Feasibility of partial A2 and A4 pulley excision: Residual pulley strength

We investigated residual digital flexor pulley strengths after 75% excision of the A2 and A4 pulleys, For direct Dull-off tests, A2 and A4 pulleys fro m cadaveric fingers were tested by pulling on a loop of flexor digitorum pr ofundus tendon through the pulley. For functional loading tests, fingers we re positioned with the metacarpophalangeal joint flexed to 90 degrees for A 2 testing, and with the proximal interphalangeal joint in 90 degrees flexio n for A4 testing (with all other joints in full extension), Excision of 75% of A2 and A4 pulleys reduced pulley strengths determined by both testing m ethods. For the functional loading tests, which are more clinically relevan t, mean tendon forces at failure after partial excision of A2 and A4 pulley s were 224 and 131 N respectively, which is sufficient to withstand flexor tendon forces expected during activities of daily living.