Dynamic analysis of profundus tendon function.

A method for analysis of hand function is reported through evaluation and characterization of flexor digitorum profundus (FDP) tendon mechanics. A testing platform is used that allows for the dynamic evaluation of intact cadaver hand mechanics under normal and pathologic conditions using simultaneous measurements of tendon load, tendon excursion, grip strength, pinch strength, and joint angle. This study of FDP tendons in normal fresh cadaver hands demonstrates that FDP tendon excursion increases as the number and size of joints flexed increases. Extensor counterweighting 500 g, increases FDP tendon load and work but not excursion requirements, and FDP loads of up to 75 N are required for single finger grip strengths of 4 kg force. These loads do not result in permanent (plastic) deformation of either the tendon or the restraining soft tissues. Detailed descriptions of the platform and the mechanical tests performed are provided.