Trigger finger release with hand surface landmark ratios: An anatomic and clinical study

The purpose of this study was to identify surface landmark ratios to locate the Al pulley and clarify the controversy of differing anatomic descriptio ns of the Al, CO, and A pulleys. Minimally invasive and percutaneous approa ches to Al pulley release maybe facilitated with surface landmark ratios, w hich identify, and predict the proximal and distal margins of the Al pulley . Two-hundred fifty-sixty fingers were dissected in 64 preserved cadaver ha nds. Measurements of Al pulley lengths and pulley margins in relation to su rface landmarks were obtained. Ve found that the distance from the palmar d igital crease to the proximal interphalangeal crease (mean, 2.42 +/- 0.03 c in) corresponds to the distance of the proximal edge of the Al pulley from the palmar digital crease (mean, 2.45 +/- 0.03 cm). The mean absolute diffe rence between these two, measured distances in each finger was 0.13 cm, wit h a 95 percent confidence interval of 0.11 to 0.14 cm. Thus, the distance b etween the palmar digital crease and the proximal interphalangeal crease ca n be used to predict the distance between the palmar digital crease and the Al pulley proximal edge with reasonable accuracy. Al pulley length average d 0.98 +/- 0.02 cm for the small finger and 1.17 +/- 0.02 cm for the index, middle, and ring fingers. The length of the Al pulley was significantly sh orter (p < 0.001) for the small finger than for the index, middle, and ring fingers. Additionally, a cruciate (CO) pulley was consistently located bet ween the Al and A2 pulleys, an average of 0.46 cin proximal to the palmar d igital crease, which can serve as guide for concluding the release of the A l pulley. Clinically, hand surface landmark ratios were used to release 32 trigger fingers with a minimally invasive technique, without a complication during 4- to 30-week follow-up. We conclude that hand surface landmark rat ios can serve to locate the proximal Al pulley edge, thus facilitating comp lete trigger finger release by either open or minimally invasive techniques . Additionally, our study clarifies the discrepancy of prior smaller report s of the pulley system anatomy regarding the existence of the CO pulley bet ween the Al and A2 pulleys. The cruciate fibers of this CO pulley can serve as the distal boundary for release of trigger finger.