If you still have part of your foot, you probably will need a custom prosthesis that is molded to fit in a shoe.If you experienced an amputation involving the ankle, including ankle-disarticulation, Symes, Chopart, Pirogoff or Boyd surgery, you’ll need a specialized low-profile foot.The cosmetic shell, which stretches around the foot prosthesis and is held in place, serves two purposes: What’s inside the shell can vary dramatically. The materials in a prosthetic foot differ by activity level.
Carbon fiber feet meet the functional needs for shock absorption and energy efficiency, and are lightweight as well. A prosthetic foot has to feel good for you to meet your activity goals.
Comfort allows you to be more active, and the function of your prosthetic foot directly affects comfort. Prosthetic feet are designed to mimic a human foot at a specific activity level.
A similar design, the SACH (solid-ankle-cushioned-heel) is still in use because of its sturdy function, especially useful for individuals with lower activity levels.
A SACH foot typically has a rigid inner structure (wood or plastic) surrounded by a compressible foam cosmetic shell.
It must act as a shock absorber as you strike your heel to the ground, adapt to uneven terrain, provide a smooth rollover from heel to toe, and provide a rigid lever for propelling forward when you finish your step (“toe-off”). Some prosthetic feet are designed to mimic the ankle, which allows the foot to move in multiple planes.
Multi-axial capability in a foot allows you to raise and lower the forefoot; move the forefoot to the left and right; and roll the foot slightly to the inside and to the outside.A good prosthetic foot should also be strong, as it will be taking on huge force and torque as you walk and run.Feet must also be small enough to fit within a foot shell, a cosmetic covering for the prosthetic foot, and thus fit within a shoe.If a practitioner or therapist has not yet identified your activity level, here are some very basic indications.If you’re on the border between two activity levels, consider products designed for both levels.Today’s more sophisticated feet, which add more functions, are secured inside a cosmetic shell.Most people never see their prosthetic foot without this exterior shell.For above-knee amputees, keep in mind that the higher the limb loss, the less control you will have of the prosthesis and the more you will need stability in your prosthetic foot.Manufacturers categorize prosthetic feet by the user’s activity level.Activity Level 1For those with the most limited mobility, prosthetic feet designed for maximum stability help maintain balance when standing or taking short, cautious steps at minimal speed on level floors.With safety as a priority, opt for these characteristics in a prosthetic foot: Activity Level 2To walk for a limited time and limited speed and be able to negotiate obstacles like curbs or uneven ground, you would benefit from a prosthetic foot that offers stability and comfort, meaning it protects the joints and residual-limb tissue.