What is the appropriate management for a patient presenting with volar surface tenderness and edema of the ring finger, along with an inability to flex the distal interphalangeal joint, suggestive of a possible flexor tendon injury or mallet finger?

Flexor Digitorum Profundus Avulsion (Jersey Finger)

This clinical presentation—volar surface tenderness and edema of the ring finger with inability to flex the distal interphalangeal (DIP) joint—is diagnostic of a flexor digitorum profundus (FDP) tendon avulsion, commonly known as "jersey finger," which requires urgent surgical referral within 10 days for optimal functional outcomes. 1

Immediate Diagnostic Steps

Obtain standard 3-view radiographs of the injured finger immediately to detect avulsion fractures or bony fragments, which are present in many cases despite this being primarily a tendon injury. 1 Radiographs may appear normal in purely tendinous avulsions, but they are essential to rule out bony involvement that could alter surgical planning. 1

Key Physical Examination Findings

• Inability to actively flex the DIP joint while the proximal interphalangeal (PIP) joint is held in extension is pathognomonic for FDP rupture 1
• Volar tenderness localized along the flexor tendon sheath, often with a palpable mass if the tendon has retracted proximally 1
• Edema and ecchymosis on the volar surface of the affected digit 1

Critical Management Algorithm

Immediate Actions (Within Hours)

1. Obtain radiographs immediately—delaying imaging can lead to missed fractures requiring surgery 2
2. Apply ice-water mixture for 10-20 minutes with a thin towel barrier to reduce swelling 2
3. Splint the finger in the position found until definitive evaluation 2
4. Arrange urgent hand surgery referral—do not delay beyond 10 days from injury 1

Advanced Imaging Considerations

MRI is the ideal imaging modality for evaluating the level of tendon retraction, quality of the tendon stump, and associated pulley injuries, which are critical for surgical planning. 1, 3 This should be obtained by the hand surgeon prior to operative intervention. 1

Why Urgent Surgical Referral is Mandatory

Early presentation within 10 days is associated with superior functional outcomes, and surgical treatment is required for all jersey finger injuries. 1 Unlike mallet finger (extensor tendon injury at the DIP joint), jersey finger cannot be treated conservatively with splinting alone because:

• The FDP tendon retracts proximally after rupture and will not heal without surgical reattachment 1
• Delayed repair beyond 10 days results in tendon retraction, muscle contracture, and significantly worse functional outcomes 1
• The ring finger is the most commonly affected digit due to its prominence during gripping activities 1

Common Pitfalls to Avoid

Do not confuse this with mallet finger, which presents with inability to extend (not flex) the DIP joint and has volar (not dorsal) tenderness. 2, 4 Mallet finger can often be managed conservatively with splinting, whereas jersey finger requires surgery. 2, 1

Do not delay referral waiting for swelling to improve—the 10-day window for optimal surgical outcomes is critical, and early intervention prevents tendon retraction and muscle contracture. 1

Do not attempt passive straightening or manipulation of the finger before proper evaluation and splinting, as this can worsen the injury. 2

Prognosis with Appropriate Treatment

When surgical repair is performed within 10 days, patients typically achieve good functional restoration of DIP joint flexion and grip strength. 1 However, injuries involving both flexor tendon laceration and proximal phalanx fracture have significantly worse outcomes with substantial loss of finger mobility. 5