Shoulder Range of Motion Measurement

Published in: Proceedings of the 13th Latin American and Caribbean Conference for Engineering and Technology: Engineering Education Facing the Grand Challenges, What Are We Doing?
Date of Conference: July 29 - 31, 2015
Location of Conference: Santo Domingo, Dominican Republic
Authors: Oren Masory
Jesse Curtin
Refereed Paper: #23

Abstract:

This paper describes a new accurate, reliable, and cost-effective tool to measure the range of motion of a joint, specifically the shoulder joint. The system consists of three string potentiometers which are mounted in a known orientation and whose ends converge at a point attached to handle. A test consists of having a patient grabbing and moving the handle through the desired motion for the specified test time. During the test, a microcontroller is used to read the potentiometer voltages as the patient moves the handle. Upon completion of the test, the data is analyzed to determine the range of motion and also to provide 3-D plots of the motion. In addition, the changing position of the center of rotation can be determined for large motions. A number of tests were performed which showed good results (accuracy within 2°) in all cases when the system was properly used. The system provides a simple and intuitive user interface to display, store and recall test results. Although the system was originally intended for use with the shoulder joint, it could be used to measure the range of motion of other joints, such as the elbow and knee, provided a different attachment is created.