Jersey finger

Jersey finger is an avulsion of the flexor digitorum profundus (FDP) tendon from its insertion at the base of the distal phalanx. The ring finger is most commonly affected. The injury occurs when a flexed finger is forcibly extended while the FDP is contracting — the classic mechanism is grabbing a jersey (or opponent's clothing) while the finger is pulled back.

The patient cannot flex the DIP joint of the affected finger. The proximal end of the avulsed tendon may retract into the palm.

Examination: the patient cannot flex the DIP joint when the PIP and MCP are held extended. Tenderness may be felt at the finger tip, the finger, or as proximal as the palm where the tendon has retracted. X-ray identifies a bony avulsion fragment. MRI locates the tendon end when plain films are negative.

Jersey finger is nearly always treated surgically; the avulsed tendon retracts and becomes ischemic quickly, making delayed repair progressively more difficult. Prompt repair soon after injury is strongly preferred.

External patient-education references and related OSI pages for additional background:

• Britannica — Hand (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language