A new testing device for measuring gliding resistance and work of flexion in a digit.
In order to move the finger the tendon force must overcome the gliding resistance of the tendon as well as the forces to move the joints, finger inertias, and external load. These sources, combined, make up the work of flexion (WOF) which has been experimentally used to evaluate the finger function. In this study, we have designed a new device, which can measure the forces at the proximal and distal end of the tendon during finger flexion, so that gliding resistance can be isolated from the WOF. Two index fingers from a pair of human cadaver hands were used for testing this device. Preliminary data showed that internal resistance occupied about 10% of WOF with an intact tendon. However, after tendon repair, the gliding resistance increased 31% of WOF for a modified Kessler repair and 50% of WOF for a Becker repair compared to intact tendon. We simulated joint stiffness by injection of saline solution into the proximal interphalangeal joint. This increased the overall WOF but not the gliding resistance. We believe that this testing device provides a useful tool to evaluate finger function after tendon repair in an experimental model.
Zhao
Chunfeng
C
Orthopedic Biomechanics Laboratory, Mayo Clinic/Mayo Foundation, 200 First Street, Gligg 1-128, Rochester, MN 55905, USA.
Amadio
Peter C
PC
Berglund
Lawrence
L
Zobitz
Mark E
ME
An
Kai-Nan
KN
D002102:Cadaver; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005385:Fingers / Q000503:physiopathology* / Q000601:surgery; D017276:Friction; D006801:Humans; D066298:In Vitro Techniques; D009068:Movement; D010808:Physical Examination / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013708:Tendon Injuries / Q000503:physiopathology / Q000601:surgery; D013710:Tendons / Q000503:physiopathology* / Q000601:surgery