotic in the neutral stance involves filling in the gap underneath a forefoot defect; in effect bringing the floor up to the foot. An abbreviated theory to this treatment is that the posting allows the foot to function more efficiently with less stress and tissue damage, as opposed to the over-pronated position.(8) The disadvantage of a neutral posting and shimming the defect is a compromising of the supinated foot mechanisms offered by the aponeurosis and peroneus during the push-of phase of gait, as the forefoot shimming prevents the natural downward plantarflexion of the forefoot.(7,9) Thus, the natural mechanisms that provide resistance to weight bearing forces on the first ray are compromised on push-off; similar to a push off from a loose-bag-of bones.(1,7,9,10) This treatment approach has also been questioned in the literature. Rodgers and LeVeau performed a study to assess the effectiveness of orthotics in runners. Their results show there was not a significant difference in the amount of pronation with or without orthotic use.(12) D’Ambrosia and Douglas (1982) report constant orthotic wear may lead to disuse of muscles and ligaments.(13)
The rehabilitation concept offers supinated alignment of the foot, as opposed to the neutral alignment posting of conventional orthotic treatment. The wedging of the heel and forefoot differs from the conventional in that it brings the foot down to the floor, as stabilized weight bearing through the first ray and large toe is emphasized. Hicks reports "the effect of a normal first ray depression is to provide a foot that does not yield to increasing weight bearing forces, but which tends to flex and thrust downwards with and additional flick at takeoff".(9)
An abnormal foot with PTTD is only abnormal if it cannot be mobilized to function as nature intended. With normal foot structure, it is axiomatic that a rearfoot weakness caused by PTTD will result in compensatory abnormalities, a common one being forefoot varus. To mitigate the defective function, Speck (2013) proposes exercise, rather than fitting orthotics to fill in the gap under the defect, as a more reasonable way to manage the problem. Mr. Speck suggests an effective exercise has been stretching by slightly inverting the heel while bringing the big toe to the floor (emphasis to avoid curling or gripping of the toes). Mr. Speck is describing an exercise similar to walking with wedged insoles to functionally perform the stretch.(14) Therefore, rehabilitation with the use of wedged insoles may assist in return to a more normal alignment and supinated function for those with early stage PTTD who also have a forefoot varus compensation dysfunction. In my case, a rehabilitation/mobilization of abnormal compensations resulted in a return of muscle balance, enhancing the natural stabilization mechanisms; an especially significant advantage as my condition also includes an additional hypermobile first ray and bunion.(1, 7)
A 3/8 inch maximal height prototype rehabilitative shoe insert was developed based on the above functional foam EVA shoe inserts, Note the minimal compression of the midfoot arch region on the pair of used inserts at the right. Several sizes have been fabricated for a study.
The results of my study can be found in the Journal of Orthopaedic Physical Therapy Practice.(15) I appreciate Dr.Robert Phillips acknowledgement of my work in the Journal of the American Podiatric Medical Association, as I understand the importance of research as it relates to my own practice. (16)
Let's take a run up Mount Hosmer