Jersey Finger (FDP Avulsion)

Jersey finger is a closed avulsion injury of the flexor digitorum profundus (FDP) tendon from its insertion at the volar base of the distal phalanx. It typically occurs when an athlete forcibly grips a jersey or other object and the finger is suddenly hyperextended while flexed against resistance. The ring finger is most commonly involved (75%) due to its biomechanical disadvantage during gripping.

Classification (Leddy-Packer modified) is based on the level of tendon retraction and bony involvement: Type I — tendon retracted into palm with disrupted vincular blood supply (urgent surgery within 7-10 days); Type II — tendon retracted to PIP joint, vincula intact (less urgent); Type III — tendon trapped at A4 pulley with avulsion fragment (delayed repair acceptable); Type IV — bony avulsion with simultaneous tendon detachment from the bony fragment (combined fixation needed); Type V — bony fragment with comminution requiring osteosynthesis.

Diagnosis includes loss of active DIP flexion with the PIP held in extension, focal tenderness over the proximal phalanx or distal palm, and bruising. Imaging includes plain radiographs to identify bony avulsion (especially Type III-V); ultrasound or MRI for soft-tissue retraction characterization. Surgical strategies include primary tendon-to-bone repair with suture anchors or pull-out sutures, bony fragment fixation with screw or anchor, and salvage procedures (DIP arthrodesis, two-stage tendon graft) for delayed presentations. Postoperative protected motion protocols (Duran or Kleinert) are essential for tendon healing and adhesion prevention.