Ultrasound Diagnosis of A2 Pulley Injuries: Landmark-Specific Tendon-Bone Distance and Flexor Tendon Curvature in a Cadaveric Study

Background A2 pulley ruptures are common in rock climbers, yet diagnosing partial ruptures remains challenging due to variability in tendon-bone distance (TBD) measurements in ultrasound assessments. Objective This study evaluated TBD at multiple anatomic landmarks to differentiate intact, partial, and complete A2 pulley ruptures; compared landmarks for optimal ultrasound diagnosis; and investigated flexor tendon curvature as an additional indicator. Methods Forty-two fingers from 14 fresh-frozen cadaveric arms were examined using high-frequency ultrasound. Fingers were assigned to 5 simulated groups: intact; low-grade partial (5 mm), medium-grade partial (10 mm), and high-grade partial (15 mm) ruptures; and complete ruptures (≥20 mm). TBD was measured at 4 anatomic landmarks: distal edge of A2 pulley (point A), 5 mm proximal to point A (point B), 10 mm proximal to point A (point C), and the midpoint of the proximal phalanx (MPP point). Analysis of variance and Bonferroni correction were used for statistical analysis. Results TBD significantly differed between intact, partial, and complete ruptures at most landmarks. Point C reliably differentiated high-grade partial ruptures from complete ruptures ( P