Amputations are becoming a more common surgical treatment as an alternative to below-knee amputation due to advanced diabetes, vascular insufficiency, or trauma. It is estimated that 10,000 partial foot amputations are performed in the United States every year.
There are several ways and places that the impact of unyielding metal - can be coerced to transfer less pounding up the spine of the prosthetic wearer. these are things you must design in to your prosthetic in relation to the wearers' height, weight and type of foot and knee being used. It is not as simple as it sounds and sometimes just one half of an inch can make the difference between using an "ideal" item or not. In the past, prosthetics have created difficulty walking and running, as a result of a lack of natural movement, weight, and absence of sensation.
To design a fully functional prosthetic foot that will emulate many of the anatomical features of the human foot, the foot must have the ability to bend out (eversion), the ability to bend forward (dorsiflexion), impact absorption, and energy return. Today many prosthetic feet are made with the same carbon fiber used in the air and space industry because of its large load capacity, small weight and flexibility. Unfortunately, many manufacturers do not take into account a conservative approach in foot height to the mount pyramid.
Ossur designed the Low Profile Symes for amputees with an active lifestyle. Made of 100% carbon fiber, it has a double spring keel, which is both flexible and strong. A fenestrated heel allows the heel to compress completely at the socket attachment site, which eliminates a jarring compression and reduces noise. The Low profile Symes has excellent energy storage and release capabilities, is lightweight and durable. A good foot also in the Elite family by EndoLite.
Endolite has on it's website an animated step of how the foot works. See http://www.endolite.com/foot_elite2.php Another product by Ossur is the Talux Flex-Foot. This prosthesis boasts a more fluid and graceful walking motion on a variety of terrains. Also made of carbon fiber, the Talux has a unique Carbon X Active Heel, which ensures maximum energy storage and release. Another thing you must consider is that while it may bear a "brand name" it indeed may not have been conceived by that brand name entity, and indeed may have been and is still made by another firm. Otto Bock sells the Luxon Max by Springlite consisting of rubber, carbon fiber and plastic,
This prosthesis cushions by absorbing shock as an "approved and one of the recommended foot types for the C-leg system. This feature of the Luxon Max design helps absorb shock before it reaches the residual limb. A particular feature that makes the Luxon Max stand out is a smooth-impact split heel, which enables independent pivot motion on toe and heel. Reduced energy loss and expanded range of motion is a result of the greater flexibility and springiness.
The Hanger Orthopedic Group Inc is currently developing the Sense of Feel System (SOF). This unique system allows amputees to feel sensations generated by their artificial foot. Pressure transducers incorporated in the sole of the artificial foot respond to pressure changes on individual areas of the foot and send signals to the amputee's residual limb via an electronic interface and electrode on the skin. This system can improve balance, permit the use of an automobile clutch or brake, and reduce phantom pain.
The amputee may gain a feeling of the foot and lower leg as if reconnected to the body due to cerebral projection, in which the brain projects the missing feedback in the patient's mind. The SOF System is still in the research and development stage and is not currently available to the general public. In this author -wearer's opinion - the SOF system is a waste of time.