A1 Pulley Study

A common hand position in rock climbing is called a "crimp", where the fingers create an extreme angle to hang onto small edges. Due to the anatomical features of this position, climbers often experience A1 pulley injuries during crimping. I aided two orthopedic surgeons in a study to understand the maximum force finger tendons can withstand in the crimp position before A1pulley failure.

A cadaveric specimen was dissected so that the A1 pulleys could be seen on fingers 2 through 4. FDSM and FDPM tendons were revealed from each finger as well. The test bed I worked on consisted of a stationary fixture and a gear system that moved a load cell. The cadaveric specimen was loaded into the stationary fixture so that the hand would create the crimp position when tendons were loaded. The tendons were attached to the moveable load cell via surgical string. An Arduino controlled a motor that caused vertical motion of the load cell. As the load cell moved upward, tension would be applied to the tendons of interest. Tension in the tendons were recorded in order to analyze the maximum force experienced before A1pulley failure. As an undergraduate research, I helped modify the cadaveric test fixture to ensure the hand would create a crimp position when tendons were loaded and that the load cell had enough vertical space to properly load the tendons. Additionally, I recorded and analyzed tendon force data.