Evaluation of finger A3 pulley rupture in the crimp grip position—a magnetic resonance imaging cadaver study

Abstract

Reduction of the VP translation distance and augmentation of the VP tendon distance are suitable indirect signs of A3 pulley rupture.

Diagnosis of A3 Pulley Injuries Using Ultrasound

“…Using a cutoff of 0.9 mm, we were able to predict the A3 pulley rupture with a sensitivity of 76 % and a specificity of 94 %. Our measurement of a shorter VP tendon distance than Bayer et al [23] can be partially attributed to their ability to achieve their measurements in a maximal forced flexion state, featuring the PIP joint at 90°flexion, due to the capacity of the MRI-based method. Such flexion is not possible in ultrasound examination, since flexion above 50°in the PIP joint causes the bone of the medial phalanx to cast an ultrasound shadow over the VP and the ultrasound probe cannot be placed in the palmar aspect of the finger any longer.…”

“…gical removal of the A3 pulley. In an MRI study performed by Bayer et al [23], a general reduction of VP translation distance and augmentation of VP tendon distance were established as suitable indirect signs of A3 pulley rupture. The VP functions as a meniscus between the two phalanges.…”

“…Following A3 pulley rupture, we observed the VP to alter in shape, returning to a longer and thinner state as a consequence of lacking the upward pull from the fibres of the A3 pulley. The augmented distance between the volar plate and the under-surface of the flexor tendon observed by Saito et al [26] was measured by Bayer et al [23] and this measurement was used for discriminating between pulley ruptures including the A3 pulley and ones that did not involve an injury to the A3 pulley. With a cut-off point of 1.4 mm, they were able to achieve a sensitivity of 81.3 % and a specificity of 100 %.…”

“…Using ultrasound, Saito et al [22] were able to visualize a sliding, elevating and rolling movement in the VP recess during finger flexion. Bayer et al [8,23] were able to show a reduction of the VP translation distance as well as an augmentation of the VP tendon distance as indirect signs of A3 pulley rupture using MRI.…”

Authors’ response re: Shek KL & Dietz H. Letter to the Editor Re: ‘Do ultrasound findings of levator ani “Avulsion” correlate with anatomical findings: A multicenter cadaveric study’

“…We disagree with this statement. Cadavers produce morphological findings generally transferable to the living subject and there are hundreds of studies that have used cadavers as a medium for assessing imaging findings . Moreover, musculoskeletal studies have found that the size of a tear increases with time in cadaveric studies, supporting the argument that if an “avulsion” was the literal detachment of the PVM from its insertion, as a consequence of traumatic vaginal delivery, this should be observed in the cadaveric specimen.…”