Biomechanical Changls of Finger Flexion After Carpal Tunnel Release with Respect to Wrist Positions

Abstract

This study was designed to investigate whether sectioning of the transverse carpal ligament (TCL) modifies the biomechanical behavior of the finger flexion in respect to dynamic changes of the wrist. Changes of work, load, and excursion of the flexor tendons were measured using fresh frozen cadaver hands with the wrist in 30° flexion, neutral, and 30° extension before and after division of the TCL. Change in work efficiency between intact and cut TCL groups was noted most with the wrist in flexed position (12.5%) compared to 3% in neutral wrist position and no change in wrist extension. The extended wrist group as a whole had greatest increase in the efficiency of work and load with greater than 16.2% and 14.8% changes, respectively. The significant decrease in the excursion efficiency of the flexor tendons was demonstrated when the wrist was in the flexed position. This effect was accentuated when the TCL was divided causing the bow-stringing phenomenon. The increase in the excursion of the flexor tendons could clinically result in decreased grip strength when the wrist is flexed. Furthermore, the effects of TCL division were least significant when wrist position was in extension. One could conclude from this that post-operative management after carpal tunnel release procedures should include placing the wrist in moderate extension.