special subjects
Limb Prostheses Options
Lower Limb Prostheses
There are many variables and options for lower limb prostheses—there are 350 different foot/ankle systems and 200 different knees. The amputee and prosthetist evaluate different joint and foot components to determine which provide optimal balance, safety, function, and gait efficiency. Most lower limb prostheses are endoskeletal because they are adjustable. There are 3 general types of lower limb prostheses: Prosthetic ankle and foot systems Prosthetic knee systems Sport-specific prosthetic foot and knee systems Prosthetic ankle and foot systemsmay include a hydraulic system that dampens impact forces. Some automatically adjust to changes in walking speed. Microprocessor-controlled ankle/foot systems regulate function in real time based on user input and/or environmental conditions. Some are passive mechanisms; others provide active propulsion, which greatly reduces energy requirements for walking. Axial or horizontal rotation lost from amputations above the ankle can be replaced with an endoskeletal torsion unit; this feature is especially helpful for situations in which the limb needs to twist while bearing weight, such as when playing golf. People who like to wear shoes with different heel heights (sometimes wearing sneakers or flats and sometimes wearing cowboy boots or high heels) can choose a prosthetic ankle that adjusts to different heights. Prosthetic knee systemsinclude passive body-powered systems with a single- or multi-axis joint. Microprocessor-controlled knee systems lower the amount of effort people need to use while walking and provide greater safety and stability control of the prosthetic knee reducing risk of falling. Sport-specific prosthetic foot and knee systemshelp people achieve the highest level of physical performance. Some systems are effective for multiple sport and recreational activities. Others are designed for specific events (such as sprinting, long-distance running, skiing, or swimming). Running is more challenging for above-knee amputees than for below-knee amputees. Socket and suspension are more critical for athletes. 