Prosthetic Knees
By Michael, John W.; First Step, Vol. 1, No. 2, pp. 46-49Publication Date: 2001
Article on choosing the best prosthetic knee. The single-axis knee is one to consider if the patient is in good health and has a relatively long residual limb for leverage, as it bends freely at the level of the anatomical knee. The major advantage of the single-axis is the simplicity of its design, which makes it light, less expensive, and durable. The downsides are that it is difficult for older adults to control, and it often only accommodates one walking speed. The stance-control knee, often called "safety knees," typically contain a weight-activated friction brake that can stop knee motion. They are best used to supplement limited amputee knee control by providing extra security in the event of a misstep. The greatest limitation of a stance-control knee is that they disrupt normal gait, as they cannot be flexed under much weight-bearing pressure. The last knee configuration, the polycentric knee, is the most mechanically complex, and has multiple axes of rotation. The polycentric knee can supplement voluntary control without disrupting swing phase movements. As a result, it may be suitable for those with the potential to be independent household or community ambulators. The main disadvantage is that it can only be used for one walking speed. Readers are encouraged to discuss their choice with their prosthesist and other members of the rehabilitation team.
Published by: Amputee Coalition of America (Website:http://www.amputee-coalition.org)
