Trigger Finger Release with Hand Surface Landmark Ratios: An Anatomic and Clinical Study

Abstract

The purpose of this study was to identify surface landmark ratios to locate the A1 pulley and clarify the controversy of differing anatomic descriptions of the A1, C0, and A2 pulleys. Minimally invasive and percutaneous approaches to A1 pulley release may be facilitated with surface landmark ratios, which identify and predict the proximal and distal margins of the A1 pulley. Two-hundred fifty-sixty fingers were dissected in 64 preserved cadaver hands. Measurements of A1 pulley lengths and pulley margins in relation to surface landmarks were obtained. We found that the distance from the palmar digital crease to the proximal interphalangeal crease (mean, 2.42 +/- 0.03 cm) corresponds to the distance of the proximal edge of the A1 pulley from the palmar digital crease (mean, 2.45 +/- 0.03 cm). The mean absolute difference between these two measured distances in each finger was 0.13 cm, with a 95 percent confidence interval of 0.11 to 0.14 cm. Thus, the distance between the palmar digital crease and the proximal interphalangeal crease can be used to predict the distance between the palmar digital crease and the A1 pulley proximal edge with reasonable accuracy. A1 pulley length averaged 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 A1 pulley was significantly shorter (p < 0.001) for the small finger than for the index, middle, and ring fingers. Additionally, a cruciate (C0) pulley was consistently located between the A1 and A2 pulleys, an average of 0.46 cm proximal to the palmar digital crease, which can serve as guide for concluding the release of the A1 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 ratios can serve to locate the proximal A1 pulley edge, thus facilitating complete trigger finger release by either open or minimally invasive techniques. Additionally, our study clarifies the discrepancy of prior smaller reports of the pulley system anatomy regarding the existence of the C0 pulley between the A1 and A2 pulleys. The cruciate fibers of this C0 pulley can serve as the distal boundary for release of trigger finger.

The Relationship Between the Intercrease Line and the A1 Digital Pulley: A Cadaveric Study

“…2,3,14 Wilhelmi et al 18,19 and Fiorini et al 6 described landmarks that use ratios that account for individual and population-based differences in hand size. The concept that the pulley location will vary between individuals by a constant ratio, rather than fixed lengths, is described in the literature.…”

“…Using the method described by Wilhelmi et al 18,19 , we measured the distance from the PDC to the PIC with a digital caliper under 2.5 × loupe magnification. We used the proximal edge of these creases.…”

Identification of the location of the A1 pulley combining palpation technique with palm landmarks and percutaneous release of A1 pulley with a 19-gauge needle: A cadaveric study

“…But knowing the anatomy of the pulley system and anatomical palm landmarks makes this method safe and effective. 7 All studies investigating different release techniques had the same aim-to make percutaneous release method less complicating and more effective. 8,9 Majority of studies have comparable results, but the best technique remains unknown.…”

“…If there is no paradoxical movement of the needle, it is safe to push the needle parallel to the A1 pulley, but not deep down. In concern about thumb nerve injury, 7,[16][17][18] we preciously used marked guidelines, the needle was inserted at the midline point of the flexor tendon, and approximation to the radial side was avoided. 17,19,20 In this study, no digital nerves were injured.…”

Liberação percutânea do dedo em gatilho com micro bisturi oftalmológico vitreorretiniano de lâmina 19

“…The surface anatomy references of the proximal and distal edges of the A1 pulley are marked on the skin. 11 The distance between the proximal interphalangeal crease (PIC) and the palmar digital crease (PDC) was used to predict the proximal edge of the A1 pulley (Figure 2a). After measuring the distance from PIC to PDC, an equal distance was marked proximal to PDC.…”