Rock Climber’s Finger! Case prepared by
UT Health San Antonio
MSK Radiology fellow Steve Hole.
20s male reports extension injury to the small finger (SF) while playing volleyball 1 week prior to presentation. He has ongoing pain with tenderness on exam, with preserved flexion and extension of the digit.
Initial frontal and lateral finger radiographs demonstrate a small, mildly retracted intra-articular fracture of the middle phalangeal base at the volar aspect (arrow). Subtle associated soft tissue swelling of the small digit at the PIP joint is present.
Sagittal T2FS MRI demonstrates soft tissue edema and abnormal separation between the flexor tendon and proximal phalanx/PIP joint. Additional edema within the proximal phalangeal head corresponds to a small fracture line on T1 image (arrow), with the small avulsion fracture of the middle phalangeal base redemonstrated.
A further look at the tendons. Sagittal T1 images showing the intact flexor digitorum profundus (FDP) tendon and a partially torn flexor digitorum superficialis (FDS) tendon, with the torn fibers stumped slightly off-axis at the level of the metacarpal head (arrow). The adjacent ring finger is displayed for normal comparison.
Finishing up with the pulleys. Axial T2FS image demonstrates complete tear of the A3 pulley radial aspect (arrow) with the ulnar side injured but not ruptured. Partial tears of the A2 pulley are also present (arrows) as well as edema within the flexor tendon sheath (arrowhead) at a level just distal to Camper’s Chiasma due to the partially absent FDS.
Thickened areas of the flexor tendon sheath create a total of 8 pulleys, 5 Annular and 3 Cruciate, in each finger (fewer in the thumb) which provide strength and mechanical advantage to flexion. A2 is both the strongest and most often injured pulley; more severe injuries tend to involve more distal pulleys in sequence.
Complete pulley tears may lead to “bowstringing”, the abnormal separation of the flexor tendons from underlying finger bones/joints (as in our case), which can be accentuated with forced flexion and results in decreased strength. Ultrasound is excellent for dyanmic assessment and easy comparison to non-injured digits.
Closed pulley injuries have been referred to as “Climber’s Finger”, a diagnosis first described in the 1980s corresponding to the rise in popularity of rock climbing. Pulley strains, partial tears, and isolated complete tears are usually treated conservatively; surgical reconstruction is favored with multiple ruptures or a single rupture with lumbrical muscle or collateral ligament injury. Our interesting case of FDS partial tear and avulsion fracture, proximal phalanx head fracture, and A2/A3 pulley injuries of the small finger reflects the atypical mechanism of injury.