Quick Primer on Climber's Finger
Climbers have a tendency to injure the A2 and A4 pulleys in their fingers, most commonly in the ring finger, but the injury can also occur in the middle, index or small fingers. It doesn’t happen in the thumb.
Climber's Finger usually presents as tenderness or pain at the base of the finger during/after training, and may be associated with a popping sound during the initial injury. Though the soreness may abate over time, the pulley is likely to sustain further injury or heal in a stretched-out position if not protected adequately.
Overview of Finger Pulley Anatomy
The pulleys hold the flexor tendons close to the bones, (MC: metacarpal; PP: proximal phalanx; MP: middle phalanx; DP: distal phalanx), like guides on a fishing pole hold the line close to the pole. The A2 pulley is the strongest and most important pulley, but sadly the most frequently injured; (A4 is the #2 most injured).
Pulley Injury Causes
Injuries happen most commonly when using the crimp grip, like one would use on a small hold. The finger joint at the first knuckle, (proximal interphalangeal joint), is flexed more than 90 degrees. This puts lots of stress on the A2, A3 and A4 pulleys, and if a foot slips or a foot hold breaks, or the climber dynamically loads the finger, the pulleys get “shock loaded” and can rupture or tear. If this happens the flexor tendons pull away from the bone increasing the tendon-phalanx distance, (TPD), as indicated by the *’s below.
Impact of the S.P.Ort on Pulley Healing
If the A2 pulley tears (as shown in Figure 1), further climbing or strenuous use of the hand will put extra strain on the A3 and A4 pulleys, putting them at risk for rupture. A4 pulley tears (shown in Figure 2) will in turn put extra strain on the A3 and A2 pulleys. Untreated, the torn pulley will heal in a stretched-out condition and will not work ideally.
Climbing after a pulley injury that is (or was) not optimally treated can be associated with finger soreness as the tendons are not in an ideal position and are more prone to inflammation and recurrent tendonitis. In the acute setting the S.P.Ort supports the pulley as it heals in close to a normal size. In chronically stretched-out pulleys, the SPOrt will not change the shape of the healed pulley, but its support decreases finger soreness and keeps climbers climbing.