Microprocessor-controlled lower limb prosthetics

Policy context

Prostheses are devices that are used to replace or compensate for the absence of a body part (present at birth, or due to illness or trauma). For prostheses used to replace lower limbs, there is a need for a device to replace the normal function of the knee and/or ankle. There are several devices available that use computer technology to enhance the function of the basic mechanical knee/ankle design. Objective evidence is needed to determine whether significant benefit is obtained.

Primary criteria ranking

• Safety = Low
• Efficacy = High
• Cost = High

Documents

• Final key questions
• Final evidence report
• Public comments and responses
• Final findings and decisions

Background

Several types of lower limb prostheses are available to replace the function of a lower extremity. The simplest artificial prostheses is a hinged leg that swings on one axis. Next is a polycentric joint that has more than one axis of rotation. Micro processor devices are newer types of prosthetic leg device and include a computer and sensors that detect movement and timing of gait/swing to then adjust the resistance via a fluid control system. At least one device senses and controls the swing phase as well as the stance phase via a microprocessor. Potential advantages of microprocessor controlled knees include: reduced energy expenditure compared to traditional artificial legs/knee joints, ability to compensate for variable walking speeds; more natural movement.