Study of Compensatory Motion While Using an Upper Limb Prosthesis

Current improvements of the design of the upper limb prosthesis include advanced technology in control systems and electronic circuitry that mimic human motion and improve function of the prosthesis. Often times these improvements require large amounts of power, circuitry and excess mass distally along the prosthesis that may require greater effort from the user. Poor function of an upper limb prosthesis may cause awkward compensatory motion. Aberrant movements, such as these compensatory movements are known to cause greater stress to remaining joints. Amputees are forced to decide if the extra function provided by the advanced electronics is worth carrying the extra mass which may cause fatigue, socket issues and greater stress on the remaining joints. An example is the wrist rotator component of an upper limb prosthesis which may allow greater function and reduce compensatory motion, but adds mass distally, potentially causing greater torques on remaining joints.

GOALS OF THE STUDY:

There are two main goals of this study:

1. to determine the impact of an upper limb prosthesis without a wrist rotator on the compensatory motion and torques in the remaining joints during common tasks
2. to determine the impact of the location (distally or proximally) of a wrist rotator on a upper limb prosthesis on the compensatory motion during common tasks

HYPOTHESES:

1. There will be a statistically significant difference in range of motion of the upper limb joints between healthy subjects, braced subjects and upper limb amputees during four common tasks.
2. There will be a statistically significant difference in joint upper limb joint torques between healthy subjects, braced subjects and upper limb amputees during three common tasks.
3. There will be a statistically significant difference in upper limb angles and joint torques between mass added distally and mass added proximally during common tasks.