Peg legs and bionic limbs: the devlopment of lower extremity prosthetics.
Gutfleisch O (2003) Interdisc. Sci. Rev. 28(2):139-148.
As shoes became more accessible to the general population, people demanded better comfort. At this time shoes were made the same. There was no such thing as a left or right shoe (a concept that would not catch on until the 1800s.) Early innkeepers recognized that most weary travelers complained of foot pain. The first insoles were made by innkeepers from matted animal hair retrieved from the local barn (later called felt).
Over time, shoe makers, or cobblers, modified the innkeepers’ foot pads and began to add leather materials to the insides of shoes to create a better, more comfortable fit--the first arch supports were born. Early arch supports were made by laminating layers of leather strips together, molding them to shoe lasts, and then shaping the arch support by hand for wearing inside shoes. These new arch supports helped create a new level of comfort for people wearing shoes. The only problem was that arch supports were often bulky and heavy.
By the early 1900’s electricity and bench grinders made cutting down leather laminated devices much faster and therefore more affordable for the general population. In addition, lighter and softer materials were combined with leather blanks to create an additional level of comfort.
The next major enhancement came in the 1960s when a new generation of thermoplastics was introduced to the marketplace. Thermoplastics mold to a form, such as a replica of your foot, when hot. Once cooled, the material retains the molded shape of the form. Thermoplastics, such as polypropylene, are lightweight especially in comparison to leather and foam materials. More importantly, thermoplastics provide a strong, durable, and thin orthotic that can support the foot and body while fitting into modern style shoes. As a further plus, polypropylene is recyclable.
The introduction of thermoplastic materials led to new theories about how to make arch supports. Instead of using a shoe last to make the device, medical professionals began using a mold or cast of a person’s foot, thereby creating a true orthotic. The medical definition of an orthotic is a brace that supports a specific body structure. More importantly, scientific principles were (and continue to be) applied to the foot’s structure and to foot orthotics to develop foot supports that can actually control the function of feet, legs, hips, back, and neck.
Since the 1960’s, the art of custom orthotic making has been continually enhanced so that today it is possible to build an orthotic that can help correct the foot deformities (such as bunions, flat feet, etc.) that cause typical aches and pains in the feet, legs, hips, back, and neck--the types of aches and pains people in all cultures and all parts of world experience. The custom orthotic is typically prescribed by a licensed Foot Care Professional who is Medically trained. Orthotics are fabricated by Professional Orthotic Laboratories.
Records from the United States patent office use many different names to describe those inventions intended to improve foot and or arch function the "Orthotic". Detailed review of over 70 different registered inventions describes only two basic design techniques for orthotics. One technique builds a device by placing mass or substance in the arches of the foot; the other fabricates a plate-contoured to the plantar surface of the foot.
Many orthotic devices currently used today and first presented almost 100 years earlier strategically place mass so as to generate support to the medial longitudinal, lateral longitudinal and transverse metatarsal arches. Earlier orthotic inventions used the patients foot, then individual foot impressions and later shoe size formulas to generate the design of their arch supporting orthotic devices. Foot and or arch supports (orthotics) constructed in this fashion were recorded in both early and more recent patent literature.
Other inventions describe fabrication of a plate contoured to the plantar surface of the foot, using milling and bending techniques to contour the material to foot impressions or scanned coordinates. This contoured plate was further stabilized with a heel post designed to control the position of the plate during weight bearing or stance phase of the gait cycle. Additional varus wedging to the contoured plate, up to 10 degrees, has been described. Both extrinsic posts and intrinsic posts (changes in the contour of the plate from its original configuration) are described. Numerous variations in plate width and material used for construction are recorded. Review of the patent literature identified designs as early as 1924 that contoured metal, rubber and wood to cast impressions taken from individual feet. Many orthotic laboratories, using a variety of plastics and even a scanned digital image as the foot impression currently use this contoured plate method of fabrication.
Many types and combinations of material both natural and synthetic have been used to construct the orthotic devices reviewed. Some use materials that are soft and said to "cushion the foot". Others use material that is highly resistant to deformation, with expressed intent to support or stabilize. Many incorporate materials that both support and cushion foot function.
Orthotics constructed of steel, wood, plastics and hard rubber have all been used to generate relatively rigid plates. Foam rubber, water, air and a variety of compressible materials have been used as cushions for the foot.
In general inventions designed to fill the arches
used softer materials, than those who contoured a plate did. Function of
a foot control devise is increased with a material less deformed during
stance phase of gait. The term functional orthotic, currently used to describe
semi-rigid to rigid contoured plate orthotics may be generally applied,
however all foot control devices alter the function of the foot.
Ptersen H & Gocht H (1907) Amputationen und Exartikulationen. Künstliche
Glieder. Stuttgart, Ferdinand von Enke
Fischer LP, Planchamp W, Fischer B, Chauvin F (2000) Hist Sci Med. 34(1):57-70.The first total hip prostheses in man (1890 - 1960)