Excursion properties of tendon graft sources: interaction between tendon and A2 pulley.

We measured excursion resistance of 4 different tendons (flexor digitorum superficialis, the portion of the extensor indicis proprius tendon beneath the extensor retinaculum, the portion of the extensor indicis proprius tendon distal to the extensor retinaculum, and palmaris longus) beneath the A2 pulley. Intrasynovial tendons (i.e., flexor digitorum superficialis and the portion of the extensor indicis proprius beneath the extensor retinaculum) produced less excursion resistance than extrasynovial tendons (i.e., the portion of the extensor indicis proprius distal to the extensor retinaculum and palmaris longus). The excursion resistance of the intrasynovial portion of the extensor indicis proprius tendon was significantly lower than that of the extrasynovial portion of the same tendon. Intrasynovial tendons may be preferred to extrasynovial tendons when choosing a tendon graft source and graft gliding under a pulley is a consideration.