The role of the transverse carpal ligament in carpal stability: an in vitro study.

A biomechanical in vitro study was performed on 16 fresh frozen cadaver forearms to investigate the role of the transverse carpal ligament (TCL) in carpal stability. The distance between the scaphoid and hamate was measured, as a reference for the length of the TCL. Distances were recorded in both loaded and unloaded conditions after gradual sectioning of the transverse carpal ligament, the palmar scapholunate, long radiolunate ligament and radioscapholunate ligament. The largest increase in spread of the carpal bones (55.3% of total spread) was noted after loading with the ligament intact. Thereafter, sectioning of the TCL resulted in a further 32.9% increase in the distance between the scaphoid and the hamate. We conclude that the intact carpal bones-ligament complex displays some elasticity. Progressive sectioning of the TCL ligament under loading further opens the palmar arch. Nevertheless it appears that the carpal arch will still retain reasonable intrinsic stability even without an intact TCL.