Closed disruption of a single flexor digitorum superficialis tendon slip: 3 cases.

Two men and one woman (age 31, 36 and 45 years) felt a painful pop in the left middle, right middle and right index finger during sport-related activities (2 sport climbing and 1 judo). Clinical examination found a painful flexor tendon in zone 2 but no function deficit specific to the flexor digitorum superficialis (FDS) tendon. MRI and ultrasonography revealed a complete disruption of the radial FDS tendon slip only, which was found retracted between the A2 and A3 pulleys. All flexor tendon pulleys remained intact. Conservative and functional treatment resulted in unrestricted normal function and return to sport. Disruption of one FDS tendon slip is a differential diagnosis for a popping incident in the finger, which is typically associated with a closed flexor tendon pulley injury.