Hand Research

A Biomechanical Study of the Finger Pulley System During Surgical Repair

J. Chow, W. Hurst, J. Sensinger, J. Tioco, M. Gonzalez, F. Amirouche

Carpal tunnel syndrome is becoming a major issue in the work place. Disorders related to work that requires repetitive motion account for nearly half of all reported work-related illness, and carpal tunnel syndrome is estimated to account for over 41% of these repetitive motion disorders. There are currently four different surgical procedures for carpal tunnel syndrome: open release; mini open release; endoscopy; and percutaneous balloon carpal tunnel-plasty. This study is designed to determine the long-term effects of open release surgery. The objective are:

• Develop a method of measuring finger excursion by simultaneous data acquisition of all finger joints.
• Formulate a dynamic model for analysis of the joint torque required for motion.
• Provide surgical reconstruction schemes for the restoration of optimal kinematic and dynamic function of the hand. 

To obtain continuous and simultaneous acquisition, four rotational potentiometers were used. One placed at each joint for angular rotation and one for tendon excursion. Programs were written in MATLAB to provide the necessary digital signal processing (filtering, conversions). A mathematical model for finger dynamics was derived. Using the data for angular rotation and it’s two time derivatives, the torque required at each joint was calculated and plotted vs. excursion. Various pulley excisions and repairs where performed. This included either full or 50% excision and repair.