Biomechanics and Motion Analysis

Modification of Extrasynovial Tendon by Carbodiimide Derivatized Hyaluronic Acid (Cd-Ha) Gelatin for Flexor Tendon Graft

Principal Investigator: Chunfeng Zhao, M.D. — zhao.chunfeng@mayo.edu

The tendon graft plays a very important role in reconstruction to restore the finger function following hand injury. Extrasynovial tendons are most often used as donor tendons to replace the injured or defect flexor tendon. However, clinical and experimental studies have demonstrated that restrictive adhesions and poor digital motion are frequent sequelae of extrasynovial tendon grafting to the intrasynovial environment. In addition to anatomic and biological differences between intrasynovial and extrasynovial tendons, recent studies have shown a significant difference in friction, with the extrasynovial tendon having the rougher gliding surface. The purpose of this study was to test the hypothesis that carbodiimide derivatized HA gelatin (cd-HA-G) improves the gliding of extrasynovial tendon grafts within short term (one week) in vivo using canine model. Work of flexion (WOF), gliding resistance, and quantification of the HA binding to the tendon surface was analyzed. In the current short-term in vivo study, we found that cd-HA-G not only increased the HA half-life but also binding strength by chemically binding carboxyl groups in the HA with the amino groups on the tendon surface. By this chemical modification, the tendon frictional force decreased due to improved surface smoothness, and improved digit function which was indicated by a lower WOF compared with saline treatment.