-Mechanism of injury: results from forced hyperextension of a flexed DIP joint. This ruptures the flexor digitorum profundus (FDP) tendon as a result of a sudden force applied to the distal phalanx while in flexion.
-Called Jersey finger b/c this often happens when the finger is caught in an opponent’s jersey or belt loop while making a tackle.
-On PE, the patient is be unable to flex the finger at the DIP joint.
-Radiographs: Will get XR to look for a bony fragment at the volar surface of the proximal distal phalanx.
-Referral to a hand surgeon: Because the risk of tendon retraction is high, patient will be referred to a hand surgeon as soon as the diagnosis is made.
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Compare to Mallet Finger.
“This injury is also seen in wrestlers. The FDP attaches at the base of the distal phalanx while the flexor digitorum sublimis (FDS) attaches at the base of the middle phalanx. Thus, it can be determined by physical examination which tendon is injured, providing for early and accurate diagnosis and proper treatment. With the noninvolved fingers held in full extension, if the patient can flex the proximal interphalangeal (PIP) joint the FDS is intact. With rupture of the FDP, distal interphalangeal (DIP) joint flexion may still be weakly present, but the patient is unable to hold flexion against resistance and this maneuver elicits pain. With rupture of both flexor tendons, the patient is unable to flex either the PIP or the DIP joint. In the scenario presented, rupture of both flexor tendons is unlikely. Rupture of the extensor digitorum tendons may cause mallet finger at the DIP joint, or a boutonnière deformity of the PIP joint. Since many of these flexor tendon injuries require surgical exploration and repair, early orthopedic consultation is recommended.” ABFM
References
Am Fam Physician 2012;85(8):805-810.