Ck. Low et al., THE EFFECT OF THE EXTENT OF A1 PULLEY RELEASE ON THE FORCE REQUIRED TO FLEX THE DIGITS - A CADAVER STUDY ON THE THUMB, MIDDLE AND RING FINGERS, Journal of hand surgery. British volume, 23B(1), 1998, pp. 46-49
The A1 pulley was released distally in consecutive stages by 25%, 50%,
75% and 100% of its length. The force required to fully flex the digi
t at each stage was recorded. The force decreased with more extensive
A1 pulley release and this became significant when more than 50% of th
e pulley was released. These changes were probably due to loss of fric
tion force rather than bowstringing of the tendon.