Researchers developed a simple pulley method that could help improve hand function after surgery.

Researchers tested the device on cadaver hands, and found it could help improve the transmission of mechanical forces when implanted inside the body, Oregon State University reported. The innovation could help people who have lost the function of their hands as a result of nerve damage. In the future the technology could even be expanded to help restore function in other parts of the body.

"This technology is definitely going to work, and it will merge artificial mechanisms with biological hand function," said Ravi Balasubramanian, an expert in robotics, biomechanics and human control systems, and assistant professor in the OSU College of Engineering.

The application of this device is still years off, but it could initially help restore the gripping function of hands post-surgery and later move onto damaged knees and ankles. In the past this problem was corrected through a procedure called tendon-transfer surgery for high median-ulnar palsy, which reattaches tendons to working muscles. This process still leaves the hand significantly impaired. This new technology is less robotic and more of a "passive technology"  that allows natural gripping action to occur using less enrgy.

"Many people have lost the functional use of their hands due to nerve damage, sometimes from traumatic injury and at other times from stroke, paralysis or other disorders," Balasubramanian said. "The impact can be devastating, since grasping is a fundamental aspect of our daily life. The surgery we're focusing on, for instance, is commonly performed in the military on people who have been injured in combat."

In the cadaver study the researchers found the device reduced the overall force needed to grasp an object with four fingers by 45 percent and lowered slippage by 52 percent. Using this method researchers may one day be able to create joints or limbs that mechanically function as effectively as before the damage occurred.

"There's a lot we may be able to do," Balasubramanian said. "Thousands of people now have knee replacements, for instance, but the knee is weaker after surgery. With mechanical assistance we may be able to strengthen and improve that joint."

The findings were published in a recent edition of the journal Hand.